Help with Mold Making

[Cregan Tur]

I know we've got a few members on this forum who are in the business of miniature making, and probably others who have a lot of knowledge to offer, so I'm hoping you guys can help me out.

I've made a few silicon molds, but I can't get consistent quality reproductions out of them. I'm using Hardcast resin from SilPak; I use their mold release spray to coat the molds before casting.

I think part of the problem might be my design and placement of the pour hole and air holes in the mold... but I'm not sure.

Do you guys have any resources on mold making you could point me to, or any advice? If you want me to provide more information about my molds or pictures, let me know and I'll post them.

[Darklord]

i dont know much about this kind of stuff but i think a lot use something to vibrate the resin when poured as this removes the air bubbles. i usde to have a link for a great article on it but on the old comp - ill fire it up and see if i can grab it for you if noone else can help

[ScottRadom]

THE dude to ask is Jeff Willhelm from Dragon Forge designs. I've yet to find an air bubble yet in any of his stuff. He posts on CMON, and is extremely friendly. Or at the veyr least he can point you in the right direction.

I heard setting some glass on top of the mold helps, but don't ask me why.

[Cregan Tur]

I heard setting some glass on top of the mold helps, but don't ask me why.

I know this is true for single piece pour molds- it allows you to keep the side with the glass on it completely flat, instead of curving natually the way pooled liquid does. It can also be used to slide an air bubble out of the mold if the glass has been coated with release properly and you do it early enough in the cure cycle.

What's Jeff's handle over at CMON, so I cam send him a PM?

[Darklord]

dragonforgedesign

[Cregan Tur]

Jeff got back to me with some good advice that I'll share.

First he told me to look into what's called Resin Pressure Casting- he apparently uses this for all his castings. You can find a lot of info on it through google. Everything I'd need to create my own pressure pot, however, would take a bit of money.

He also said that ideally resin should be filling up the mold from the bottom so that it can push out the air easier. His suggestion was creating some sprue in the shape of a 'J'. This is one idea I'll definately be using.

Oh, and he also suggested using resin with a longer cure time (the hardcast I'm using sets in 15 minutes). That way gravity has longer to work on any bubbles you don't get out by shaking/vibrating the mold.

[Darklord]

good advice.
what is it your casting cregan?

[Cregan Tur]

what is it your casting cregan?

For now I'm going to remold the London Cobblestone base I created for my Fury of Dracula project and see if I can consistently get quality reproductions. I might do another base or two after that for some more practice... not sure yet.

My ultimate goal is to eventually mold and cast some minis I'm currently sculpting.

[ScottRadom]

Glad he could help you. Jeff really is a great find! I've been using his bases for since I discovered them about a year ago and I love everything about doing business with him.

Also, he is a former slayer sword winner and bagged some more demons this year, so he's no slouch with a brush!

[poots]

Another resource you might want to look into...

www.smooth-on.com

And a little bit more useful,
http://sculpt.com/

Its a link to a store here in New York called the compleat sculptor. They carry a pre-made pressure chamber along with both a pressurizer and a vacuum pump. According to them you use the vacuum during mold making to ensure that no air gets trapped. Then when your casting you use the pressure chamber during resin casts like you said.