Difference between revisions of "Adhesive"

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An '''adhesive''' is a compound that [[adhesion|adheres]] or bonds two items together. Adhesives may come from either natural or [[synthetic]] sources.  Some modern adhesives are extremely strong, and are becoming increasingly important in modern construction and industry.
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=Adhesives By Type=
  
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== History ==
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==Cyanoacrylate==
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The first adhesives were [[natural gum]]s and other plant [[resin]]s.  Archaeologists have found 6000-year-old [[ceramic]] vessels that had broken and been repaired using plant resin. Most early adhesives were [[animal glue]]s made by rendering animal products such as the Native American use of [[American Bison|buffalo]] hooves. Native Americans in what is now the eastern United States used a mixture of [[spruce]] gum and fat as adhesives and as [[caulk]] to waterproof seams in their birchbark canoes.  During the times of [[Babylon]]ia, tar-like glue was used for gluing statues.  Also, [[Egypt]] was one of the most prominent users of adhesives. The [[Egyptians]] used animal glues to adhere tombs, furniture, ivory, and papyrus.  Also, the Mongols used adhesives to make their short bows.  In Europe in the Middle Ages, egg whites were used to decorate parchments with gold leaves.  In the [[1700s]], the first glue factory was founded in Holland, which manufactured hide glue.  Later, in the [[1750s]], the British introduced fish glue.  As the modernization continued, new patents were issued by using rubber, bones, starch, fish, and casein. Modern adhesives have improved flexibility, toughness, curing rate, temperature and chemical resistance. (HSL)
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[[image:800px-Super_glue.jpg|right|185px]]
  
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==Categories of adhesives==
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* aka superglue, crazy glue
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===Natural adhesives===
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* CA (cyanoacrylate) is famous for accidentally gluing skin together
 +
* debonders available to unstick skin,
 +
* cyanoacrylacte activators are available to speed up setting to 2 or 3 seconds, but these reduce final strength.
 +
* For non-porous surfaces.
 +
* Its low shear strength enables it to be used as a removable glue in some cases, eg for mounting items to a block on a lathe.
 +
* can be used as a thread lock
 +
* Cyanoacrylates are used to glue human and animal tissue after accidents. The medical grade is a slightly different formula with improved medical properties, but standard superglue also works and was previously used medically.
 +
* CA is also effective at stoping bleeding at trauma sites.
 +
* When added to baking soda (Sodium bicarbonate) Cyanoacrylate glue forms a hard, lightweight filler/adhesive (baking soda is first used to fill a gap then the adhesive is dripped into the baking soda). This works well with porous materials that the glue doesn't work well with alone.
 +
* Thin CA is occasionally used as a tough glossy wood varnish for small items such as turned pens.
 +
* Moisture triggers setting
 +
* Opened bottles keep longer if stored in a container with a [[desiccant]] (eg silica gel)
 +
* Cured CA can be removed with acetone or [[Paint|methylene chloride]].
 +
* A few hours in the freezer can make it brittle
 +
* Accidetal gluing of eyes is a real risk with CA
 +
* Very low flash point
  
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Adhesives based on vegetable (natural resin), food (animal hide and skin), and mineral sources (inorganic materials).
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==Epoxy Resin==
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[[image:Clear epoxy 0067-6.jpg|thumb|Clear epoxy resin]]
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[[image:Epoxy 0070-4.jpg|thumb|Epoxy resin]]
 +
[[image:epoxy_putty_1647-2.jpg|thumb|Epoxy putty]]
  
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===Synthetic adhesives===
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* Araldite is a well known epoxy resin formulation
 +
* 2 part resin
 +
* Available as liquid resin tubes, putty sticks, or in 400ml cartridges with self mixing nozzles.
 +
** cartridges are used with a self mixing nozzle, which is replaced after each use
 +
* Epoxies come mixed with many different fillers and modifiers, giving them a range of properties
 +
* Epoxy formulations may be runny, gel, paste or putty, each best suited to its own uses.
 +
* Tough
 +
* Good chemical resistance.
 +
* Car accessory shops sell tougher epoxies than Araldite.
 +
* The quick setting types are much weaker
 +
* Vulnerable to UV, which causes degradation.
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* Heating the mix (in tinfoil on a low ring, or over boiling water) until runny makes it set very much faster. Don't overheat it.
 +
* Some formulations are heat resistant, some not. The ones that aren't may claim they are on the basis that they survive heat, even if they do lose all strength when hot.
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* Heat while setting makes it more heat and chemical resistant once set.
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* More strength and cost than polyester or vinylester resins.
 +
* Epoxies are used as powder coatings (a tough [[paint]]-like finish)
 +
* Very good electrical insulation (once cured), good for EHT insulation repairs.
 +
* Metal loaded epoxies can be conductive
 +
* Suitable for work where failure could cause injury, eg chairs, fixing heavy loads to walls, structural repairs to wood & masonry, etc.
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* Suitable for wood, metal, glass, stone, and some plastics.
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* Vinegar will clean up uncured and semi-cured epoxy, but not once cured.
 +
* 1:1 resin to hardener ratio typical, but ratios of upto 5:1 are also available.
  
