"Pressure casting opne face molds? " Topic
10 Posts
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Dr Mathias  | 21 Oct 2013 10:32 a.m. PST |
Hello,
I'm working on a conversion part and I think it can be cast using a one part open face mold. It does have some detail though and I am concerned about bubbles. I have a vacuum chamber, and yesterday I picked up a pressure pot, and I was wondering what would happen if I pressurize an open face mold. Do people that cast custom bases and other parts from one part molds use pressure casting? Thanks! EDIT: Apologies for the typo in the title :( |
| Jeff W | 21 Oct 2013 11:05 a.m. PST |
Did you vacuum de-gas the rubber when you poured the mold? If you did it will be fine, otherwise it may deform. Jeff |
| captain canada | 21 Oct 2013 11:24 a.m. PST |
Yes I use pressure for one faced mold. It works fine and I wouldn't do it any other way now.
KAM
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| Tango India Mike | 21 Oct 2013 11:26 a.m. PST |
I only use vacuum, not pressure for my casting. So I don't have personal experience of pressure casting but I understand from what I've read on casting discussion forums that it should be fine, taking Jeff's point into account. I'm sure Jeff has more experience than me.
Tim |
| Dr Mathias | 21 Oct 2013 11:54 a.m. PST |
Jeff, I degassed most of my molds. For this project I intend to de-gas and I've read that it's also a good idea to cure the mold under pressure too, so that it behaves properly under pressure. The molds I have made so far are pretty much just for open face 'Hirst Art' style plaster casting so those won't need pressure casting. One of the reasons I bought a pressure pot is because I sculpted some African shields with feathers and they're just not filling well with simple gravity casting and there's only so much gating I can do. Those are two-part molds and it got me wondering about pressure casting molds with a lot of resin surface area after the pour. |
| Jeff W | 21 Oct 2013 12:08 p.m. PST |
Are you making top-pour molds, Dr M? Most of my two-part molds are now made to fill from the bottom (envision a barometer?). It helps to eliminate some trapped air during the pour. Combined with a pressure pot, it gives pretty good results. I've been casting my own 15mm sci fi figs for myself recently. |
| Dr Mathias | 21 Oct 2013 1:11 p.m. PST |
Yes, they're top pour. I'm curious how a bottom pour would even be possible. Seems like you'd need to inject that way? Clearly I need to do some research :) |
| Jeff W | 21 Oct 2013 1:28 p.m. PST |
This has a pretty good explanation: link Scroll down to the two-part, underpoured mold graphic. |
| Tango India Mike | 21 Oct 2013 2:27 p.m. PST |
Great link, think I'll bookmark that one. |
| Dr Mathias | 21 Oct 2013 3:59 p.m. PST |
That makes sense, thanks for the link. Very useful! |
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