Step 5: Feel the burn!!!

Why anneal glass?

A quote from Bandhu Scott Dunham - a famous Hot Glass Master...

"The basic principle of annealing is to hold the hot glass at a temperature where it is fluid enough for internal stresses to relax, and then to cool the glass so slowly that both the inside and the outside, the thick sections and the thin sections, have a chance to shrink evenly. This way, no stresses are developed or 'frozen' into the finished piece."

Soft glass - most commonly known as moretti - has a fluid temperature of approximately 1770F. (again, I repeat - this kiln ramped up to 2000 degrees in a test run - 2000F will seriouly melt any soft glass you may be using & cause it to drip onto your elements, hence, ruining your kiln. Realistically, very little should ever touch your elements. If something drips, turn everything off, unplug, cool slowly, then clean it off!)

If you're into slumping glass, this is wonderful, however, if you're annealing beads, this isn't a good thing!

Hard glass, commonly known as borosilicate, or, pyrex, is a much harder glass, not recommended or tried in this small kiln.

To anneal beads, make a couple of supports with extra grid wire to support bead mandrels.
(see image)
This keeps the beads from touching any grid wire & possibly getting marked up.
It also supports the bead mandrels & prevents them from falling into the kiln &
coming into contact with the exposed elements and any exposed wiring - should
one of your mandrels or any tool fall into the kiln & contact the wiring, unplug it
before removing, or you could be in for a nasty shock.

I simply folded a section of grid wire in half, sort of in a tent like shape & placed it
inside the kiln.
Two pieces folded this way easily support a number of bead mandrels.
To slump, use a small piece of kiln washed kiln brick to place your glass on.
(don't forget, the glass will stick to the brick without some kind of coating - kiln wash is
cheap and can be purchased at any hot glass or ceramic supplier, or kiln manufacturer)

The tricky part of these 'do it yourself' kilns is the annealing process...

I'll use annealing soft glass beads as an example.
Soft glass, (moretti) with a COE of 104 needs an annealing schedule of:
Approximately 1 hour at 960F.
Temperature down, 100 degrees per hour to 800F for another hour.
Temperature down, 100 degrees per hour to room temperature.

With a modern kiln, the process of slowly cooling down or ramping up is
usually done with a computer controller.

Our wee waffle iron, however, has no controller.

Heat regulation is done by powering on and off, and, once you've settled into
a routine, a timer is helpful.

You'll have to monitor your first few firings closely to be certain your temperature
isn't getting too high, and your probe is fairly accurate.
(if your beads begin to droop & melt off the mandrel, it's too hot!)

Also, I found with the insulation packed in well, simply turning the kiln off
after the 800F hour, refaining from 'peeking' & keeping the heat it, the kiln lost heat at less than the required rate of 100 degrees per hour...

Once again, I stress SAFETY in all aspects - don't forget to VENTILATE!!!
(should you be indoors, which, I reiterate, is not a good idea...garage, maybe ok...with a fan)
Keep a fire extinguisher handy.
I personally use a power bar, at all times, during an anneal with this kiln.
If there's a problem, I can disconnect while being fairly far away from the danger zone.

Lead glass in itself produces fumes of an unwanted nature, I can't even begin to imagine how bad a lungful of galvanization would be!!!

I strongly suggest this "DIY" kiln only be operated out of doors.

Always open to new adaptations of my waffle kiln!

