Casting Parts.

[mylo]

Hey all,

I'm getting to the point in my VIIc/41 build where I'm soon going to be casting some of the parts from the masters that I have built. Can anyone provide some kind of tutorial on how to do that ? What materials I need ? Tools ? (like maybe that pressure pot thing). I would like to start gathering my supplies for this phase and educating myself on the process.

Thanks,

Mylo

[magpie]

Dave Merriman is the best

Dave Merriman is the best I know of on that subject!!!
Here's the address of his page of links to his Cabal Reports and articles. Take particular note of the 'Casting Human Heads' parts 1 & 2 on it.

http://vabiz.com/d&e/articles.html

Jason

[mylo]

Jason,

Thanks for that.

Mylo.

Jason,

Thanks for that.

Mylo.

[anonymous]

Mylo,

you can always write to

Mylo,

you can always write to me if you need. Email is best.

It's very easy to cast parts. You just need the masters. Some sulfur free clay and some good RTV. GI 1000 IMO is the very best. Easy to use. Lasts forever and is not so sensitive as some can be to even a drop of sweat. Good stuff.

As far as casting if your not going into the kit biz I would worry about the pressure pot too much although they are nice to have.

I just make one entrance to the RTV mold big enough for a syringe to fit snug. I put a couple of very small vents in the troubled areas and inject the Alumilite.

Done. the pressure pops the bubbles and you get a great piece every time.

Steve

[tmsmalley]

Here is my dirt simple

Here is my dirt simple casting setup for my work on the Alligator prototype model...




I made the appendage masters from a nifty expanded styrene product called "Sintra". It cuts and shapes easily and its fairly inexpensive. Clockwise]http://www.rc-submarines.com/Alligator_Junior/077f4910.jpg[/img]

Here are the supplies I am using to make molds of the masters so I can produce multiple copies of the parts. Lego parts make a great mold box that you can re-size to fit the part you want to duplicate. Surprisingly - the box doesn't leak if you squeeze the parts together tightly. I use Micromark mold making rubber - it works fine and you don't need to buy it in Industrial quantites for small jobs. I use Alumalite casting resin to make the part.



You are supposed to use "Klean Klay" in the base of the box in which
to press the master to make the first half, but the local hobby shop
was out so I got some nice soft Play-Doh. It took a little more time
to clean up than Klean Klay does but hey, "any port in a storm!" Be sure to push the part half way down into the clay.



Here is what the bottom of the mold looks like with the Play-Doh showing through.



I used a paintbrush handle to make dimples in the Play-Doh. The craters
will create raised bumps in the rubber mold that will lock the two halves of
the mold together in perfect "registration".




Here is the mold after the mold making material is poured in on the
top of the master part pushed half way down into the Play-Doh. The part
has a light coating of mold release painted on to keep it from sticking to
the rubber. You are supposed to pour in the RTV in a thin stream and try
to avoid mixing in a lot of bubbles. The couple that are showing popped
a second after I took this photograph.




First half done. Note the clay funnels used to make wide sprue holes to pour in the resin casting material.




Coat the rubber, master, and box with release agent...



pour in the rubber and...




...viola! you have your mold.



Then it is a simple process to cut a couple of plywood strongbacks and rubber band them around the two mold halves (to keep them from bulging out) and pour in the casting resin to make your parts.




Rudder in casting box. Note the hooked brass rod at the top of the picture. That rod creates a channel so air doesn't get trapped and create a bubble in the casting. Pour in an adequate amount of Alumalite casting resin so a little runs out all your vent holes and tap the mold on your workbench to drive out any bubbles.




And this is the rudder with the sprues still attached. Sprues are the result of excess casting medium that has filled up the vent channels. They are simply clipped off with a wire cutter.

Thanks to Matt Spade for the idea of using Legos to make the mold box!

[mylo]

Steve,

Thanks for the offer.

Steve,

Thanks for the offer. You can expect an e-mail or two from me asking questions. I value your experience and if you're giving me an open door to tap into your knowledge base.......I'll take it.

Tim,

Fantastic tutorial. That's exactly what I was looking for. A real "laymans guide to casting parts". I love your supply pics.....a shot right out of Romper Room Play-doe and Lego.....and to think my mom gave all mine away. Pretty high tech operation you got there.....I love it.

KISS principle at it's finest.

Thanks again gents.

[tmsmalley]

Me like pretty colors... http://www.subcommittee.com/forum/icon_biggrin.gif

Me like pretty colors...

[JWLaRue]

See that? Everything we needed

See that? Everything we needed to know about casting parts for R/C subs we learned in kindergarten.

(btw: I use the same 'tools' as Tim, though I use the Lego box as the strongback when casting parts.)

-Jeff

[mylo]

Well......I see a trip to

Well......I see a trip to Toys "R" Us in my future.

If I knew then ....what I know now....I would have paid more attention in Kindergarten.

Mylo.

[dietzer]

Hey Tim,

You did a great

Hey Tim,

You did a great job with your casting tutorial. Many thanks for documenting this and sharing it with us!

I was wondering if maybe a copy of this thread could be moved to the Modeling Tips and Tricks category and made sticky so that it stays at the top of the page..? This is a common enough question that it deserves to have such a well done tutorial saved where its easy to find!

Thanks,

Carl

[tmsmalley]

Thanks! I copied my post

Thanks! I copied my post and stickified it over on Modeling Tricks & Tips.
T