The following is a true story, only the names have been changed to protect the guilty.

Monday, January 28, 2013

Heat

Roll up the body
 While wasting time on the internet, just like you are now, I saw some examples of guys using small home built stoves in their 1-2 man retrofitted tents. The stoves looked interesting but were of crude construction and seemed dangerous. They were built from everyday items found in department stores, hardware stores, garages or dumpsters, and re-purposed into wood stoves. While I was inspired by, and admire the creativity of these stoves, I would not be able to bring myself to construct something that is well below my ability, and level of craftsmanship. I'm a sheet metal worker by trade and have all the materials and equipment at my disposal to craft something at a much higher level of quality.
I added 2 beads for strength 

Forming roll, used to shape the ends so they can be spot welded inside the body


The various stages of the ends during forming


I wanted my stove to be relatively light, and most importantly safe. My plan is to use it on short overnight bike-packing, back packing, and kayak trips during the cold months from late fall to early spring. I decided to go with a round body as opposed to a squared off one simply because thought it would look cool and be a greater challenge to build. As I mentioned, safety is of prime concern, I want to be able to use it with my kids. Many of the hacked together stoves look very dangerous, some rely on gravity to keep them together while others are so flimsy they look as if they would fall apart with a accidental tap of a booted foot or windy conditions moving or shaking the tent. In particular the vent/stack seems to be the most dangerous component of the stoves I've seen. Simply sleeveing together a multi-piece stack without any kind of fastener is an accident waiting to happen. Just because they slide together doesn't mean they will stay together. My solution is to pre drill holes in the stack and run long pins through the entire diameter. My stove also has a protruding collar in which to attach the stack. This may get in the way a little but it makes for a solid attachment of the stack and a place to put a proper damper. Some stoves are designed to have the stack fit inside the body of the stove, this is a bad idea since there is no way to secure the vent and the air flow is all wrong. Typically in the HVAC trade you want to "observe" air flow by telescoping the pieces in a manner that naturally will not leak. Small end goes into large end with air flow transitioning through the overlap in the same direction. I have not included pics of the stack but I have three different options that I will go over at a later time.
Spot weld the ends and follow up with a forming roll to get the crimp nice and tight

Di-acro bender used to form the legs

Legs in place
For the body of the stove I chose to use stainless steel, it looks cool and most people have neither the access or wherewithal to work with it so I thought it would be unique if nothing else. In testing I believe the stainless is not the best option, heat doesn't seem to radiate as well as black iron. Since making the first two out of stainless I have since constructed several others from black iron that seem to radiate heat better. Black iron is lighter, much cheaper, and easier to work with. The first stove was missing a damper in the front and the rear, I thought since this thing was so small the "rules" would not apply, I was wrong. The 2nd-5th generation of stoves all have two dampers and work a lot better.  
Door with clever but simple way to keep it shut

Layout of the vent collar

The collar is dove tailed and spot welded to the inside of the body
This little project is a work in progress, since my first stove was finished I have made several more including one with a heat exchanger to get as much out of these things as possible. I will share more when I perfect my system and have more pics for you to take a look at. Now I need to get going on a small tent suitable for a wood stove.
first test

I got most of the center section of the stove to turn red without warping. I need to make some changes and add dampers for better control



5 comments:

  1. That is awesome. Mostly for showing me how to lay out a proper cut line and how to form the tins. The stove is rubbish. :)

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  2. Dave at Bedrock and Paradox has been monkeying around with a DIY woodstove and hacking his B.D. Megamid to match. You might be interested. http://bedrockandparadox.com/2012/11/11/wood-stove-acalculia/

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  3. His site and links is where I got the idea to build my own. his is a top notch site that i frequent often

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  4. Good to hear! I've been enjoying going "back in time" reading through your stuff. Your tale of "Coward" regarding the Arrowhead is great - that big ol' pig of a bicycle may have been a pain but it sure looked cool.

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