View single post by Ray Dunakin
 Posted: Tue Nov 14th, 2017 03:23 am
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Ray Dunakin


Joined: Wed Jul 25th, 2012
Location: San Diego
Posts: 1228
A few days ago I posted this photo of a styrene test piece for the covers on the engine:

My plan was to make a rubber mold and cast these things in resin. But that test piece was too rough. Well, I tried a couple more and couldn't get it to look as good as I wanted. So I tried a different approach, making it out of 1mm Sintra and scribing the indentations. That turned out even worse:

Even if I could have created a suitable master, I had doubts about how well such thin pieces would reproduce as castings. So I scrapped the whole idea and decided to come up with a non-prototypical design that would be simple enough that I could make all 20 of them individually. My first test of this was extremely simple, just a flat piece of styrene with rounded corners and a nut/washer in the middle:

But I felt that this was TOO simple. I wanted something that looked a bit more interesting. The design I settled on was made by layering two pieces of .020" styrene. Both pieces had the corners rounded, and I beveled the edges of the smaller piece before gluing it on top of the base piece. Here's how they turned out:

I also did some work on the base for the engine and generator:


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