So I picked up some molds

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So I picked up some molds

Postby cagee13 » Wed Nov 21, 2012 1:35 pm

In my quest to learn how to resin cast I picked up a few molds about a week ago from Rixvette over on SCI. I'm still in the process of learning just how to do this right but I'm fairly happy with the progress that I'm making. I've received some excellent help from people from the forums. I've tried to pressure cast in the molds but believe the molds have some small air bubbles in them. So I've started to do some squash casting with them which makes a smoother outside surface but allows voids in some smaller areas. Here are some that I have popped out of the molds so far.

The Lola GT was cast in the pressure pot and shows some "warts" on the outside of the body. The detail is really good except for those "warts".
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The Aston Martin was cast by just squishing the two mold halves together. It allowed a few voids but has a much smoother outside appearance.
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The Porsche has come out ok. I tried to pressure it the first time and it came out looking like the Lola but I have been struggling to keep the air bubbles out of the lower marker lights when just squash casting.
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Open to some feedback. I have really enjoyed watching these come out the mold every time. What do you guys think so far?
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Re: So I picked up some molds

Postby dreinecke » Wed Nov 21, 2012 1:53 pm

With the way that looks, it appears that the silicone was not de-gassed before pouring over the master. As a result, air bubbles in the silicone can form against the body, creating areas for the resin to be trapped when casting resin. No amount of pressure casting will get rid of it as those air pockets exist in the mold.

This why I won't use other people's stuff - you have no guarantee how they made it or the quality of the mold.
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Re: So I picked up some molds

Postby cagee13 » Wed Nov 21, 2012 2:27 pm

That is what I was thinking about the mold. I'm not gonna be too picky because the purchase of the molds were cheaper than getting a master. I plan on cleaning one of these up and trying to make a new mold in the future but for now it is interesting just to see what comes out.
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Re: So I picked up some molds

Postby HomeRacingWorld » Wed Nov 21, 2012 2:44 pm

The little bathtub looks good to me. I see a Slot Classic/PCS (whatever you want to call it) easily under that :)
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Re: So I picked up some molds

Postby Dangermouse » Wed Nov 21, 2012 3:36 pm

Are you planning on offering any of these bodies for sale?

I had thought about getting the Lola off Rixvette when he was selling them on SCI - but the timing didn't work out...

cheers
David
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Re: So I picked up some molds

Postby waaytoomuchintothis » Wed Nov 21, 2012 4:04 pm

I love that Lola GT, warts and all. I'd love to get my hands on one of those. And who can resist a 356?
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Re: So I picked up some molds

Postby ddyke » Wed Nov 21, 2012 5:29 pm

On making a master, cast it solid as it will not flex as you work on it. I would make my next cast the master as these types of bubles started appearing on molds at the end of their life.
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Re: So I picked up some molds

Postby dreinecke » Wed Nov 21, 2012 11:41 pm

Chris - you'll also get similar warts when the mold goes bad and rubber starts to chunk and the mold starts to crack. Those really mess things up. As for solid masters - I'll never use them. Too hard to turn into 2 part molds, but I know they work well for others.
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