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Adhesives based on elastomers, thermoplastic, and thermosetting adhesives.
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See also:
 +
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/e4ac9fba7b81f84f/4ce5eb9d5783102f?tvc=1&q=araldite#4ce5eb9d5783102f Discussion of epoxy adhesives on uk.d-i-y]
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* [http://www.wessex-resins.com/pdf/English.pdf Epoxy manual]
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* [http://www.seqair.com/skunkworks/Glues/WestSystem/Thinning/Thinning.html Thinning epoxy]
  
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=== Drying adhesives ===
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==Hot-melt glue==
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These adhesives are a mixture of ingredients (typically [[polymers]]) dissolved in a [[solvent]]. [[Glue]]s such as white glue, and [[rubber cement]]s are members of the ''drying adhesive'' family. As the solvent evaporates, the adhesive hardens. Depending on the chemical composition of the adhesive, they will adhere to different materials to greater or lesser degrees. These adhesives are typically weak and are used for household applications. Some intended for small children are now made non-toxic.
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[[image:Heissklebepistole.jpg|right|185px]]
  
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=== Contact adhesives ===
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* Almost instant setting
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''Contact adhesive'' is one which must be applied to both surfaces and allowed some time to dry before the two surfaces are pushed together. Some contact adhesives require as long as 24 hours to dry before the surfaces are to be held together<ref>[http://www.thistothat.com/glue/contact.shtml Information about contact adhesive]</ref>. Once the surfaces are pushed together the bond forms very quickly<ref>[http://composite.about.com/library/glossary/c/bldef-c1257.htm Definition of ''contact adhesive'' on About.com]</ref>, hence it is usually not necessary to apply pressure for a long time. This means that there is no need to use [[Clamp (tool)|clamps]], which is convenient.
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* Handy for creating structures where glue needs to set at each stage before the next can be glued
 +
* Not a strong durable glue
 +
* Most common hot melt glue stick chemistry is amorphous polypropylene plus tackifiers and [[filler]]s. Several other chemistries also exist.
 +
* Polyethylene requires temperatures above those of standard retail glue guns to work, if you put polythene in an ordinary glue gun it will just soften enough to block it.
 +
* Low melting point glues and guns are also available. Often used by kids due to nearly instant setting and less burn risk.
  
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===Hot adhesives (thermoplastic adhesives)===
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[http://www.bostik-us.com/products/index.asp?fa=categories&divisionId=3&categoryId=54 Pdf hot melt glue datasheets]
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[[Image:MVC-013F.JPG|right|thumbnail|200px|A glue gun, an example of a hot adhesive]]
 
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{{main|Hot glue}}
 
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Also known as "hot melt" adhesives, these adhesives are [[thermoplastic]]s; they are applied hot and simply allowed to harden as they cool. These adhesives have become popular for crafts because of their ease of use and the wide range of common materials to which they can adhere. A glue gun, pictured right, is one method of applying a hot adhesive. The glue gun melts the solid adhesive and then allows the liquid to pass through the "barrel" of the gun onto the material where it solidifies.
 
  
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=== Reactive adhesives ===
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==PVA==
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A reactive adhesive works by chemical bonding with the surface material. They are applied in thin films. Reactive adhesives are less effective when there is a secondary goal of filling gaps between the surfaces. These include two-part epoxy, peroxide, silane, metallic cross-links, or isocyanate.
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[[PVA]] has a wide range of uses in building and DIY.
  
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Such adhesives are frequently used to prevent loosening of bolts and screws in rapidly moving assemblies, such as automobile engines. They are largely responsible for the quieter running modern car engines.
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* There are White and yellow types of PVA
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* A good general purpose wood glue
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* Reduces permeability of [[Mortar Mixes|cement mortar]] & increases adhesion
 +
* Use as a plaster size
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* softens when wet
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* Exterior grade PVAs available, but are not waterproof
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* Not suitable for woodwork where failure could cause injury, eg chairs, beds ets.
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* [https://groups.google.com/group/uk.d-i-y/browse_frm/thread/2464c8abd971d4b0?hl=en# Brands of PVA]
  
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=== Pressure sensitive adhesives ===
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==Acrylic sealant==
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Pressure sensitive adhesives (PSAs) form a bond by the application of light pressure to marry the adhesive with the adherend.  They are designed with a balance between flow and resistance to flow.  The bond forms because the adhesive is soft enough to flow, or wet, the adherend.  The bond has strength because the adhesive is hard enough to resist flow when stress is applied to the bond.  Once the adhesive and the adherend are in close proximity, molecular interactions such as van der Waals forces become involved in the bond, contributing significantly to its ultimate strength.
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* A cheap replacement for silicone
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* tends to turn to cottage cheese if it stays wet
  
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Pressure sensitive adhesives (PSAs) are designed for either permanent or removable applications.  Examples of permanent applications include safety labels for power equipment, foil tape for HVAC duct work, automotive interior trim assembly, and sound/vibration damping films.  Some high performance permanent PSAs exhibit high adhesion values and can support kilograms of weight per square centimeter of contact area, even at elevated temperature.  Permanent PSAs may be initially removable (for example to recover mislabeled goods) and build adhesion to a permanent bond after several hours or days.
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==Caulk==
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[[image:Decorators caulk 0069-3.jpg|right|185px]]
  
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Removable adhesives are designed to form a temporary bond, and ideally can be removed after months or years without leaving residue on the adherend.  Removable adhesives are used in applications such as surface protection films, masking tapes, bookmark and note papers, price marking labels, promotional graphics materials, and for skin contact (wound care dressings, EKG electrodes, athletic tape, analgesic and transdermal drug patches, etc.).  Some removable adhesives are designed to repeatedly stick and unstick. They have low adhesion and generally can not support much weight. 
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* Caulk is a low cost slightly flexible acrylic formula used for filling
 +
* [[Paint]]able
  
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Pressure sensitive adhesives are manufactured with either a liquid carrier or in 100% solid form.  Articles are made from liquid PSAs by coating the adhesive and drying off the solvent or water carrier.  They may be further heated to initate a crosslinking reaction and increase molecular weight.  100% solid PSAs may be low viscosity polymers that are coated and then reacted with radiation to increase molecular weight and form the adheisve; or they may be high viscosity materials that are heated to reduce viscosity enough to allow coating, and then cooled to their final form.
 
