Wax in PR

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T

TXTRNR

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Joined
Jan 17, 2011
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32
Location
Keller tx
I am having problems with wax coming off my Dixie cups while mixing. I have noticed in a few blanks. I have only found it on the top surface after the PR has set up. Will this cause a problem? I'm not sure why this is happening except maybe the temps here in Texas are heating up and softening the wax?

Thanks
Chris
 
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Ditch those cups and go to #5 Plastic Cups. The #5 is the number inside the recycle sign on the bottom of the cup. I use the walmart brand in bulk.
 
Unless the wax migration is causing you color mixing issues, it shouldn't be a problem. It's common practice in the fiberglass industry to mix wax in with the resin for the final coat. The wax rises to the top during set-up and forms an air-barrier which enables the surface to cure without being tacky.

Regards,
Eric
 
I use the dixie cups. While I haven't noticed the wax coming off the cups, it shouldn't be an issue. During the curing process, the was will melt, rise to the top of the blank and be on the outside of the blank.
 
The wax doesn't make any difference with fiberglass so I wouldn't worry about it unless little pieces are showing up in your blank.

You will see a lot of people say their cast didn't set properly because the exposed side is tacky. Fiberglass and polyester resins will only fully cure if NOT exposed to open air. They even sell a product to spray on top of wet resin to ensure it isn't tacky on top once hardened. Not sure if this is the same as aluminite as I have yet to work with it.
 
DestinTurnings said:
Fiberglass and polyester resins will only fully cure if NOT exposed to open air. ... Not sure if this is the same as aluminite as I have yet to work with it.
Click to expand...

Polyester and vinylester resins will fully cure when exposed to open air -- it just takes longer. Fiberglass workers take advantage of that property by doing thick layups in multiple layers. They wait until the previous layer cures (but the surface is still tacky) before applying the next one. That way, each layer bonds chemically with the previous one. For the last layer, they'll either add wax to the resin, or spray PVA on top to form an air barrier. That lets the top cure without being sticky. The polymer should be hard enough to work in about a day, but really continues curing for at least a week.

I demold my polyester resin blanks when they are still warm and tacky. Then I wrap each casting in wax paper until it cools. The surface is typically hard by then. If not, I just put it someplace warm for an hour or two.

Alumilite cures much quicker than PR, with a dry (not tacky) surface. It is still flexible at that point, however, and continues to harden over time. According to Alumilite Corp, multiple pours of Alumilite will chemically bond, even though the surface is hard to the touch.

I hope that helps,
Eric
 
Yeah...I did misspeak there. I only should only have said the surface will remain tacky. I have blanks in my storage cabinet that are more than a year old and still are tacky enough on top that they stick to other blanks in the drawer.
 
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