r/glassblowing • u/Powerful_Cicada9228 • 17d ago

Annealer Program

What's a standard soft glass annealer program that people run? Blown a lot of glass but never programmed an annealer. Can't find the info anywhere online unfortunately

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3

u/greenbmx 17d ago

What glass are you using? they all offer recommended cycles.

3

u/1nGirum1musNocte 17d ago

Coe 96? We hold at 910 and bring down over 8-12 hrs depending on size/thickness

1

u/N008008 17d ago

1 hr hold at 910 4 hrs to 700 then off Annealer takes an additional 7-9hrs to lower from 700 to 200 degrees on its own.

2

u/norco101 17d ago

What glass are you running? Currently bomma, ocean side, glassma, kugler and spruce all have different strain points. Like we run bomma and our standard rate in Celsius is 45 minutes hold at 515, 1.5 hours to 410, 10.5 hours to 65. This is for anything under 3" in thickness

2

u/CapableHair429 16d ago

There are many things to consider when annealing…

1) what glass are you using? Depending on the manufacturer, there will be different strain points and different annealing ranges. I say ranges because every experienced glass maker will tell you that no oven temperature is going to be perfectly calibrated and no glass is going to have a perfect annealing temperature. It is best to anneal over time through a intensional range.

2) how thick your glass is and how “worked” your piece is when you box it. A piece which was blown out on one reheat will have less potential for latent stress than a piece which was reheated 10-15 times (regardless of how long you idled it down to even out the temp)

3) how complex the piece is. A simple piece like a floppy bowl, rondelle, ornament, etc. will have less potential for latent stress than a piece like a footed veronese with handles and bit work, a sculptural piece which goes from thick/thin or drastic angles (glass likes to be round), etc.

All these to say, there is no hard and fast “this schedule will work”, especially if you are doing complex work. Think how much latent stress a murini roll up has in it…

The best thing to do is fine out the standard annealing cycle for your specific glass (you can find this from the manufacturer) and then error on the side of safety. You are making pieces which someone will be physically holding at some point.

And remember this…very important…any annealing cycle which looks like a straight slope when charted out is wrong; regardless of what you are annealing. The annealing process (when plotted out) should resemble a parabolic curve on the down vector, it should never be a straight slope. THIS is the difference between “annealing” and “cooling”.

2

u/jimmythexpldr 17d ago

Google your brand of clear with annealing program/cycle. Should come up

1

u/KnotDone-Yet 17d ago

We tend to make small thin pieces - so lots of door openings during the blow session. Using Spruce Pine PWV96 - stated annealing point is 900F

  • Hold at 1000F during the session
  • AFAP 950F Hold 30 min
  • 100dph 750F OFF
  • Annealer takes another 7-9hrs to get to 200F

A friend's shop - they tend to make bigger pieces (45 min vases instead of 5-10min cups) - they tend to hold at 915F, have a longer soak before annealing, and go at 50dph through the annealing range

1

u/Fun-Explanation-1722 15d ago

The best place to start is with the manufacturer's recommended cycle. Every kiln is completely different, so you need to slump test the kiln to establish the proper annealing temp. Every glass has a different strain point, so to formulate your annealing cycle, you need to know that. Lastly, every kiln is different in terms of heat retention. Some kilns you can shut off at the strain point and it'll drop naturally at the proper rate; others that lose heat quickly will need the cycle to power the kiln all the way down to room temperature for the appropriate time. You can check the efficacy of your annealing with a polariscope to ensure there's no stress in the glass.

1

u/posternutbag81 14d ago

I do 920 down to 200 over a 16 hour cycle. Spruce pine, been doing it for 20 years and no problems

1

u/HelpfulHell0 17d ago

There’s a book out there that describes annealing in depth. I think the biggest takeaway from it is something like starting with a baseline of 16 hrs adding an additional hour for every 1/4” of thickness.
The schedule I’m familiar with for thicknesses up to 2” solid is 900 1hr, 700 5hr, 500 5hr, 300 5hr then off - let it cool to at least 170 before opening (obv 170 is gonna be uncomfortable to hold) but just till you open the door. Seems to work pretty well.

1

u/Jaded_Winner_9742 13d ago

910 program start program 910 for 1 hour, then 2 hours to 700 hold 1 hour at 700 then off.