  
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Also see [[adhesive tape]] and [[gaffer tape]].
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==No more nails==
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[[image:Instant nails 0060-5.jpg|right|185px]]
  
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[[Plastic wrap]] displays temporary adhesive properties as well.
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* Water based
 +
* Acrylic adhesive with filler
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* Solvent free
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* High grab
 +
* Designed to replace nails for some jobs
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* e.g. solvent-free Gripfill, No-more-nails etc
  
 +
==Solvent based building adhesives==
 +
(Gripfill etc)
  
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==Choosing a Suitable Adhesive==
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==? type==
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Table of best adhesives for any 2 given materials:
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"Sticks like SH!T" etc
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http://www.elessar.org.uk/adhesives.pdf
 
  
 +
==Polyurethane==
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[[image:PU adhesive 0571-5.jpg|right|185px]]
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* Exterior & interior use
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* Sticks well to wood, metals & masonry
 +
* Fully waterproof as long as it gets to dry out regularly
 +
* Turns to goo if it stays wet for a month
 +
* Adhesive activated/set by damp
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* Foams slightly to fill small gaps, but this foamed adhesive has very little strength, so in practice its not good for gap filling applications
 +
* [[Paint]]able
 +
* One surface should be porous
 +
* [[Clamps|Clamp]] while setting
 +
* Slight dampening of one surface helps to maximise final joint strength.
 +
* Remove glue with acetone before fully set, or a chisel or [[Knives|knife]] once set.
  
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==Mechanisms of adhesion==
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==Polyester resin==
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{{mainarticle|adhesion}}
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[[image:Leakfix 0067-4.jpg|right|185px]]
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The strength of attachment, or adhesion, between an adhesive and its substrate depends on many factors, including the means by which this occurs. Adhesion may occur either by mechanical means, in which the adhesive works its way into small pores of the substrate, or by one of several chemical mechanisms.
 
  
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In some cases an actual [[chemical bond]] occurs between adhesive and substrate. In others electrostatic forces, as in static electricity, hold the substances together. A third chemical method involves [[van der Waal's forces]] which develop between each's molecules. A fourth chemical means involves the moisture-aided diffusion of the glue into the substrate, followed by hardening.
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* tough
 +
* sticks a wide range of materials
 +
* used in fibreglass work
 +
* used to fill damaged exterior woodwork, eg sash windows
 +
* available in clear or colours
 +
* car body filler is polyester resin
 +
* All resin glues contain various fillers to reduce cost and modify their properties.
 +
* 10:1 resin to hardener ratio is typical
 +
* ideal for filling rusted metal windows
  
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== Failure of the adhesive joint ==
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See also:
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When subjected to loading, debonding may occur at different locations in the adhesive joint. The major fracture types are the following
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* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/e4ac9fba7b81f84f/4ce5eb9d5783102f?tvc=1&q=araldite#4ce5eb9d5783102f Discussion of epoxy and polyester adhesives on uk.d-i-y]
  
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=== Cohesive fracture ===
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==Vinylester Resin==
 +
* Stronger than polyester resin, not as strong as epoxy resin
 +
* contains styrene
  
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“Cohesive” fracture" is obtained if a crack propagates in the bulk polymer which constitutes the adhesive. In this case the surfaces of both adherents after debonding will be covered by fractured adhesive.  The crack may propagate in the centre of the layer or near an interface.  For this last case, the “cohesive” fracture can be said to be “cohesive near the interface”. Most quality control standards consider that a “good” adhesive bonding must be “cohesive”. 
+
==Silicone==
 +
[[image:Silicone 57-4.jpg|right|185px]]
  
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=== Interfacial fracture ===
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* [[Silicone Sealant]] is a satisfactory glue in shear, but has little strength in tension.
 +
* Silicone is used to glue glass aquaria together, but this is a tougher formula than builders' silicone sealant.
 +
* Building silicones are RTV, room temperature vulcanised.
 +
* There are several types of silicone
 +
* For more information see [[Silicone Sealant]]
  
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The fracture is “adhesive” or “interfacial” when debonding occurs between the adhesive and the adherent.  In most cases, the occurrence of “interfacial” fracture for a given adhesive goes along with a smaller fracture toughness.  The “interfacial” character of a fracture surface is usually detected by visual inspection, but advanced surface characterisation techniques such as spectrophotometry allows to identify the precise location of the crack path in the interphase.
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==Plastic cement==
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[[Image:adhesive2.jpg|thumbnail|450px|Failure of the adhesive joint can occur in different locations]]
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[[image:UHU_Alleskleber.jpg|right|185px]]
  
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=== Other types of fracture ===
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Solvent based plastic cements are plastics dissolved in a solvent. These cements, and solvents alone, are used to glue soluble plastics.
 +
* acrylic (perspex) in acetone is used to glue [[Sheet Materials#Acrylic|acrylic (perspex)]].
 +
* Solvent weld is used to glue [[Make Things from PVC Pipe|PVC pipe]] and trunking
  
