Attempts at casting my own 28mm miniature sculpts so far...

[space corsair]

Greetings! I'm a sculptor of 28m miniatures looking to learn how to improve my knowledge of resin casting.

I tried resin casting several years ago and gave up after a few casting attempts when they turned out full of air bubbles:

http://battlesuits.blogspot.com/2012/01 ... aking.html
http://battlesuits.blogspot.com/2012/01 ... sting.html

Eventually, I found a caster who was willing to cast them for me instead:

http://battlesuits.blogspot.com/2012/02 ... ine47.html

Then I left the hobby for a couple years and lost touch with my caster.

Recently I got around to trying my hand at mold making and resin casting on my own again, this time with a pressure pot and compressor set up:

http://battlesuits.blogspot.com/2015/10 ... -clay.html

While the overall quality of the casts has improved, I still have some air bubbles at the toes and other extremities:

http://battlesuits.blogspot.com/2015/11 ... rtles.html

While my main interest is sculpting miniatures, I want to be able to share my minis with others. I'd appreciate any advice or constructive criticism you can offer to improve my skill and knowledge at mold making and casting of miniature figures.

Thanks!

[mangozac]

Hi Space Corsair, welcome to RA!

Your sculpting looks great, so it's awesome to see you duplicating them! It sounds like you've got a pretty good handle on the casting process - the compressor and pressure pot have been the first big step to improving cast quality.

It looks like you've already worked out venting techniques. You may have more success having the resin enter through the bottom of the figure and only vent through the top. Otherwise the only other way to get perfect results would be to add a vacuum pump to your equipment. You already have a reservoir built into the moulds so they should work as is with combination vacuum and pressure casting

[space corsair]

Thanks for your reply and kind words about my sculpting.

Reservoir in the moulds? Is that what that's there for?

I bought the moulds of my female marine figures from my old caster and I've using them as reference in making mine. Her molds all had that space at the top so I just put it on my mold too. I had no idea that the space at the top of the mold was for vacuum casting!

So, do you pour the resin into the mould first, then put into the vacuum chamber? I had thought that you vacuumed the resin prior to pouring it in the mould. I take it the reservoir prevents the resin from overflowing when it rises?

If using a vacuum pump will help get rid of those pesky bubbles at the toes and noses on my casts, I'm all over it

[mangozac]

Hahaha you're on to it!

You hook the vacuum pump up to you pressure pot (it can handle both pressure and vacuum). The process is then:

1. Mix resin and pour into mould
2. Place mould into chamber and apply vacuum
3. Once a deep enough vacuum has been reached apply pressure
4. Leave under pressure until cured

You will get flawless casts every time

Correct, the reservoir allows the resin to expand while being vacuumed. You get used to estimating the required reservoir volume as it's closely related to the part volume.

[Fleafa]

Loving the turtles!