Wood stove experiment
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Colin Krusor
(ckrusor)

Locale: Northwest US
Same old wood stove design, trying out a new material... on 08/15/2008 09:55:10 MDT Print View

I got ahold of a scrap of 3.6oz/yard ceramic fabric and decided to try using it for the inner chamber of a wood stove. I sewed the sock-like inner chamber together with quartz thread from McMaster Carr. It has screen on the bottom for primary air, and nickel eyelets near the top to let in secondary air. The pot stand is titanium wire sewn into the upper edge of the sack, and sits on the rim of the stove. The pot stand and fabric sock can be set on the ground to permit use of a backup esbit tablet when no dry fuel can be found (see pic below). The outer jacket of the stove is a two-liter japanese beer can. The aluminum can seems fine after several good long burns. The inner chamber is about 3.75" diameter, and the outer aluminum bit is about 4.5". Without the pot stand sticking up the whole thing is about 5.5" high. It all weighs 2.80 oz (79g).

getting ready for making pasta on the porch

Lighting it from underneath

After a minute or two

Secondary combustion (flames coming from eyelets)

heating water for pasta

After the test, embers still in the bottom, fabric blackened near the top

Inner chamber with attached pot stand...soot around the top

After a test burn

esbit can be put right on the fabric

Edited by ckrusor on 08/15/2008 11:19:26 MDT.

Colin Krusor
(ckrusor)

Locale: Northwest US
boil times on 08/15/2008 09:56:46 MDT Print View

I'll post a little more info, like boil times, etc. when I've had more time to play around with it.

Edited by ckrusor on 08/15/2008 11:18:26 MDT.

Dan Yeruski
(zelph) - MLife

Locale: www.bplite.com
Re: Same old wood stove design, trying out a new material... on 08/15/2008 11:34:59 MDT Print View

Bravo!!!!!! Very very innovative. Well done!!!!!!

Is it slow starting?

Is that a stainless steel mesh sewn onto the bottom of the sock?

You are definately thinking outside the box. Well done!!!

Colin Krusor
(ckrusor)

Locale: Northwest US
Mesh on 08/15/2008 12:01:48 MDT Print View

Yes, that's stainless steel mesh. It doesn't seem particularly sluggish to start, but I haven't timed it. I use a little piece of a vaseline-smeared cotton ball to get it going. Thanks for the accolades, Zelph. Any input is welcome.

Dan Yeruski
(zelph) - MLife

Locale: www.bplite.com
Re: Mesh on 08/15/2008 20:05:49 MDT Print View

If you make another one try lining the aluminum can on it's interior with a light weight ceramic cloth to keep the aluminum from deteriorating from intense heat. Use the same thread that you used on the sock, to attach it in strategic places.

I dont't feel good about secondary holes in a wood burner. Do away with the grommets on your next one and see how it performs. Don't pack your fuel tight, see how it works out.

The nice thing is the aluminum shell, it won't rust, the ceramic cloth will preserve the aluminum even at the cost of a small amount of weight.

Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: Same old wood stove design, trying out a new material... on 08/16/2008 12:33:47 MDT Print View

Colin, really innovative thinking. Cool! I find myself wondering if the ceramic fabric is porous enough to allow air flow / gassification without the grommets. All things considered, your creation is under 3 ounces, so the grommets aren't a big deal, but I wonder...

Nia Schmald
(nschmald) - MLife
Re: Same old wood stove design, trying out a new material... on 08/16/2008 20:52:33 MDT Print View

I really like this idea. Along Zelph's line of thought, if the top holes are eliminated it's no longer a double wall "woodgas" stove. So why not get rid of the outer wall and replace it with a light weight stand to support the cloth sack. It seems like the titanium spoke stand might work.

The result would be a collapsible wood hobo stove for about 1 oz. That's something I would definitely be interested in.

Anyone know where I can get a small amount of this ceramic cloth to try this out? I'd love to measure against my homemade double wall paint can stove.

Also are there any health concerns for the cloth? I've seen mention of issues with breathing in the fibers and skin irritation but not sure if it relates to what was used here.

Edited by nschmald on 08/17/2008 23:57:15 MDT.

Dan Yeruski
(zelph) - MLife

Locale: www.bplite.com
Re: Re: Same old wood stove design, trying out a new material... on 08/17/2008 09:46:41 MDT Print View

I like how this is progressing =)



WOW!!!! collapsible wood stove, let's make it happen.

The cloth is available at Ace Hardware stores and Automotive parts stores "Autozone" being one. Ask for "Bondo" fibberglass cloth body repair kit. Or just the cloth by it's self.

ke wu
(asidesign) - F

Locale: Block seven
Re: Re: Re: Same old wood stove design, trying out a new material... on 08/17/2008 10:21:35 MDT Print View

Hi~Dan,
Hanging stove could make your thinking come true...

Edited by asidesign on 08/17/2008 12:01:49 MDT.

Colin Krusor
(ckrusor)

Locale: Northwest US
ceramic fabric on 08/17/2008 11:35:38 MDT Print View

Nia and Zelph,

I really like your idea for a titanium-tent-stake stand, Nia. I've been thinking about that, too. I was actually thinking about exactly what you proposed but inside a shroud made of the same fabric, foil (titanium or aluminum), or Kapton film (good up to about 900F), so it could still take advantage of preheated secondary air (a double wall design). Then it would still be collapsible.