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Beside these two cases, other type of fracture are
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==Latex==
 +
[[image:Copydex 0063-4.jpg|right|185px]]
  
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*The “mixed” fracture type which occurs if the crack propagates at some spots in a “cohesive” and in others in an “interfacial” manner.  “Mixed” fracture surfaces can be characterised by a certain percentage of “adhesive” and “cohesive” areas.
+
* Flexible when dry
 +
* Repairs [[carpet]] cuts & frays
 +
* used for carpet patching
 +
* not tough
 +
* occasionally used to glue clothes, eg trouser turnups
  
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*The “alternating crack path” fracture type which occurs if the cracks jumps from one interface to the other.  This type of fracture appears in the presence of tensile pre-stresses in the adhesive layer.
+
==Bitumen adhesives==
 +
[[image:Bitumen 2537-2.jpg|right|185px]]
  
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*Fracture can also occur in the adherent if the adhesive is tougher than the adherent.  In this case the adhesive remains intact and is still bonded to one substrate and the remnants of the other.  For example, when one removes a price label, adhesive usually remains on the label and the surface.  This is cohesive failure.  If, however, a layer of paper remains stuck to the surface, the adhesive has not failed.  Another example is when someone tries to pull apart [[Oreo]] cookies and all the filling remains on one side.  The goal in this case is an adhesive failure, rather than a cohesive failure.
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* Roofing adhesives are primarily bitumen & petrochemical solvent
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* Let it go tacky before applying the roofing felt, so it holds the felt down
 +
* may be thinned / dissolved with various [[oil|petrochemical solvents]]
  
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== Design of adhesive joints ==
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There are 3 types of Bitumen adhesive:
 +
* Solid bitumen, which is heated to melt it
 +
* Bitumen in solvent, as pictured. Solvents include naphtha, white spirit, or even [[Oil|paraffin]]
 +
* Bitumen emulsion. This is bitumen dispersed in water, and is usually acidic.
  
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A general design rule is a relation of the type: "Material Properties > Function (geometry, loads)"
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==Tile adhesives==
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[[image:Tile adhesive 2364-2.jpg|right|185px]]
  
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The engineering work will consist in having a good model to evaluate the "Function". For most adhesive joints, this can be achieved using [[fracture mechanics]].  Concepts such as the stress concentration factor K and the energy release rate G can be used to predict failure. In such models, the behavior of the adhesive layer itself is neglected and only the adherents are considered.
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* Most are modified cement or glue formulae
 +
* Ready mixed cement types contain a set preventer that evaporates on use.
 +
* See BAL Adhesives guide for information on different types
 +
* Waterproof ones only survive if they dry out regularly.
 +
* Swimming pool types are required where they will stay wet.
  
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Failure will also very much depend on the opening "mode" of the joint.[[Image:mode.jpg|thumbnail|350px|Modes of failure]]
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==Wallpaper Paste==
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*'''Mode I''' is an opening or tensile mode where the loadings are normal to the crack.
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[[image:Wallpaper paste 3643-3.JPG|right|185px]]
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*'''Mode II''' is a sliding or in-plane shear mode where the crack surfaces slide over one another in direction perpendicular to the leading edge of the crack. This is typically the mode for which the adhesive exhibits the higher resistance to fracture.
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* Starch modified to disperse in cold water, sometimes with added pva
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*'''Mode III''' is a tearing or antiplane shear mode.
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* other chemistries have also been used, such as cellulose and starch
 +
* Dries clear
 +
* Water soluble
 +
* Contains mould inhibitor
  
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As the loads are usually fixed, an acceptable design will result from combination of a material selection procedure and geometry modifications, if possible. In adhesively bonded structures, the global geometry and loads are fixed by structural considerations and the design procedure focuses on the “material properties” of the adhesive (i.e. select a "good" adhesive) and on local changes on the geometry.
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==Starch==
 +
* Glue for wallpaper, card & paper.
 +
* To make starch glue, boil some starch (eg flour, oats, etc) in water until it changes from white to semi-clear. Add a little alum to prevent mould if you're not using it immediately.
 +
* To make a starch gluestick, parboil a potato. Suitable for gluing paper, just wipe with the potato and press together. Will not store.
 +
* Low cost, complete safety and easy to wash out; ideal for kids
 +
* Old black wallpaper adhesive is starch; the starch mouldered before drying out.
  
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Increasing the joint resistance is usually obtained by designing its geometry so that:
 
−
*The bonded zone is large
 
−
*It is mainly loaded in mode II
 
−
*Stable crack propagation will follow the appearance of a local failure.
 
