Duplicating plastic parts

[aurfalien]

Hi,

I've read a few posts with regards to casting parts.

I was wondering if Alumilite would be good for casting based on a plastic part that I already have.

Basically I was missing those parts from this kit and bought another one just for them.

To make the most of my situation, I'd like to see if I can have 2 complete kits.

Attached is a pic, parts A7 and A8 are what I'd like to duplicate.

It's a 1/24 scale Fujimi Chaparral 2D.

If you'd be so kind as to letting me know your approach to this, I would be grateful.

It seems I keep posting odd dilemmas but believe you me, I'd much rather things go smoothly. However its like a crash course if you will.

Edited June 2, 2015 by aurfalien

[Ace-Garageguy]

I haven't used Alumalite specifically, HOWEVER...ALL the common silicone-mold / urethane-part ("resin") casting products use similar chemistry and procedures.

I have used a number of products made by Freeman Manufacturing for professional model building, prototyping, and mold-making / casting. If you need information, they have a FREE online series of instructional videos, here... http://www.freemansupply.com/video.htm

Smooth-On also has a collection of how-to videos here... http://www.smooth-on.com/media.php

[Ace-Garageguy]

And here's an entire thread about casting resin parts: http://www.modelcarsmag.com/forums/index.php?showtopic=74224&hl=video#entry936252

[aurfalien]

Bayam, a-sha-weeeeet! thanks ace, much appreciated.

[Crazy Ed]

You might check around and see if there's someone in your area with a Vac - u - Form type of machine and just try to make replacements out of styrene! They'd be a touch large but should be serviceable.

[aurfalien]

That's an interesting idea Crazy Ed.

Taking it a step further, do you know any one who provides such a service were I simply send them the parts needed to be copied?

[Ace-Garageguy]

Taking it a step further, do you know any one who provides such a service were I simply send them the parts needed to be copied?

I'd think it would be cheaper to just buy another kit. There's the mold-making step that takes some skill and judgment, and then the casting of the part itself. This is complicated further if the part requires a two-part mold.

Vacuum molding also takes skill, and it would only be appropriate for gently curved parts with no undercuts or mold seams; a vacuum molded part will also always be either larger or smaller...by the thickness of the material, at least... than the original part, if the original is used for the mold. To get a vacuum-molded part that is the same size as the original, another additional precision step or 2 would be required.

Skilled labor costs money...especially when you only want one of anything.

Edited June 2, 2015 by Ace-Garageguy

[aurfalien]

Good points as usual. Thanks man.

[Kit Basher]

If you would like to learn casting just for the fun of it (I personally think it is a lot of fun), then you could definitely cast those parts. It would be a bit tricky because there are some undercuts, and it would have to be a two part mold. Maybe not the best choice for your first attempt, but with some experience you could get there. I am no casting expert, I've just been fooling around with it, but I've used both Smooth On and Alumilite, and both have worked well for me. For starting out I would recommend Alumilite, just because they sell smaller quantities of the mold rubber, and mold rubber has a fairly short shelf life once you open it.

[aurfalien]

Hey Kit Basher, with the Alumilite, it seems one must buy the resin mix separate from the molding putty correct?

I'm seeing this resin kit;

http://www.ebay.com/itm/281352856869?_trksid=p2060353.m1438.l2648&ssPageName=STRK%3AMEBIDX%3AIT

And this molding kit;

http://www.ebay.com/itm/301642902662?_trksid=p2060353.m1438.l2648&ssPageName=STRK%3AMEBIDX%3AIT

Edited June 4, 2015 by aurfalien

[Kit Basher]

Hey Brian. I've been buying Alumilite at Hobby Lobby with their 40% off coupon. They have this starter kit http://shop.hobbylobby.com/products/mini-casting-kit-579714/. The only problem with it is that it does not include mold release, a necessity for two part molds. They do have the mold release as a separate item.

They also have this http://shop.hobbylobby.com/products/super-casting-kit-580068/ which has everything you need.

I started out with a Smooth On kit, but the rubber went bad before I could use it all. The resin was still good, so I've been buying this http://shop.hobbylobby.com/products/quick-set-rubber-579599/. I usually use it up before it goes bad. If you end up making a lot of molds, or big ones, I think the Smooth On kit is more cost effective, even without the 40% coupon. Like I said before, I'm no expert, but if you ask a question I actually know the answer to, I'll be glad to help.

[aurfalien]

Thanks KB, I picked up the kit at Hobby Lobby w/coupon!

By the way, have you used Smooth-On mold release by chance? Is the Alumilite mold release as good as the Smooth-On?

[Kit Basher]

Both mold releases seem to work fine. The Alumilite one is a bit more stinky.