Mold Release Agents

Mold release wax, PVA and sealers, and how they work together

Release is the cheapest part of a mold job and the one that decides whether the part comes off or the mold is scrap. Wax, PVA film and semi-permanent sealers all do the same job differently, and on a new mold the sensible answer is to use two of them.

Paste wax is the base layer

Partall #2 and Meguiar's Mirror Glaze No. 8 are the two standards. Build up several thin coats rather than one heavy one, let each haze, then buff. On a brand new mold plan on five or six coats before the first pull, then a single maintenance coat every few parts after that.

PVA when you cannot afford to lose the part

PVA is polyvinyl alcohol, sprayed or wiped on over the wax, and it dries to a film that physically separates part from mold. It is water soluble, so it washes straight off the finished part, and it leaves a faint texture that you would not want on a show surface. Use it over wax on a first pull, on a complex shape, or any time losing the part would be expensive. Wax and PVA together are belt and braces, and that is the right call on a new mold.

Semi-permanent and high temperature

TR 104 and Formula Five are semi-permanent release systems that chemically bond to the tool and last many pulls rather than one. They cost more up front and pay back on a mold you are running in production. The high temp waxes are for tooling that will see a post-cure oven, where a standard carnauba wax softens and transfers to the part.

Cleaning a mold that has stopped releasing

Release build-up, silicone contamination and oxidation all cause sticking, and adding more wax on top makes it worse. Formula Five Mold Cleaner #2 strips it back, and Clean 'N Glaze polishes the surface back up before you re-wax.

Getting the part off

Release wedges in rigid, flexible and high flex, plus air injection wedges, break the seal without gouging the flange the way a screwdriver does.