  
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== Testing the resistance of the adhesive ==
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==Rubber cement==
 +
* Rubbery plastic in solvent
 +
* for gluing rubbery plastics, mainly bike tyres & inner tubes & inflatable furniture
 +
* non vulcanising, so not as tough as vulcanised rubber
 +
* not tough enough for shoes
 +
* eg Platignum studio gum
 +
* [http://uk.news.yahoo.com/22/20090715/tod-oukoe-uk-germany-mattress-1a5e080.html Risks]
  
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A wide range of testing devices have been imagined to evaluate the fracture resistance of bonded structures in pure mode I, pure mode II or in mixed  mode.  Most of these devices are beam type specimens. We will very shortly review the most popular:
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=Adhesives By Purpose=
  
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*'''Double Cantilever Beam tests (DCB)''' are used to measure the mode I fracture resistance of adhesives in a [[fracture mechanics]] framework.  These tests consist in opening an assembly of two beams by applying a force at the ends of the two beams.  The test in unstable (i.e. the crack propagates along the entire specimen once a critical load is attained) and a modified version of this test characterised by a non constant inertia was proposed called the '''Tapered double cantilever beam specimen (TDCB)'''. [[Image:tests.jpg|thumbnail|450px|Testing devices]]
+
==Wood==
 +
* PVA
 +
* Animal
 +
* Resin
 +
* Polyurethane
 +
* Acrylic
 +
* Epoxy
 +
see [[Wood glues]]
  
−
*'''Peel tests''' are used to measure the fracture resistance of a thin layer bonded on a thick substrate or of two layers bonded together.  They consist in measuring the force needed for tearing an adherent layer from a substrate or for tearing two adherent layers one from another.  Whereas the structure is not symmetrical, various mode mixities can be introduced in these tests.
+
==Metal==
 +
* Epoxy
 +
* Polyurethane
 +
* Contact
  
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*'''Wedge tests''' are used to measure the mode I dominated fracture resistance of adhesives used to bond thin plates.  These tests consist in inserting a wedge in between two bonded plates.  A critical energy release rate can be derived from the crack length during testing.  This test is a mode I test but some mode II component can be introduced by bonding plates of different thicknesses. 
+
==Plastics - PVC, ABS==
 +
* Plastic welding solvents form the strongest bonds by far
 +
* plastic cement
  
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*'''Mixed-Mode Delaminating Beam (MMDB) tests''' consist in a bonded bilayer with two starting cracks loaded on four points. The test presents roughly the same amount of mode I and mode II with a slight dependence on the ratio of the two layer thicknesses.  
+
==Plastics - hard==
 +
* Epoxy
 +
* Polyurethane
 +
* ...
  
−
*'''End Notch Flexure tests''' consist in two bonded beams built-in on one side and loaded by a force on the other. As no normal opening is allowed, this device allows testing in essentially mode II condition.
+
==Plastics - polyethylene, nylon==
 +
* It has long been accepted that no glue can effectively stick these directly, however one now claims to: [http://www.henkelna.com/cps/rde/xchg/SID-0AC83309-DDF5935D/henkel_us/hs.xsl/1554_USE_HTML.htm?&parentredDotUID=brands&BU=ut&countryCode=us&redDotUID=0000000I20 Loctite Plastix advanced plastic bonder]
 +
* A weak bond can be achieved with evostick contact adhesive
 +
* Flamed polythene and nylon can be glued
 +
* Melting the surfaces together also works, if both materials being joined are the same substance. Local heating can be achieved on flared circular joints by spinning while applying pressure.
  
−
*'''Crack Lap Shear (CLS) tests''' are application-oriented fracture resistance tests. They consist in two plates bonded on a limited length and loaded in tension on both ends. The test can be either symmetrical or dis-symmetrical. In the first case two cracks can be initiated and in the second only one crack can propagate.
+
==Fabric==
 +
* Latex, eg Copydex
 +
* Water based starch glues are good for temporary gluing, eg while sewing. They wash out later.
 +
* Its also possible to melt plastic to bond fabrics together. This is often used for trouser turnups, film plastic is positioned and the fabric sandwich ironed on hot.
  
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==References==
+
==Paper & Card==
−
<references />
+
* PVA
 +
* Gum
 +
* Glue sticks (eg Pritt-stick) ([[PVA]] or PVP)
 +
* Spray-type photo fixing etc
 +
* Wallpaper paste
 +
* Starch
  
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[[Category:Adhesives| ]]
+
==Oil lines==
−
[[Category:Art materials]]
+
* Red hermetite
  
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[[cs:Lepidlo]]
+
==Plaster==
−
[[de:Klebstoff]]
+
to consolidate & stabilise loose plaster:
−
[[es:Adhesivo]]
+
* very dilute PVA (allows it to soak in further)
−
[[fr:Adhésif]]
+
* limewash
−
[[io:Adherivo]]
+
* Loose plaster may also be drilled and dilute pva poured in to rebond it to the wall
−
[[he:דבק]]
+
* L&P ceilings may have dilute pva poured on from above to re-attach them to the laths. Sagged patches can be propped back into place first if the damage is only localised.
−
[[nl:Lijmen]]
+
 
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[[ja:接着剤]]
+
 
−
[[pl:Klej]]
+
=Adhesive Selector Grid=
−
[[pt:Cola]]
+
Which adhesive is best for any 2 given materials?
−
[[sv:Lim]]
+
* http://www.elessar.org.uk/adhesives.pdf
−
[[zh:胶粘剂]]
+
* http://www.thistothat.com/
 +
 
 +
 
 +
=Structural Adhesives=
 +
Structural adhesives or engineering adhesives are used where failure could cause injury or other undesired consequences. These high strength & higher reliability adhesives include:
 +
* epoxy
 +
* polyurethane
 +
* acrylic
 +
* cyanoacrylate
 +
 
 +
 
 +
=Preparation=
 +
In the great majority of cases, to obtain a good bond surfaces should be prepared so they are:
 +
* clean
 +
* dry
 +
* loose or flaky material removed
 +
* degreased
 +
 
 +
Roughening smooth surfaces increases the adhesive bond strength, and in many cases is necessary to obtain sufficient strength.
 +
 
