Why would annealing cause devit?

Lyssa · #1 2011-10-21, 10:28am

Hi all, some of the beads that came out of my batch anneals in the last two days are partially devitrified. Does anyone know what is causing this and how can I prevent it?

I've heard people say you can soak devitrified beads in stuff to get the devit off, is that true and what stuff do I use?

Thanks!

DreamMuse · #2 2011-10-21, 11:37am

I had that happen with opaque cobalt beads that I batch annealed, before I got my kiln. I remember asking what caused it, and no one ever had a perfect answer. Since the kiln I was using had a tight seal on the door, it was assumed that I had a reduction atmosphere in the kiln. Unfortunately, I don't think there's a solution for that. I've heard of adding charcoal in a dish on the kiln floor, but I think that's to preserve a reduction atmostphere, if the kiln is removing the shine off your reduction glass beads.

I ended up etching them to remove the devit, but hopefully someone else has a better solution for you.

For what it's worth, it doesn't happen now that I have a toolbox kiln and garage them immediately. But opaque turquoise still will get that reduction.

Lyssa · #3 2011-10-21, 11:46am

Thanks Disa, when I did a search for "anneal+devit' it came up with your 2005 thread. I saw all those answers and you're right. No one actually said how to prevent it. I don't remember exactly which thread I read, but there was a *hint* that it might be caused by going up too high, or maybe going down too fast... but again, that was just a *hint* I got from some of the posts. Not sure if I was gleaning the truth or not.

Lisi · #4 2011-10-21, 1:26pm

Devitrification does not happen out of the flame. It is a change in the chemical composition on the surface of the beads while they are being worked in the flame. Very few glass colors devit, and here is a handful of the familiar ones:

Effetre Purple 254 aka EDP or "evil purple"
Effetre Sedona
Zimmerman Purple Rose which is rare and hard to find now
Old stock of Vetrofond black has done it

What you have is something else and it's not devitrification. It is probably reduction effects aka scum, greyish scum, copper build-up, there are many names for it. It may not actually look grey in color, but on dark colored beads, it leaves a dull, patchy, or non-shiny finish. You can probably remove it just fine with a solution of toilet blow cleaner.

Here it is:

Two parts Toilet Duck or Snobol toilet bowl cleaner mixed in one part water. Store in a plastic jar with good fitting lid, to be used over and over again. If you don't have a plastic jar on hand, you can store it in a glass jar temporarily. I had mine in an olive jar for a long time, but it's really better to have it in plastic. It will "eat" glass over time.

String your beads on fishing line with a "stopper" at the end, I use an E bead or a pony bead. Dip them in the solution and leave them in for 15-20 minutes, and check after rinsing them in warm water. Use dish soap to wash them thoroughly to get all residue of the cleaner off.

Do you have a picture of these beads?

Lisi · #5 2011-10-21, 1:29pm

Oh, I forgot to mention - the other day when I annealed copper green beads, they turned a greyish green and a little dull. They weren't that way going in the kiln. I cleaned them up bright and pretty like copper green is supposed to me, with the solution.

Lyssa · #6 2011-10-21, 1:57pm

Thanks Lisi, I'm trying to get a picture from my phone to my computer. Let's see how that works out.

The wi-fi here at work ain't so great.

Jody Lee · #7 2011-10-21, 2:08pm

I had a bead fall behind my mandrel rack once and it probably had around 50 firings before I found it. It was pea green, and the shiny-ness had come off, leaving a finish much like devit on edp. I suppose it was from the rapid ramp up. It was certainly well annealed LOL

Lyssa · #8 2011-10-21, 2:11pm

I'm amazed the bead didn't crack with its first rapid ramp up! LOL

Quote:

Originally Posted by Jody Lee

I had a bead fall behind my mandrel rack once and it probably had around 50 firings before I found it. It was pea green, and the shiny-ness had come off, leaving a finish much like devit on edp. I suppose it was from the rapid ramp up. It was certainly well annealed LOL

Lyssa · #9 2011-10-21, 4:09pm

Here's a picture of what's coming out of my annealer:

Quote:

Originally Posted by Lisi

Devitrification does not happen out of the flame. It is a change in the chemical composition on the surface of the beads while they are being worked in the flame. Very few glass colors devit, and here is a handful of the familiar ones:

Effetre Purple 254 aka EDP or "evil purple"
Effetre Sedona
Zimmerman Purple Rose which is rare and hard to find now
Old stock of Vetrofond black has done it

What you have is something else and it's not devitrification. It is probably reduction effects aka scum, greyish scum, copper build-up, there are many names for it. It may not actually look grey in color, but on dark colored beads, it leaves a dull, patchy, or non-shiny finish. You can probably remove it just fine with a solution of toilet blow cleaner.

