SpudFiles

I have been told that epoxy resin will make a better piston than hot glue. When I make the piston, how should I prevent it from sticking to the mold? The mold is PVC pipe. Thank you for the helpful input. 

Make sure the pipe is clean and smooth on the inside(Do not sand)
Wax the inside of the pipe with this.

Just rub on with a rag and wipe off the excess. The piston should pop out with a firm tap from a dowl or hammer handle. I have done this several time with great success.

I've used automotive grease and even butter in the past, the important thing is that the surface is smooth and well smeared with something slippery. It should also be a perfect cylinder, one of the reasons why I favour casting in syringe tubes.

The inside of pvc isnt always perfect so it may require a little gentle persuasion to remove the casting.

yep im with jacksmirkingrevenge here go with grease , i use car bearing grease works like a charm.

Wow thanks! Just got a great piston from fiberglass resin.