Everyone seems to gate their molds a little differently, so it is interesting to see what works and what doen't work.
Nice work !
The castings look great.
I bought a small package of granulated coal a few years ago, but I can't find where I purchased it.
I was planning on using green sand with coal dust, but was having trouble with green sand, and went back to using resin-bound sand (OK85 to be exact).
My plan was to grind the coal up into pellets.
I have seen discussions about whether regular coal can be ground and used in green sand, or whether it has to be sea coal.
From what I have read, seal coal burns more cleanly than regular coal.
I guess you could grind up a little regular coal and try it on one mold, since it is possible that it would work as well as sea coal.
You can buy a 40 lb sack of coal from Tractor Supply for dirt cheap, perhaps $9.00.
https://www.tractorsupply.com/tsc/catalog/coal
People still use coal as a heating fuel, and at that price, it is pretty economical.
They say burning coal is not as environmentally unfriendly as some would say, but it does tend to have a sulphur smell, and I would worry about my neighbors complaining before I worried about the environment, not that I don't care about the environment.
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