Here it is:

Two parts Toilet Duck or Snobol toilet bowl cleaner mixed in one part water. Store in a plastic jar with good fitting lid, to be used over and over again. If you don't have a plastic jar on hand, you can store it in a glass jar temporarily. I had mine in an olive jar for a long time, but it's really better to have it in plastic. It will "eat" glass over time.

String your beads on fishing line with a "stopper" at the end, I use an E bead or a pony bead. Dip them in the solution and leave them in for 15-20 minutes, and check after rinsing them in warm water. Use dish soap to wash them thoroughly to get all residue of the cleaner off.

Do you have a picture of these beads?

squid · #10 2011-10-21, 4:13pm

Actually, devit does happen in the kiln as it is often a problem with kiln fired glass - but it's usually in a temperature range above annealing temps. A funky atmosphere in the kiln can cause devit - I would suggest propping your door open slightly when ramping up.

A good article here:

http://www.clearwaterglass.com/Tutor...ification.html

Table 1: General causes of devitrification

Inadequate cleaning of the glass

Firing too hot and too long

The type of glass used is prone to devit

The glass has been fired more than once

The atmosphere in the kiln

Lyssa · #11 2011-10-21, 5:04pm

Great article. It's making me think that we're comparing apples and oranges that happen to have both been genetically engineered from a banana. I think that regardless of which chemical reaction is causing the change in appearance of my beads (as opposed to EDP's devit in the flame, for instance), the change to my beads can be called devitrification, which just means that the glass has lost its glossiness.

Just a thought.

Thank you for the article, it's helping.

Quote:

Originally Posted by squid

Actually, devit does happen in the kiln as it is often a problem with kiln fired glass - but it's usually in a temperature range above annealing temps. A funky atmosphere in the kiln can cause devit - I would suggest propping your door open slightly when ramping up.

A good article here:

http://www.clearwaterglass.com/Tutor...ification.html

Table 1: General causes of devitrification

Inadequate cleaning of the glass

Firing too hot and too long

The type of glass used is prone to devit

The glass has been fired more than once

The atmosphere in the kiln

Lisi · #12 2011-10-21, 6:55pm

I think the article is referring to kiln fired glass, which is fired hot enough to melt. Therefore, glass that gets hot enough to have devitrification problems. That makes sense to me. But not with the temps used for annealing lampwork beads.

I have used every type of glass imaginable, made thousands upon thousands of beads for nine years, ran the kiln for 12-16 hours at annealing temp, and never had a bead with devitrification problems. Only certain colors like EDP would get this from working it in the flame and getting the glass too hot. I've had plenty with reduction scum, the dull surface which is easily cleaned up. Sometimes I could go back in the flame and get EDP shiny again, but the devit would still show around the holes. Those familiar with EDP and Sedona know exactly what I'm talking about.

Besides, if a kiln temp for annealing beads is "too hot", don't you think the beads would slump?? I have never heard of beads getting devitrification from annealing.

What is the base color of the bead? Is that copper green?

DreamMuse · #13 2011-10-21, 9:26pm

Quote:

Originally Posted by Lisi

Devitrification does not happen out of the flame.

Quote:

Originally Posted by Lisi

But not with the temps used for annealing lampwork beads.

Yeah, I'll respectfully disagree *chuckles* That dark cobalt order of beads got the devit specifically from the batch annealing in my kiln. They were pristine and beautiful after cooling in vermiculite. It was the only color that got devit from my schedule in my closed kiln, aside from the other colors that get devit with the torch, like turquoise.

Aimee, that looks like the same nasty scum I got on those cobalt beads. Are you using a closed kiln like the AIM kiln that caused mine? I never did find a solution. That was an impetus for my getting a toolbox kiln to garage them immediately.

Lisi · #14 2011-10-22, 3:05am

Cobalt? What glass, and do you mean the transparent cobalt? Effetre? The reason I ask is that some people refer to the opaque lapis blues as cobalt.

