WarmGlass.com

Hi... This is my first post here although I have been coming here for over a year now. Basically my problem is this:
I just taught a lampworking class at my local arts center. One of my students brought in a slumped bottle "hors dourves tray" and now wants me to teach her how to make them so she can "make some money" I know the process and have been slumping/fusing for a while so that's no problem. The thing is that the kilns that the center has are ceramic kilns and I know *nothing* about them. Neither does the director. He knows how to turn them on. I know i need cones but i don't know what number. Also how do I flash the kiln if I don't know when to do so? the switch is hi med lo and no thermometer... nothing. I would say "no way" to this lady but her husband is a big donor to the center. also how well does the borax devit spray work b/c if it works well I wont have to worry about flashing as much...right? no? gah!

jeez, it seems like firing up a big ceramic kiln to do some bottles wouldnt be very efficient, and you dont want her doing constant production work there, using the facilities as a factory. in the past there has been discussion here about doing things with bottles ... why dont you try the "Old Archive" as well as "Search" (which is newer, after we changed board format) and see what you can learn. i really think this lady would be better off getting a small kiln for her money-making scheme. maybe you can keep your contribution down to just giving advice. i think there might be some stuff in the Tutorial (see up above?) about bottle projects.

well it isn't really the bottles I am worried about. More like the kiln. I was wondering if anybody has slumped glass in a ceramic kiln. If so could I get some advice about my mystery kiln with no thermostat, a manual control etc etc? I am starting to think trying this project is a bad idea...anybody else?

it certainly can be done. i think you'll fine the info in the archives i mentioned. i haven't done it myself, but i've read about it, and the ceramic kilns should be fine. there are a number of people here who talk about using ceramic kilns for fusing.

rachael r wrote:well it isn't really the bottles I am worried about. More like the kiln. I was wondering if anybody has slumped glass in a ceramic kiln. If so could I get some advice about my mystery kiln with no thermostat, a manual control etc etc? I am starting to think trying this project is a bad idea...anybody else?

The kiln will be fine. Glass slumps at a lower temperature than pottery or ceramics is normally fired. You just need to experiment to find the right temperature for slumping the bottles she will be using. I have been fusing in 2 ceramics kilns for over a year...they're just a little more difficult to control and need more attention than a programmable glass kiln. A pyrometer is also essential to know what temperature is inside the kiln, along with testing the kiln for evenivity (most kilns are not the same temperature throughout). I believe Brad has a tutorial somewhere on this site for slumping bottles.

On top of that I am more concerned about the ethical questions surrounding using a hobby kiln in a community center for income generating activities. If she's a major donor, you might want to get approval in writing from the manager, executive director or whomever is in charge that they support this use. Let the exception be made by them, not yourself. Then again, if she's a major donor you just know she can afford her own kiln...

Carol

I use a ceramic kiln all the time.. it is the only large size kiln I have access to. I also only have two on-off switches. I use cone 15 or 16...
It all depends on how many shelves you have in the kiln and how much glass on each shelf... I also have NO thermostat.
with cone 16 I get a full fuse on the top shelf and a great slump or fire polish on the bottom shelf.
I have 2 switches.. I turn each on low for 1 hour... then both on medium for one hour... then both to high.... this is where it gets tricky... I check the glass after 20 minutes.. if it is not fully fused or slumped I let it go for another 10 minutes. (you should ofcourse wear gloves and eye protection when looking in the kiln). If it is ready I turn the kiln off and raise the lif 3 times real quick to vent. then let it set over night.
I put the cones in only for protection in case I am doing something and forget to check and turn the kiln off. I also do not have the plugs in the holes located on the sides of the kiln. after a few test drives you should be able to do the slumping easily. I do small 2 inch jewelry up to 10 inch slumped plates and drop rings too.
what I wouldn't give for a programable glass kiln... I would think I'd died and gone to glass heaven.

if you have any questions i can be reached at karen@teemer.com
I am on vacation but do read my email daily.
karen

Did you really mean cone 15 or 16? That's hotter than porcelain fires to, but I'm thinking cone 015 or 016 is what's used to fire lustres on ceramics and wouldn't be hot enough for glass. Maybe cone 5 or 6? That'd be stoneware level.

Cecilia (confused and curious)

My kilns are ceramic ones, and I´ve fused bottles a lot.
My kiln don´t have a controller, so I control the heating and cooling the manual way. To fuse bottles, I use the brick kiln, I turn it on and let it heat till 540 C - 1000F, at his own hate that is very slow ( about 2 1/2hours ) soak for 30 min, rise to 600 C - 1110 F soak 30 min, rise to 800C - 1470 F soak 10 min ( I use to look if it´s ok before cool crashing).
Cool crash to 540 C close and let cool to amb. temps.
Luiza

All right! sweet! thanks you guys that was just what I needed to know! I have a chart on cones somewhere I an refer to. She probably can afford her own kiln but... NMB. I'll look in the archives and stuff and then its on! Sorry to hear that some people dont have a programable kiln for fusing, I don't either but my school does. thanks again you all rock!

