I’ve had a potential project kicking around for a little while that I thought I might get some feedback on from the brain trust.
I’ve got a few small items that I’m interested in casting in a cube or other shape of clear resin. They’re not flat, so it would have to be at least a couple inches deep, probably a 4-5" cube most likely. For those of y’all who work with resin, do you think it would be feasible to just use a regular deep pour epoxy and set them in between a couple of pours of it? My main concern is bubbles in the epoxy since I want it to look good and not bad.
Any thoughts off the top of your heads on the best way to approach this?
Ok tips for mitigating bubbles without investing in a pressure pot (the only way to truly get a bubble free project consistently).
Mix slowly so as to avoid folding air in, then take your mixing vessel and put it in a bowl of warm water to encourage the bubbles to the surface, use a lighter or heat gun to pop the bubbles.
Pour slowly down a popsicle stick or something similar.
If you want to make a smaller investment than the pressure chamber, you can buy a cheap-ish vacuum chamber off Amazon and that will help to remove a decent amount of your bubbles from the mix.
Very helpful, thank you. I was wondering whether or not a chamber of some sort would be required, but it sounds like if I’m careful, I can at least mitigate most of the bubbles by just taking my time and doing it right.
For something this small that’s just for me anyway, that’s probably what I’ll end up doing.
If the stuff I’m trying to put in the resin is mostly hollow, is it safe to assume I’ll want to fill any voids with epoxy first before flooding whatever mold I put them in?
That would probably be a good idea, or at least painting a thin layer of epoxy on it first, for whatever reason that seems to help as well.
I should caution that the warm water bath is very helpful but epoxy and water don’t get along well, so be careful that the water does not get into your epoxy.
Bubbles can be created pouring too fast and in so doing trap a pocket of air (bubble). Prior advice to mix carefully is good advice and allowing the viscous liquid to fill voids and all air escape pockets in the model - or prep the model so there are no overhangs.
Putting a mold assembly in a vacuum chambers will cause any bubble to expand in size increasing it’s boyancy in the resin and cause it to float. Micro bubbles can cause cloudy pours. A pressure pot will decrease the size of the bubbles. I don’t have one.
I have a couple of tips / things to watch out for:
If the objects are heavier than resin and you run the risk of them sinking to the bottom of your mould, you might have to do the pours in two (or more) layers. Avoiding the witness lines where the layers meet could be tricky, but you’re looking for the lower layer to reach the “barely set” or vaguely gelatinous (for lack of a better word) stage. Then you can set the object on top without it sinking into the resin, and do the second pour.
Another option is to create a thin “post” for your object to hold it up, then follow it with the main pour. Doing this would avoid the horizontal witness line, but it does run the risk of making the post somewhat visible. If you have the time/resin to spare, I suggest testing it out.
I did use a Harbor Freight paint tank modified into a pressure pot in order to minimize bubbles. There are plenty of how-tos on how to do it out there, but it’s still… kinda sketchy.