Dealing with bubbles WITHOUT a pressure pot

[MaddieResin]

Hi there lovely people!

I'm new to resin casting and do not yet have a pressure pot or vacuum chamber and have been trying to figure out how to eliminate the large amount of tiny bubbles that are all over the surface of my resin pieces. Currently, I can't afford a pressure pot/vacuum chamber and was wondering if there was a possibility that I could get around buying it for now. Possibly, I made the mold incorrectly or I could be introducing moisture to the environment. I called Reynolds Advanced Materials and they said that I didn't need to buy a pressure pot and that the mold shouldn't be getting the small bubbles that it is on the surface. Reynolds suggested I leave the mold in the sun for a few hours and that the resin I had bought was too slow of a set time and that the bubbles wouldn't form if I bought a faster setting resin. Also possibly using talcum powder on the surface of the silicone. I tried casting with a hot mold and also mixing the resin in a tub of hot water, which was recommended from a video that I found on youtube. Nothing has worked.

The silicone is Rebound 25.
The resin is Smooth-Cast 321.
I'm adding a few drops of UVO green for coloring.

My mold was a brush-on with a two-part plaster mother mold on top of it

Here is a link to my a picture on my instagram of the casting with bubbles:



I'm contemplating finding a resin-casting artist in Los Angeles that I could intern for in exchange for having access to using their vacuum pump and pressure pot.

Thank you so much for reading and have a wonderful day!

[mangozac]

Welcome to Resin Addict

Wow that's a lot of bubbles! You should be able to have less than that!

How thick is the 321 once mixed? In thicker resins it's harder for the bubbles to escape. You could try thinning with acetone. Alternatively there are "Anti-foaming" agents out there which can be added to the resin to help with this kind of thing (), although they can be difficult to get your hands on.

Talc won't help much with that kind of bubbling.

Another technique you could try is to first mix and pour a small amount of resin, pour it into the mould and then slosh it around constantly until it gels (although that will take a while with the 321 resin!). You end up coating the mould with a thin, bubble-free layer of resin. You can then pour in the rest of the resin later.

Keep us posted on your progress!

[RageofAchilles]

Hi,
Have you tried casting without the pigment? My first casts with Smooth cast 325 showed the same results as you have shown, it really didn't like pigment, even though it was designed specifically for that purpose.

also make sure your resin hasn't been sitting idle too long i.e. shake the bottles to make sure it hasn't settled.

apart from that Mangozac had a good suggestion.

And ask Reynolds if they have an antifoaming agent, they may be able to send a sample.