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www.TK560.com Vacuum Forming, Movie Prop, Sci-fi and GIjOE Forum
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jegner Site Admin
Joined: 30 May 2003 Posts: 2144 Location: Texas, USA
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Posted: Tue Oct 31, 2006 10:24 am Post subject: Molds to be reworked. |
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Well, I pulled a suit over the last couple of weeks and realized my molds have had it. The all need major repairs, and some need to be resculpted completely. Looks like my Fall and Winter are going to be spent in the workshop.
The chest mold needs the most work as a resculpt. My version is too flat, and needs more of a round body.
The thighs need more 'meat' and the ends need to be reworked to be more screen accurate.
The biceps are breaking apart, and just need a total rebuild. The shoulders have too steep of a curve, and need to be rebuilt with a better taper.
The shins need some fine tuning, and the collars need to be resculpted this time with arches.
Oh, by. |
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dman Novice
Joined: 09 Oct 2006 Posts: 34
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Posted: Tue Oct 31, 2006 11:26 am Post subject: |
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LOL I hear ya. I've been thinking about making a new mold. My lights are selling pretty good and if my molds screw up, I'm in bad shape. I think I read that fiberglass molds are the best. Is there a decent way to make a fiberglass mold exactly like my mdf ones or do they need to be made from scratch? |
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jegner Site Admin
Joined: 30 May 2003 Posts: 2144 Location: Texas, USA
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Posted: Tue Oct 31, 2006 11:55 am Post subject: |
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pull a sheet of .060 or even .040 HIPs over your mold, then lay up some fiberglass resin [be sure to use mold release] and once that sets, then do up the glass mat, and do this in several layers. Remove the .060 or .040 HIPs and volia! |
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knightshade Expert
Joined: 19 Jun 2005 Posts: 123 Location: Rochester NY
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Posted: Tue Oct 31, 2006 12:04 pm Post subject: |
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I've converted a few of my molds to fiberglass....
Basically - I made pull of my existing mold using styrene
Coated the inside of that pull with vaseline..
Fiberglassed the inside (~1/4"-1/2 thick)
My experience is that the styrene slightly bonds to the fiberglass, but will seperate without to much effort.
The surface of the new mold is somewhat pitted - and needs a very good sanding.
If you had any air bubbles, you may need to fill them in. (Bondo or fiberglass resin work well.)
Hope that helps!
So far, I've not had any of my fiberglass molds damaged - but I haven't given them that much of a workout yet.
(LOL - Jim posted as I was typing) |
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TK 109 Guru
Joined: 11 May 2007 Posts: 712 Location: Galena, Ohio
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Posted: Mon May 14, 2007 4:53 pm Post subject: |
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i pulled my suit, and realized i looked like a mutant football player...
i'm trying to rework the molds to make me look better, and to conform to the new stuff, ie the boots...
the calves are really "kicking my butt!" (quote from Jim), the contour is so confusing... maybe i'm thinking too hard... _________________ -Alex
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jzawacki Novice
Joined: 12 Jan 2007 Posts: 70 Location: Illinois
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Posted: Tue May 15, 2007 7:26 am Post subject: |
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Try gelcoat on your pull when setting up the fiberglass. This is the release agent I have read the most about when working with fiberglass, and is what was on my professional ground effects for my car. |
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drcrash Guru
Joined: 04 Sep 2006 Posts: 705 Location: Austin, Texas
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Posted: Tue May 15, 2007 8:02 am Post subject: |
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jzawacki wrote: | Try gelcoat on your pull when setting up the fiberglass. This is the release agent I have read the most about when working with fiberglass, and is what was on my professional ground effects for my car. |
Ummm... gelcoat isn't a release agent. It's a layer of unfilled resin that you put on the mold before laying up the cloth, so that you have a layer of solid plastic on the outside.
The normal thing for fiberglass parts is that you put mold release on the mold, then paint a layer of gel coat on, being careful to get rid of any bubbles before it sets. Then you wet it with more resin put on cloth, wet that out, and repeat until you have as many layers as you want.
For making vacuum forming bucks (molds) this is a bit tricky---which is one reason I haven't actually done it yet and am talking out my ass. If you don't have a perfect mold and intend to sand and fill the cast buck, you may not want to use conventional gel coat---unfilled resin is really hard to sand. (That's why Bondo has microballoons in it---so that it won't be solid plastic, and is lighter and easier to work.)
