A few weeks ago when my cups came in I took the smallest one and melted some 999 silver in it. It went well with the MAPP torch untill something funky happened, Looks like contamination or something like that.

Today I took my T26 brick and put in an oven shape and stuck my MAPP touch in it. I tried to melt the screw up to see if I could reverse it but everything I tried it refused to melt. So what I did was take some photo of it.

http://wetlands.simplyaquatics.com/d/22614-2/IMG_1821.JPG

http://wetlands.simplyaquatics.com/d/22610-2/IMG_1808.JPG

I suspect I managed to get carbon or something in the metal and it's totaly ruined now. Anyone know what I goofed on and what this is?

Also with these cups I had to get the torch head directly on top because on the outside it would just turn red and not penetrate thru. On the metal side and close to the head was the only way it would turn red.

Ed

the crucibles need to have a coating of melted flux in the bowl before you start anything. even fine silver and other non ferrous metals also need to be fluxed when melting them. it is also better to have a reducing flame when melting,but with just a plain MAPP torch or a standard plumber's propane torch you make due with what you have.

ok so i should get a big box of boax from target then, yes?

Ed

borax will work,but it just takes a small pinch when melting the metal after the crucible has been "seasoned". you also need some kind of pickling solution to remove the melted flux and oxidization from the melted metal once it has cooled.

ok i did not season them nor did i use any form of flux. These are fused silica with a clay bond, 7.5 oz and measures approximately 2 3/4" x 1 1/2" (70 x 38 mm).

what do I do to season them?

Ed

borax

The instructions I got for seasoning crusibles is to heat to 1600 degrees for 1hr and then sprinkle some borax on the inside to coat the surface leaving sort of a glaze when it cools. I was also instructed to wrap it in a plastic bag to prevent the crusible material from absorbing moisture out of the air. If I suspect that the crusibles have absorbed moisture out of the air or have gotten wet, I will need to repeat the heating. Another thing is that once a crusible has been used to melt a certain metal or alloy to reserve it for that use only.

Doug Lester

You may also find that you really want a torch with oxy.

A graphite stirring rod will also do wonders.