Can anyone give me some advice on getting the materials I need to copy some parts that I need?
Thanks in advance.
You will need:
Material to make a box to make the mold in it.
Silicon or RTV rubber to make the mold itself.
Resin to cast the part.
Depending on if you want to do a 1-part or a 2-part mold there will be other materials that you will need(like non-drying clay, Vaseline, etc).
For most parts a release agent will not be needed.
Here is an extensive article on mold making and casting from Armorama. It should point you in the right direction and give you all the details you need. It is really pretty easy when you get the hang of it.
http://www.armorama.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=469
Good luck.
The article that HeavArty is pretty comprehensive.
A few things I would like to mention in connection with it.
1.) You can make your Mold box from Lego bricks, I do that and it works well.
2.) Rather than using a wooden stick to mix the stuff hit the chemical supply store and
get glass sticks. They are very easy to clean(wipe and you are done), they also have the advantage of a very smooht sruface which DOES NOT trap air on it that gets transfered into the rubber and resin while mixing.
3.) Clamping pressure on the mold is important too light and resin will get betwen the mold halves and create flash, too strong and your part might be distorted and get a bad mold-line.
4.) When pouring the resin pour it slowly into the mold, alternatively let it run down one of the glass sticks into the pour hole, this will reduce the amount of air getting into the resin.
5.) Once poured tap the mold slightly on the table this will help the trapped air to collect together and allow it to escape the resin and mold. Slower curing Resin will also aid this process.
6.) If you have problems with bubbles or resin not getting in part sof your mold than you have trapped air and will need to drill small venting holes. You can do those with a pinvise.
One final thing hardly ever mentioned.
The smoother your original part the better the mold will be and the easier the casted part will pop out of the mold.
Rough surfaces will result in excess trapped air and the rubber wil get a stronger grip on the cast part. Here is where a release agent will help.
Lastly moisture and liquid resin DO NOT go together, if you have any moisture in the mold or too much humidity you will experience bubbling of the resin(fun to watch when the bubles overflow the mold)
HTH.
Check out Micro-mark’s web site, they have a starter set with pretty much everything you need to get going for about $85 US. I got it for Chrsitmas and got some great sprockets on the second pouring. It’s opened up a whole new ball game in modelling for me.
Thanks for all of the help guys. The link was terrific HeavyArty, and the extra tips VERY helpful Model Museum. Spamicus, I got the Micro-Mark stuff from my LHS today and I’m planning on throwing something down tonight, though I feel as though I out to start with a spare part or something first so I don’t ruin anything I need.
I do still have a couple of questions though . . .
I’m sure there’s a reason (I can think of a couple of possibilities), but, what about plaster molds? Also, I was told not to use sculpey when making the mold, but that it’s good for masters (thoughts, opinions?). What is Kleen Klay and where can I get it? My LHS had reservations about me using petroleum jelly for mold release and instead sold me on some (expensive) Micro-Mark mold release agent (thoughts?).
Thanks again.
Also try www.hirstarts.com. It has extensive articles on mold making and casting.If you get really frustrated and can’t get it right. Send me an e-mail; I’ll be glad to help out.
Excellent, thanks again guys. I just pulled my first roadwheels out of the mold, and now things are really ticking. I think I’m going to start having a lot more fun now!