The fabric is actually not fiberglass. I tried the two major varieties of fiberglass (E glass and S glass) in earlier designs, but the E glass melted and the S glass became brittle and disintegrated after several trials. It's alumina (aluminum oxide) ceramic. The piece I used is a scrap left over from a research project. There are a lot of companies that make it, but it isn't easy to find in light weights or small batches. Heavier weights (8oz-30oz/yard) are sometimes used at foundries or for welding blankets. Cheaper silica (silicon dioxide, or quartz) fabric would probably work, too (the thread I used is silica).

The fabric I used is very tightly woven and just looks and feels like lightweight canvas. It isn't dusty or brittle, and I don't think it's porous enough to allow much gas exchange through it.

A collapsible wood stove would be great. You guys all have excellent ideas.

Nia Schmald
(nschmald) - MLife
Re: ceramic fabric on 08/17/2008 12:49:32 MDT Print View

Colin, thanks for the reply. I was just about to go out and get some fiberglass. I knew e-glass wasn't going to work but thought s-glass had a chance.

Mcmaster-carr has an 18 oz/yd silica fabric that might work but at a significant weight increase. Omnisil OS120, shown here looks good at 3.6 oz/yd and a service temp of 2000F and melting point of 3100F, but a web search didn't turn up any retail sellers. I think it's too light for a welding blanket.

How about carbon fiber like this? If it's actually pure carbon than it should hold up to heat and is readily available.

Bill Fornshell
(bfornshell) - MLife

Locale: Southern Texas
Ceramic Fiber Collar for a Cook Pot on 08/17/2008 13:29:06 MDT Print View

Back around Aug of 2005 I tried a ceramic fiber collar or cozy for one of my cook pots. The link below mentioned the idea. I think I have pictures of the ceramic fiber collar / cozy posted someplace on here but haven't been able to find the thread yet. I have rolls of ceramic fiber, you can also buy it in thin sheets sort of cheap. Check out a local pottery supply store. Potters use this stuff to build or help insulate their kilns.

My original idea was to use the ceramic fiber collar or cozy on the outside of a pot used to melt ice. I wrapped the ceramic fiber in aluminum foil to help keep it clean. I was hoping the insulation would help reduce the amount of canister gas or what ever fuel someone was as they were melting ice.

I was never able to give the idea a good (cold) field test.

I still have the ceramic fiber collar.


Some information about Ceramic Fiber

Nia Schmald
(nschmald) - MLife
Re: Ceramic Fiber Collar for a Cook Pot on 08/17/2008 13:51:39 MDT Print View

Thanks Bill. I had discounted this based on the thickness but I see in your post a discussion of separating layers. Did you try this? How well do you think it would hold up to getting poked by twigs. There is also ceramic paper sold for kiln shelf liners. I don't know how this would hold up for long term use.

Steve Martell
(Steve) - MLife

Locale: Eastern Washington
Re: Ceramic Fiber vs. CarbonX on 08/17/2008 14:14:12 MDT Print View

How about this stuff:

http://www.concordcoinc.com/index.aspx?Command=GroupInfo&GroupID=9937

Bill Fornshell
(bfornshell) - MLife

Locale: Southern Texas
Re: Re: Ceramic Fiber Collar for a Cook Pot on 08/17/2008 14:36:41 MDT Print View

Hi,

I divided the "blanket type" ceramic fiber in half. It worked OK. To make it a bit more durable I wrapped the ceramic fiber in aluminum foil.







I have some of the ceramic paper. It is a lot like blotter paper. It is sort of strong but can be torn. It also could be layered with aluminum foil or something to protect it. This ceramic paper is 1/8" thick.


A few rolls of ceramic fiber.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: ceramic fabric on 08/17/2008 15:20:22 MDT Print View

> How about carbon fiber like this? If it's actually pure carbon than it should hold up to heat and is readily available.

Have you considered that the glowing coals in a wood fire are really glowing carbon?

Nia Schmald
(nschmald) - MLife
Re: Re: Re: Ceramic Fiber Collar for a Cook Pot on 08/17/2008 15:37:10 MDT Print View

My goodness Bill that's quite a stash you have. How many cook pot collar's were you planning on making? :)

What is the weight? I've seen references to 4 - 8 lbs/ft^3. That would be 24 oz/sq yd for a 1/2" thick piece. If right, that seams a little heavy.

That carbonx blanket looks interesting, but I wish it came in smaller pieces. I saw a reference suggesting it's a carbon/aramid mix and that it can carbonize above 570F. Does that mean it would become brittle?

Nia Schmald
(nschmald) - MLife
Re: Re: Re: ceramic fabric on 08/17/2008 15:42:58 MDT Print View

>> How about carbon fiber like this? If it's actually pure carbon than it should hold up to heat and is readily available.

>Have you considered that the glowing coals in a wood fire are really glowing carbon?

Thanks for pointing out the obvious. I got focused in on melting point, which is quite high. But I ignored the ignition point.

Bill Fornshell
(bfornshell) - MLife

Locale: Southern Texas
Ceramic Fiber Weight on 08/17/2008 17:52:01 MDT Print View

Hi,
I cut and weighed a small piece of my ceramic fiber. It is 1.5" x 2.75" x 2.75" and weighed 10 grams.

Nia Schmald
(nschmald) - MLife
Re: Ceramic Fiber Weight on 08/17/2008 21:46:45 MDT Print View

Thank you for the info Bill.

That puts the weight at about 60 oz/sq yd. And if the thickness is reduced to 1/2" it would be 20. Not too bad. That's about the weight of .005" Ti foil.