Don't be sorry for the folks who don't have a kiln controller! We're our own controller and less likely to fail than the mechanical kind.... LOL! If you think you're limited by a ceramics kiln without, you're missing out on a lot of good fusing.... and not just the simple stuff like flattening bottles.

Cone 015- approx 1481 degrees F
Cone 016- approx1463 degrees F
cone 017- approx 1418 degrees F
cone 018 - approx 1328 degrees F
cone 019 - approx 1220 degrees F
cone 020 - 1202 degrees F
cone 021- approx 1139 degrees F
cone 022- approx 1121 degrees F
look for conversion chart in any pottery book

I meant cones 015 and 016... I always forget to use the 0 infront of the numbers.
karen teemer

Don't be sorry for the folks who don't have a kiln controller! We're our own controller and less likely to fail than the mechanical kind.... LOL! If you think you're limited by a ceramics kiln without, you're missing out on a lot of good fusing.... and not just the simple stuff like flattening bottles.

wow... that's excellent... I never knew how easy it would be. I am a glassblower/ Lampworker but I "dabbled" in fusing so I knew the tech. to a point. Never knew that a ceramic kiln was just as good. I was just being worried/ paranoid b/c I didn't know my equipment. More like cautious, didn't want to waste time and money. Thanks a lot!!!!

And don't forget to lift a glass to the kiln god/goddess. It concerns me when you comment on "how easy it is"... sort of like tempting the fates, you know what I mean? I have a few fused flats hanging on the wall with double D bubbles... never did figure out the causes. Just got a little too cocky, I guess!

rachael r wrote:wow... that's excellent... I never knew how easy it would be. I am a glassblower/ Lampworker but I "dabbled" in fusing so I knew the tech. to a point. Never knew that a ceramic kiln was just as good.

I feel compelled to make one small comment here.

You can use a ceramic kiln to fire glass, just as you can use a tack hammer to hammer 3 inch nails. It might get the job done, but that's not the same thing as saying that it's "just as good."

I've use both kinds of kilns, and while ceramic kilns can be used to fire glass (especially small items and easy firings where control is not that important), they do require some special effort and a bit more experimentation. And if you do larger items and move into more complicated firings, you will probably want to invest in a pyrometer (or even a controller).

Good points..... I only fuse up to four layers and up to 20 inches and almost everything painted, of course. Obviously, I don't feel creatively limited by that since I have yet to feel strong need for a controller. But, I do have a timer, kiln sitter, and pyrometer on each kiln... and, of course, I'm always in the studio to monitor. I do think if you're getting into techniques that require holding kiln temperatures at certain degrees for certain periods of time, you'll have problems without a controller. Some day when I want to learn all the tricks, I'll probably resort to buying one... in the meantime, I paint and am happy.

I am about to start my first fusing project in my Skutt automatic ceramic kiln. I've read all of the posts here, but am still confused. I still have a few specific questions:

1. I have an automatic kiln, so can just fire to cone 016m or program it to follow the System96 standard firing schedule?

2. Is the flash cooling step necessary, or can I set up the program and let it run over night, like I do with ceramic firings?

3. Can I load more than one shelf with glass?

Thanks for your help.

Cheryl

1. Maybe, maybe not. Depends on what glass you're firing, how you want to fire it, and exactly what the "standard" program is. Sometimes these pre-programmed schedules work, sometimes they don't.

2. For most situations you shouldn't need to flash vent.

3. Yes, but the top shelf will be a different temperature than the bottom, so you'll need to figure out the temperature difference and what can best be fired on each shelf.

#3. does your kiln have zone controll? if so it will be pretty even. keep your shelves at least 4 inches apart. keep your bottom shelf above the bottom elemant. the middle shelves will get more done. they are surrounded by more mass. hold for about 20 min around the softening temp for your glass. if you have an orton kiln vent, do not put large things on the top shelf if it is within 6 inches of the top. which scutt do you have? rosanna

Thanks for your replys.
The kiln is going. I set a ramp hold program following Spectrums recommended schedule.

The high temp was 1465, and the kiln shut off on schedule, but the temp kept rising, so I opened it a crack to flash vent down to 1000. Then, the temp started rising again, so I stopped the program and let it cool to the next stage.

My question is, how do you use the standard controller to regulate the cooling rate? Do those of you using a ceramic kiln just manually monitor the firing for the entire process?

c