Viewing window in homebrew fibre kiln

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adrian
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Viewing window in homebrew fibre kiln

Post by adrian »

HI Folks
With help from some of the regulars here, I made myself a homebuilt fibre kiln a couple of years ago.
It's a clamshell construction, 4ft x 2ft x 12 inches, with two overlapped layers of 1" fibre blanket in the lid.
The outer frame of the kiln is angle iron with metal mesh.

All good - so far - fires beautifully.

It would be nice to be able to see inside without lifting the lid - particularly for tricky slumps.
It so happens that I have some 6" x 4" pieces of new 'stove glass'......

I was planning on slipping a piece of this glass between the metal mesh and the fibre blanket, securing it in place with nichrome wire,
and cutting through the fibre blanket so as to create a viewing window (with, say, a 1" overlap onto the glass all round.
Securing the loose edges of the blanket with the same ceramic 'buttons' I've used to hold the rest of the fibre in place.

What do we all think - any snags I've not thought of?

Thanks
Adrian
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Re: Viewing window in homebrew fibre kiln

Post by Brad Walker »

Check the melting temperature of your "stove glass." Most glass made for wood stoves and such melts at around 1400F, which makes it unsuitable for a kiln.

Kiln windows are usually made from quartz glass, which has a higher melting temperature than stove glass.
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Re: Viewing window in homebrew fibre kiln

Post by Bert Weiss »

Just cut a hole and slip in something like a brick, or a wad of fiber blanket. Pull the plug out and look in.

2" of fiber blanket is under insulated. It must run hot to the touch. It will work though.
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adrian
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

HI Brad

Thanks for the comments.
I'll double-check, but I remember that one piece of the glass refused to budge when I tried slumping it -
and I went up to 800c (1482f) before I gave up!

I guess if I was to try fusing a piece, and take it up to 850c or thereabouts -
if it survived that then would you think that it was OK?

Thanks
Adrian
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

Bert Weiss wrote:Just cut a hole and slip in something like a brick, or a wad of fiber blanket. Pull the plug out and look in.

2" of fiber blanket is under insulated. It must run hot to the touch. It will work though.

Hi Bert.
That'd involve cutting through the (rather heavy) metal mesh.....

From inside to outside of the kiln it goes

2 x 1" (actually about 2.5") fibre blanket
Layer of 'proper' aluminium reinforced foil
Metal mesh (diamonds - about 1" tall)

So that's why I was thinking about just trimming a hole in the fibre and the ali foil, and sitting the glass behind the mesh.
Easy enough to revert to 'no window' later, if required.
The top of the kiln is all 'clamshell' - so any 'stuffing' in a hole would need to ride up & down with the lid opening, it's hinged at the back.

As to how hot the kiln runs - you can rest your hand on the top at 800c inside -
so I guess it's not too 'leaky'.

It's probably not ideal - but it did cost about 30% of an equivalent commercial kiln - it's about 4ft x 2ft 6 external.

Thanks for the comments
Adrian
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Re: Viewing window in homebrew fibre kiln

Post by Marty »

Adrian- Now you have to post photos!
You said clamshell- lifting the top a little to peek won't lose much heat...
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Re: Viewing window in homebrew fibre kiln

Post by Rick Wilton »

What Bert said.....

The two homemade kilns I built I cut a hole and placed a insulated fire brick into the hole. I mounted a handle onto the brick to make removal quick and easy. It works great.

The one kiln was made from expanded metal (sounds like yours) and the other was made from rectangular steel tubing stacked up. So I definitely know about cutting a hole into the side, trust me it's worth it. Both kilns are winched to raise and lower them but the removable kiln brick is the way to go imo.
Rick Wilton
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

Marty wrote:Adrian- Now you have to post photos!
You said clamshell- lifting the top a little to peek won't lose much heat...
HI Marty

Don't know if this'll work...? <edit - looks like it did!>
2014_04230005.jpg
2014_04280004.jpg
2014_04280001.jpg
Shows the general look of the kin. There's a pulley & counterweight system to make it easier to raise/lower the clamshell.
The large round fuchsia suncatchers are about 12" diameter.

