Simply put, annealing glass is the process of raising the temperature of the glass to a point where the viscosity reduces enough to allow the glass to move and relieve any stress in the glass, and holding at that temperature until the stress is relieved. The next step is COOLING the glass in a manner that does not introduce any new stress into the glass. This is usually accomplished by cooling the glass slowly down past the lower stress point, the temperature at which any stress introduced into the glass is not permanent. And finally cooling the glass to room temperature at a rate that will not cause breakage.

One does not need high tech equipment to accomplish this, one does need to heat the glass to a sufficient temperature, hold it there, and cool the glass slowly. The ancients accomplished this in wood and coal fired ovens, we do it with digital controlled electric ovens. Will the Devardi device anneal beads, yes if you understand what need to happen and when. Is it a reliable and repeatable process, not really, one would need to error on the side of caution and as Lyssa stated, it was possible but a serious pain.

Contemporary Lampworking does an excellent job in explaining the annealing process AND the supporting mathematics. Once you grasp what is happening to the glass the physics and math become a guide to finding an annealing schedule that works for you. There is no magic.

I've tried to stay our of this discussion, but the Engineer/Scientist in me needed to state the facts. I have no intention of offending anyone, I am just stating the facts as I understand them.

Double Post

I'm not getting the correlation between Devardi and dog breeders, barring the fact that there's disreputable people in both factions. Not a fan of either, really...but that's neither here nor there... :-s

You can not win this one..... From past experiences all you are doing is making yourself look like a whiner and poor sport.... Let it go.... It will eventually die on its own time..... But in archive it live on forever no matter how you feel about it.....

Dale

The drop test reminds me of that part in Napoleon Dynamite when Kip puts the plastic container under the van tire and backs up over it.

Glad I am not the only one confused by that post! They both start with the letter "D" ?

This.

It may not be helpful input for the OP, but this forum is a go-to source of information for people researching lampworking, and this thread will always be findable through the search function. It may be read by dozens or hundreds of other newcomers. For their benefit it's important to state accurate facts so that other readers don't come away from it believing that the "throw test" is a real test of annealing, or that the mini-annealer will properly anneal their beads so as to be suitable for selling.

At the very least, having the accurate information available in a thread that will most likely come up if anyone searches "Devardi mini-annealer" could save a newcomer $150 and the heartbreak of some broken beads. Alternately, they might decide to buy one because it will help reduce their loss rate as they practice, and will serve as a rod warmer later on when they get a real kiln.

Either way, they will have accurate information to make their decision with, and I feel passionately that newcomers to lampworking deserve to have access to the best and most accurate information possible.

As the OP said,

It doesn't have a door or a window or a pyrometer. It's open on both ends and a rheostat knob turns the temperature up or down.

You're correct when you say that if the temperature could be monitored and kept constant, there's no reason it couldn't be used to anneal something properly. The problem is, none of those conditions are met on the product as it is sold.

Thank you!! This is what I was trying to explain! Science is science. Period.

You don't understand because you didn't really read Becky's post thoroughly. It's not a matter of reading between the lines either. It's right there.

I'm curious about the history behind annealing glass as electric kilns with digital pyrometers are recent inventions.

http://www.artsmia.org/mia/images/21/mia_21306g.jpg

This piece of glass is from the 1st to 5th century A.D. Did the manufacturer understand annealing other than if he cooled the glass too slowly it would shatter?

I'm genuinely want to know. There are glass pieces hundreds and thousands of years old. Were they properly annealed as the term is now known?

Read about an interesting experiment in annealing glass the "old fashioned" way, done by a lampworker with an historical bent. They found that the ashes from the firepit or oven affected the bead, and that the newly made bead resembles old beads from the start. Not clear or really bright but kind of ashy/eroded. Like that picture. There would have to have been some process developed to allow the transparent glasses and bright colors to be used that the Romans and maybe Egyptians did? But, apparently some old glass beads looked old from the start.

Great question and beautiful vase, but did you mean, "if he cooled the glass too quickly it would shatter"? I wonder of Dunham addresses it in his books. Anyone know?

Scott did not address the historical aspect in his books. A good place to start would be the CMoG Rakow library.

This isn't the exact video I was looking for, but it's close enough. There was one with a gentleman that had a furnace similar to this and off to the side, using the radiant heat from the furnace pots was a small annealing area where he'd put finished work. The earthen materials used to construct the whole thing gave enough insulation to provide a kiln like enclosure that would hold the temperature close enough.

http://www.youtube.com/watch?v=wvxBjgxOW7c

edit: I think this is the one I was looking for: http://www.youtube.com/watch?v=ajoGFeuru0o

This

This

I love this answer. Just have to say it.

Wood fired kilns
Roman mold formed bottles
http://www.youtube.com/watch?v=PMNIEfo6vZY

Cool Aimee and with that I found...
http://www.darkcompany.ca/beads/beads.php?submenu=B
Scroll towards the bottom for beads

D'oh! I messed up, you have it right! Thank you!

And thanks for the resources. I have some researching to do. I am so interested in the history of glass and the annealing process seems to be something overlooked. Maybe because it would only be interesting to a person who worked with glass.

New here. New to Boro and lampwork No classes. No instruction other than YouTube videos. Never even made a piece I’m happy with yet. They crack or just look crappy.
All my gear so far is Divardi gear. Torch melts divardi Boro but I’m just a baboon with a new toy so far.
I’ve never had glass bubble or shock , torch melts glass , I’m just totally unaware of what I’m doing. And in sure the only reason my stuff cracks is I don’t have a garage or cooling blankets.. I just stick them in a crappy little fusing kiln...that I have to heat and stop manually with no thermal reading.
I guess my question is what is wrong with divardi ? They seem to be a sore spot here....
Again , just a question ?
Thanks for input.

In many peoples' opinion (mine included) Devardi sells second rate products, with inflated claims regarding some of it, and outright misinformation on some of it.

Other people love it and disagree heartily. Your best bet, in order to form your own opinion and avoid the drama of the disagreements, is to either forge ahead in blissful ignorance and see if you can make it work, or buy other product and learn the difference.

There are informed opinions, uninformed opinions, and bandwagoneers on both sides of the argument.

:badgrin:=D>

I just threw away ALL of my remaining Devardi glass (@8 lbs) because I was tired of growling at it every time I sat at my bench. That was more liberating than a bra-burning!!! (Showing my age. LOL)

I've not bought glass coe 104 yet from devardi. I'd love to hear your frustrations with their glass. thanks

Just an FYI

I use a Devardi mini annealer and it works great as an rod warmer, annealer, and as a garage kiln. But, I have made some modifications to get it to be great. So, here's what I did:

First, I bent the thick wire support away from the opening until it was at the same level as the bottom of the opening (Keeps rods level). Next I created a removable 'door' that I use to block the opening when running the annealing cycle (It's a ceramic tile wrapped in thick aluminum foil with formed hooks to mount it) Lastly, I bought a cheap controller kit with thermocouple and relay, then I wired the thermocouple through the front of the kiln so it touches the floor about a half inch before the back wall (the 'door' has a small cutout to allow the wire through). I also created a box to hold all the electronics.

Costs were about $100 for kiln shipped and $80 for controller kit shipped plus $20 in supplies. The controller was the toughest part to set up but can be done if you stay persistent. Some controllers come with better instructions than others plus there are several examples of the controller set up online.

I encourage anyone to try this since you get a small digital kiln that goes up to 1100F for about $200. Perfect for beads, pendants, and small boro work....I've even made little fume spoons and annealed 4 at a time.