Annealing Cycles

[MikeAurelius]

I've been asked many times to publish the annealing cycles I use in my controllers and kilns, here they are:

Ambient = Room Temperature
Garage Temperature - Hot Kiln Temperature (soft glass between 900 and 950, boro between 950 and 1000 degrees)

1 - Batch Cycle (Soft Glass only)

from ambient, ramp to 960 over 3 hours (5.33 degrees per minute)
HOLD 960 for 1 hour, 30 minutes
Ramp DOWN to 850 over 2 hours (0.83 degrees per minute)
HOLD 850 for 10 minutes (the pause that refreshes)
Ramp DOWN to ambient over 1 hour (or shut off the kiln)

2 - Daily Annealing Cycle, soft glass (assumes kiln is at garaging temperature)

from garage temperature, ramp to 960 over 10 minutes
HOLD 960 for 1 hour, 30 minutes
Ramp DOWN to 850 over 2 hours (0.83 degrees per minute)
HOLD 850 for 10 minutes (the pause that refreshes)
Ramp DOWN to ambient over 1 hour (or shut off the kiln)

3 - Daily Annealing Cycle, Boro, Color Strike (assumes garaging temperature)

from garage temperature, ramp to 1000 over 10 minutes
HOLD 1000 for 30 minutes (this allows the last piece to soak at least 30 minutes)
Ramp UP to 1150 over 30 minutes (5 degrees per minute)
HOLD 1150 for 4 hours (longer the hold, the more the crystals grow)
Ramp DOWN to 1050 over 30 minutes (3.33 degrees per minute)
HOLD 1050 for 30 minutes (this is the actual annealing part of the cycle)
Ramp DOWN to 950 over 30 minutes (3.33 degrees per minute)
HOLD 950 for 10 minutes (the pause that refreshes)
Ramp DOWN to ambient over 1 hour (or shut off the kiln)

4 - Daily Annealing Cycle, Boro, no strike (assumes garaging temperature)

from garage temperature, ramp to 1000 over 10 minutes
HOLD 1000 for 30 minutes (this allows the last piece to soak at least 30 minutes)
Ramp UP to 1050 over 10 minutes (5 degrees per minute)
HOLD 1050 for 1 hour, 30 minutes
Ramp DOWN to 950 over 30 minutes (3.33 degrees per minute)
HOLD 950 for 10 minutes (the pause that refreshes)
Ramp DOWN to ambient over 1 hour (or shut off the kiln)

These are fairly conservative cycles, but I will note that in using these, I have not broken a single bead, sculpture, or pendant.

[paintingwithglass]

Thank you for sharing Mike! It is great to have all of the schedules in one place.

[Roseanne]

Thank you, Mike! Very useful & a great reference

[JulieV]

Thank you Mike!! I too love seeing all the schedules in one place.
Just one question....maybe 2...
I don't understand why you need to ramp up over 3 hours (batch annealing). Doesn't the actual "anneal" occur during the soak and ramp down schedule? Does ramping up quicker affect or have an effect on the out come of the anneal? Not trying to argue, just need to understand........

[MikeAurelius]

A slow ramp up from room temperature will help keep un-annealed beads from cracking due to heat shock.

If the bead is marginal, a fast heat up from room temperature to 960 may cause the bead to fracture and fail.

300 degrees per hour isn't all that fast, but if you just turn on the kiln and set it for 960, they usually will get to that temp in about 20 minutes, which translates to 1800 degrees per hour, which is very fast.

And yes, the actual annealing does take place at 960, but what you need to do is to protect the bead from excess heat shock while it is warming up to that temperature.

As I said at the bottom of the post, these are fairly conservative times, and I've never had a broken bead from using them.

[JulieV]

Thank you so much. I've read SO MANY opinions and hordes of different annealing schedules ,it's great to find one from a "master"!!

[MikeAurelius]

"Master"???? OMG!!! ROFL!!! Certainly not me! I am still a grasshopper!

[JulieV]

BTW, I've got the clip on 92's from you and really love 'em. I took an old pair of my subscription glasses in and had larger nose pads put on them to help accomodate the weight of the 92's. Then I just keep the clip ons on them and switch glasses each time I go to torch. The glasses I wear everyday, all the time have very small nose pads that kinda dug into my face with the weight of the clip ons added. Larger nose pads really, really help! Anyway, works for me.
Thanks again for the annealing advice and the glasses!

[firegrl]

Hi
This is an old posting but I thougth it was very helpful so I brought it forward again..

Thanks Mike I have search and searched for bathch annealing recipe and for helpful hints and yours was the clearest .

Cathy

[Julz]

What temp is it "safe" to remove beads to room temp?
I sometimes torch, garage and anneal in the morning to late afternoon, take a break for several hours, then want to torch again in the evening/night/wee hours. So, if my firebrick kiln is down to 400 or 500 degrees, is it safe to flash it open a few times to speed the cooling so that I can remove the annealed beads and jump back up to garaging temp so I can torch some more?

Thanks for your help.
Julz

[MikeAurelius]

If it's down to 400, you can certainly take the beads out - personally, I'd put them into a bead blanket to cool down the rest of the way -- 400 degree beads left in the open are an invitation to a burn.

[JulieV]

Originally Posted by MikeAurelius

If it's down to 400, you can certainly take the beads out - personally, I'd put them into a bead blanket to cool down the rest of the way -- 400 degree beads left in the open are an invitation to a burn.

Thank you Mike! I too was waiting to see the response to this one.........

[BarbaraD]

Thanks so much Mike for sharing this info.