 +
=Moulding tools=
 +
Sometimes adhesives need to be moulded.
 +
 
 +
===Fugee & Fugenboy===
 +
Shaped polypropylene tools to achieve a nicely shaped seal around baths etc.
 +
 
 +
===Polythene===
 +
Adhesives don't stick to polythene, and its readily available as polythene film (eg binbags, dust sheet, rubble bags). Can be used under adhesive to obtain a flat smooth underside, or gently brushed onto the top of wet adhesive to get a smooth flat (or curved) finish.
 +
 
 +
===PTFE===
 +
As polythene but much more flexible.
 +
 
 +
===Wood===
 +
Wooden tools may be used on silicone if kept wetted with 50/50 washing up liquid & water. Wooden kitchen implements are often to hand.
 +
 
 +
 
 +
=Fillers=
 +
Fillers are low cost dry powders used in a lot of adhesives. They reduce cost and in some cases can improve strength. They also affect the adhesive properties to some extent.
 +
 
 +
Additional fillers can be mixed into adhesives to reduce cost further. Each type of filler will have effects on the glue formulation. Adding fillers does reduce final strength in most cases, but fibrous fillers can sometimes increase it.
 +
 
 +
2 part adhesives should always be fully mixed before adding fillers. Bond strength may be maximised by using a very thin layer of fillerless adhesive on each substrate before applying filled adhesive to fill the gap.
 +
 
 +
Common fillers:
 +
* Dry powders such as talc and iron oxide are often used to extend adhesives, but weaken the final result.
 +
* Colloidal silica is used to thicken (gel)
 +
* Sand is very tough, and can be mixed into resins, which bond to it well. This reduces cost, but the resulting mix is not toolable / sandable.
 +
* Sawdust consists of lots of short fibres, and thus can act as reinforcement as well as a bulk filler. It is rather less hard than most glues, but will strengthen some. Its also lumpy.
 +
* milled wood fibres - much improved performance compared to sawdust
 +
* Glass microbeads for bulk
 +
* Carbon or graphite, for some electrical conduction
 +
* Silver - electrical & thermal conduction, but resistance rises as the metal oxidises, and reliability is often a problem, so not recommended for electrical purposes.
 +
 
 +
Fillers should not be added to adhesive sand compounds such as Geotex, which is used to fill gaps in block paving work, as this generally results in failure. Such products aren't cheap and are already thinned as far as they can be. The addition of sand is a common cause of failure.
 +
 
 +
=Suppliers=
 +
* Builder's merchants
 +
* diy sheds
 +
* car accessory shops
 +
* http://www.cfsnet.co.uk/
 +
* [http://www.gorillaglueonline.co.uk GorillaGlueOnline.co.uk]
 +
 
 +
=See Also=
 +
* West system epoxy manual
 +
* [[PVA]]
 +
* Book: 'On boat construction' by Gougeon Brothers is an expert guide to use of epoxies.
 +
* For a general and scholarly article about Adhesives see [http://en.wikipedia.org/wiki/Adhesives Wikipedia]
 +
* BAL Adhesives tables
 +
* [http://www.diyinfo.org/wiki/Glue_Terminology Glue Terminology]
 +
* Low cost [http://en.wikipedia.org/wiki/Homemade_glue homemade adhesives]
 +
* The [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/0fa11b83cc858239?hl=en# Burn test] for gluing plastics
 +
* [[Special:Allpages|Wiki Contents]]
 +
* [[Special:Categories|Wiki Subject Categories]]
 +
 
 +
 
 +
[[Category:Adhesives]]
 +
[[Category:Plastics]]
 +
[[Category:Wood]]
 +
[[Category:Repair]]
 +
[[Category:Basics]]
 +
[[Category:Fixings]]

Latest revision as of 19:46, 30 April 2012

Adhesives By Type

Cyanoacrylate

800px-Super glue.jpg
  • aka superglue, crazy glue
  • CA (cyanoacrylate) is famous for accidentally gluing skin together
  • debonders available to unstick skin,
  • cyanoacrylacte activators are available to speed up setting to 2 or 3 seconds, but these reduce final strength.
  • For non-porous surfaces.
  • Its low shear strength enables it to be used as a removable glue in some cases, eg for mounting items to a block on a lathe.
  • can be used as a thread lock
  • Cyanoacrylates are used to glue human and animal tissue after accidents. The medical grade is a slightly different formula with improved medical properties, but standard superglue also works and was previously used medically.
  • CA is also effective at stoping bleeding at trauma sites.
  • When added to baking soda (Sodium bicarbonate) Cyanoacrylate glue forms a hard, lightweight filler/adhesive (baking soda is first used to fill a gap then the adhesive is dripped into the baking soda). This works well with porous materials that the glue doesn't work well with alone.
  • Thin CA is occasionally used as a tough glossy wood varnish for small items such as turned pens.
  • Moisture triggers setting
  • Opened bottles keep longer if stored in a container with a desiccant (eg silica gel)
  • Cured CA can be removed with acetone or methylene chloride.
  • A few hours in the freezer can make it brittle
  • Accidetal gluing of eyes is a real risk with CA
  • Very low flash point

