Woodgas stove – is ‘gas wick’ really needed?

[Terra _]

Hello BPL – newbie here :)

My question: I just made a Woodgas stove (used this great vid as our how-to) last night. It works great (my kids are thrilled at all the FIRE we've been producing) but I'm curious about the gas-wick aspect of the stove. No matter how narrow or short a can I use, it snuffs my fire right out (cue rolling clouds of smoke pouring off our apartment porch – must alarm the neighbors!). The stove works just fine without it, boils water like a charm. What's the purpose of the gas-wick exactly? Is it worth continuing to fiddle with getting one to work?

Thanks for your thoughts. Glad to have found this place – fantastic information on so many projects, I kind of don't know where to turn (says I, with a backpack, an aluminum can alcohol stove and a wood-gas stove in various stages of completion around the living room :D)

[Tim Marshall]

if it works without it don't worry about it. I have never read about using a "gas wick" with any of these stoves and i have made a few of diff sizes.

What r u using for a pot stand?

-Tim

[Rog Tallbloke]

Throw out the gas wick, make the holes in the outer can bigger, and make a pot stand out of some mesh or another can to go on top.

The 'pro' design is here:
http://bushbuddy.ca/indexs.html

[Terra _]

Tim – I've only seen the gas wick on a few designs :)

For a pot stand I'm currently using a coat-hanger zig-zag around the top. Holds the pot at just the right height, but offers no wind protection. I'll need a tin snips to make a better one I think :)

[Terra _]

Rog – I enlarged the bottom holes a bunch earlier today – really helped! Currently I've rigged a wire pot stand, but I want to fashion one out of a can so I'll have some wind protection. The Bushbuddy photos are a good guide for that :)

Water boils! So far, so good – gas wick or not :)

[Benjamin Levine]

Regarding the use of a gas wick. I haven't used one myself but here is what I think about it.
If you are not using forced air and you need to mix more for secondary combustion then you need to suck in the air into the gas flow.

One way to do this is to use a venturi effect. Basically when a gas is going faster, its pressure will be lowered. Because the presence of the gas wick limits the space available for the gases, these will go faster there and the pressure will be lower inside the gas wick. So on the walls of the gas wick, if you drill holes, the hot gases will stay inside and outside air will get mixed in.

Just look at the color of your flame and the soot, measure the time it takes to bring water to a boil (or weigh the water before and after five minutes of boiling time for example). Then do the same with gas wick + holes, you should definitely see an improvement, and maybe a blue flame with no soot…

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