Tried my first melt - what happened?

[SF Gold Buyer]

Total newbie to this. We got a real nice "cowboy" furnace. My store buys scrap gold, and we want to test pieces we bought from time to time. So I put a jewelry piece in the crucible, probably weighed about 5 or 6 grams. Waited till we could see that it was melted. However when we went to pour it out into the mold, by the time it got half way out of the crucible, it just solidified, with some impurities on the surface. We were able to get it out and salvage it, but as a test, we weren't able to really figure out the fineness, it was too much of a mess. What should we do differently?

 

[fireguy]

Total newbie to this. We got a real nice "cowboy" furnace. My store buys scrap gold, and we want to test pieces we bought from time to time. So I put a jewelry piece in the crucible, probably weighed about 5 or 6 grams. Waited till we could see that it was melted. However when we went to pour it out into the mold, by the time it got half way out of the crucible, it just solidified, with some impurities on the surface. We were able to get it out and salvage it, but as a test, we weren't able to really figure out the fineness, it was too much of a mess. What should we do differently?

Did you use any flux? If your material is primarily gold, you might consider just borax. This will lower the melting temperature and cause the pour to be more fluid.

Are you sure the furnace was hot enough? You may need to get above the melting temperature to achieve a good pour. You might get a simple thermocouple to check the temperature.
This one probably requires a hole drilled in the furnace:
http://www.lmine.com/product/26620X.html
Or, an optical unit:
http://www.lmine.com/product/18354.html

 

[Aerogrudge]

It's probably better it did if you poured this into mold without flux I quite possibly would of bounced out and splattered everywhere. Always preheat before you pour into if not the sudden temp change will condensate and that is very dangerous. The flux cushions the gold when it pours out to keep this from happening I have good luck with borax with sodium carbonate 3 parts borax 2 parts or less soda. The soda thins the flux a bit.