Annealing Schedule

[julieann1674]

Hi everyone, how long is a typical annealing schedule? I typically start mine in the evening and "sleep" through it..... For 104, and I have a glass hive. I'm really new at the kiln stuff.

[whatwhat]

I use a different schedule depending on the size of the pieces in the kiln. Contemporary lampworking has a good explanation of why different rates matter and what rates to use depending in the size. My chains can be annealed in less than an hour but a large pendant or marble takes much longer.
Dan

[Polgarra]

Glass hive has their default schedule on their website. That is what I have always used.

[bbisker]

It is my understanding that the Glass Hive kiln is preprogrammed before they ship it so that when you turn it on it heats to the holding temp and when you are done for the day you start the program to finish the annealing schedule. I have my kiln on order from them and this is what they told me.

[Eileen]

Julie, are you talking about batch annealing?

[julieann1674]

Contemporary lamp working, I will look into that. Yes, the Glass Hive does come preprogrammed for the normal annealing schedule. I do have to program it for Batch annealing and set it as program 2...but I haven't done that yet.

I am just curious how many hours one standard program takes to run through....I really need to learn more about this as well. Can I run it early in the morning and then work like crazy in the afternoon and run it again? Or should I just garage all day then run only at night. I guess I will figure it all out as I go too.

[mandyjw]

Usually at least 8 hours I think.

[Eileen]

Just as info, I normally run 10 hours at garaging, then when I finish working, I skip to the anneal stage. I anneal for an hour, then ramp down at 150° an hour to ... 450 I think? 500?
I leave it (a Chili Pepper) to come down on it's own from there. So when I stop working, I can go turn the kiln off in about 4 hours.

With your kiln being brick, I think people shut them down hotter though, so even less time I would think.

[glass butterfly]

Hi Eileen, Do you run the 10 hour garage temperature as you are working and what is your garaging temperature? However,if you finish working earlier, do you then change to the annealing temp for one hour and at what temp is your annealing temperature? Do you then program for the kiln to ramp down at 150 to 450/500?and then let it come down on it's own? At what point do you shut the kiln off. Is this the schedule you use for all your glass? Thanks. I'm still learning and wondering about the best garaging and annealing temperatures to us to anneal the glass properly for maximum color, minimum unwanted color shift and no cracks. Tall order, no? Lydia

[Eileen]

First let me say that I am far from an expert, but this is what my schedule is, and so far I haven't had any problems. I don't guarantee it will work for your kiln, different kilns, different pyrometers, etc. may read differently.

My personal schedule is close to this (don't know if I have the degrees perfect or not)

Ramp to holding temp of 923 I think. (if I have some beads I want to heat already in there, I do it slow, if not I do it fast - like 1600° per hour)

Hold for 10 hours. (*when I finish working I skip the rest of this step, I never work 10 hours but this makes sure it never goes to the next step too soon)

2nd ramp (this isn't too important to me, since I'm already pretty much where I need to be, so I just use the 923° or around there)

Hold 1 hour
at 925? Depending on your kiln & special glass requirements, this may work for you or you may have to adjust. I used to use a higher annealing temp (940°-950°), but dropped it to try to make my occasional silver glass piece happier.

*I haven't made anything larger that needs more than one hour yet, but if I do plan to do something larger, I would change this to the longer time needed.

Ramp at 150° to 450°
Hold 0
Shut off.
(I personally turn the switch to off at this point (usually unplug) or at least before I go to bed, just in case of a power glitch, relay failure, whatever, but many don't)
I leave them in the cooling kiln until they are down to touching temp. (for me, I'm OK with 190 or below, some leave them until room temp)

You may or may not find that this fits your needs.

I have heard that Lauscha (for example) needs higher temps. I only have a little, but so far using it at the beginning of my session so it is in the kiln longer has been OK. I need to try a few other colors to see how they do. Most of my glass is Effetre, and so far I've only had one bead crack after the fact, and it had a color of CIM that I read has some "issues", so I need to check into that more.
Many people with brick lined kilns turn them off at a higher temp, but I have a chili pepper that is in an outside shed, and this works for me so I don't have to worry that it is coming down too fast while I'm not there. I used to use 600° to shut down, but it made me worry, so I dropped it down.

PS. So far I've only been working 104. I know for sure that boro needs more heat, have to research still for 96 and 90

[glass butterfly]

Thanks for your input, Eileen. I've been keeping the kiln at 960 while I work and then just about an hour after the last bead I shut the kiln off and unplug it in case of any mechanical or electrical problem. However, since I've started playing with silver glass and tried some kiln striking pysche and other glass, my silver colors are yucky and the kiln striking hasn't been working, so will try setting the kiln at about 920-923 for garaging while working and then shut off after working to see if the silver glass is happier, especially the kiln striking ones. I have a Paragon SC2 kiln which is a brick kiln, so I just shut it off rather than ramping down. I did make several beads from the veiled 96 glass that I bought in the Garage sale and garaged and annealed them at 960 and had no problems with them but they were tiny beads. Since I've been fusing for years, I have a lot of BE 90 glass that I'd like to try lampworking with but don't know what the garaging or annealing temperature would be. I have a lot of 90 dichroic glass that I'd also like to play with but will wait until I stop getting wonky off center beads first. Lydia

[28676bhe]

BE is 90 COE and they recommend annealing at 900 degrees. Don't worry about mixing 104 and 90 in the same kiln load. Just program it to hold at 925 and then another hold at 900 for about the same amount of time.

