Batch annealing schedule - moretti glass beads in an SC2.

[Ali Mesley]

Thanks for asking the question as I was totally stumped with my new kiln too.  Had to get a mathematician to help and your advice was just sitting there.  Great!

Ali 

[Jane C ♫]

What a helpful thread! So glad this is here. Thank you.

[Andy Davies]

Hi Shirley
Thanks for the link but I really want to try and find the manufactures spec rather than someone else's interpretation of it.

I'm sure the details are sound but you never know what allowances have already been added etc. If it had been extended when that person got it and they added extra 'safety time' well you could see how things get corrupted.

Bullseye glass is well technically documented but this Effetre is a b it elusive.

By the way it's for a kiln I've built for myself.

But again thank you for taking the time to get the link.

      Kind Regards ... Andy 

[Pat from Canvey]

Paragon, who produce the SC2 have the following schedule, http://www.paragonweb.com/files/manuals/IM227_Annealing_Beads_v2.pdf but each kiln behaves slightly differently so the schedule needs to be modified to suit how the kiln behaves and also the size of the items being annealed. If the kiln runs hot for example, you will need to lower the top temperature in the schedule. Anathema to someone used to precise measurements but there is no one schedule for annealing beads that fits all kilns.

[Shirley]

I don't remember seeing anything from Effetre about annealing. Certainly not on paper. The glass is pretty well-behaved and compatible and the schedule given here should be fine. I guess the real point is that kilns vary enormously, even within themselves, and this necessitates working within a range of acceptable values rather than with precision.

Some types of glass can be more temperamental. Silver glass and some of the CIM range, for example. There are threads on here about experimenting with different temperatures and holding times to get the best out of the glass.

Something that might appeal to you. I remember Sally Carver (Redhotsal) using UV filters to inspect the beads to check that they were properly annealed. Could be one to look into.

[Andy Davies]

Thanks' Pat Thanks Shirley.

I just wanted to get a better handle on issue, but it looks like they suggest ramping down from a three hour 'hold' at 537°C at a rate of 222°C per hour down to 371°C

And Shirley, do you mean 'UV' filters or do you think that might have been 'polarizing' filters?

I've got some polarizing filters here that I use but I'm always interested in, and distracted by, anything  new or different.

                      ... Andy   

[JanieD]

Paragon, who produce the SC2 have the following schedule, http://www.paragonweb.com/files/manuals/IM227_Annealing_Beads_v2.pdf but each kiln behaves slightly differently so the schedule needs to be modified to suit how the kiln behaves and also the size of the items being annealed. If the kiln runs hot for example, you will need to lower the top temperature in the schedule. Anathema to someone used to precise measurements but there is no one schedule for annealing beads that fits all kilns.

I used that schedule when I first got my SC2 earlier this year, but found that I kept getting 'kiss marks' on the beads, even when I played around with the top temp. I found the best one for me was the garaging schedule from the "Moretti bead annealing schedule as-you-go - SC2 with bead door" thread.
My kiln overshoots on full ramp so I ramp at 700 as in the edit to the thread, which has been so useful to me as a resource.
I don't know what I'd do without Frit Happens, (well I do but hitting one's kiln with a large hammer may make you feel better at the time, but leads to dismay later).



Jane

[Shirley]

Thanks' Pat Thanks Shirley.

I just wanted to get a better handle on issue, but it looks like they suggest ramping down from a three hour 'hold' at 537°C at a rate of 222°C per hour down to 371°C

And Shirley, do you mean 'UV' filters or do you think that might have been 'polarizing' filters?

I've got some polarizing filters here that I use but I'm always interested in, and distracted by, anything  new or different.

                      ... Andy   

Sorry, yes, polarising. Not something I'm into myself.

[flame n fuse]

I also use the SC2, but find that a top temperature of 482 is better - at 537 the beads are too soft. Never had any problems with the resulting beads when annealed on our amended programme. We let the kiln cool naturally from 371, and don't open the door until the temp is less than 100. Presumably the calibration of the kiln is 'out'.

We have similar problems with another kiln which is used for fusing Bullseye glass. We run a cooler program than BE recommend for it, and get a better finish (less devit, better edges) as a result. 

[Essex Girl]

I also have an SC2 and have to use temps of 20c less to stop my beads going tacky!

[Sarah]

I just wanted to get a better handle on issue, but it looks like they suggest ramping down from a three hour 'hold' at 537°C at a rate of 222°C per hour down to 371°C

                      ... Andy   

That sounds like a very fast ramp down to me Andy. I've always believed - and no matter how much I rack my poor old brain I can't remember where the figure comes from - that you need to ramp down at about 1 c per hour till you've passed the strain point. Once you've passed that you can cool more quickly but still need to be wary of thermal stress. From a quick search it's also the conventional wisdom - doesn't mean it's right of course!

A three hour hold at the annealing point is probably longer than you need but, as you can't over anneal glass, won't cause any stress in the bead. Some colours don't like a long anneal especially some of the silver glasses (although some like pandora need a long hold) and I think some runs of rubino have issues too.

I think you're going to have run some beads through your kiln a few times and work out your schedule from there. Both of my kilns run hot but I have got to know them well and cope with their individuality. I've just started casting and have been able to apply adjustments to the standard schedules before the first run with some success but have still adjusted according to results.

Bullseye have some downloadable kiln sheets which enable you to track what you're doing on each run and what your results are. They are designed for fusing but will help with annealing too. And they'll help with colour combos that do/ don't work or which come out of the kiln looking entirely different to how they go in.

Bullseye are far better about making technical info available than the Italian manufacturers. It's a pain but I've always assumed that this is partly cultural and partly because Bullseye's business is art glass whereas the Italians make all sorts of glass for lighting etc.

Apologies for my verbosity

Sarah
xxx

[Andy Davies]

Thanks Sarah, that's why I questioned it, how would you interpret what's said in the link?

http://www.paragonweb.com/files/manuals/IM227_Annealing_Beads_v2.pdf

Regards ... Andy

[Shirley]

Andy, that extract from the manual is not a batch annealing schedule, it's a garaging programme where you make a bead and then put it in the kiln immediately rather than popping it into vermiculite and annealing later. That explains where the 3 hour hold comes from, but in this case it is 3 hours of working time before the kiln is programmed to move on to the next segment. If you wanted a different amount of working time you could increase or decrease the hold time. On my kiln I have an 8 hour hold to allow me two work sessions per day if I need it. It isn't saying that on a batch anneal you would hold the beads at the annealing temperature for 3 hours.

On my garaging programme I hold at 510C, then up it to 520C for an hour to anneal, and then it ramps down to 371C, and then turns off. 537C seems rather high. Higher than I would think most people anneal at.

[Andy Davies]

 Thanks Shirley

At what rate do you ramp down at to the 371°C point?

                      Kind Regards ... Andy

[Shirley]

Off the top of my head I can't remember. Couple of years since I programmed the kiln. Probably the 50C in the programme at the beginning of this thread. It's not too quick. Works fine.