Annealing question

playswithfire104 · #1 2007-12-21, 3:13am

I know everyone has their own annealing schedule they like and all, but I have a question I've never seen asked. In one boro class I took, the instructor said it was OK to anneal the boro at the same temp as soft glass. All the kilns in the classroom were set to somewhere around 960. One bead I made cracked in half but everything else seems to be fine. The instructor was asked about the annealing temp being so low and he said that temp is what he anneals all of his boro at. I have never heard of anyone annealing boro at such a low temp before or since. What do you boro gurus think about this?

Blair · #2 2007-12-21, 5:25am

I'm really new to boro, so I may not be the best person to answer this, but it is my understanding that that IS the annealing temp, but you probably want to strike the color of your beads at a higher temp first, then bring the kiln down to annealing temp and let them soak for a while. Some colors don't flame strike very well and need to bloom in the kiln.

Wonker · #3 2007-12-21, 5:34am

960 is about the stress point for boro. That wouldn't be where you wanted to anneal it. I anneal at 1050 and that works quite well. There are some annealing charts around that will give you the times for various thicknesses. I recommend Contemporary Lampworking if you don't have a copy. It has almost everything you can think of in it.

I usually garage everything I make in the kiln at 1050; wait about an hour after I quit and slowly ramp it down. If there are things in the kiln that I want to kiln strike I'll ramp it up at that point before I ramp it down. I know that most of my stuff is annealed far longer than necessary, but it holds up well too.

Blair · #4 2007-12-21, 6:14am

Ooh! This is good for me to know, too! Thanks!

playswithfire104 · #5 2007-12-21, 11:29am

Wonker I do pretty much the same thing. Its just that some days I want to work with both boro and soft glass and don't want to take an hour or so break to ramp slowly to 960. I just wanted some input on this subject from more experienced peeps.

Mr. Smiley · #6 2007-12-26, 10:43am

960 would take months to anneal anything made out of boro, if it will anneal it at all. Read up on annealing and what the process is doing. More and more people are sharing the misconceptions about annealing... and that quite honestly scares me. Boro needs to be soaked @ 1050 and all types of glass need to be ramped down slowly from soaking temp to strain point before they are "annealed". For boro, strain point is @ 950. Just because something has been hot in a kiln, doesn't mean it's annealed. Same goes for a bead or piece of work that doesn't crack... some times it can take years for a piece that isn't properly annealed to fail. Study it and understand it before you say your work is properly annealed. There is tons of scientific information available about this process if you look it up.

playswithfire104 · #7 2007-12-26, 10:52am

That's what thought too Brent. I always garage and soak at 1050 sometimes I ramp it up to 1075 for a while. Then I slowly ramp down to 960 and run my regular annealing program. If I work with both boro and soft glass in the same day I take a break while the kiln soaks and ramps down to 960 then when I'm finished I run my program.

It's just that when this instructor said 960 was OK to anneal at I questioned it - but he has been doing torch work much much longer than I have and no one else in the class seemed to have any issues with it either. And many of them have been at this much longer than I have too. I didn't think it sounded right but I wanted to check with you experts in here!

glasspyro · #8 2007-12-26, 7:16pm

I think the reason there is so much confusion on annealing is due to the fact that there is not "a single" temp, where it anneals, but a range of temps where annealing occurs, Anything over the strain temp is considered annealing, plus the fact that the overall mass of a piece plays a critical part...

Depending on the kiln it might actually get hotter then what it set for ?
and if the pieces are small there's a good chance they will anneal properly.

If yeh really want to know if some piece is annealed properly look into getting a polariscope, there easy to make, works best with clear.