Is there a resin that cures....

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Herb G

Herb G

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Without using a pressure or vacuum pot?
I'd like to make some blanks, but I seriously can't afford a casting pot setup, let alone all the extra goodies involved in casting.
Thanks for any help.

And while I'm at it, is all resin pressure cured, or is some vacuum cured?
What's the difference anyway?
 
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Herb G said:
Without using a pressure or vacuum pot?
I'd like to make some blanks, but I seriously can't afford a casting pot setup, let alone all the extra goodies involved in casting.
Thanks for any help.

And while I'm at it, is all resin pressure cured, or is some vacuum cured?
What's the difference anyway?
Click to expand...
As far as I know, none of the popular resins require pressure or vacuum to cure. The problem is with air bubbles, without using either pressure or vacuum (depending on the resin), it can be difficult to avoid bubbles in the final blank.

The idea with pressure is to compress any bubbles so small that they're not at all visible. With slower setting resins, you can use a vacuum to make the bubbles larger, so that they're more likely to float up and break at the surface.

As was previously stated, polyester resin doesn't require either, as it sets slow enough that the bubbles can often float on their own, but I have seen posts about setting the mold on a vibrating table to encourage the bubbles to dislodge and float.

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Liquid Diamond does not need a pressure pot or vacuum. However it takes 24 hours to cure, 48 if you want it rock hard when turning.

A heat gun will help any bubbles float to the top with just about any resin.

I haven't been able to cast Alumilit without pressure and get bubble free. (some use vibration to help the bubble to the top)
 
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I'm pretty sure no resisns require pressure or a vacuum to cure. A chemical reaction occurs regardless of air pressure or lack of. What you have to watch out for in curing is the ambient temperature and the amount of resin you're curing. The more resin, the more heat given off and therefore the faster the cure rate no matter what the container says the pot life is.
Pressure and vacuum are just use to deal with air bubbles.
 
FWIW, custom fishing rod builders have a spray that you can spray on the thread epoxy and bubbles disappear. Wonder if it will work on castings?
 
Woodchipper said:
FWIW, custom fishing rod builders have a spray that you can spray on the thread epoxy and bubbles disappear. Wonder if it will work on castings?
Click to expand...

interesting but castings are thicker than rod threads so i'm guessing this stuff only works on the surface in which case a torch works well.
 
I wouldn't use an open flame around polyester. The flash point is pretty low; I think around 86-90 degrees for most brands, I believe.

I warm the resin to approx. 85 degrees and mix the colorants in. Then I let it set while maintaining the temp. for about 10-15 mins. The temp. makes the resin very thin, so the bubbles from mixing in the colorants can escape easily in the time it sets aside. Then carefully add the catalyst as not to introduce excessive air and let set for 5 mins. and pour.

I rarely get a bubble.
Just keep in mind, raising the temp. of the resin, will cause the resin to gel faster, so the catalyst should be adjusted accordingly.
 
Herb my thought is that do you want to get by or do you want to make nice blanks? As mentioned you don't have to have pressure but it sure does help. When I first started I didn't use a pot and I did get by. I was casting in a vertical mold which allowed the bubbled to float straight up. Most of what I cast where stamps or something smooth which didn't give any rough surfaces for the bubbles to hang up on. I'm not saying you will but I had and I'm still having my share of troubles so not dealing with stray bubbles sure helps. Also when I did use pressure it really made the clarity of the resin much better. If you decide to go without a pot be sure to select the rest of your equipment to help reduce possible problems.
 
No pressure is needed for polyester or alumilite and your blanks will come out just fine . Don't stir it into a foam and any surviving bubbles will float out . Heat your resin in a small pot with warm water in it (just keep the water away from the resin) and the warm resin will be bubble free and there will be no change in clarity .
 
I have enjoyed reading the answers which will help when/if I begin to cast.

Thanks to all.
 
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