Thanks for looking!
<p>Kiln liner bricks have a much better insulation factor, if available and affordable they will serve you better!</p><p>nice instructable</p>
I am looking to build a kiln to use for enameling metals. Wonder if an old and small toaster over would work. Basically following the same steps, laid on its back inside a suitable container so the elements are on the sides instead of top and bottom. If it had the Pyrex glass window I would be able to monitor the project. Since the firing time is pretty short and no annealing is required I should be able to do it. Any ideas?
My kiln instruct able might help you.
I like that toaster idea if you build it (or already have) you should post it up here.<br/><br/>1 suggestion: I don't know the temperatures that you use for enameling metals but I would suggest that if you want to add a window to a kiln use <em>fused quartz</em> glass instead of borosilicate (pyrex) glass. Quartz glass has a much higher melting point and is the standard for high temp viewing windows. Good luck.<br/>
Actually, I'd like to see that too, if it gets done! (that was the problem with the waffle iron - it works great, as long as you don't need to see inside it!) Yes, that's a great idea too, (I just didn't know it was called quartz glass!) I'm assuming you could buy this glass at a place that deals in wood stoves - as I'm also assuming that would be the type of glass in the front of my woodstove. (and, for certain, is has gotten hot enough in there to melt boro) Thanks for the tip! Janice
Old fashioned wood stoves used to use a mica sheet as a window. its thin and available from the same places.<br />
Hi,<br /> Yep, we used to be able to get it, but I'm not certain anymore.<br /> We heat with wood stoves, and the &quot;Safetly Standards&quot; stuff sure has changed over the last few years.&nbsp; I'm not sure you're even allowed to use Mica anymore, too bad too, we have a georgeous antique corner stove, and I'd like to have an insert put in it to make it airtight, but I believe I'd still have to remove the mica, I'll have to check for sure.<br /> Thanks for bringing that up!<br /> <br />
A thought, if instead of the mica sheets (and I realize this may be an expense unless you can scrounge one from an old discarded oven) the Pyrex type glass in sheets would serve as an acceptable window, I would think......albeit, it will complicate the construction a bit. <br /> <div id="refHTML">&nbsp;</div>
Hi Goodhart, <br /> Pyrex might do, but you'd have to be sooo careful!<br /> (and attentive too - something I'm so not good at!!!)<br /> Pyrex - or Borosilicate - has a different COE, and melts at approx.<br /> 1570 F. <br /> (old corningware makes some awesome bracelets!)<br /> I've easily ramped this baby up to 2000 F.<br /> I'd have been so dissapointed if I'd have melted it!<br /> (I already have lots of melted 'experiments')<br /> A great idea for a PMC kiln though I would think.<br />
Ok,&nbsp; then maybe savaging the &quot;window&quot; from one of those electric ovens that have a Self Cleaning feature (where temps reach up so high it pretty much burns away everything inside the stove, yet the window survives)?&nbsp; I am uncertain what that temperature might be, that the oven reaches, however.&nbsp;<br /> <br /> That is, only if one wished to observe what is going on inside. <div id="refHTML">&nbsp;</div>
Ok.....&nbsp; I have to know more about using broken CorningWare for jewelry.&nbsp; Can you post a picture and some basic instructions?&nbsp; By the way I finally broke down and bought a used small kiln.&nbsp; I ran into so many safety issues that I gave up on the homemade.&nbsp; I would get one problem figured out and then another would pop up.&nbsp; I was spending more time trying to build a kiln when I could have been enameling and melting stuff.&nbsp; Even the mistakes are fun.
in your opinion.. Do you think this would work for small clay objects?
About the Mica brought up above: http://antiquestoves.com/st/products.php?cat=1<br><br>There you go. <br><br>Do you think this method could be used to build a small Kiln for burning out wax in lost wax casting?<br><br>I'm thinking about gutting a used table top grill for the heating elements.
Hey, Thanks for the link!<br>I don't see why not -If you can't find a suitable &quot;waffle iron&quot; there's no reason you couldn't build your own - a metal box - lid, insulate the inner with stove bricks, scavenge some elements, insulators &amp; other necessities, and build to suit!<br>(it's one of those projects on my ever growing &quot;todo&quot; list - I'd be interested in how it goes for you if you do try... )<br>Good luck!
