Hello Resin Heads! I was wondering if anyone has any tips for a fledgling resin-caster that doesn't own a pressure chamber. I've heard all kinds of crazy tips to ward off bubbles, like dunking your cup of mixed resin into ice water before pouring into the mold, taping a hair clipper to your silicone mold, tapping the sides of the mold for a few minutes... Do any of these methods actually work, though? Would roto-casting by hand be easier than trying for a bubble-less solid cast? Thanks!
It really all depends on your mold. If you have a lot of undercuts then there will be more of a chance you will get bubbles. Taping on the sides works well and so does using a toothpick to dislodge bubbles.
Thin stuff like toothpicks to dislodge bubbles and ive heard sticking the mold on a vibrating surface...
It depends on how fast your resin sets also. When Alumilite (tan) came out thats all we used and that had a fast setting time. You dont want water invading your resin or it'll foam up so I dont know about the dunking in water thing. What i did was to fill the mold up (on new molds) and see where the bubbles poped up consistently. I mix a tiny amount of resin in a cut up paper cup and prefilled the areas where the bubbles appreared consistently using a toothpick. It was labor intensive but it worked for the most bart. There was the occasional pinholes but you can minimize those by coating the inside of the mold with baby powder prior to filling. My advice is save up for a pressure pot and suitable air compressor. The amount of resin and time wasted would eventually cost as much.
You can also build a pressure pot, im sure you have seen the vids on youtube. You might as well because you will end up spending money on trial and error...
Another tip: resin viscosity and cure times are huge factors. But really everything varies by project type
I strapped an old electric toothbrush to my mould lately - hasn't eliminated bubbles altogether but has made a huge improvement. Any vibrating device that you have around the home would do just as well. Not making any assumptions here...
Honestly I would just save up and wait till you can get a pressure pot + compressor. The basic setup (harbor freight pressure pot, cheapo pancake compressor) which you can find videos of on youtube should run you less than $200 and in my opinion is well worth it. The difference in my casts was huge, and like robert said, the amount of resin you will save from better casts will break even with the setup cost.
Sadly $200 is way too much for me to be spending at the moment. Would put a serious dent in my wallet... Honestly, I'm working with opaque white resin, not looking to do clear resin or even pigmented casts. I'll be painting everything. Would bubbles still be an issue, like certain parts not filling in all the way? I heard you can make vents to get around that issue with things like hands/feet.
The filling in all the way depends on how you decide to mold your figure. And really depends on the figure itself, if its not complicated you just have to make sure everything is going with the flow of gravity (if you are molding the whole thing as one piece) in my experience ive learned that molding seperate pieces was much easier and less problems. But to be honest it comes down to how you execute the mold and how complicated/simple what it is you are molding. In the wnd without a pressure pot you will find that there will be tiny bubbles that you will fight no matter what, but I have heard from people that they get "perfect" pulls without one, its all trial and error and the materials you use. Goid luck with your project!