That's weird, I've never seen or read about any problems with transparents getting a dull surface after being in the kiln. Like I said, the turquoises and copper green were the scummy ones because of the copper.

jaci · #15 2011-10-22, 6:22am

What kind of kiln do you have???
Try vacuuming out your kiln, and if brick coating it with a thin layer of kiln wash.
Over time if you have had lots of metals (silver glass beads, beads with silver leaf, reduction stuff, coper mesh, etc) You can get a build up of 'stuff' in the kiln walls. it just needs to be cleaned usually. I dont think there is an easy way to 'clean' the fiber blanket insulation w/ out replacing it, or taking a layer off basically (i do not recommend this, if you dont know what you are doing)

The other possibility is that your kiln is running hot, or you are putting beads into the kiln too hot/cold and they are adjusting to the temp causing the reaction(probably not the answer here looking at your bead). Try turning it down 10-20 degrees (start with 10 and go from there). Try cooling your bead more before you put it in the kiln.

DreamMuse · #16 2011-10-22, 10:08am

Ahh, yes, it was the pastel lapis. The "official" name is P-246 Lapis Cobalt Blue, so I always just said Cobalt.

Lisi · #17 2011-10-22, 6:39pm

Ahh...seems to me I read something somewhere about lapis being an occasional troublemaker. Have you tried soaking the lapis beads in Coke (Pepsi is better) overnight or the 15 minute toilet bowl and water solution? (2 parts to 1 part H2O)

DreamMuse · #18 2011-10-22, 9:56pm

Well, this was several years ago, so I don't have the beads anymore. I never did find a solution for the batch annealing problem, and I got a toolbox kiln soon after which didn't create the problem.

I did try soaking the beads in toilet cleaner, and jeweler's pickle. Neither really helped.

http://www.lampworketc.com/forums/showthread.php?t=1936

But even if it was due to the cobalt, why would Lyssa's pea green do it, I wonder? That is pea green, isn't it Lyssa?

Lyssa · #19 2011-10-23, 12:30pm

CIM Olive. Other beads that were devitrified or scummed up were CIM Peace, CIM French Blue, CIM Butter Pecan and some unknown ivory.

I can't find either Toilet Duck or Snobol here on Kauai so I tried another toilet bowl cleaner (extra strength with rust cleaner in it) and it didn't work after soaking overnight.

Thank you for everyone's advice. I don't know how to prevent this and I am not finding a solution to fix it, so I'm just gonna go sit in a corner and cry now.

squid · #20 2011-10-23, 12:41pm

Prop the door open when annealing.

Lisi · #21 2011-10-23, 1:48pm

Quote:

Originally Posted by Lyssa

CIM Olive. Other beads that were devitrified or scummed up were CIM Peace, CIM French Blue, CIM Butter Pecan and some unknown ivory.

I can't find either Toilet Duck or Snobol here on Kauai so I tried another toilet bowl cleaner (extra strength with rust cleaner in it) and it didn't work after soaking overnight.

Thank you for everyone's advice. I don't know how to prevent this and I am not finding a solution to fix it, so I'm just gonna go sit in a corner and cry now.

Oh wow, all those colors?? I'm so sorry! I was thinking it was a color or two that was doing this and we could narrow down the cause. Like squid says, prop the kiln door open and see if that gives you any improvement.

Could you look up other beadmakers in your area? Maybe they could batch anneal for you until the problem is worked out or when you get the new kiln. If your beads are small (less than 13-14mm), you're cooling them in a blanket, vermiculite, or the annealing bubbles and you don't mind shipping them to me, I could batch anneal them for you. I'll pay the return shipping.

Lyssa · #22 2011-11-01, 1:42pm

Ok, I ran a batch last night with half batch annealing beads and half brand new beads hot off the torch. (Of course I ramped up to garage temp then started making the new beads.)

About half of the batch annealed beads got the icky scum around the bead hole and half did not. NONE of the new beads got the scum. So it's either something about the ramping up, OR as someone suggested it might be my mandrels. I'm going to run a test of batch annealing my beads on mandrels coated in bead release and see if 1) I can get 3/32" holed beads onto 1/16" mandrels with release on them and 2) if the release protects the beads. I'm thinking it will protect the beads. That would be a great solution right now, I'm looking forward to testing it tonight!

jaci · #23 2011-11-01, 4:53pm

wait.. you are removing the extra bead release when batch annealing but leaving them on a mandrel? I suppose that the mandrels could be 'fuming' the beads.... Just take them off all together and pile them up in the kiln or dont clean the release off the rods. How fast are you ramping up?

Lisi · #24 2011-11-01, 6:09pm

Did you mention that your mandrels were not stainless steel? Where did you get them?

