HELP!! My Chalcedony turned brown in the kiln!!

pgglass · #1 2009-08-30, 4:43pm

I tried out my new Chalcedony stringers last night and am very disappointed. I was able to strike the glass and get the most gorgeous pinks, blues, lavendars and yellows (stringer designs on a vetrofond black base) but when the bead came out of the kiln, the once colorful designs were a brownish yellow. I put the bead directly into my 945 degree kiln and can't imagine what went wrong. Any suggestions are appreciated.
Thanks, Pam

squid · #2 2009-08-30, 5:02pm

Try reducing the temp in your kiln. Try 25 degrees first and then try 50 if that doesn't work. If your Chalcedony is darkening in the kiln, it is likely hotter than it says it is in there.

pgglass · #3 2009-08-30, 5:14pm

I'm not sure that's the problem. At one time, I had my kiln up to 960 and couldn't get any of my silver glass to stay silver. I lowered the temp to 940 and have no problems with any of the silver glasses now. Raku is no problem either. I can't imagine that this one glass is different from all of my other glass. I also use a lot of 96 glass and never have a problem. Is there anything else you can think of? Do you use a lot of Chalcedony and what temp do you anneal at?
Thanks

Cherry · #4 2009-08-30, 6:53pm

Hi Pam. There's another thread (33 pages!!)on Chalcedony under the Gallery with messages about similar problems with annealing. Also lots of great photos of this wonderful glass! I found that if I batch annealed the beads the colours went brown (?silver coming up), but when I annealed as I made them the colours stayed the same.
Good luck. It's great glass considering all the range of lovely colours it goes!
Cherry

Elizabeth Beads · #5 2009-08-30, 6:57pm

925 degrees for 1.5 hours and slow ramp down.

squid · #6 2009-08-30, 7:15pm

The only reason it would get dark in the kiln is if it is striking in the kiln - which means it is getting too hot. It may be too close to the elements or it could just be too hot. I put all my silver glass on the bottom rack in the kiln away from the elements - and I anneal at 925. Reduce the temp or move away from the elements. It's easier to just reduce the temp in many cases.

stacied · #7 2009-08-30, 7:20pm

Are the Chalcedony beads the first and only beads you are making during your session. I find that if I want to make siver glass beads I wait till the end of my torch session so they soak less time. HTH.

killerbeedz1 · #8 2009-08-30, 9:33pm

I was using a similar silver glass and was getting gorgeous colors when they went into the kiln. When they came out they weren't gorgeous anymore. I was told I was overstriking them in the flame. I had already tried lowering the temp of the kiln, putting charcoal in it and so forth. So try not to strike it so much and see what happens.

pgglass · #9 2009-08-31, 2:55am

Thanks everyone for your advice and tips. I'm going to keep the beads further away from the element and if that fails, I will lower the temp in the kiln. The colors are so beautiful that it's worth adjusting just for that one glass! Also, thanks for the suggestion to not overstrike. In other words, the colors may develope further during the annealing process?

Firebrand Beads · #10 2009-08-31, 9:31am

You might try encasing them, too. My TAG Dalai Lama beads turn from purple back to brown in the kiln if I don't encase them.

squid · #11 2009-08-31, 9:52am

Quote:

Originally Posted by pgglass

Thanks everyone for your advice and tips. I'm going to keep the beads further away from the element and if that fails, I will lower the temp in the kiln. The colors are so beautiful that it's worth adjusting just for that one glass! Also, thanks for the suggestion to not overstrike. In other words, the colors may develope further during the annealing process?

They will if your kiln is too hot. My colors coming out are the exact same as going in due to my lowered annealing temp.