u/NerdyOldMan

(This is AKA "How I learned to stop melting cans and love Zinc)
On the left you have Zinc - On the right you have aluminum
Both cast into two sided graphite molds from Timeless Foundry (love their stuff!)
Left was Zinc, poured in, then popped out.
Right was Aluminum, Pre-heated the molds to try to help flow, and still had surface tension issues. (You can tell as it doesn't pick up those details NEAR as well as the zinc). The best I've gotten from aluminum is partially overcoming that surface tension by adding ground up Potassium Chloride as a fluxing agent (seems to help "fluidity").
All coins were then given 24 hours in a vibrating tumbler with Walnut shells and brasso to clean them up/polish.
Overall, Zinc produces a MUCH better natural finish, has a heftier feel to them, and takes around half or less the propane to melt. I used to only do zinc/die cast when I had a bunch piling up, but now that I've learned to control the temp better it's become my favorite "Cheap white metal" (Silver will always hold the title for white metals when cost isn't a concern)

I have started playing around teaching myself the ins and outs of lost wax casting. My big hurdle is that in my current workshop/workspace I don't have space for a kiln (yet). So I have been melting and then drying my molds in a toaster over with a max temp of 500 degrees. This was the most recent test which came out "ok". Bottom part was lost wax, top part was easy to do with sandcasting. The bottom had some minor cracks in the mold. Process was 200 degrees with it upside down to melt/drain wax, then once it was empty up to 500 and let it sit overnight at 500 to dry as much as possible.
Still very flawed process, and I know eventually I'm just going to have to figure out how to fit a kiln into my kit, but it's fun and I feel like I'm learning/improving.
(Material was scrapped extruded aluminum (old patio sliding door frames)

So through trolling eBay I came across a "reasonably" priced lot of scrap silver jewelry. So this became an intersection of two of my questionably beneficial, and definitely expensive hobbies. Those being metalcasting and stacking silver...
It said it was "Sterling" but I already knew that wasn't true, and sure enough every piece I tested came out at .800 or so purity (common silver jewelry level). But I still like the results. Total weight was just over 22oz.

• The Yes/No coin was a sand casting
• The coins across the top were two sided graphite molds from Ancient Foundry
• The cross was a graphite mold I found on Amazon.

So decided to spend the weekend unwinding and getting some repetition in on copper casting to try to get a little better at it...

Notes from the weekend....

• Always use some copper phosphorous to degas and avoid the little pits and bubbles on the surfaces (You can see those in some of the above coins, especially the two just right of center on the bottom row)
• Best polishing is around 48 hours in a vibrating shell casing polisher with crushed walnut shells and a heavy dose of brasso. Got a beautiful reflective finish.
• Overheat it a bit to keep it maximally liquid while you pour
• Heat all the molds as well to prevent "quick freezing" when you pour (unheated I only got around a 20% real success rate with the two sided graphite molds, well heated the molds and got almost all cast well)
• Zinc is SOOO MUCH easier to get perfectly detailed pours on ;) But copper is just so much more pleasing to have.....

For those curious, most of those coins I made with two sided graphite molds you can get from Timeless Foundry (search for them on etsy) two sided molds aren't cheap, but they're pretty and fun. Almost all these coins clock in at almost exactly 1.5 oz each....