Ever want to make parts for spares or for additional details in a project?
Rei Villamil (aka Muttley) shares his technique for making them with Latex.

Feature

If you have comments or questions please post them here.

Thanks!

slick little way of doing things isn't it..

I've used the Latex mould method for years and there are a few things you have to watch out for:

The latex hardens by drying and not curing (RTVs cure) so shrinkage is _always_ a problem. Adding the gauze is a good way to limit shrinkage, so don't forget it. If there's no gauze, the mould will end up 2-4% smaller than the original and, for size-critical items, they just won't fit after you pour them.

Don't be tempted to lay down a lot of latex, hoping to reduce the number of layers needed to make the mould. Thicker material actually takes longer to dry than many layers of thin material.

Whenever you are finished with the mould and remove the master, let the mould sit and continue to dry on the interior surfaces for at least another day or two. Longer if you can spare the time.

The latex can be used for moulding more normal Polyeurethane resins (Alumilite and the like), just make sure you spray the mould with mould release before each and every pour. Unlike RTV, resin will stick permanently to latex moulds without a release.

Latex moulds are based on natural materials, that means over time, they will deteriorate, even if you're not using them. They will continue to shrink for some time after hardening and may actually start to rot if left in a mildew/fungous friendly environment. Bottom line is that they are not stable and shouldn't be expected to last long.

Still, they are useful and inexpensive moulds, so use them as you need them.

Paul

Very useful feature as I bought some latex on impulse recently while shopping for paintbrushes

Very Cool Technique. Thanks for the info.

This is what I don't get about many modelers: they spend thousands on kits and aftermarket accessories and then cheap out when it comes to glue, paint, brushes, airbrushes and casting supplies.

Come on, why waste an inordinate amount of time trying to brush yukky and stinky latex in every nook and cranny of your master, wait days for it to fully dry and then end up with sub-standard (and possibly under-scale, due to shrinkage) parts made of (ugh) glue, when for a mere $30 you can get enough RTV silicon rubber and Alumilite to easily and "professionally" cast your small parts for months, if not an entire year?

http://www.alumilite.com/ProdDetail.cfm?Category=Starter%20Kits&Name=Mini%20Casting%20Kit

t34-85,

First of all I dont spend thousands on kits and aftermarkets, in fact I dont even use aftermarkets on my models, I improvise or "scratchbuild" which is actually an older practice in modeling before aftermarkets came out.

Sorry to say but, every model hobbyist has every right on how to spend their money to get the job done the way they want it- and no that is not "cheaping out" - its being practical and at times creative.

I put up this article simply to offer others an old technique that they can try out if they want to, and not to tell them this is the only way to go and push them to it. It is an OPTION should you want to accept it or not.

Lastly, a jar of latex from the art store is about $5.00, still around $25 less than your Alumilite and this jar can last longer and make more simple molds, which is what this article is pointing out, making simple molds for simple parts. You wanna spend $30 to cast a simple flat 2 inch piece of a 1/35 scale Sherman then by all means go for it!

Hey Scott thanks for the idear, Been looking at makeing molds for some time now might play around with it a see what we come up with

Easier to use Alumilite RTV Molding rubber to make the master mold, then Alumilite 2 part plastic to duplicate.

^^Ditto^^

I don't see the point in this time consuming and imprecise method. I'll stick with RTV rubber and 2-part casting resins.

Well the point is there are those who don't want to spend whatever amount the Alumilite package goes for these days only to use it for a few small parts. In my case, I'd be paying upwards of 50 euros for a similar package that would need to be used within a month or two, not going to happen unless I'm planning on casting a lot of stuff. Additionally, the latex makes a pretty good masking liquid and can be used to make torn tarps and so. Just because you find it pointless, doesn't make it so for others. You could just as easily have said why bother messing about with casting? Just pay someone a hundred bucks to do it for you.

Kimmo