While I’ve been pretty happy with the packs I’ve built so far, I’ve found a couple of the parts I’ve constructed lacking. I’m not looking to buy stuff from anyone else, I just want mine to be better.
With that in mind, I thought I’d try to mold and cast some resin pieces. It took me a bit before I actually took pictures of my casting efforts. Overall, I’m very pleased at how the pieces turned out.
My first attempt at molding and casting was done using a starter Aluminite kit I got at Hobby Lobby. The quantities in the kit are pretty limited, so I was only able to create two molds; the crank knob and a small resistor.
My second round of molds included the larger resistor and a heat sink constructed of polystyrene and MDF. I also attempted to cast a gun tip and another resistor but met with abysmal failure. And here’s the pics:
The original pieces:
The crank knob and resistors are from the GB Store (thanks AJ!)
The yellow molds are oozing orange goo and starting to turn brittle. I’m not sure if I mixed the rubber with the catalyst incorrectly or its just crappy rubber. That said, they’ve worked pretty well so far.
The pink is a softer rubber and great for undercuts. It also makes de-molding a lot easier.
Most likely a bad or incomplete mix… The Alumilite fast silicone that you have pictured does seep a little yellowish pigment for the first few casting, you won’t notice it except in bright with or clear casting, but I have never had it ooze like yours appear to be doing and I have molds that are several years old… Because it’s a fast set silicone though it will dry out and wear out sooner then others…
Also I don’t know if you tried to cast anything else in those molds, but casting epoxy will burn out the silicone MUCH faster then the traditional urethane… And it will literally look like it’s burnt the surface of the silicone by changing the color…
Yep, silicone picks up lots of details it will even pick up finger prints…
I don’t mean to sound like an advertisement but I really stand by this:
When it comes to silicone or casting resin/plastics I get all of my materials from Polytek. They offer a wide range of molding and casting materials and thier products have never let me down.
My favorite silicone molding product for molds such as the ones your using is a product they call “Tinsil 70”. It is a tin based silicone (cheaper than platinum based) and is wonderful for casting urethane as well as polyester resin.
Small pieces such as the resistors would come out very well in a material called “Easyflo”, it is a 2-part casting urethane that pours almost like water and yields a very strong and lightweight casting in small pieces. It is so thin that it will certainly pick up every subtle detail in the mold. I prefer Easyflo-60 for small solid parts and Easyflo-120 for rotocast hollow parts.
