Instructables

Easy large portable woodgas stove


This is a CHEAP version of my first Instructable

If you need to get a BIG stove going  right now, this is the one.

Video of stove operation at end of Instructable.

Read and BUILD!

 
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Step 1: Tools and materials

Tools:

- Tin snips
- Sharp chisel and hammer
- Corded or cordless drill or screwdriver
- Optional hacksaw
- Optional Dremel with fiberglass cutting wheel

Materials:

- Large tin can. 10 inches wide, 11 inches tall (roughly)
- Smaller can about 8 inches wide. #10 food can type
- Computer style fan. (80 or 92 mm)
- 1/8" diameter metal tubing (flux brush, golf club tubing, small copper tubing from old fridge?)
- 2 1/2 inch deck or drywall screws. Any long screws will do.

The large tin can might be a popcorn or cookie tin. It can be a 5 gallon kerosene or hydraulic fluid container. It could be a metal paint pail with lid that seals. The container has to have a flat top and be completely intact.

The inner burn pot can be made from a #10 food can, or 2 stainless steam table pots (bain marie).
I use the inner pots from my other instructable in this one. Look there for more info.

The single wall burn pot will work fine. It will radiate enough heat to melt your computer fan though.
The fan pictured below melted in this close configuration.

Cut the top hole in the outer can with a sharp chisel and hammer. Or use the chisel and hammer to get a hole started, then use tin snips to finish the top hole. Take your time and make the top hole PERFECT. The #10 food can/inner burn pot must fit TIGHT. This allows the gasifier to work best without needing weird exotic sealants you have no access to.

Next step will show how to make a basic duct to keep the fan a small distance away.

All this instructable shows is how to make a fan duct and gasifier if you have barely any tools and supplies.



use a metalic fan and put it on a long tube at some distance from the stove! or use a hair dryer ;)
Hi interested in the possibility of producing steam from a wood gas stove. i want to build a sauna while out trekking and rather than heatiing up rocks to use in the sauna to create the steam. i am now considering piping the the steam directly into the sauna from the wood gas boiler. the sauna is a converted 2 man tent. any ideas from you guys on producing continuous steam would be great. i am going to backpack this so size and weight is an issue. robert
KoffeeKommando (author)  Timofte Andrei3 years ago
There are only so many metal fans out there. They are normally expensive also. I want to show something anyone can build.

A tube would work just fine for a plain computer fan. I built square ducts out of metal 2x4 wall studs for a few of these stoves.

Hair dryer is out because you can only use it near a house. It's too much air also, fire will burn really hot and die out fast.

check my idea :D i'm not an artist in Paint but you get the idea ;)
ideea mea.jpgideea mea 2.jpg
KoffeeKommando (author)  Timofte Andrei3 years ago
Get Google Sketchup and learn it. We need more people that can rock that stuff.

They have CPU fans in the 3D warehouse I bet.

My duct was similar, I made a rectangle box and had the fan blow down then do a right turn. I didn't have any tubes available.

Did you check out my other Instructible? The silver gasifier? No tubes needed. Part of the reason I did the better stove.

do you have a can?...you can use a tomato can instead of a tube or any can you have in your house :D think green ;) recycle!
KoffeeKommando (author)  Timofte Andrei3 years ago

Here is what I'm thinking of. Just drew it in Sketchup.

http://sketchup.google.com/3dwarehouse/details?mid=ebd00cc74bd9486a155fd428fcb8c5ea
PoorMansFanTube.jpg
that's what i'm talking about! but...you need that sheet of steel or something to mount the fan to it and then to the tube ;) that ring it's not enough ;)
KoffeeKommando (author)  Timofte Andrei3 years ago
There you go.
PoorMansFanTube2.jpg
KoffeeKommando (author)  Timofte Andrei3 years ago
You have to look at the drawing within Sketchup. It is a sheet of metal exactly like yours.

