Casein glue
Casein Glue is a simple home made glue costing next to nothing. Experiment has shown it to be stronger than PVA when sticking wood.
Making it
- Add vinegar to lukewarm skimmed milk so it curdles.
- Drain the liquid component off from the solids. You now have low fat cottage cheese
- Put solids onto a paper towel to absorb excess liquid
- In a bowl, add a base (such as sodium bicarbonate, ammonia or washing soda) to the curds, bit by bit, until they change into a creamy mixture. You now have casein glue.
Performance
Experimental test showed this casein glue to be 40% stronger than commercial PVA when gluing wood.
Storage
This preparation lacks the antomicrobials present in commercial glue, so will spoil in storage. It may be frozen in ice cube trays for later use, or made when wanted.
This also means it is not recommended for damp or wet use, which is also true of PVA.
A mould inhibitor can be added to obtain longer storage life at room temperature, such as alum or a copper compound. Maybe a chemist will offer us a preservative option that enables it to store wet indefinitely at room temp like PVA.
Cost
Made from new ingredients its cost is similar to PVA, maybe a little higher.
If made from unwanted milk that's been stored too long and vinegar from pickles, then it costs nothing but a few minutes.
Uses
- Gluing wood
- Kids project at home or school
- One of the glues used in interior grades of plywood