Hey, just happy to help. My google-fu is very strong. :)<br><br>I live near a good will. I intend to simply pick up one of those George Foreman type grills, they normally have a dozen of them, and strip it. I need something that can fit a crucible though as I'll be using it for investment casting uses.
Very good instructable but the safety warnings are a bit weak. How about using bold text for <strong>ELECTROCUTION</strong> warning.<br/>You also mention keeping a fire extinguisher handy - some are water based and should not be used on live wires! <br/>
On top of the fire and electrocution hazards, and the vapors, remember that the &quot;white fireproof outer shell&quot; on the wires and whatever is insulating the heating element are almost certainly asbestos if the waffle iron was made before 1980.<br><br>Very cool, but way too risky for my blood!
Thanks Tina!<br>(do you drive? Don't check the 'risk ratio' involved in auto accidents then...)<br><br>Yes, that would be something to check on...and I guess I should have mentioned that! (I've done alot of kiln building/repairing, and that's what's so awesome about Instructables, if you've forgotten or omitted something, there are always peeps out there willing to help!)<br>When in doubt, do check! (I did mention ventilation...and I've done uber amounts of research on this over the years, although, my research certainly isn't going to stop someone else's foolish behavior, as Patrick pointed out...LOL)<br><br>Investigation &amp; research turns up alot of useful info on this sort of thing.<br>www.asbestos.net is a valuable resource.<br><br>The insulators are made of ceramic, very much the same as those used in a more modern kiln setup, if a different shape. <br><br>If the wire covers in any particular item are white, and unbound, it's very highly doubtful that they would, or could, be asbestos. Unbound asbestos wire cover becomes 'friable' (disintigrates) in a very short amount of time. <br>(for that matter, why anyone would use any electrical appliance that had frayed wire or insulation is beyond me...)<br><br>Keep in mind that asbestos is most hazardous when it's in a friable state, meaning the dust particles can become airborne.<br>(very much the same as fumes from glassblowing/lampworking &amp; dust from bead release &amp; kiln wash can be hazardous)<br>This is far more of a hazard in home and industrial applications, around furnaces, insulation, in walls, ceilings, floor tiles and roofing materials where it may fray or dust may become airborne during renovation or construction projects, and for those who frequently repair old appliances such as crock pots and popcorn makers.<br>(I worry more about whats in my old home...I happen to KNOW the old wiring was asbestos, and I'll tell you, that wasn't fun! Makes one wonder what else may be lurking in the walls)<br>Most often, this type of wiring is a sleeve made of fiberglass, safe unless it too becomes brittle and the particles may become airborne.<br>Of course, if one is uncertain, it's simple enough to replace those wires, after all, the iron is already half disassembled.<br><br>As for the electrocution hazard...I have two modern (circa 2000ish) &quot;pro&quot; glass kilns, and one very large (circa 1970) ceramic kiln. Their elements aren't covered either.<br>Vapors, yes, nasty, dangerous, but a risk easily taken care of with proper ventilation &amp; masks. Been done for many years.<br>(If you're into lampworking, or anything involving fumes, (I'm guessing not, but you never know!) I have a mega huge list of safety resources &amp; such that I've compiled over the years, if you want a copy, just let me know!)<br><br>Anyway, so, everyone...listen up!<br>NO ASBESTOS!!!<br>DON'T POKE ANY EXPOSED WIRES OR ELEMENTS!!!<br>WEAR A DAMN MASK &amp; AN APRON!!! (rubber boots and a stick add to the costume immensely!)<br>STAY OUT OF VEHICLES!!! (just joking Tina!)<br>
:) Thanks Patrick... I did put this in the "not liable" category... (and, I had warnings everywhere, but culled them out due to repitition) I worried more about ventilation, as in my experience, people are aware of electrical hazards, so aware in fact as to ignore others. I'm assuming (and hoping!) one who would undertake such a task would have some minimal knowledge, or, at least do some research on the subject before starting...or else they'd probably have already thinned themselves from the herd... And, yes, I agree on the fire extinguisher, but...isn't that a common sense issue taught in Grade school? (I know it was for me) So, (Thanks Patrick) please heed what Patrick has to say, as he is correct - most fire extinguishers have a rating on the outer hull which indicates what they are. Some would be bad news on electric fires. (I believe mine are Pyrene based...) Janice