The basic idea seems right, though. You could put on a layer of bondo, maybe thinned with a little extra resin to make it easier to get the bubbles out. (But not too much, because you don't want the result to be unsandable.) Then you could lay up cloth... or maybe just slather on Bondo-Glass, which is Bondo (polyester) resin plus short glass fibers rather than microballoons. The glass fibers make it way stronger than regular bondo, so you may not need to lay up glass cloth at all. (Or you could do a layer or two of cloth, a thickish layer of Bondo-Glass, and another layer or two of cloth. _________________ Paul (a.k.a. Dr. Crash)
Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com |
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jzawacki Novice
Joined: 12 Jan 2007 Posts: 70 Location: Illinois
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Posted: Tue May 15, 2007 10:31 am Post subject: |
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Hmm.. I thought the gelcoat was the reason the paint wouldn't stick. I guess it must have something else on it. |
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drcrash Guru
Joined: 04 Sep 2006 Posts: 705 Location: Austin, Texas
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Posted: Tue May 15, 2007 11:19 am Post subject: |
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BTW, if you're content with a plaster-or-something cast buck, and only getting one or two copies, an easy and moderately-priced way to copy an existing buck or a new clay sculpt is using alginate, like lifecasters use.
Alginate is not exactly cheap, but it's a lot cheaper than 2-part silicone. It's made from seaweed, and is like super-Jello. You mix it with water, smear it over your thing, and then make a plaster bandage mother mold around that, like you would with silicone. It sets up to a rubbery consistency in a few minutes.
The downsides are that
1. you have to use it right away, because it's full of water and starts shrinking. You can usually pour two, maybe three copies in it, and that's about it.
2. you can't cast resins in it. (But it works very well for plaster or water putty or gypsum cements like Hydrocal or Ultracal.)
Alginate captures incredibly fine detail, much like silicone.
My wife uses it for copying face casts and modeling clay mask sculpts. For a normal face-sized mask, you need about $5 worth of slow-setting alginate. (Which is less than the cost of the water putty she usually casts in it, and a fraction of the price of silicone.)
My wife's got some nice pictures of this process that I can post when I get ahold of them. _________________ Paul (a.k.a. Dr. Crash)
Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com |
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gobler Novice
Joined: 23 Mar 2007 Posts: 30 Location: So Cal
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Posted: Sat May 19, 2007 6:28 pm Post subject: |
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drcrash wrote: |
The downsides are that
2. you can't cast resins in it. (But it works very well for plaster or water putty or gypsum cements like Hydrocal or Ultracal.)
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drcrash, you are spot on with the description and uses of alginate. I must point out there is one urethane that does set up with alginate. BJBs TC1630 works wonders. It makes a great surface coat for vac bucks. I use it for loads of other things as well so it fills lots of uses.
Cheers,
Jeff _________________ Hey, how hot does this plastic get?.....Holly JEEEZZ it burns!!!! |
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drcrash Guru
Joined: 04 Sep 2006 Posts: 705 Location: Austin, Texas
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Posted: Sun May 20, 2007 3:22 pm Post subject: |
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gobler wrote: |
drcrash, you are spot on with the description and uses of alginate. I must point out there is one urethane that does set up with alginate. BJBs TC1630 works wonders. It makes a great surface coat for vac bucks. I use it for loads of other things as well so it fills lots of uses.
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That's VERY interesting. There may be other urethanes it works with. I might be confused because it doesn't work with two peculiar urethanes we've bought but haven't tried yet. One has water in it, and after you cast it, it shrinks, so you can use it to scale stuff down. The other is hygroscopic, and after you cast it, you can soak it in water so that it swells up and scales stuff up. (Then you generally cast a new mold from the shrunken or enlarged thing, and make the final version in whatever you want.) Of course, those urethanes would be sensitive to the water in the mold alginate.. But if one urethane works, maybe there are others. Cool!
I'll check out the TC1630. _________________ Paul (a.k.a. Dr. Crash)
Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com |
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drcrash Guru
Joined: 04 Sep 2006 Posts: 705 Location: Austin, Texas
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Posted: Mon Jun 18, 2007 12:56 pm Post subject: |
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I did a little googling, and found some people saying that alginate molds generally do work for fast-setting urethanes. Cool. _________________ Paul (a.k.a. Dr. Crash)
Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com |
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