I have always been told that you cannot over anneal......but you sure can under anneal!

[Eileen]

Originally Posted by glass butterfly

However, since I've started playing with silver glass and tried some kiln striking pysche and other glass,

Lydia, I'm under the impression that psyche is a reducing glass. Are you reducing it before you put it in the kiln? Pandora is kiln striking, but not pysche unless I'm mistaken (which could well be, but the DH web site says reducing)

[glass butterfly]

OOOps, You are right Eileen. No wonder it didn't strike in the kiln, duh!!!!!! I didn't try to reduce it first - just got confused Today I used DH Gaia and Oxalis and reduced them before putting into the kiln. I didn't even try the psyche again - next time. I need to keep a chart near my torching area to remember which glass does what. Thanks for the reminder Lydia

[Eileen]

You're welcome. I just learned that myself, so I remembered

[glass butterfly]

Barbara, Thank you for the annealing info for the 90 glass and you are right about the under annealing. I have a few mandrels with cracked beads which I under annealed . I left them on the mandrels and plan on trying to save them by warming them up gradually in the kiln and then trying to heal the cracks at the torch. Hope it works because they are some of my non wonky beads. Lydia

[glass addict]

I hold at 970 while torching
then hold at 970 for 3 hours
ramp to 680 over another 3 hours
hold at 680 for 2 hrs
off

[glass butterfly]

Do you use the 970 for Silver glass also? Can you use that temperature for kiln striking glass like Pandora? Thanks. Lydia

[glassmaker]

Originally Posted by glass butterfly

Do you use the 970 for Silver glass also? Can you use that temperature for kiln striking glass like Pandora? Thanks. Lydia

Although it depends somewhat on the individual kiln and how accurately it can hold a temperature, generally speaking it's a pretty solid "no" on holding a long time at 970F for silver glass Lydia - at least the stuff I make. Most of my glasses will change color if held at that temperature for a substantial length of time. I believe most 104 silver glass from other makers probably will too.

Kiln striking glasses typically contain copper, which normally strikes at a higher temperature than 970. But a long hold at that temp might do it too.

Oh, and I would recommend against trying to reheat and heal cracked beads unless the crack doesn't reach the mandrel. Most of the time the bead release cracks along with the bead and getting the glass hot enough again to seal the crack will usually just stick it to the mandrel.

Brad

[28676bhe]

I don't understand the hold at 680.....Could you explain the whys? Thanks!

[glass butterfly]

Aahhh, I've been garaging and holding all my glass including your SC glass plus other silver glass at 960 for about 4 hours, Brad and getting a khaki poo color So lowering my garaging and annealing temperature to 920 could avoid the yucky khaki color. I have a Paragon SC2 kiln which is brick lined so it holds temperatures fairly well and I don't ramp down, just shut the kiln off after letting the last bead anneal for about 30 - 60 minutes depending on size of bead. I guess that I'm going to have to experiment to see what the ideal garaging and annealing temperatures for my kiln are. I may have to stop shutting my kiln off after annealing and start ramping down to avoid cracked beads.

Okay, I'll also check to see if the cracks on my beads extend to the mandrel and I suspect that they do since many are small beads where I've attempted to make 2 or 3 per mandrel to try and get identical or at least close sized beads for earrings. I need the mandrels more than I need plant stakes.

Thanks for the help. Lydia

[Hayley]

For those of you who just shut off the kiln after holding for a period of time at annealing temperature, I'd suggest you add a slow (about 100F/hour) ramp-down schedule to your schedule even if you have a brick-lined kiln, then shut off at 700 (some people are conservative and shut off at 400).

I have written about annealing silver glass on my blog for those who are interested:
http://envisionsf.blogspot.com/2009/...mperature.html

[glassmaker]

I hadn't seen that page before Hayley. It's great advice for annealing silver glass.

However I did spot a typo under the heading "One Last Thought". In the sentence that says "To make sure that your kiln does spike pass your annealing temperature, you may consider lowering your garaging temperature as well. " I assume you meant "does not" instead of "does".

Brad

[glass butterfly]

Hayley, Thanks for the good advice on annealing glass. I printed it out and am now looking for my instructions on how to reprogram my kiln so I can add a ramp down and change the garaging and annealing temps. Lydia

[julieann1674]

Ooohhh, thank you Haley!!

[glass addict]

I hold at 680 since that is around the strain point. I haven't done much with silver glass, so I can't comment on what temp works for that.

I chose 970 a long time ago based on the annealing range for effetre.