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Boro annealing schedules

Started by garishglobes, June 24, 2010, 03:24:20 PM

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garishglobes

I thought it might be useful to do a quick thread on boro annealing schedules so that the info is in one place. I've copied bits from various other threads, so that we have one thread to look at rather than several.
I think there may well be as many boro schedules as there are boro workers - but I hope these will give a start to anyone wanting to have a try with the hard stuff.

Boro can (specially for small pieces) be garaged with soft glass, run through the soft glass annealing schedule and then batch annealed later - useful to know if you just want to play at the end of a session using soft glass.

http://mikeaurelius.wordpress.com/2007/12/26/annealing-cycles-for-torch-made-glass/

I used to use this schedule: (all in degrees C)
garage at 505, then ramp up to 565 at 80 degrees to anneal for an hour. I then ramp down at 90 to 510 to let the glass "rest" for 10 mins and then down to 370 and switch off

but now use one closer to Glenn's (Dendrobium) below, with a longer annealing time (my stuff has got larger) and a striking part at 590 added in. I have seen striking temps go up much higher than this - quite a bit over 600.

Hope he won't mind, but here's Glenn's schedule (also degrees C):

"I've seen various advice on garaging everything from 510 up to 540, but the important bit is ramp up to 567 for about 1hr, then a slow ramp down (about 46deg per hour) to about 525 for a short rest (10mins to 1hr depending how thick) then a slow ramp down to 370. Thicker bits will need a longer anneal, and if you've got ruby colours you will need to do an extra ramp up before the anneal to about 582 to strike the reds which tend to strike better in the kiln rather than in the flame"


Nick

Hi,

Thanks for the schedules. Can you please confirm is it degrees C or F

garishglobes

Good point! Have amended above!

Steampunkglass

I read somewhere there are as many boro annealing schedules as there are people working boro!  :D

Just to add to the general confusion, I've started garaging even higher, at 560-565 deg c (1050 deg F) after reading Margret Meers book and other clever USA people who garage at the annealing temp to allow the stresses to come out, then they can take things back out of the kiln to work again with the advantage of it already being hot and partly annealed. I still ramp up the whole extra 2 degrees to 567 and leave kiln untouched and unopened at the end of day when I run the annealing program.

Although alot of the time lately I'm batch annealing cause it's just too hot! Most things seem fine, I think I've lost one marble to cracking in the past couple of weeks - and it was a lousy marble anyway!  ;D

julieHB

Great info for us softies who'd like to venture over to the dark side now and again... 8)
Julie xx

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garishglobes

Glenn, does garaging at 560+ affect the colour at all, or do you notice no difference?

Steampunkglass

Quote from: garishglobes on June 24, 2010, 10:11:44 PM
Glenn, does garaging at 560+ affect the colour at all, or do you notice no difference?
I've not done it very much yet at the higher temperature, touch wood so far it's not seemed to have been a problem, but that is a good point as I know some of the colours like (I think) unobtainium have warnings about over garaging - I've had that cause cracking at lower temperatures.

The only colour that I've ever had a problem with is Red Elivis which tends to self strike, and I forget about the higher strike on the cycle and had that come out a rather grim shade of raw liver by over striking. Thats only really a problem though if I've used really thick layers of it.

garishglobes

Just to update this, I've now done a few sessions garaging at 565, and it seems fine

fionaess

A batch annealing schedule would be nice - anyone got one?


If it's got a hole, it's a bead !

Steampunkglass

I tend to batch anneal with this schedule too - I leave everything in the kiln, warm it up to garage temp then carry on working. When it's full or I've had enough for the day (usually the later!) I let it ramp to 567 and anneal.


fionaess

Being an absolute dummy as far as my kiln is concerned - could you spell it out for me.. ie  do I just tell it to go to  to 505 from cold then increase by ? minutes to ? temp - hold it for ? and then decrease by ? degrees... Im confused now..... HEEEEEEEEEEEEEEEEEEEEEELP


If it's got a hole, it's a bead !

garishglobes

Fiona, I now do this:
Ramp up to 565C at 700 degrees  (ie full-ish), hold for however long to garage, then ramp up to 590C at 80 degrees and hold for 20 mins. Down to 565C at 80 degrees to anneal for 2 hours. I then ramp down at 90 degrees to 510C, hold to let the glass "rest" for 10 mins and then go down to 370C at 90 degrees and switch off

fionaess

Thanks Emma  - I'll see if I can 'program' that in... awwww shit now I have to remember how to do that :):) :)


If it's got a hole, it's a bead !

fionaess

Is this right?

Seg    Rate   Temp   Hold
1        700    565C     ---
2          80    590      20 mins
3          80    565      2 hrs
4          90    510      10 mins
5          90    370        ---


If it's got a hole, it's a bead !

fionaess



If it's got a hole, it's a bead !