Take a very close look at that pic. You will see the gap between the fan and the plate with tabs cut.
KoffeeKommando (author)  KoffeeKommando3 years ago
Basically you take computer fan screws, the stubby ones, and screw in from the back side. From the plate into the fan.

You can also take put the tabs inside the pipe. Screw small sheet metal screws from the outside of pipe inwards (into the tabs). This would create better air sealing. Or just use high temp RTV on it all. Whatever ya got.

If you have a powerful enough fan it won't matter. If the fan is wimpy it won't allow a big gasifier like this to work right. You have to get the right fan power for your enclosure to get the correct burn rate. In a smaller gasifier, any old computer fan would work perfect.

Thanks for the inspiration. I'll work on the fan tube drawing some more showing how to attach tube to gasifier body.

You can take the drawing and run with it too. Learn Sketchup. I've been using Sketchup for 3 weeks now and the drawing still took me 2 hours. Takes a while when you are thinking out concepts as you go. It's easier to make things in real life. But...without documenting things for other people...it's all a waste of time. Hence the Instructables website ;)
KoffeeKommando (author)  Timofte Andrei3 years ago
Hey I got another idea from your drawing. Make the tabs longer, then put them outside the tube. Use a large metal hose clamp to go around them, holding them tight to the tube.

I'll get my old gasifier out and try to do this idea, will then add the pics to this instructible.
mspaeth4 years ago
 What's the difference between the woodgas stoves people are making without fans and the ones being made with fans? What is the functional difference? Are the ones with the fans more efficient gasifiers? 

KoffeeKommando (author)  mspaeth3 years ago
Yes, the ones with fans run better/smoke less. They don't blow out in the wind either. Computer fans and car batteries are available all over the planet by now. I'm a fan kinda guy cause I WANNA SURVIVE ;)
oh...and let me give you another idea...put a copper tubing serpentine between inner and outter chambers an you can make hot water or a small steam boiler :D
KoffeeKommando (author)  Timofte Andrei3 years ago
Yes, that would be pretty easy. And don't forget the pressure relief valve. Or it will blow up in your face. This gasifier runs way more than 300 degrees around the top rim. Lower down the body it's 200...towards the bottom its 100. These are EXTERNAL temperatures.

wgrube4 years ago
You could use peltier elements attached to the body of the stove to power the fan, what do you think? By the way, nice stove! I'm planning to build one a little smaller, for my camping trips.
baudeagle4 years ago
I noticed that you have two different stoves shown above, One with large holes near the top and one with samll holes near the top. 

Could you explain the benefits/detriments and or purpose of each configuration?
KoffeeKommando (author)  baudeagle4 years ago
The picture showing large holes is just to show the most simple method of making a burn pot. It is a #10 food can I believe.

The pictures with the small holes depict a completely different double wall burn pot. This pot is detailed in my other instructable.

It's basically a large stainless pot with another smaller pot that fits inside.
The smaller holes on the top and bottom of this setup create a very different (and better) burn.

I used the pot assembly from the better stove just to illustrate how well it works with different fans.

You use what you have on hand to create one of these stoves.
Build the simple one, then get some money together and build the better one later.


LCsDad4 years ago
Might try yellow-bottle Heet for priming fuel.  Burns wicked clean. Used in most penny stove write-ups.  Thanks for the video!
KoffeeKommando (author)  LCsDad4 years ago
Sure, that would work too. I just happen to have a big drum of old jet fuel. It burns just like diesel.

I like lamp oil also. Clean burning, and it soaks into the pellets quickly.

Heet would be cheap and easy to get anywhere. I'll try that tomorrow.
Going to do another startup video with my final gasifier.

Make sure you look at my other video. It shows the construction of the double wall burn pot.

I'm going to make a smaller double wall pot gasifier soon. This one is way too hot for most jobs. You can stay warm at night standing around it for sure.

I'm going to design a heat exchanger to go over it to do small scale hydronic heating. That is where this design is heading.