24 replies to this topic

[alarmstrong]

This is how I've been casting my engines. Block and all components are cast as individual pieces. Some are tougher to do than others! LOL If you have any questions, feel free to ask...

Is there any special prep to resin cast parts for painting? I.E. do I need to primer before painting or wash in any special way?

[1320wayne]

Is there any special prep to resin cast parts for painting? I.E. do I need to primer before painting or wash in any special way?

It's always best to thoroughly wash each part that you cast and add a coat of primer before painting. Resins have an oil base to them that need to be washed away as well as any mold release chemical that may have been used.

Also, when it comes to breaking down the components for casting it's best to realize that the more pieces you try to cast as one unit will produce more undercuts for the resin to have to penetrate as well as considering how fragile the mold will be with all of those extra angles to access and as time goes by the mold will most likely start to break apart, especially in those small detailed areas.
Breaking down a complete engine in a format that would allow you to cast all parts as a one-piece mold works the best, in my opinion. However, some folks don't like all of the added assembly and lining up parts.

[alarmstrong]

i went back to hobby lobby today to look for more silicone mold material and found the two part mold putty. is this any good for making molds to use more than once? can you make a 2 part mold with it? or is it a waste of time and money?

[Aaronw]

The mold putty has its uses, but very limited.

I've used it for small simple bits like duffle bags, marker lights etc but wouldn't use it for anything complex. It doesn't really work well for two part molds, and it can leave a little lip around the edge on a one part mold if you do not get it mashed down over the part really well.

On the plus side it is really easy to set up and use when you want to make a quicky mold. I've only used it for simple parts of things I don't need a ton of duplicates of so the molds have lasted me for many years.

The one place it really shines is when you want to make a mold of something that is attached to another part. It works well for things like door handles, emblems on the hood or side trim etc. Understand that it is kind of tricky to make those kinds of molds well, and you will usually end up having to sand down some resin from the back of each casting, but there is no real way to use the usual liquid silicone mold material.

Edited by Aaronw, 12 November 2012 - 01:42 PM.

[bnl]

check out my website for resin engines and parts
b-n-lresins.com