To anneal or not to anneal?

[Steampunkglass]

I've been playing around with using thin clear glass to make mesh patterns both regular and irregular (I prefer the irregular designs) and I have plenty of ideas to upscale these to make larger sculptures. However doing that will make them too large to anneal in my present kilns, even if I did them in parts then joined them together as the joints would need to be annealed  

Looking into this in a bit more depth I found that Susan Plum makes enormous sculptures over 3ft tall like this, often on site with 3 or 4mm clear rods, and doesn't anneal anything. Looking at what I've made between some polarised filters I'm finding it really hard to find areas that are showing stress, and I suspect these are areas where I've gone back to parts I've already worked on. I think a lot of Murano sculptures weren't always annealed, and as the techniques I'm using are the same as glass ships used to be made out of at fairgrounds. I am wondering if this is a case where annealing is really needed?    Most of the glass isn't more than 3 or 4mm in thickness

[GlassWorks]

i say make em full size and check it out then.. i suspect that flameworking the boro with a free hand torch would allow you to flame anneal the bits as you work you way up?.. i have seen huge HUGE 104 glass pieces made by the muranese masters which are not annealed and are in the most well known museums and collections worldwide...

[Ian Pearson]

Great subject. I have oven annealed scupltures cracked and oven unannealed sculptures not. Dont foregt one doesnt have to use an oven to anneal. Just even distribution of heat and coolonmg. I am in process of making a full size stags head from 9mm borosilicate rod and hating it. Getting to heavy to hold and one antler fallen off. Could use  ahand lamp but using bench lamp. Its is cracking all the time so i just heat up the cracks and keep on and on. I will anneal in oven at Lybster maybe next month but not sure if I would hang it as nothing is for sure.

So just make sure you have the right heating/cooling style and you are probably annealing without realsing it. Covering glass with soot is another way - messy so i dont use it but I know those that do.
Ian

[Ian Pearson]

Forgot to say use a heat resistant blanket to slow down cooling after heating two parts joing if like. A lot of vacuum systems in universities are metres and metres long and are just flame annealed

[tuffnell glass]

Hi ,
As an apprentice I was taught to flame anneal tubing , joints and rod. Turning the propane up to the point were the glass started to pick up a black carbon skin we would cover the whole creation in carbon and warm the whole creation , believing that this would give us extra time to think about whether we needed to anneal or not , must be honest their was some stuff that never made it into the kiln .

martin

[Steampunkglass]

Hummmm..... interesting! Maybe if the stags head survives I might get a chance to see it when I'm up there next month! I did think about trying the soot annealing thing, or popping bits in the kiln as I go, but I didn't think about using a heat resistant blanket. I did warm it up a few times in a bushy flame, so maybe that helped a bit 

I put it in the freezer a couple of hours ago (in a plastic bag, just in case!) taken it out, bashed it on the bench a fair few times, and so far, touch wood, it's all stayed in one piece..... so there's hope there!

[tuffnell glass]

Hi ,
I thought you had lost it then Glenn when you said you had popped it in the freezer , is that a new annealing technique?

martin

[Steampunkglass]

Hi ,
I thought you had lost it then Glenn when you said you had popped it in the freezer , is that a new annealing technique?

martin

I'll try just about anything once!    I was expecting the cold to cause it to crack and turn into frit though!

[garishglobes]

Having worked with Janis Miltenberger last summer, her general take seemed to be that you should anneal. She makes huge structures in clear glass, though I think she does then sandblast and paint, which would probably add stresss if a point was already weak.

I think she would say, componentise by all means, so that parts of the sculpture slot/fit together, but if you have flame worked, you should anneal. However, I think (don't quote me!) that she also said that the occasional joining of thin pieces wouldn't be too bad left un annealed. I have to say that the more you add to a lace like structure, the more stress seems to build up and after a while, from experience, it just needs annealing. But that could also be because I very definitely wasn't making any effort to keep an even temp as I went along or to do any form of flame annealing!

[Steampunkglass]

Lace-like structure! Perfect, I was wondering what to call this, and sounds better than 'glass crocheting'! 

Interesting! I think I read that sandblasting can add stress as well, but I may be wrong on that! I thought about how I can make some things in sections, but with my current kiln set up I can't make any large curved items unless they aren't taller than a couple of inches tall, so if I made a ball I'd have to do it in slices meaning there would be a lot of joins anyway. 

However this is yet another 'side project' to the stuff I really should be getting on with, so I should really leave it along and go and get on with finishing one of the other hundred half finished projects!

[Pat from Canvey]

Glen, what kiln are you using now. When I made some larger roses that wouldn't fit through my SC2 bead door, I just opened the main door and popped the roses inside with no problems.

[Steampunkglass]

It's a paragon bluebird Pat, I've also got another little kiln that's got a 150x140x160mm chamber, but I was playing around with the idea of making things much larger than this. The bluebird is ok to do large 'flat' things in it, as the chamber is about 1/2mtr long inside, but not much height if I want to do more spherical or egg shaped things 

[Magpie]

Hi ,
I thought you had lost it then Glenn when you said you had popped it in the freezer , is that a new annealing technique?

martin

Wasn't the freezer bit that had me cringing, it was the thought of it getting bashed on the bench after!

[Steampunkglass]

Hi ,
I thought you had lost it then Glenn when you said you had popped it in the freezer , is that a new annealing technique?

martin

Wasn't the freezer bit that had me cringing, it was the thought of it getting bashed on the bench after!

Seemed not to bother it, even giving it a good few hard bashes! Although probably not as tough as Ian who makes hammers out of boro! http://northlandscreativeglass.wordpress.com/2014/02/28/guest-post-rebecca-milling-rsa-artist-in-residence/ Don't click on this if you can't look at broken glass!

[Miriam]

In Murano they anneal everything. Like Lucio, he does batch annealing and has all sizes of ovens to fit his pieces in. I know some beadmakers over there they batch anneal also.

We have been to Lauscha and they seemed not to anneal their stuff.