Epoxy Resin

Clear epoxy resin
Epoxy resin
Epoxy putty
  • Araldite is a well known epoxy resin formulation
  • 2 part resin
  • Available as liquid resin tubes, putty sticks, or in 400ml cartridges with self mixing nozzles.
    • cartridges are used with a self mixing nozzle, which is replaced after each use
  • Epoxies come mixed with many different fillers and modifiers, giving them a range of properties
  • Epoxy formulations may be runny, gel, paste or putty, each best suited to its own uses.
  • Tough
  • Good chemical resistance.
  • Car accessory shops sell tougher epoxies than Araldite.
  • The quick setting types are much weaker
  • Vulnerable to UV, which causes degradation.
  • Heating the mix (in tinfoil on a low ring, or over boiling water) until runny makes it set very much faster. Don't overheat it.
  • Some formulations are heat resistant, some not. The ones that aren't may claim they are on the basis that they survive heat, even if they do lose all strength when hot.
  • Heat while setting makes it more heat and chemical resistant once set.
  • More strength and cost than polyester or vinylester resins.
  • Epoxies are used as powder coatings (a tough paint-like finish)
  • Very good electrical insulation (once cured), good for EHT insulation repairs.
  • Metal loaded epoxies can be conductive
  • Suitable for work where failure could cause injury, eg chairs, fixing heavy loads to walls, structural repairs to wood & masonry, etc.
  • Suitable for wood, metal, glass, stone, and some plastics.
  • Vinegar will clean up uncured and semi-cured epoxy, but not once cured.
  • 1:1 resin to hardener ratio typical, but ratios of upto 5:1 are also available.

See also:

Hot-melt glue

Heissklebepistole.jpg
  • Almost instant setting
  • Handy for creating structures where glue needs to set at each stage before the next can be glued
  • Not a strong durable glue
  • Most common hot melt glue stick chemistry is amorphous polypropylene plus tackifiers and fillers. Several other chemistries also exist.
  • Polyethylene requires temperatures above those of standard retail glue guns to work, if you put polythene in an ordinary glue gun it will just soften enough to block it.
  • Low melting point glues and guns are also available. Often used by kids due to nearly instant setting and less burn risk.

Pdf hot melt glue datasheets

PVA

PVA has a wide range of uses in building and DIY.

  • There are White and yellow types of PVA
  • A good general purpose wood glue
  • Reduces permeability of cement mortar & increases adhesion
  • Use as a plaster size
  • softens when wet
  • Exterior grade PVAs available, but are not waterproof
  • Not suitable for woodwork where failure could cause injury, eg chairs, beds ets.
  • Brands of PVA

Acrylic sealant

  • A cheap replacement for silicone
  • tends to turn to cottage cheese if it stays wet

Caulk

Decorators caulk 0069-3.jpg
  • Caulk is a low cost slightly flexible acrylic formula used for filling
  • Paintable


No more nails

Instant nails 0060-5.jpg
  • Water based
  • Acrylic adhesive with filler
  • Solvent free
  • High grab
  • Designed to replace nails for some jobs
  • e.g. solvent-free Gripfill, No-more-nails etc

Solvent based building adhesives

(Gripfill etc)

? type

"Sticks like SH!T" etc

Polyurethane

PU adhesive 0571-5.jpg
  • Exterior & interior use
  • Sticks well to wood, metals & masonry
  • Fully waterproof as long as it gets to dry out regularly
  • Turns to goo if it stays wet for a month
  • Adhesive activated/set by damp
  • Foams slightly to fill small gaps, but this foamed adhesive has very little strength, so in practice its not good for gap filling applications
  • Paintable
  • One surface should be porous
  • Clamp while setting
  • Slight dampening of one surface helps to maximise final joint strength.
  • Remove glue with acetone before fully set, or a chisel or knife once set.

Polyester resin

Leakfix 0067-4.jpg
  • tough
  • sticks a wide range of materials
  • used in fibreglass work
  • used to fill damaged exterior woodwork, eg sash windows
  • available in clear or colours
  • car body filler is polyester resin
  • All resin glues contain various fillers to reduce cost and modify their properties.
  • 10:1 resin to hardener ratio is typical
  • ideal for filling rusted metal windows

See also:

Vinylester Resin

  • Stronger than polyester resin, not as strong as epoxy resin
  • contains styrene

Silicone

Silicone 57-4.jpg
  • Silicone Sealant is a satisfactory glue in shear, but has little strength in tension.
  • Silicone is used to glue glass aquaria together, but this is a tougher formula than builders' silicone sealant.
  • Building silicones are RTV, room temperature vulcanised.
  • There are several types of silicone
  • For more information see Silicone Sealant

Plastic cement

UHU Alleskleber.jpg

Solvent based plastic cements are plastics dissolved in a solvent. These cements, and solvents alone, are used to glue soluble plastics.

Latex

Copydex 0063-4.jpg
  • Flexible when dry
  • Repairs carpet cuts & frays
  • used for carpet patching
  • not tough
  • occasionally used to glue clothes, eg trouser turnups

Bitumen adhesives

Bitumen 2537-2.jpg
  • Roofing adhesives are primarily bitumen & petrochemical solvent
  • Let it go tacky before applying the roofing felt, so it holds the felt down
  • may be thinned / dissolved with various petrochemical solvents

There are 3 types of Bitumen adhesive:

  • Solid bitumen, which is heated to melt it
  • Bitumen in solvent, as pictured. Solvents include naphtha, white spirit, or even paraffin
  • Bitumen emulsion. This is bitumen dispersed in water, and is usually acidic.

Tile adhesives

Tile adhesive 2364-2.jpg
  • Most are modified cement or glue formulae
  • Ready mixed cement types contain a set preventer that evaporates on use.
  • See BAL Adhesives guide for information on different types
  • Waterproof ones only survive if they dry out regularly.
  • Swimming pool types are required where they will stay wet.