I liked the idea of plugging the unit into a power strip. I was taught in multiple fire safety trainings, once you cut the power, a so called &quot;electrical fire&quot; becomes a plain old &quot;material fire.&quot; <br> <br>Still doesn't help with the original electrocution aspect, but I guess you could also always plug into a GFI. And wear a rubber suit, carry a rabbit's foot and a rosary . . . <br> <br>This is a wonderful 'able. I've been fusing glass at 1500* in a small high fire kiln (overkill) and plan to experiment with the wedding present waffle iron c. 1977.
Yes, well, ahem, I have issues with electricity to begin with!<br>(I fell on a cut open large power cable when I was a kid &amp; got a major electrocution - my sister used to say &quot;that's what happened to her...)<br>So, the power strip was a necessity for me! :)<br>I'm sure I was a sight doing this too...<br>I wore my rubber boots, overalls &amp; welding mask and carried a big stick!!!<br>(sounds like something out of a scary movie...)<br>Good luck, I've planned to do some fusing in this little guy using a small fire brick covered with kiln wash, yet I've never gotten around to it.<br>Do let me know how it goes, if you will.<br>(circa 1977 - in some ways, that saying &quot;they don't make em like they used to&quot; is most certainly true!)
I think the majority of people on this site are bright, inquisitive, and have common sense. My concern is that a small minority need protecting from themselves - because quite clearly, judging by their posts, they are dumb as a bucket of bolts! You have to think for them because they aren't going to think for themselves. I just wouldn't like to see anybody die even if it was as a result of their own stupidity.
.<br /> Wow..... you can grill chops and work - all at the same time.<br /> <br />
Terrific! I was just scrubbing out an abandoned refrigerator drawer saying this has got to be useful for something... Now I'll find a waffle iron. Will have electrician hubby see if he has any ideas on controller or high temp wiring. Thank you for the post, I'm just starting in glass and don't want to buy a kiln until I find out if I have any talent. One question. Is normal gravel okay for agregate, or should I look up some lava rock? - I'm overthinking aren't I... Thank you again for posting this it's fantastic. Tami
yes, any potentiometer used will have to be able to handle the amperage channeled through it, this is the same problem I have been having with trying to regulate the temp of a crock pot more accurately, for a specific type of cooking (needs to be within one degree of the set temp.). <br /> <br /> If one opts for a high amp, multiple position switch, they still need something (some form of high temp probe) to detect and regulate temperature.&nbsp; Many high amperage devices are expensive new....but if one lives near an appliance reclamation place, one may be able to pick up something for very cheap.&nbsp; Or, as someone suggested, the used appliance shop.&nbsp; <div id="refHTML">&nbsp;</div>
Hi, Awesome!!! (Those metal fridge drawers are hard to come by now) An electrician hubby - lucky you...do you loan/rent him out? Understand that you're hesitant to spend on a kiln, they are expensive... you should do some other scouring on the net, theres a few places that have instructions on kiln building, both large and small, and, you have an electrician! (the most expensive part of that operation - LOL) Anyway, I'm using regular gravel, it's all about pea sized chunks. I'd think lava rock would actually be less insulatory, (is that a word?) due to it's porousness. The small gravel settles down into all the nooks & crannies underneath & insulates really well. You can buy firebricks fairly cheap too - hardware & anywhere that sells wood stove supplies should have them - they can be used in place of the gravel, but you've have to cut them to size. So, best of luck to you - go buy an aloe plant before you start, if you don't already have one. (helps with the wee burns!) ;) If there's anything else I can help you with, feel free to post me. Be well, Janice
