glass kiln plans

[Beau Lyons]

I am in australia and glass kilns are very expensive here, I would like to make my own.
Small for jewellery etc are there plans available.
regards,
Beau Lyons

[Ralph]

Try here

[Kevin Midgley]

http://richardlalonde.com/retail.html
Book1

[Beau Lyons]

I am planning to use a plywood mold to cast the kiln insulation box with a mixture of vermiculite and portland cement at 4-1 mix, total size 400x 400 mm with bottom and walls 75 mm thick, top loading. With a 75 mm top. fusing area 225mmX225mm x 140mm.
Any comments.

[Tony Smith]

Come up with a design that will fully support your cast insulation box as it's likely to crack in multiple places.

Tony

[Beau Lyons]

Is there a better mix that I should use.

[Tony Smith]

Not for a cast box. Consider segmented sides.

Tony

[Beau Lyons]

thank you for your commernts, i appreciate it

[GuyKass]

Beau-

If you are stuck on the casting idea, go to Craftweb. The hot glass guys talk about casting various furnace parts ( a much more punishing environment than a standard fusing kiln) all the time. Search their archives. There are probably about a bazillion posts on casting things such as furnace crowns, bases, walls, ports, etc.

Most of these types of refractory materials seem to be made by Harbison Walker, with Kastolite 30 being their favorite for most things cast.

In fact, I think if memory serves me right, the very top thread on the board is about some guy who just built his hot shop and there are a ton of pictures (granted they are furnaces, not kilns, but you will get the idea.)

Guy

[Bert Weiss]

I suggest building with HD fiberboard as the inner surface, and back up with either calcium silicate board, mineral wool board, or fiber blanket. All fiber blanket is acceptable, but not as durable as the boards. The Chinese make reasonable products for all of this, if you have access to buy their stuff. I have used a 5" thick brick floor. I plan to experiment in the future with Vermiculite boards backed up with calcium silicate boards. This costs less than bricks. The question is can you get it to not warp at all, like a brick floor.

For regular fusing, I use top elements only. Ideal, is elements on both roof and floor. For casting, ideal is elements on all 6 surfaces. Your goal is to heat and cool evenly.

I have never worked with building a kiln with a homemade cement mix. I kind of doubt it would A: not crack and B: be durable over the decades. All methods described above are durable for decades.

[Lynn Perry]

Beau, this is probably a much larger kiln than you would want to build, but there is a lot of useful information in this presentation by Phil Hoppes.

http://www.enfusiasm.fusedglassartists. ... ilding.pdf

[Beau Lyons]

I have worked with vermiculite alot in the past but not as the high temperatures required for glass fusing.
A number of members have commented on my suggestion of a vermiculite /high alumina cement cast mix, cracking. What if I was to use a loose mix of vermiculite behind the 1 inch ceramic fibreboard hot face enclosure. Comments?

[Tony Smith]

What's the attraction to vermiculite vs ceramic fiber blanket?

My suggestion would be to build your first kiln in a more traditional manner, then as you gain experience, you can improve the design or experiment with less traditional materials.

Tony

[Bert Weiss]

When designing, I tend to look to industry to see what they are doing. When it comes to kiln design, I immediately found that kiln manufacturers have a large tendency to try and adapt what they have been building for the ceramic industry to the glass industry. This seldom translates as ideal for glass. The next thing I found was that many companies will cut as many corners as they can to provide a less expensive model. When designing to build yourself, you are already cutting a huge part of the cost of buying a manufactured kiln, so you can easily afford to add features that benefit you, the kiln user. For this reason, I like to line my kilns with fiber board, as opposed to raw blanket.

I was really lucky to have a very close advisor who is an engineering expert in temperature control. He taught me that low density fiber insulation coupled with PID electronic control (including electronic relays) is the most efficient way to build. Even though this is not how the traditional ceramic industry builds, it is true for them as well as for glass. When it comes to fusing glass, we need a heat work profile that yields our envisioned results. I found out quickly, that a dense refractory (fire brick) kiln has severe limitations in the kind of heatwork it puts out. It tends to do a lot of work, by the time you get up to a top temperature. In a fiber lined kiln, you can get to the same temperature with much less change actually happening to the glass. The good news for fiber is that you can get any where you want to by programming a series of ramps and holds. So, fiber gives you, far and away, more options in your outcome. The other huge factor is that, with a denser insulation, you pay more to heat it up, and you wait longer for it to cool down. For us, firing glass, this is a double negative.

