Hi, I'm new here & will get straight in with a problem.
I have been experimenting with very basic float glass snowflakes. They are 3mm glass from a window with a copper wire inclusion as a hanger & originally some gold flakes but they fell off!
See pic below.
(http://www.catswhiskerscattery.co.uk/glass/Problem%20Snowflake.jpg)
I like the devitrification because it makes the snowflake look frosty but I cannot get it to actually fuse.
So far I have tried to fire them 4 times, as follows.
1]
Segment Ramp Rate (ºF/hour) Target (ºF) Hold (minutes)
1 250 1100 15
2 200 1245 30
3 9999 1510 15
4 9999 1100 35
5 150 900 0
Try 2] holding for 5 more minutes on segment 3
Segment Ramp Rate (ºF/hour) Target (ºF) Hold (minutes)
1 250 1100 15
2 200 1245 30
3 9999 1510 20
4 9999 1100 35
5 150 900 0
Try 3]
Segment Ramp Rate (ºF/hour) Target (ºF) Hold (minutes)
1 250 1100 15
2 200 1245 30
3 9999 1520 22
4 9999 1100 35
5 150 900 0
4th attempt
Segment Ramp Rate (ºF/hour) Target (ºF) Hold (minutes)
1 250 1100 15
2 200 1245 30
3 9999 1550 20
4 9999 1100 35
5 150 900 0
I've cooked them so much the copper wire has burnt through.
My kiln is a Skutt Firebox & I would appreciate any advice from the knowledgeable out there. :)
Hello Sharon
I've never fused float glass, but it sounds as if your programmed temperatures should be within the right range. Have you used this kiln before ? (I'm wondering if the temperatures are reliable).
Yes, I've used it very successfully with both Bullseye & other float projects.
When I tack fused float it took me a few tries to get it right with a certain softness to the edges but this has me stumped.
With my firebox on its auto fast and full which it states to be 1465 I get a mid fuse on float. Were you wanting a full fuse or are the pieces not sticking together?
I wondered the same as Silkworm - do you mean they're not sticking, or do you mean you want a full fuse? They look nicely tacked to me?
1550F is 843C which is about what I do a full fuse of float glass at.
Are these pieces that you've re-fired several times? Or tried different pieces at the different temperatures?
If they are ones that have been back in several times, I'd guess that they're now beyond re-working, as the devit will probably be doing something to stop it fully fusing together. Try using the 4th schedule with a new batch. Or even one on its own if you don't want to waste loads more time cutting lots of snowflakes (kilns cost a lot less to run than you think)
Are you sure it's float glass, did you buy it from a store or could it be from a double glazed window? If so, could you be working with K glass or E glass, that's a very even de-vit you're getting there otherwise? Actualy, for float, it looks very 'water white' float normally shows quite a green tinge - is it possibly Optiwhite, which I've never tried working with but I wonder if it fires differently due to it's altered formula?
(https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/307687_265028973530591_699214494_n.jpg?oh=0605e19e5ffb2f5df36889859b5ddfe4&oe=5521290B&__gda__=1433296821_abde353510bd8650ad0f820c66e56e09)
Although this was only tack fused, I find it very difficult to get a full fuse to the treated side of Pilkington K/Planibel E glass (to the point I stopped trying)
Some good points there, thanks to everyone who responded.
To try and answer all points in one go.
When I said fuse I meant full fuse not tack fuse. As I mentioned I have tack fused float glass no problem & these are most certainly tacked, sorry I thought you could see this in the photo.
All pieces fired 4 times. I was wondering if the devit somehow was holding the form so that it couldn't draw up properly.
I've looked back at my records & the first fuse was in fact a tack fuse because I needed another piece of float tacked urgently. There was no devit after tack fuse & they were tacked OK.
The second firing was supposed to be a full fuse & this is where the devit appeared. The devit seemed to increase with each firing.
I have no idea what the glass was originally, it could have been window, greenhouse or double glazing, but I doubt if it was Pilkington K. The original pieces of glass did have the green tinge to the edges.
When I first tack fused float it took 4 attempts for the edges & points to soften enough, I got some devit but not as much. My second attempt was right first time using the 4th attempt firing schedule.
My biggest problem is patience. It seems as though I just have to learn from experience with this one. The trouble is I hate to throw any glass away, even if was a feebie. Any ideas as to what I can do with 3 failed snowflake experiments???
You might try using devit spray and see if that helps, see http://www.warmglass.com/making_your_own.htm
Quotehttp://When I said fuse I meant full fuse not tack fuse. As I mentioned I have tack fused float glass no problem & these are most certainly tacked, sorry I thought you could see this in the photo.
