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I have a quick question. A while ago I made a load of coasters. I use a long bubble squeeze. I know that holding too long at certain temperatures can cause devit. My question is the sky blue came out fine, but the spring green was covered in devit. Is the green more prone to devit? Both colours were uncapped and transparent.

Thanks
Karen

You say the colors were transparents - was the Spring Green the 126? That's an opalescent, and more prone to devit than the transparent sky blue.

Hi, both were transparent. Spring green Spring comes in both...

In my experience Bullseye's 1426 is no more prone to devit than any of the other greens and blues.

Since cleaning is most often a difficulty in creating devit, was the cleaning different between the two?
Need more information on preparation and firing conditions to help

I agree with Steve's comment about cleaning---personal experience! To cure the devit, I followed a tip from this Board and sprinkled a fine layer of clear glass powder on top and then fired to a brief full fuse temp. Got a beautiful glossy surface again. If you do this, pay special attention to the edges--the powder likes to fall off the edge.

Sorry for misinformation - I went back and had a better look at the glass today. The green has noticeably more 'scum' on the surface, but if I look carefully at the blue it has devit too. I think the brightness of the green just shows it more...a lot more.

The next batch should be ok as I am not using the really slow bubble squeeze program - I only used this for them as there was space in the kiln.

have you ever tried a devit spray? you can make a cheep efective spray with borax and distilled water works great.

Although I have a tip on preparation of a borax solution
http://glasstips.blogspot.co.uk/2009/07 ... prays.html
I would not recommend the routine use of it.

You need to find the cause of the devit and work to prevent it. Use the devit sprays, commercial or home made as a last resort.

Thanks for info but i don't want to use any harsh chemicals, especially as my workspace is in my house and not outdoors.

Borax is also used for household cleaning and laundry, so it's not much worse than, say, cleansing powder and probably quite a bit better than bleach or ammonia.

However...I know people successfully use (and love) borax sprays and clear powder for devit prevention/concealing, but I'm with Stephen; they're just as likely to cause issues as to fix them. The better plan is to figure out what's going on with the glass/schedule/cleaning processes to cause the undesirable result, and solve it there.

Morganica wrote:However...I know people successfully use (and love) borax sprays and clear powder for devit prevention/concealing, but I'm with Stephen; they're just as likely to cause issues as to fix them. The better plan is to figure out what's going on with the glass/schedule/cleaning processes to cause the undesirable result, and solve it there.

Along with a couple of other glass friends, I'm in the middle of a very large set of tests for devitrification minimization/elimination in glass castings. We've tested borax sprays independently and along with combinations of glass cleaners, mold compositions, temperatures, hold times, kiln bricks vs Plaster/Silica, etc. We've probably got over 100 test results in a 3"x"x3" casting, as well as thinner fused pieces. The preliminary results are that, at least in castings, the borax spray (2% solution of 20 Mule Team Borax in distilled water) does tend to minimize veiling internal to the casting, but does little for surface devit. So there are benefits to using it, but probably not much effect for surface devit.

Once we are ready with our complete tests later this year, we'll be publishing what we've found. Actually we are probably on a fools errand here but anything to eliminate the tedious hours of coldworking is beneficial.

Please keep us updated! You must have a lot of patience