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Ok guys, as I have received a bunch of emails from members since I posted in a thread that I would repo a Jrx2 body, I propose to make all my available info public. I'm far from being an expert, so any contribution/comments/experiences here would be much appreciated...


The best thing to mold a body is very thin particle plaster (like molding plaster), you don't have to use any releasing agent, the body should come off easily and unharmed if you do it right.

Here are a few links, though some in French, but most of the pictures speak for themselves.

http://www93.sakura.ne.jp/%7etime-tunne ... dy-01.html

http://www.rc-scale.com/francais/_model ... ge_p1.html

http://membres.lycos.fr/crook77/newpage.html

http://rcmag.com/reviews/technique/dive ... dial05.htm

And here is a picture of what a friend of mine did, as you can see the result is pretty good:





I hope this can help!

Cheers,

David

How durable is the mould once made it this material? How many bodies can be pulled from it?
I'm interested in making some wings, but need the mould to be durable, is there a better material?

Thanks for the info.

Cheers,

G

I guess you can make about 10 to 20 bodies out of it, depending on the power of the vacuum molding device you use... A better material would be wood, but that's another story and different skills involved... When I started browsing Ebay a long time ago, I saw a Protech I body "mould" completely made out of wood, it also had a stand, that thing was a pure work of art, too bad I didn't bid on that

If you want something durable that's going to be capable of standing up to a production run you really need an industrial grade urethane tooling resin. I've been quoted a trade price of £42 per kg (you need 2-3kg per body) for a minimum order of 5kg.

If you aren't moulding anything then wood can be used to carve to shape. I recommend using jelutong, hard to get hold of these days (not many places stock it) but it is knot and grain free and using a timber sealer you can get a really great finish on it for vac forming.

I've been thinking about trying to use fiberglass epoxy. Anyone have any luck with that? Wondering how to get it to not bond to the body.

you should be able to save money on resin but inserting some dowel's or "dead space" (small container or something) into the bottom of the mold to save alot of excess casting material.

i was screwing around with my crappy forming machine, and found that even a small decent handheld vaccuum works just as well as my high power shop vac to be honest. i think the stronger vaccuum actually pulled the material harder and made it too thin. this was with crappy plaster molds i made that looks like they would definetly stand up to alot of pulls, not thousands but i cant imagine not being about to get at least 50+ from them.. although i could be wrong.

Erich Reichert wrote:I've been thinking about trying to use fiberglass epoxy. Anyone have any luck with that? Wondering how to get it to not bond to the body.

I have a driver I did using fg epoxy and it came out OK. I did a couple repos and they looked real good. The only problem I had was impatience. I pulled the glass way to early and the mold was sticky and ruined the original part. I think if it had dried thoroughly, pulling it would not have been a problem.

I use plater of paris for the bodies. The wings are tough because the sides are thin.

Tadracket wrote:I have a driver I did using fg epoxy and it came out OK. I did a couple repos and they looked real good. The only problem I had was impatience. I pulled the glass way to early and the mold was sticky and ruined the original part. I think if it had dried thoroughly, pulling it would not have been a problem.

I use plater of paris for the bodies. The wings are tough because the sides are thin.

Tad did how did you get the epoxy to not stick to the lexan? Did you have to put something on it?

I was thinking of using a professional grade of epoxy body filler (bondo) but need a good release agent. I think just about anything silicone would work. It would be easy since you can get silicone in spray cans. Your thoughts?

NEVER use silicone on anything you want to eventually paint. if there's any (and there will be) residue left on the inside of the body, your gonna have problems.

silicone + paint = BIG 'ol problems

Erich Reichert wrote:

Tadracket wrote:I have a driver I did using fg epoxy and it came out OK. I did a couple repos and they looked real good. The only problem I had was impatience. I pulled the glass way to early and the mold was sticky and ruined the original part. I think if it had dried thoroughly, pulling it would not have been a problem.

I use plater of paris for the bodies. The wings are tough because the sides are thin.

Tad did how did you get the epoxy to not stick to the lexan? Did you have to put something on it?

I think it is the natural desire to not stick on the part of the lexan. If the lexan has no scratches on it, the epoxy really has nothing to get hold of. I pulled the part way too soon, maybe that helped but I would like to think the longer it sets, the easier it is to remove. Think about a mixing cup or coffee can lid. When I use those to mix epoxy, after the drying is done, I just twist the cup or lid, breaking the connection and popping out the hard epoxy. I think the lexan will work the same way.

I'll give it a try this weekend with a spur cover. I have been wanting to make some of those. On second thought, I'll poor it tonight and pop it tomorrow night, giving it 24 hours to set. I think it will work.

I just remembered something I did do a few months ago. I took 2 sheets of acrylic, some fiberglass, epoxy resin and RIT dye and made some really cool fiberglass sheets. I laid one piece of acrylic down, mixed up some epoxy and added a few drops of RIT to darken the mix. Then I brushed on the resin, then laid glass, then resin etc. I built up about 8 sheet then laid the other piece of acrylic on top and laid some weight on it. In a few hour, I had a beautiful black piece of fiberglass where the fibers could be seen through the resin because I only used a couple drops. The mix was transparent. And because of the acrylics slick texture, it pulled right apart and the fiberglass had the same surface texture as glass. It was awesome. Then I chewed it up in my chop saw

scr8p wrote:NEVER use silicone on anything you want to eventually paint. if there's any (and there will be) residue left on the inside of the body, your gonna have problems.

silicone + paint = BIG 'ol problems

Good point!

I tried some resin body filler and it stuck like crap to a blanket to the lexan, and made it go cloudy

G