I know that lifting the lid for a peek won't make that all that much difference - but you know what it's like - the desire to improve! <g>

Thanks
Adrian
Last edited by adrian on Tue Mar 01, 2016 4:49 am, edited 1 time in total.
adrian
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

Rick Wilton wrote:What Bert said.....

The two homemade kilns I built I cut a hole and placed a insulated fire brick into the hole. I mounted a handle onto the brick to make removal quick and easy. It works great.

The one kiln was made from expanded metal (sounds like yours) and the other was made from rectangular steel tubing stacked up. So I definitely know about cutting a hole into the side, trust me it's worth it. Both kilns are winched to raise and lower them but the removable kiln brick is the way to go imo.
Hi Rick
Thanks for the comments - but I can't see how a "brick" would work in my particular case - see pics below....
It's not a straight lift like yours - but hinged at the back.
Thanks
Adrian
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Re: Viewing window in homebrew fibre kiln

Post by Marty »

nice! I wouldn't cut holes in it, maybe your next one...
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

Marty wrote:nice! I wouldn't cut holes in it, maybe your next one...
<grin> - Thanks Marty
I'm not planning on there being a 'next one'.... think this'll do me for a while!
But - I could fit a 'suitable' glass window, without cutting anything more structural than the fibre blanket.... perhaps...

The plan in building this kiln was to be able to do fused door-panels in one 'hit' -
but it does come in very handy when I'm making lots of suncatchers..

...feel a bit guilty when I'm using it for fire-polishing a dozen earrings and pendant-pieces, as I am at the moment -
but sometimes deadlines dictate...

Adrian
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Re: Viewing window in homebrew fibre kiln

Post by Rick Wilton »

I have built two separate types, on is a bell kiln and other is hinged like yours. The only difference is that the majority of the sides stay on the base and only the top few inches are hinged. (Your design is better)

I would still cut a hole into it if that was mine as the ability to peek is invaluable in my opinion.

You could either put the brick in the side to avoid it falling into the kiln when lifted or still put it in the front and mount a face onto it so it can't fall in.

Anytime you open a large kiln like that to view your work you create a breeze that I have found moves fibre fibres and/ or powders around. I use a lot of sand, talc and powdered kiln wash in mine that can get stirred up easily.

I also do a lot of firing based on sight rather than rigid schedules, I find too many people have very little idea what happens between the time they put in cold glass and remove a finished cold piece.
Rick Wilton
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Re: Viewing window in homebrew fibre kiln

Post by Rick Wilton »

MY kilns were both made from fibre board rather than blanket however. This may complicate it for you. As the board gave my brick a bit more structure to rest on.

Nice job on yours however.
Rick Wilton
adrian
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

Rick Wilton wrote:I have built two separate types, on is a bell kiln and other is hinged like yours. The only difference is that the majority of the sides stay on the base and only the top few inches are hinged. (Your design is better)

I would still cut a hole into it if that was mine as the ability to peek is invaluable in my opinion.

You could either put the brick in the side to avoid it falling into the kiln when lifted or still put it in the front and mount a face onto it so it can't fall in.

Anytime you open a large kiln like that to view your work you create a breeze that I have found moves fibre fibres and/ or powders around. I use a lot of sand, talc and powdered kiln wash in mine that can get stirred up easily.

I also do a lot of firing based on sight rather than rigid schedules, I find too many people have very little idea what happens between the time they put in cold glass and remove a finished cold piece.
HI Rick
I think I copied the general design from a commercial kiln (which I couldn't afford! <g>)
I do have some of the fibre-board that I used for the base of the kiln (it's 1" blanket with firebrick spacers and then 1" fibreboard on top).
I guess I could cut a 'plug' from the board - in the same way you've used a brick...
But I did like the idea of a window....

