flame annealing

mikestuart282 · #1 2013-09-18, 4:48pm

I know it exists and most of us probably already do it to some extent but does anybody know how to actually do it?
-mike

RSimmons · #2 2013-09-18, 6:05pm

It doesn't really exist. There are all sorts of claims and conspiracy theories about flame annealing but the bottom line is that the only way to properly anneal glass in with a kiln.

Robert

menty666 · #3 2013-09-18, 6:09pm

Yup, it's a bit of a misnomer. You can "flame anneal" to bring the stress to a fairly reasonable level in order to get the piece to simmer down on a molecular level enough assemble stuff, but it's still in a pretty chaotic state of existence.

kandice · #4 2013-09-19, 12:45am

Yep - no such thing. I think a better term for that is bathing - the process of slowly cooling a bead in the outer flame to get the glow to go down before popping it into a heated kiln.

Maui Greenstone · #5 2013-09-19, 5:09am

Ok to do the thing that doesn't actually exhist, penetrate heat base to the core of your piece and work it outwards(think of it kind of like squeezing toothpaste out of a tube only work it out in all directions). You will be able to bench cool things that before you weren't. It is NOT a real anneal and doesn't work if you have foreign objects like Mandrels in the glass. Also doesn't work if unless you make perfect welds or if your piece is very thick.
Handy trick for doing traveling demos without a kiln or if you want to save on electric and batch anneal.

pattycake · #6 2013-09-19, 5:31am

being new at this still, I do but into kiln and let sit at least half an hour after i put in my last bead or boro, then can i just turn off and let my big kiln paragon 130 cool down naturaly or do i need to hold at a certain temp? thanks

istandalone24/7 · #7 2013-09-19, 5:54am

no....crashing your kiln and letting it cool on it's own (while this may prevent breakage) is not annealing.
you really need to have the kiln progammed so that it will ramp down slowly. once your at a certain point, you can crash it.
i usually turn mine off at 450f....way below the strain point.

losthelm · #8 2013-09-19, 1:32pm

Most kilns don't have the thermal mass to cool as slow as beads need to cool.
You can take a thermal probe or thermalcoupler and chart the data between an annealing cycle and what occurs naturally with your kiln.

Things like ambient temp, humidity, and air circulation in the room will effect how quickly a kiln will cool.

Kilns can be built in the shop if you have time and money for tools and materials.

AKDesigns · #9 2013-09-19, 4:33pm

Quote:

Originally Posted by RSimmons

It doesn't really exist. There are all sorts of claims and conspiracy theories about flame annealing but the bottom line is that the only way to properly anneal glass in with a kiln.

Robert

Quote:

Originally Posted by menty666

Yup, it's a bit of a misnomer. You can "flame anneal" to bring the stress to a fairly reasonable level in order to get the piece to simmer down on a molecular level enough assemble stuff, but it's still in a pretty chaotic state of existence.

Quote:

Originally Posted by kandice

Yep - no such thing. I think a better term for that is bathing - the process of slowly cooling a bead in the outer flame to get the glow to go down before popping it into a heated kiln.

Careful now....you'll get Brad all riled up again:
http://lampworketc.com/forums/showth...lame+annealing
Of course we were all talking about beads and he went off on some other tangent.

Talonst · #10 2013-09-19, 5:09pm

There absolutely is such a thing as flame annealing. It's used in different ways depending on what's being made

In some cases flame annealing is used as a substitute for kiln annealing. The clearest example of this can be see in Suellen Fowler's video toward the end where she's making her hobnail bottle. In that demo she selectively strikes the color of the vase and then flame anneals the piece and cools it in vermiculite. She makes them this way because the even heat of the kiln would remove the selective striking and make the bottle one uniform color.

Another place where flame annealing is used is in the construction of soft glass incalmo and montage pieces. Traditionally these were only flame annealed at the end and not kiln annealed. Flame annealing is also used during the buildup to de-stress the sections as they are built. You can see one of these in the video of Thomas Mueller-Litz here http://www.youtube.com/watch?v=6OtXezwd3Go

Flame annealing is also what is being done when you see Vittorio or Lucio working on soft glass sculptures. This is the working one end - to the other method Maui is describing. Here the work proceeds in one direction and the residual heat is slowly moved away from the area that was last worked allowing the piece to remain between the strain and softening points for a while so that the molecules can move without the piece distorting resulting is removal of most of the stress. In many cases the final piece is annealed but even then the annealing usually takes place at lower temps and for less time that would be ideal so as to preserve the form and prevent slumping.