Lyssa · #25 2011-11-01, 6:24pm

Jaci: ramping up over 2 hours. I batch anneal with several beads on each mandrel, not one bead per mandrel still attached with bead release. I have hundreds of beads I need to batch anneal.

Lisi: yes, my mandrels are not stainless steel. I made them myself with piano/music wire from the hobby store. Much cheaper, and work FANTASTIC for making beads, but obviously not so much for batch annealing. Also, they rust like nobody's business if I don't dry them completely after cleaning. But that's Hawaii on rustable objects for you.

Lisi · #26 2011-11-01, 10:03pm

Quote:

Originally Posted by Lyssa

Jaci: ramping up over 2 hours. I batch anneal with several beads on each mandrel, not one bead per mandrel still attached with bead release. I have hundreds of beads I need to batch anneal.

Lisi: yes, my mandrels are not stainless steel. I made them myself with piano/music wire from the hobby store. Much cheaper, and work FANTASTIC for making beads, but obviously not so much for batch annealing. Also, they rust like nobody's business if I don't dry them completely after cleaning. But that's Hawaii on rustable objects for you.

Oh my...then it's very likely this metal (alloy compound likely) is fuming into the atmosphere of your kiln. If you need mandrels you can get them from Howaco glass, by the piece and her shipping will be very reasonable.

I will bet you that's what it is!

Howaco · #27 2011-11-01, 10:50pm

I would be very, very careful about not using stainless steel for your mandrels. Find out what your mandrels are made of and find out what type of fumes they can put off when they are getting to such a high temperature in your torch flame. I would be worried that you might be breathing in toxic fumes. I hope that is not the case, but please check into it.

DreamMuse · #28 2011-11-01, 11:41pm

I don't mean to belabor my own experiences, but my dark lapis cobalt beads that got the same type reduction were batch annealed off the mandrel. I'm still wondering if my beads got devit due to a reduction atmosphere in my AIM.

Lyssa, I don't know if you ever mentioned if your kiln was the kind that closes tight?

jaci · #29 2011-11-02, 7:14am

Quote:

Originally Posted by Lyssa

Jaci: ramping up over 2 hours. I batch anneal with several beads on each mandrel, not one bead per mandrel still attached with bead release. I have hundreds of beads I need to batch anneal.

Lisi: yes, my mandrels are not stainless steel. I made them myself with piano/music wire from the hobby store. Much cheaper, and work FANTASTIC for making beads, but obviously not so much for batch annealing. Also, they rust like nobody's business if I don't dry them completely after cleaning. But that's Hawaii on rustable objects for you.

Try a slower ramp, and just pile your beads in a terra-cotta flower pot tray. (a few bucks tops at any general surplus store, walmart etc*see picture below*) No mandrels You don't really need the mandrels at all. if you are removing the beads anyways, leave them off. I am betting that yes the metal you are using has some weird alloy in it and is the problem.

You can also cut your own mandrels for just a few bucks that are stainless steel. Go to a welding shop/ gas supply such as airgas/abco whatever you have in hawaii and ask for 316L stainless TIG welding rods. You can get them in any diameter you want. 1/16, 3/32, 5/64 5/32 whatever. Then you can cut them to the length you want. One end will be stamped, don't use that end!!!!! You will never get the bead off!!! LOL Just use a pair of bolt cutters or a cutter on a dremel or saw made to cut metal. I do this all the time. Just watch the top. You may want to grind it smooth. It can flare when you cut it and it may be difficult to get beads off if your release is on the thin side. Its still super easy to do with a dremel!!!!

My 3/32" 316 L cost me about $20 for a 1lb tube. I don't remember how much was in it, but I got a lot of mandrels out of it. They come in 36 inches pieces.

You can also use 308, 312, 314, whatever is similar. Explain to your welding guy that you need this or similar in stainless. They will hook you up!

<<< the thing that is on the bottom under the flower pot. You can get them in so many sizes its easy to find one to fit your kiln.

Lyssa · #30 2011-11-03, 12:14pm

Well, the terra cotta flower pot dish didn't work. All the colors that got icky in previous batches got icky in last night's batch. I have two more ideas to try, but now I've ruined about half of all the hundreds of beads I've made over the last 6 months and I have no more beads to batch anneal. I'm gonna make a handful of beads tonight then batch anneal them tomorrow changing yet another variable: there is a stainless steel metal plate in the bottom of the annealer that could be causing it. We'll see. Wish me luck.