Wallpaper Paste

Wallpaper paste 3643-3.JPG
  • Starch modified to disperse in cold water, sometimes with added pva
  • other chemistries have also been used, such as cellulose and starch
  • Dries clear
  • Water soluble
  • Contains mould inhibitor

Starch

  • Glue for wallpaper, card & paper.
  • To make starch glue, boil some starch (eg flour, oats, etc) in water until it changes from white to semi-clear. Add a little alum to prevent mould if you're not using it immediately.
  • To make a starch gluestick, parboil a potato. Suitable for gluing paper, just wipe with the potato and press together. Will not store.
  • Low cost, complete safety and easy to wash out; ideal for kids
  • Old black wallpaper adhesive is starch; the starch mouldered before drying out.


Rubber cement

  • Rubbery plastic in solvent
  • for gluing rubbery plastics, mainly bike tyres & inner tubes & inflatable furniture
  • non vulcanising, so not as tough as vulcanised rubber
  • not tough enough for shoes
  • eg Platignum studio gum
  • Risks

Adhesives By Purpose

Wood

  • PVA
  • Animal
  • Resin
  • Polyurethane
  • Acrylic
  • Epoxy

see Wood glues

Metal

  • Epoxy
  • Polyurethane
  • Contact

Plastics - PVC, ABS

  • Plastic welding solvents form the strongest bonds by far
  • plastic cement

Plastics - hard

  • Epoxy
  • Polyurethane
  • ...

Plastics - polyethylene, nylon

  • It has long been accepted that no glue can effectively stick these directly, however one now claims to: Loctite Plastix advanced plastic bonder
  • A weak bond can be achieved with evostick contact adhesive
  • Flamed polythene and nylon can be glued
  • Melting the surfaces together also works, if both materials being joined are the same substance. Local heating can be achieved on flared circular joints by spinning while applying pressure.

Fabric

  • Latex, eg Copydex
  • Water based starch glues are good for temporary gluing, eg while sewing. They wash out later.
  • Its also possible to melt plastic to bond fabrics together. This is often used for trouser turnups, film plastic is positioned and the fabric sandwich ironed on hot.

Paper & Card

  • PVA
  • Gum
  • Glue sticks (eg Pritt-stick) (PVA or PVP)
  • Spray-type photo fixing etc
  • Wallpaper paste
  • Starch

Oil lines

  • Red hermetite

Plaster

to consolidate & stabilise loose plaster:

  • very dilute PVA (allows it to soak in further)
  • limewash
  • Loose plaster may also be drilled and dilute pva poured in to rebond it to the wall
  • L&P ceilings may have dilute pva poured on from above to re-attach them to the laths. Sagged patches can be propped back into place first if the damage is only localised.


Adhesive Selector Grid

Which adhesive is best for any 2 given materials?


Structural Adhesives

Structural adhesives or engineering adhesives are used where failure could cause injury or other undesired consequences. These high strength & higher reliability adhesives include:

  • epoxy
  • polyurethane
  • acrylic
  • cyanoacrylate


Preparation

In the great majority of cases, to obtain a good bond surfaces should be prepared so they are:

  • clean
  • dry
  • loose or flaky material removed
  • degreased

Roughening smooth surfaces increases the adhesive bond strength, and in many cases is necessary to obtain sufficient strength.

Moulding tools

Sometimes adhesives need to be moulded.

Fugee & Fugenboy

Shaped polypropylene tools to achieve a nicely shaped seal around baths etc.

Polythene

Adhesives don't stick to polythene, and its readily available as polythene film (eg binbags, dust sheet, rubble bags). Can be used under adhesive to obtain a flat smooth underside, or gently brushed onto the top of wet adhesive to get a smooth flat (or curved) finish.

PTFE

As polythene but much more flexible.

Wood

Wooden tools may be used on silicone if kept wetted with 50/50 washing up liquid & water. Wooden kitchen implements are often to hand.


Fillers

Fillers are low cost dry powders used in a lot of adhesives. They reduce cost and in some cases can improve strength. They also affect the adhesive properties to some extent.

Additional fillers can be mixed into adhesives to reduce cost further. Each type of filler will have effects on the glue formulation. Adding fillers does reduce final strength in most cases, but fibrous fillers can sometimes increase it.

2 part adhesives should always be fully mixed before adding fillers. Bond strength may be maximised by using a very thin layer of fillerless adhesive on each substrate before applying filled adhesive to fill the gap.

Common fillers:

  • Dry powders such as talc and iron oxide are often used to extend adhesives, but weaken the final result.
  • Colloidal silica is used to thicken (gel)
  • Sand is very tough, and can be mixed into resins, which bond to it well. This reduces cost, but the resulting mix is not toolable / sandable.
  • Sawdust consists of lots of short fibres, and thus can act as reinforcement as well as a bulk filler. It is rather less hard than most glues, but will strengthen some. Its also lumpy.
  • milled wood fibres - much improved performance compared to sawdust
  • Glass microbeads for bulk
  • Carbon or graphite, for some electrical conduction
  • Silver - electrical & thermal conduction, but resistance rises as the metal oxidises, and reliability is often a problem, so not recommended for electrical purposes.

Fillers should not be added to adhesive sand compounds such as Geotex, which is used to fill gaps in block paving work, as this generally results in failure. Such products aren't cheap and are already thinned as far as they can be. The addition of sand is a common cause of failure.

Suppliers

See Also

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