Many of the scientific flameworkers will tell you that they were taught to make their pieces without kilns using only flame annealing. At the end of the day the master would examine their work under a polariscope and the pieces that showed stress rings were discarded - the idea being you didn't progress until you could make the pieces stress-free. This was necessary because often the apparatus was too large to be put in a kiln or an existing apparatus was being modified with a new part in situ.

So yes flame annealing does exist. Most often it's used to de-stress the piece during assembly before kiln annealing. Other times it is the only annealing.

If a piece had a some requirement, like Suellen's bottles, that prevented kiln annealing then the artist would have to spend significant time working through the process of making the piece in clear or transparent glass and using a polariscope to check the resulting stress. Only then could a piece like that be sold with confidence that it wouldn't shatter.

Generally the success of kiln annealing is relative to thickness and the soundness of the construction methods and joints.

With beads you have the mandrel running through the center so that is a problem. Flame annealing can work with hollow tubing style beads though.

Talonst · #11 2013-09-19, 5:26pm

I'd also direct you to this link which is David Willis's recent Corning demo
http://www.youtube.com/watch?v=Uni21...CBBC08&index=4

If you Fwd to about 45 min in you'll see him working on a loop where the tail is wrapped back around the rod. This is cold-seal city right? It's just asking for a crack, yet he's basically flame annealing it to remove the stress to create something which flameworkers are taught never to do.

LarryC · #12 2013-09-19, 6:29pm

Talonst is right in the sense that if you use the torch flame to bring the whole piece being worked to a consistent temp within the annealing range for the glass being used and keep it there for a period of time, the glass may be destressed. Of course then you must slowly drop it through the strain point and back to ambient at a rate which does not induce any new stresses. Bottom line is that a flame anneal is not the equal of a full kiln anneal under digital control and good practice dictates that you not use it as a substitute.

caliente · #13 2013-09-19, 7:03pm

Quote:

Originally Posted by Talonst

Flame annealing is also what is being done when you see Vittorio or Lucio working on soft glass sculptures. This is the working one end - to the other method Maui is describing. Here the work proceeds in one direction and the residual heat is slowly moved away from the area that was last worked allowing the piece to remain between the strain and softening points for a while so that the molecules can move without the piece distorting resulting is removal of most of the stress. In many cases the final piece is annealed but even then the annealing usually takes place at lower temps and for less time that would be ideal so as to preserve the form and prevent slumping.

Talonst, I have to disagree with most of what you are saying but perhaps it's mostly semantics with the term "flame anneal". However, having been working in Lucio's studio for a week earlier this year, I can tell you that the above is not true. There is no effort to ensure that the part that was just worked on stays warm and that the heat moves slowly out of it. Once you are finished with an area, you can move completely away from it without ensuring it stays warm for any period of time. The work gets annealed at soft glass temps for the standard amount of time after the sculpture is completed. It's not considered to have any sort of head start on annealing based on the method of construction.

Scientific glass blowers are not using soft glass so their rules differ quite a bit re: annealing.

I agree you can reduce the stress in glass by using your flame to ensure the heat leaves the piece as slowly as possible but I don't think you can consider that annealing.

AKDesigns · #14 2013-09-19, 7:26pm

Quote:

Originally Posted by caliente

Talonst, I have to disagree with most of what you are saying but perhaps it's mostly semantics with the term "flame anneal". However, having been working in Lucio's studio for a week earlier this year, I can tell you that the above is not true. There is no effort to ensure that the part that was just worked on stays warm and that the heat moves slowly out of it. Once you are finished with an area, you can move completely away from it without ensuring it stays warm for any period of time. The work gets annealed at soft glass temps for the standard amount of time after the sculpture is completed. It's not considered to have any sort of head start on annealing based on the method of construction.

Scientific glass blowers are not using soft glass so their rules differ quite a bit re: annealing.

I agree you can reduce the stress in glass by using your flame to ensure the heat leaves the piece as slowly as possible but I don't think you can consider that annealing.

Stamp that.

jaci · #15 2013-09-19, 8:23pm

Flame annealing is conceptually like taking ice tray out of the freezer on a really hot day, and putting it in a cooler to try and cool it slower. It will still melt, and become an unstable liquid, its still water, but you dont want it jn your drink to cool it, it just wont work. Your glass can be taken to a state of "not broken yet" without the kiln, but they need to go in the kiln either garaged or batch annealed to be an effective and stable piece.

