OK looks like its been a while since I visited this thread.
Yesterday I said to hell with it and played with the furnaces, I tried to pour the belt buckle pattern that Harry had sent me. with the same results that I had before the last two times I poured it.
I poured this with a half inch sprue gated directly into the back of the buckle, I also added on the first try yesterday three vents into the belt loop, that one almost filled with only about half and inch of gap in the loop not filling, but had some slag inclusions specially around the sprue which was gated so that it set half way onto the cavity. sorry no pics of the backs.
The first melt was at 2100 degrees as checked by the digital thermometer that I have acquired it may be off EVIL BAY purchase but it works. second melt I didn't check furnace temp.
The metal used was a mixture of some old keys that I had tried with before, to which I had added some yellow brass and a couple of old mig gun nozzle's which are pure copper, there also might of been some chrome plating added that I stripped off of a glamor cover off of a 20" Ford Truck Wheel.
The melt was degassed and fluxed with N400 degasser/deoxidzer for Small Foundry Supply this was used for both melts. As a degasser it has a very aggressive bubbling action but for no more metal then I had in the crucible didn't cause any splashing in the furnace. I didn't weigh the amount of chemical used but will next time along with metal used, because one a full crucible it might cause problems with the crucible boiling over. The metal as you can see from the picture has a nice luster to it, there is some pitting in the rim but I think that is strickly from the sand that I used, which has a large quanity of regular play sand in it, I should of face the front of the buckle with a finer sand (which I have mixed).
The rim of the buckle was handed sanded with 400 grit paper and then polished with Mother's Metal Polish.
This buckle was poured right at the point of the zink burning out of the melt, in other words I was starting to see yellow around the rim of the exhaust hole in the lid of the furnace and on the block I set on top of it.
I am thinking about casting that loop as a solid part then milling out the excess. also I may mill the back flat and then add it on to an oval rectangular plate for a larger buckle, but first I need to figure this out so I can progress forward from here.
Forgot, I also added a slight dap of ferro silicon to the pot due to adding all the copper, I filed the edge of the rim with a needle file and found that the metal was almost to hard for the fine teeth on the Swiss file to cut, but the metal sanded and polished great. Of course the files may of been pre-used files from Boeing Aircraft In Witicha Ks.
