Resin Casting

[Green_Elite_Cab]

As far as bubbles in your resin mix, one tip I have seen used when casting water features is to use a stick or tool as a chute to pour the resin down to the molding surface to avoid air bubbles.

This is also recommended. This is how I do things in the laboratory to avoid splashes or bubbles.

You can also get a pressure cooker style device (though it costs $180) that removes the bubbles, but this is more for clear castings like window.

Is HS3 the pink or blue rubber stuff, like I've seen used in Model Railroader? Ever since I tried with Composimold I couldn't help thinking that my molds may work better if I tried this stuff. Especially since I want to repeatedly reuse the mold. I appreciated the step-by-step ideas you gave me in your first post, I have been thinking about how to make a better mold and try it again. The only thing I can't figure out is where to put the conduit to pour into and the conduit for air to escape without trapping some bubbles around the gondola body, or without having a significant area to carve away afterward, do you have any ideas for these? Questions like this are basically the main things that discouraged me from trying to cast again.

Its a specific type of casting rubber sold by alumilite. HS2 Is "Tough and Strong", very stiff but difficult to damage. HS3 is strong and highly flexible and stretchy, good for smaller molds with lots of details. HS3 is probably find for small stuff but HS2 will hold its shape better for bigger stuff.

All of it comes out light Pink. The only rubber I've seen that is blue (but I haven't seen all!) was the Micromark rubber, which I don't necessarily recommend for this project. Its fine for small simple stuff, The Alumilite is a better product for larger and/or more complex pieces.


You don't really need to worry about conduits or anything. The type of mold I suggested is called a "Squish" mold. You quickly pour the resin into one part of the the mold, then squish down the other half. When you squish to the two pieces together, it completes the mold and excess resin flows up into the seams between the two parts making some flash. If there aren't a lot of bubbles in your resin when you introduce it to the mold, you will probably not introduce to many additional bubbles, if any. Even if you do get some bubbles, they shouldn't be impossible to fix with some filler and polishing.

"Injection" molding can really only be done under high pressures, and that is not going to be the kind of molding you'll be able to do at home.