(And as I'm typing im realizing that this's for more spence in my head, and I'm really tired! Lol)

giraffetech · #16 2013-09-19, 8:46pm

its not really flame "annealling" its more like letting your piece cool slowly out side of a kiln, i have had pipes in the flame for 10 min after i finished attempting to anneal it didnt do anything magic. but what is magic is even heating, and letting things air cool, you can make a pipe and let it sit out and it will likely crack but if you make it and get the most stressed parts warm again then let it air cool it will have a lot higher chance of survival. people say you cant flame anneal because you simply cant but you can dramitcally increase the strength of un annealed glass by letting it it cool uniformly. an example is pushing a bowl popping a carb, *reheating the bowl/carb part of the pipe*, compaired to pushing a bowl and poping a carb then letting it air cool, dont waste your oxygen trying to keep something from cracking, give it a nice even heating and wait, only time will trually tell and the only half fool proof way to make things survive is a kiln..

Lorraine Chandler · #17 2013-09-19, 10:43pm

I have always thought the terminology should be changed to something like FLAME SETTING instead of flame annealing.

I think the words flame annealing are misleading and very confusing for people new to glass, not on purpose of course.

kandice · #18 2013-09-20, 12:15am

Oh, for fuck's sake - SEMANTICS. Boro glass is not as sensitive to temperature change as soft glass, so annealing is not as necessary, from what I have read.

In the beadmaking world, kiln annealing is necessary, most of the time, depending on the size of the bead. It's debatable whether it's necessary for tiny beads. In fact, the whole issue is and has been debatable for decades.

It might be helpful to know what the OP meant by "annealing" - but in the beadmaking world, that generally refers to cooling the beads slowly IN A KILN to avoid internal stress in the glass and increase durability.

Maybe "flame annealing" means something different in the boro/sculpture/off mandrel world, but here, where most people are beadmakers, it's a misnomer.

BellaBean · #19 2013-09-20, 5:27am

Quote:

Originally Posted by losthelm

Most kilns don't have the thermal mass to cool as slow as beads need to cool.
You can take a thermal probe or thermalcoupler and chart the data between an annealing cycle and what occurs naturally with your kiln.

Things like ambient temp, humidity, and air circulation in the room will effect how quickly a kiln will cool.

Kilns can be built in the shop if you have time and money for tools and materials.

I primarily work boro. I also always run an annealing cycle. That said.... I have a Glass Hive kiln. I've actually charted its "cooling down" process once "crashed" at 1150. It is VERY close to the minimum annealing requirements for boro. I've also examined pieces that were in the "crashed" kiln with a polariscope. They showed no stress points. I still like to run an annealing cycle, but it's good to know that in the event I need to crash the kiln (like a power outage or needing to leave the house) the pieces are probably fine.

menty666 · #20 2013-09-20, 6:54am

Boro *does* still need to be kiln annealed. But it also handles thermal changes better than soft glass.

The David Willis demo does show an example of what folks call flame annealing, which is what I described above as a stop gap measure to bench cool for later assembly. That piece he made? It still went into the kiln to anneal.

Suellen Fowler's piece indeed didn't go into a kiln as she said, because to have it hit a striking temperature would undo what she selectively did. However, I'm pretty sure if you asked her, she wouldn't say it was annealed. It was slowly cooled in a less controlled fashion.

If it's not a controlled cool down past the strain point, it's not annealing.

Watch the Cesare Toffolo demo that was done recently at Corning. He "flame anneals" a few times, but his piece will still ultimately be annealed. It's nothing more than a way to manage the glass temporarily while you're assembling something.

Again, that's boro so the rules are a little different.

Generally with soft glass, the Italians will move from one side of a piece to another with the goal being not to wash the flame over anything that's cooled down. In that way you can work a bit bigger off mandrel, but in the end you'll still want to anneal the piece, most likely from cold up to hot and back down again so you don't cause thermal shock by putting cold glass into a hot kiln. If you're going to try that, don't go too thick.

Maui Greenstone · #21 2013-09-20, 5:27pm

This annealing thread got heated(pun intended)..... Sorry couldn't resist.