As density of insulation goes, cement is even more dense than insulating fire bricks, which in my thinking, are already too dense. This is the #1 reason I would advise against a cast kiln. Glass blowers have a very different task. They tend to turn their furnace on, fire it up, and leave it there for up to years at a time. They are more focused on durability than ease in heating or cooling.

My advice remains, line with 1" fiber boards, back up with either mineral wool block, calcium silicate boards, or 8 lb density fiber blanket. Floors can be made with insulating fire brick. Many manufacturers make their floors thin. I prefer 5" thick (2 layers of insulating fire brick, with offset seams). There are computer programs that will give you hotface/coldface temperature calculations for various insulating materials. I don't have this. I rely on my insulation suppliers for this help.

I plan to experiment with vermiculite board backed up with calcium silicate for the floor. The trick is to get a floor that does not warp.

[Beau Lyons]

Thank you Bert for your excellent comments,
I agree with your initial comments, just because everyone else does it, does not make it the best method.
I will use 1 inch ceramic fibreboard for the initial box, but I thought filling the gap between the outside steel frame (4 inches all around ) with loose vermiculite may be a suitable option.(at least it can't crack)
Loose Vermiculite is readily available and cheap, I know they use it here in Australia, when casting bronze sculptures.
My glass fusing box is 10 inchesX 10 inches x 8 inches high. Toploading

I have ordered a Kanthal kiln heating element 240 Volt X 2400watts.(australian mains electricity)
I will also need a Bartlett controller or something similiar, I suppose.

[Bert Weiss]

Thank you Bert for your excellent comments,
I agree with your initial comments, just because everyone else does it, does not make it the best method.
I will use 1 inch ceramic fibreboard for the initial box, but I thought filling the gap between the outside steel frame (4 inches all around ) with loose vermiculite may be a suitable option.(at least it can't crack)
Loose Vermiculite is readily available and cheap, I know they use it here in Australia, when casting bronze sculptures.
My glass fusing box is 10 inchesX 10 inches x 8 inches high. Toploading

I have ordered a Kanthal kiln heating element 240 Volt X 2400watts.(australian mains electricity)
I will also need a Bartlett controller or something similiar, I suppose.

Beau, I have never seen loose vermiculite used in a glass kiln, so I have no idea how it will work. Your issue will be settling. You don't want the top of the kiln wall to be less insulated. I wonder what the weight per cubic foot or meter is for loose vermiculite?

Boards can shrink if overheated, which is why you need to have the boards rated properly for their placement. That said, the kiln I built in 1983, backed up with mineral wool block is doing fine today.

[Buttercup]

Beau, it seems you want to build a jewellery kiln, not a casting kiln? (I accidently posted a question in this forum, too.)
This is currently on eBay. It's on the Darling Downs and is at $305.00. It has a Harco controller. Harco is a NZ company which kindly sent me a controller manual for a second-hand kiln I bought.
http://www.ebay.com.au/itm/180996693834 ... 500wt_1156

You couldn't build one for 305.00, even if it goes to $600.00 you'd be hard pressed to build for that and buy a controller.

If you do want high density fibre board and other refractory materials Morgan Thermal Ceramics has a warehouse in Acacia Ridge, 3272 1800. They'll probably answer the phone 'DSE'. Pottery Supplies in Milton sells kiln brick I believe and I have the name of someone who winds elements. If you need it let me know. (It's not with me right now). Ditto for thermocouples.

I checked out the link Ralph supplied. Seems that 'even women and senior citizens' can build kilns with their guidance. WOW!! (No other printable comment.)Jen

[Buttercup]

Beau, further to my last post....if you set fire to your cave with a non-approved (home-made) kiln your insurance will be void. I wonder how the DIY kilns mentioned in the previous post are certified? Jen

[Buttercup]

More.... Morgan thermal ceramics also has kiln bricks and refractory castable.

Pyro sales in Salisbury has thermocouples.

Kilnworks in Zillmere make elements.

Jen