Understand about stirring up the dust, I do try and get the maximum 'mileage' from each piece of Thinfire or Papyrus - so sometimes I'm firing on dust rather than on paper - and it does tend to fly about a bit...
Like you - I'd like to be able to 'see' what's happening during fusing / slumping.

I guess I'll go for "plan A" - and see how the glass I've got stands up.
If I'm neat with it I can always replace the piece of blanket I've cut out if it turns out to be a Bad Idea..

Thanks
Adrian
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Re: Viewing window in homebrew fibre kiln

Post by Morganica »

One suggestion, whatever you use: Remember that it can be very dark inside a kiln. ;-)

Only half joking. I have a nice big quartz window in my new fiber kiln and I love it...as long as the kiln is actively firing. That way the elements illuminate the interior. When the kiln has gone into the downramp, though, and the elements shut down, you can't see a daggone thing in there.

I'd considered putting windows in either end of the kiln for exactly that reason, so that I could bring in enough light when the elements weren't glowing. Then I figured quartz was expensive and not as insulating, and sp two windows was a dumb idea. So...one window.

Now I wish I'd stuck with my dumb idea. I'm trying to rig video to capture processes and it's hard to both light the interior and film it at the same time. A backlight coming from the other side of the kiln would have been perfect. Or, possibly, one from above...
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Re: Viewing window in homebrew fibre kiln

Post by Bert Weiss »

My first kiln is a front loader just a bit smaller than yours. The door is made of a combo of mineral wool covered with blanket (interior surface) with an expanded metal skin. I cut a round hole, about an inch and a half in diameter, in the expanded metal and insulation, and stuffed a wad of blanket in the hole. At 1500ºF inside, I can remove the blanket with my bare fingers. If you were to put a cigarette in your mouth, put it in the opening, and take a drag, it will light right up. (I built mine in 1982 when cigarettes were a bit more prevalent.)
Bert

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Re: Viewing window in homebrew fibre kiln

Post by adrian »

Morganica wrote:One suggestion, whatever you use: Remember that it can be very dark inside a kiln. ;-)

Only half joking. I have a nice big quartz window in my new fiber kiln and I love it...as long as the kiln is actively firing. That way the elements illuminate the interior. When the kiln has gone into the downramp, though, and the elements shut down, you can't see a daggone thing in there.

I'd considered putting windows in either end of the kiln for exactly that reason, so that I could bring in enough light when the elements weren't glowing. Then I figured quartz was expensive and not as insulating, and sp two windows was a dumb idea. So...one window.

Now I wish I'd stuck with my dumb idea. I'm trying to rig video to capture processes and it's hard to both light the interior and film it at the same time. A backlight coming from the other side of the kiln would have been perfect. Or, possibly, one from above...
HI

How big is 'big' ?
Just wondering whether a bigger window is the way to go - rather than a 'peephole' ?
Understand about it being dark inside the kiln when the elements aren't 'lit'..
I think some folks shine a flashlight through the window - but a way of lighting it from 'inside' would seem good...
Interesting!
Thanks
A
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Re: Viewing window in homebrew fibre kiln

Post by Rick Wilton »

I keep a small flashlight beside my kiln. You shine that into a glowing a kiln and the glass looks almost normal. In otherwords the light from the flashlight let you see the glass as if it wasn't glowing orange. It makes it much easier to see the definition and roundness of the glass in the kiln even at top temp.
Rick Wilton
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Re: Viewing window in homebrew fibre kiln

Post by Rick Wilton »

My window hole is approx 4" x 6" basically the standard size of an IFB. A peep hole is borderline useless to me.
Rick Wilton
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Re: Viewing window in homebrew fibre kiln

Post by adrian »

HI Rick
Thanks for the flashlight tip - I'll remember that.
OK on the 6 x 4 - that's the lines I was thinking along.
What's an IFB?
Thanks
A
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