Is this from dirty propane?!?

[cherylsart]

62356
The bead on the left was what I was trying to replicate. The bead on the right was what I got. Bleah! The only thing I did different was I used some cobalt glass with the black, and I got some propane (1 lb bottles) from Home Depot, a different brand than I usually get.

The whole bead just sort of turned black. Then it cracked. I noticed some of the other beads I made seem off as well. I think it's the propane. Do you?

Thanks,

Cheryl

[elle]

I can't tell from the picture, but do the beads have an oil-slick looking sheen on them? I've had that happen with a nasty tank, and it happens when I get down to the bottom of a good tank. It happens more regularly with black and cobalt than the other colors, in my experience.

[squid]

It could be dirty propane or it could be you had your torch adjusted too high or were working too close to the end of the torch. I would try turning the torch down a little.

[cherylsart]

Yes, the beads have that oil slick look. The frit and most of the glass turned that yucky grey with that sheen to it. Since that's the only thing I did different, I think it's the fuel. I can use this fuel for small spacers and pulling stringer, I think, but not for more involved work. Too bad I bought it in a 4 pack so it's probably all the same stuff! The bottles I get a Kmart are fine.

Thanks!

[beadgoodies]

I think it's the propane too. I've had a bad bottle (20 pounds, unfortunately!) and I couldn't make a clean bead to save my life! That's nice that you were able to figure it out so soon. It took me a loooong time to realize what the problem was. I suppose I should have just asked!

Candy

[MikeAurelius]

The crack is from letting it chill too long before putting it into your kiln. When a bead cracks along the mandrel line, that is usually the cause.

[cherylsart]

Mike, I don't have a kiln. I put my beads in vermiculite and have them batch annealed. I wish to Heaven I could afford a kiln but it's just not in the budget right now. I have a bead crack occasionally but not many, luckily.

[kbinkster]

Are you working on a HotHead? I have not heard of "dirty propane" issues from the one pound cannisters of propane. It looks like you may have reduced or fumed your color, though. Hot Heads tend to have a reducing atmosphere. And, sometimes, depending on the colors you use, you can fume the metal from the glass and it can leave a deposit onto your bead like you describe. Some colors are more sensitive to things than others and some just don't play nice. There could be something going on with the cobalt and black.

I would first try making the bead again, but without the cobalt, and see what happens. Try working some other colors, too, and see if they seem to reduce. You could also try keeping the flame set like it should be for a Hot Head (don't turn it down) and working a little further out if you think you might be reducing your glass.

And, I agree with Mike that the crack is probably due to thermal shock (cooling too fast).