metal refrigerator are still available from non-chain appliance stores. Those kind that advertise "You're part of our family, too" or similar are the best. Head there on a Tuesday or Wednesday afternoon, when they aren't especially busy. If you have already bought myriad appliances there, you are wayyy ahead of the game. Anyway, go on in and take a seat while the (lone) salesman takes care of the elderly lady who wants to spend forever deciding between an 'almond' or a 'bone' colored fridge. Wait politely, even if you want to strangle her. When she leaves, (hopefully after buying an appliance), wait until the salesman (it's always a man, God knows why) comes over to wait on you. Tell him that you need a favor, and that you hope this isn't a bad time to ask. Since the salesman is often the guy who owns the place, he should be okay about making a decision in your favor. Give him a couple of those nice business cards you got for free from that online site or the ones you made yourself on the inkjet printer, preferably wrapped in a $10 bill. (I said these weren't hard to come by, I didn't say they were free) Tell him that you would love to have a metal refrigerator drawer when one comes in on a pickup. Most of these Mom/Pop places offer free pick up and disposal of your old appliance. A lot of people are getting rid of very, very old appliances. The business cards are for him to contact you when one comes in. If you are really lucky, he'll hand you back your $10 and cards and take you out back, where a couple of sketchy looking guys are unloading old fridges. He'll tell them to fetch you the drawers you're looking for, and to load them into your car. (You'll probably get more than one, since each old fridge had at least two drawers.) When the guys load the drawers into your car, give them the $10 "for a beer after work." If you are less lucky, they won't have one in the back. Thank the owner, and give them a week to call you back. If they took your $10, you're a paying customer looking for her merchandise, so call and ask if your metal drawer came in yet. Since there is almost no call for these things, they'll remember you. After two or three phone calls, they'll get the hint that you aren't going away, and will get you the drawers post haste. If the guys are especially helpful when you go pick up the drawers, give them a $10 for "a beer after work." Why the tip, when they did practically nothing? Well, you are getting a kiln part for a steal, when most kilns will set you back a whole heck of a lot more than $10. Besides, you might want to buy an appliance one day, and having the people there remember you as "the nice lady who tipped us," is a whole lot better than "that pest who wanted the old fridge drawers." Just saying. Another place to get the drawers with a lot less waltzing around is at your town's department of public works, if your town offers free appliance pickup. Just stop by on a lazy afternoon and ask for the drawer. Usually, each DPW lets the fridges build up before calling the recycler, so you might even have your pick. if you are unlucky and the fridges just got picked up, leave a couple of cards (no $10), ask someone to call you when someone drops an old fridge off. No one will call, so just drop by from time to time until you get what you want. Another solution is to find the lower drawer from an old stove. Those are also made of metal, although these aren't nearly as well made. Good luck, and this is a wonderful instructable. Thank you so very much for posting it.
Wow! Great ideas!!! (I never even considered the used appliance place - we're pretty far out in the woods, so the potential for older 'cottage' appliances is probably right out there!) These days, I'm pretty sure the steel to make such a drawer would cost $10 - I'd gladly buy the beer! Never considered a stove drawer either, and some of those older ones have the heavy duty broiler pan in the bottom - they'd be perfect too. I've recently been eyeballing an old 'coffee' heating element, and wondering if I can adapt it for Precious Metal Clay or Polymer, and our recently retired hot water heater has potential for a much larger kiln...who knows! (my husband gets nervous when I start cutting things up...snicker...) Anyway, Thanks so much for your input!!! I'm certain your ideas will come in handy. Be well, Janice :)
Very cool idea. I do enameling, fusing and slumping and I wish this info had been available to me when I was getting started. Would have significantly cut my startup costs. I&nbsp;have four &quot;real&quot; kilns in different sizes now, but I&nbsp;may build one of these just for fun, or maybe to take to my kid's Cub Scout meetings to let the kids enamel some stuff.
I'm still amazed at how durable these little things are...<br /> I did once kinda get 'distracted' and by the time I realized it, the coupler read<br /> 2000!&nbsp; Once I&nbsp;peeled the melted glass off &amp;&nbsp;fired it up again, it was fine.<br /> (and when it's cold, you can tuck it under your arm &amp; off you go)<br /> Just keep the kiddies away - it does get really hot!<br /> (might be able to roast a marshmallow or two if you're close enough!)<br /> Good luck with the Scouts!<br /> <br />