RSimmons · #22 2013-09-20, 6:08pm

I was once told by a famous bead maker that flame annealing was all that as necessary for beads and that kiln annealing was part of a conspiracy by kiln makers to sell expensive and un-needed tools. Not made up, there were witnesses. The 'flame annealed' bead made in the demonstration, quite predictably, shattered. The bottom line is that glass needs to be kiln annealed if it is going to last.

Robert

Robert

giraffetech · #23 2013-09-25, 7:47am

since people were talking about the cmog videos, i cant remeber who but he was recently put on youtube on cmog making a big cup that holds two liquids, if you watch it you can clearly see that he actually sets the cup down on its rim(compared to garaging it) so he can make the handle and base. and if anyone here knows glass you know 99.9% of the time you cant let hot glass cool on a cool surface or it will brake, even if it is boro(thats what he was using). so it clearly does a lot to flame anneal if done entirely right. its pretty hard considering your torch is presumably hot enough to melt glass and keeping it from not glowing at all takes some practive. a cc+ is like 4000 degress f. i think.. good luck keeping that glass under 1000 degress. regardless flame annealing is really only for batch annealing in my opionion so the concept of "flame annealing" is the art of letting things survive outside the kiln, its very usefull and a must know for any serious artist but i wouldnt waste a tank of oxy trying to let your work completely cool give it a good even heating the let it sit back in the flame for a minute or 3 and every few seconds slowly move further out, till its not making any soda flare or glowing and let it sit for a second and maybe pray a little.. and let it air cool! this is way more then simply "flame annealing though"its the concept of glass, dont jus flame anneal because that isnt enough, you have to work the glass in a way that makes little to no stress in the glass, i may be mistaken but i believe the Venetians mastered this art.. i dont want to go off on glass theory anymore, but i hope this helps someone a little bit:]

LarryC · #24 2013-09-25, 7:53am

Quote:

Originally Posted by RSimmons

I was once told by a famous bead maker that flame annealing was all that as necessary for beads and that kiln annealing was part of a conspiracy by kiln makers to sell expensive and un-needed tools. Not made up, there were witnesses. The 'flame annealed' bead made in the demonstration, quite predictably, shattered. The bottom line is that glass needs to be kiln annealed if it is going to last.

Robert

Robert

If I had a dollar for every comment similar to that I could retire today.

losthelm · #25 2013-09-25, 8:56am

If you have someone handy with a few tools a basic kiln can be made at home.
I think the mailbox kiln was running around 150 in parts and materials before adding a digital controller.
without the digital controller you need to ramp manually so a cheap kitchen timer and a schedule can be helpful.

mandyjw · #26 2013-09-28, 7:02pm

I just wanted to add for those who may be reading this who aren't familiar with flame annealing...

Flame annealing not to be confused with kiln annealing is a very important skill in preparation before putting your bead in the kiln or a fiber blanket to avoid kiln marks, (or santa claus beads in the case of the fiber blanket) or in the case that you let the bead cool too much... cracking.

This is how I flame anneal. When you are ready to put your bead in the kiln heat your bead to glowing and keeping the mandrel turning evenly, wave the bead in and out of the flame reducing the amount of time in the flame gradually. Spinning the mandrel slightly faster than normal the whole time to ensure even heating throughout the very brief amount of the time the bead is in the torch flame, flash the bead in the flame keeping it there only a couple seconds and out of the flame longer maybe 4 or 5. You probably want to do this at least 10 times before putting the bead in the kiln. From there run the appropriate kiln cycle to properly anneal the COE glass you are working with.

phentron · #27 2022-01-12, 5:29am

I did a 12 month scientific glass blowing course in 1971, mostly we use soft glass (because of cost) & only used flame annealing (I still have many of the pieces - thus they were annealed correctly).

1. EVENLY heat the object with a cool flame - do not melt the object, you may need to move it in & out of the flame (thick objects will take longer to EVENLY heat - several minutes)
2. Turn the oxygen (or air) off, keep the glass in the flame, the flame will go white & smoky & coat ALL the glass with a thick layer of carbon (soot)
3. Put the object on a stand (nothing that will absorb its heat & cool it too quickly), cooling should take about 20 minutes
4. When cold, wipe the carbon off a soft cloth or paper towel (use a brush to get into small areas)

Nowdays, I mainly use boro, I use step 1 & then put it in a thermal blanket to cool. I then use the kiln to batch anneal any glass I want to sell (often 7 days after it was made)

Flame annealing (if done correctly) does work for both soft & boro glass.

Peter