I thought it looked like it had tacked quite well, that was the confusing thing as you said it hadn't fused. :)
Quotehttp://All pieces fired 4 times. I was wondering if the devit somehow was holding the form so that it couldn't draw up properly.I wondered that.
Quotehttp://The second firing was supposed to be a full fuse & this is where the devit appeared. The devit seemed to increase with each firing.
1510F = about 821C - I only get tack fuse at that.
Once devit has started, it will get worse each firing, as it's where the glass has crystalised, and the crystals will grow.
Quotehttp://I have no idea what the glass was originally, it could have been window, greenhouse or double glazing, but I doubt if it was Pilkington K.
If it did come from a double glazing unit, why do you doubt it could be Pilkington K? It's been used in DG units for years.
Quote from: Sharon the Cat on January 07, 2015, 07:48:15 AM
My biggest problem is patience. It seems as though I just have to learn from experience with this one. The trouble is I hate to throw any glass away, even if was a feebie. Any ideas as to what I can do with 3 failed snowflake experiments???
Am much the same, hate to throw anything away. However, after nine years of fusing, I really need to think about getting rid of something things! :D
Quote from: Zeldazog on January 07, 2015, 09:17:53 AM
Quotehttp://When I said fuse I meant full fuse not tack fuse. As I mentioned I have tack fused float glass no problem & these are most certainly tacked, sorry I thought you could see this in the photo.
I thought it looked like it had tacked quite well, that was the confusing thing as you said it hadn't fused. :)
My abbreviations I use to myself Tack = tack fuse, Full = full fuse, Slump = slump. Why use 2 words where I know what one means? ;)
Quote from: Zeldazog on January 07, 2015, 09:17:53 AM
QuoteThe second firing was supposed to be a full fuse & this is where the devit appeared. The devit seemed to increase with each firing.
1510F = about 821C - I only get tack fuse at that.
At what temperature do you normally get a Full Fuse with float?
Quote from: Zeldazog on January 07, 2015, 09:17:53 AM
Quotehttp://I have no idea what the glass was originally, it could have been window, greenhouse or double glazing, but I doubt if it was Pilkington K.
If it did come from a double glazing unit, why do you doubt it could be Pilkington K? It's been used in DG units for years.
I know the house concerned & if it came from double gazed units it would have to preceed those in place which have been there for over 20 years, & Pilington K I believe has been around for 21 years ish. Do you know if Pilkington K causes particular problems?
Perhaps I will be verrry brave & consign 3 first attempt experimental snowflakes to the bin. :'(
Depends if you consider a beautiful, sometimes, white, sometimes pink/green iridescent effect a problem :-)
But the coated side will repel and the only way I've been able to get anything to full fuse to the coated side of K or E glass is to make sure it's covered completely and overlapped with the non-coated or plain float glass.
As said in an earlier post, I full fuse at 843 deg C and that gives a nice rounded edge with float or greenhouse glass.
I wonder if K glass was the first low emissivity glass? Certainly the most well known I guess, but I have no idea if they were the first - a quick look on Pilkington site and it doesn't shout about being the first to develop it, so perhaps the glass was still coated with something?
Either way, I find the older the glass, the more issues I get with de-vit. Someone gave me some old glass from their house, and that has gone cloudy, like devitrification without even going in the kiln! Be interesting to see how that fires, although I am not looking forward to cutting it, expecting a few not going so well....
I personally like the fact that they're not fully fused, but I guess if that's not what you planned then you aren't going to be satisfied.
Glass fusing certainly is a waiting game, not just because of the length of the firing cycles, but that "will it work this time, were the kiln fairies kind?" questioning doesn't go away! ;D
I'm not much of a fuser but have done some pieces with bottle glass and like this site
http://glasswithapast.com/recycled-glass-firing-schedules/
I haven't done any window glass but thought you might be interested
Thank you Pauline. I originally read up on higher temperatures for float glass on that site.
It is great source of information.
This is a common problem when using float glass from he local merchants. Unfortunatly the second and hird generation thermal efficency glass have a higher quality coating and is not always decrnable and as more 3mm glass is being used this will become an increasing problem You used to be able to detect using a magnetic light but since the composite of the coating has altered it is not so readily identified. Can I suggest that if it is 3mm that you are going to need that you look at horticultural float glass it is 3mm thick and can be identified with a slight oragnge peel finish. THis is npot coated and will be considerably less expensive or alternativly go for a sheet glass.
I hope this helps