Thanks, I'll definitely put this one on my list. This sounds like an excellent starter enameling kiln (2K is way hotter than enameling requires), and it'll give the kids a chance to be creative <em>and</em> play with fire at the same time, without hosing up my Quick-fire kiln. Everybody wins!
Great Instructable! I was looking for something just like this. Has anyone here tried other kitchen appliances? I was wondering which ones might be able to produce similar effects and be able to handle the heat.
Thanks! I have had some success with an older hotplate style coffee warmer/percolator adapted into a mini pmc kiln - the bottom was a simple ceramic channel into which the element had been placed, and covered with steel - easiest way to describe it I guess - then covered with an insulated terra cotta pot! (what can I say, I'm cheap...hehe) Worked great, the pot even had a convenient little hole in the bottom, (or, top, depending on your perspective!) to drop the probe into! Seems the older appliances have the heavy duty metal casings & ceramic element holders most often. I'm pretty sure some of the newer electric appliances in their pretty plastic cases couldn't hold up to such abuse. Guess there is some truth to the 'They don't make em' like they used to" statement. Thanks for the comment, Good Luck Janice
can you use this kiln for the bakable clay that turns to silver or gold?? need to know im going to be working with it. any help will be appreicated. Thank you The LdyRavenvrmor
Hi, Not sure... I don't see why not though, I'm not certain of the curing temperature of precious metal clay, but I think it's lower than the annealing temp of glass. I imagine as long as you have the patience to control the temperature by turning it on and off, and a decent probe thermometer to read the temp, it should work. (That clay is awesome, by the way, if you haven't worked with it yet!!!) Good Luck & Be well, Janice
I've been wanting to get back into lampworking, but didn't want to drop money on a kiln, so this is really great. Thanks!
That is a great idea! Very nice "ible" good pics and well written.
I think I'm going to have to make one of these. I think that you could get better heat control if you added something like a light dimmer switch to the power cord in place of cycling the power on and off, this also would mean that you wouldn't have to have the kiln on at "full power" if it wasn't needed.
A suitably rated power controller would work but I am not sure that a "light dimmer switch" would be up to the task. Most light dimmers handle a few hundred watts of power, whereas a waffle maker may be a kilowatt or more.
I did wonder about that...would it carry the load... Thanks, (um...just where would one find a suitably rated power controller?) Janice
I can't really advise where the best place to get one is as I'm in the UK and I assume you are not (waffle irons are a bit of a rarity over here). However, they do use variable power controllers for varying kiln temperature. You may also be able to get a heavy duty lighting controller <a rel="nofollow" href="http://eraser.com/catalog.cgi?mode=details&product_id=1367">here is one</a> this is probably a bit bigger than you need.<br/><br/>I hope that helps<br/><br/>Pat. Pending<br/>
Hey! I never even thought of that... (I was happy with the timer!) That's a great idea - I don't really use mine enough to warrant it, (I have pro glass kilns) but I'm building a new version shortly & might consider that feature...Let me know how it goes, I'd be interested to know! Janice
Very nice. An easy upgrade would be a relay and microcontroller to switch the power so you can have proper temperature control and profiles. Overkill unless you are doing this commercially, or are big into microcontrollers! You are right about the fumes from the galvanised grid. Those zinc fumes will give you the headache to end them all! Zinc headaches make nitro headaches seem like nothing at all!
Thanks Yep, that would be good too...after all, the most expensive part of a commercial kiln is the fancy digital controller & thermocouple... I have a Paragon glass kiln with a one of those wonderful controllers, and when I used these little kilns alot, I was always sitting right beside, making beads at the same time, so the on/off routine wasn't such a hassle for me. I figured about the fumes, thankfully I have not had such an experience! (well, not with Zinc, anyway...I have issues with ventilation...didja notice? hehe...)
Very cool! While I have not yet wandered into the wonderful world of making beads, it is on my 'must do before I die' list, and I'll be most certain to return to your fab instructable! Karen Marie
Hmmm...Yes, well, there can never be too many beadmakers! Good luck to you when you do. Janice

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