Mold release in baby soda bottles???

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Drstrangefart

Drstrangefart

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Woodstock, Ga. U.S.A.
So, I've been working with fiberglass resin in baby soda bottle molds. Without mold release they DO NOT come back out of the tubes easily. I tried some oilve oil aerosol, and it caused WAAAAAAAY more problems than it solved. I need to find a mold release for this that works before I start pouring precious, precious PR in them. I don't mind learning on the fiberglass resin as I didn't have money tied up in it, but I don't wanna waste a bunch of PR. What is the mold release agent of choice? We also have some silicone molds but those are Dad's, not mine. Any suggestions there?
 
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Most regular (not epoxy) fiberglass resin is either polyester resin or vinylester resin, so the basic problem of sticking to the mold should be similar. The most important difference between polyester casting resins (such as Silmar 41) and the polyester resins made for fiberglass layup (besides color) is the type and amount of promoter mixed in. Casting resin is formulated for thick pours. Layup resin is made for thin applications. If you use layup resin for casting, it can get too hot.

Regards,
Eric
 
I am waiting to hear your results Mr. Fart. I bought some soda bottles last week and I don't want them to ruin them by the casting not coming out. I will be using PR and am awaiting your trial to see what I should do when I start using them.
Thanks for asking the question. "Inquiring minds need to know".
 
Tim'sTurnings said:
I am waiting to hear your results Mr. Fart. I bought some soda bottles last week and I don't want them to ruin them by the casting not coming out. I will be using PR and am awaiting your trial to see what I should do when I start using them.
Thanks for asking the question. "Inquiring minds need to know".
Click to expand...

Yeah, man. So far I've drilled small holes in the bottoms of the two I have for a push stick to feed into to help it break loose. You just put some painter's tape over the hole before you pour. Clean it up before you use it again. I'd go ahead and try the wax and see if it works, the worst that happens is you have to tap it against a wood block for a while to get the blank broke loose. Unless someone else posts something they do that seems like it would work better for you.
 
I haven't been casting long but pvc is where its at. I paste wax the inside by pushing a saturated paper towel through a couple of times before the pour. I have used the same four tubes now about two dozen times. Total $ spent was less than $5.
 
I have used the pvc tubes as well for casting. But you can't see through the pvc to make swirls or mix the pr as you would like or see anything for that matter. I bought some baby soda bottles to try so I can see what I am doing with the cast. I am awaiting information as to if a mold release is necessary. The pvc is cheaper but I want to see what I am making.
 
I use baby soda bottles and pvc pipe and I dont use any type of mold release. If you leave alittle room at one end the take a dowel and a hammer and tap from the other end it should just slide out as long as they are 100% curred. If they have any uncurred area on the outer side of the blank then it will stick to the side. And it will take a army to get them out.. Oh and by the way some people like to put their blanks in the over for a few minutes to speed up the curing process but do not put the baby soda bottles in the oven. It will make getting the blank impossible to get out damhikt!
 
I have used air to remove them by blowing it in the hole I drilled in the bottom. It is wise to have something to stop the blank on it's way out though. They can come shooting out pretty quick. DAMHIKT.
 
They are the plastic bottles before they are expanded to the 2 liter size bottles of pop.
I ordered and got some but have not used them yet. They are for casting PR. You can see to make swirls and see what you are doing after the pour.
Here is the link for the site I bought them from. There are more sites to purchase from but this is the first one I saw and ordered 10.

Alexander's Outdoors, LLC Product List

Tim.
 
Thanks for the info and the links! Like the idea of being able to see the mix. At at < $1 each even with shipping these are cheap enough to play with for some PR experiments.
 
I use the PET preforms (baby soda bottles) applying a thin (very thin) coat of 3 in 1 oil to the inside. My cast come right out with a little tap.
 
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