Aluminum Casting

Overview

Green sand casting is a casting method where you make a part then use a sand-clay mixture to make a mold of that part. The part is then removed from the mold and the mold is used to cast the desired material, in this case aluminum.

Motivation

I wanted a part out of aluminum on my guitar to stop it from going out of tune as fast but still allow for the whammy bar to be used. So I designed a part and carved it out of some balsa wood.

Molding the Part

I used the green sand mixture in 2 halves to mold the part. I added some gates to let the aluminum in and out at the high parts.

Building the Forge

I set that asside and built the absolute jankiest hole in the ground forge you have ever seen. I had a steel crucible out of some pipe fittings and ran a tube to the bottom of the hole to connect a shop vac to.

Melting the Aluminum

I then filled the hole with charcoal and the crucible. I had some aluminum from cans and a rain gutter. I fired it up and started melting everything down. Occasionally I would add some borax flux and remove the draught.

Casting

Once everything was hot and I thought I had enough aluminum I brought the casting over. Not sure how it was done, but somehow I got the crucible out and filled up the mold.

Results

It didn't turn out great but it did do what I wanted it to. There was a little post-processing done on it to get final finish a bit better.

Finishing Touches

I drilled some holes and tried to file it down a bit. It was mostly to fit it cleanly into the back of my guitar without interfering with the whammy bar.

Lessons Learned

Really I should have added better gating because as you will see there are a lot of voids on the part.