Gear

There are no end of threads on various sites about tin can stoves. But I've been trying to make something close to the specs of a Bushbuddy. So here's my final solution and how I arrived at it.

I started with these two cans. The Heinz can has a 4inch diameter which is the closest I can find to the Bushbuddy for around £1.65. The sweetcorn was about 35p so in all £2.

Let's start with the outer can, the Heinz tin. I cut slits to the outer most inward facing ring. I have also scored with a Stanley knife around the ring. I then pour out the contents, in a bowl for lunch if I'm hungry, and tear off the triangular pieces.

 Then drill 12 10mm holes around the base.

Next take the top piece and use a pair of pliers to slightly flare it out. This will help it slide over the other half. Carefully slide the top over the larger section of the can. I found it best to do this with the top piece laying flat on the bench. Once it was started and mostly level I used a vice to press fit them together until the larger section rested against the lid of the top piece.

Sorry I didn't take pictures of this part I was in a rush. I'll add some when I make another.

Now the inner can. When you buy an inner can you need to look for one that's made to stack on top of another can. This makes the bottom diameter smaller than the top. This is important when the two cans are put together.

Begin by drilling 12x8mm holes around the top lip.

Next cut the can so that the top half is 52 mm high.

On the bottom section mark four tabs that are 12mm wide equal distance from one another. Then measure up from the bottom 18mm and draw a line all the way around the can. Cut out the excess above the line, leaving the four tabs.

The finished can will look something like this.

Now slide the inner can into the hole in top of the outer. Because of the smaller diameter of the bottom half the ring across the top will rest against the lid of the outer. If you have JB Weld or similar put that around the outer edge of the inner can.

You now have the finshed product.

A picture of it burning.

Post burn. Burnt down to fine ash.

The specs:

500ml water roiling boil time - quickest 5min, average 6min.

Weight - 155grams with mesh pot stand and grate.

96mm high x 100mm wide

Good photos Robert

 and boil times (though tis summer) - are you using the 'continuous feed method' or 'top down burn of a full stove' for fueling?

here's a thread from a while back Trying to make a Wood Stove

there is some useful discussion and results in amongst the traditional OM thread drifting..........

Probably the best way I think Robert - certainly quicker for boiling water.

No BB - I have lots of tin cans with holes in though - much more entertaining

I take it you did the 'cut & shut' thing with the cans to get them to be the same size as a Bushbuddy?

On closer inspection, I see that the inner cut & shut creates the 2mm primary air gap.  That's interestingly small, but the restricted air flow might actually be beneficial.  I never got around to building the 'testbed' version with air port baffle rings described on thread Mole linked to.

> I take it you did the 'cut & shut' thing with the cans to get them to be the same size as a Bushbuddy?

That's correct. The outer is cut where the top flat section turns into the ruffled section. When put back together and ground and cleaned it's only on second inspection that you really notice it.

>On closer inspection, I see that the inner cut & shut creates the 2mm primary air gap.  That's interestingly small, but the restricted air flow might actually be beneficial.

I've played around with the primary airflow. This is about 5th or 6th wood stove of various types, though all double walled. I found a post (http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=14765) where someone said the best ratio between primary and secondary air is 3:1 or 4:1. I found this to be largely true.

Too much primary air and the wood burnt extremely quickly, too little and it went out to easily. But when I first tried slits instead of holes the results where interesting. I did the calculations and cut slits that had the same area as the holes but the fire struggled for air. It would seem the slits don't funnel air as well as holes. The slits on the posted stove may vary between 2 and 3mm wide.

>I never got around to building the 'testbed' version with air port baffle rings described on thread Mole linked to.

I think you mean the one with the primary and secondary air sources seperated. That would be an interesting experiment. I'm now beginning  to regret my decision to not put this post in the other thread.