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Re: Mold Release Agent
By:Bart Castleberry
Date: 10/13/1999, 11:35 am
In Response To: Re: Mold Release Agent (Ian Johnston)

> The mold is for a seat. Haven't started yet. How much wax if I am only
> going to use the mold once or twice?

> I built a fiberglass soapbox racer for my daughter a few years ago and am
> considering doing another one or maybe two. I'll use the body I have now
> to make the mold but I want to do it on the cheap, so any way to save
> money will be considered. (Not much call for professional soapbox racers!)

> Ian

How much wax....It really depends on how good your mold is(how smooth). It really is judgment call I guess. Most of my experience has been with pretty smooth, almost glassy molds. After waxing and PVA the release was real easy.

One way you might be able to get the desired surface is to put a final coat or two of west system clear coat resin on the mold, let it cure a week, wash then wax as best you can, PVA if possible, and then lay up. The clear coat epoxy has a better gloss to it than others that makes release easier and your finished seat easier. As I recall the reason for both pva and wax was that the wax prevented the pva from sticking to the mold and the pva prevented the resin from eating through the wax to the mold, kind of a symbiotic relationship. Afterwards the pva washes off with water.

PVA is cheap, relativly easy to find. And you can brush it as the post earlier suggested. However brushing will make a difference in the finished surface, no concern for a seat but possibly for the racer? I don't have ANY experience with this but I seem to remember someone using diluted elmers white glue for pva... They are both PVA--might work.

As far as the seat I might try using the elmers trick. Even if it does not work you are only out a little mat and resin on the mold and some cloth on the seat.

Messages In This Thread

Mold Release Agent
Ian Johnston -- 10/11/1999, 2:01 am
Re: Mold Release Agent
Steve McDonald -- 10/13/1999, 4:42 am
Re: Mold Release Agent
Bart Castleberry -- 10/12/1999, 9:54 pm
Re: Mold Release Agent
Ian Johnston -- 10/13/1999, 12:45 am
Re: Mold Release Agent
Bart Castleberry -- 10/13/1999, 11:35 am