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Shewie
30-01-2008, 17:34
I was in a homeware shop this afternoon and as usual couldn`t help checking out the stainless steel section. Amongst all the tea and coffee jars there were some really nice ice buckets for £3.99 which looked remarkably like the zebra billys. They were about 16cm in diameter and had a good solid bail arm on. The lid had a naff rubber seal which could easily be removed but then there`s the question of the double wall

Now I know it`s not the brightest idea to put on over a flame but has anybody ever thought about maybe drilling a few air holes somewhere in the cavity and making it safe. The wall on the one I saw was 10mm thick so I thought of perhaps drilling four holes in the bottom and top of the wall.

Would it work guys ??

I thought for the sake of £4 it could be a good little project to try.



Rich

bikething
30-01-2008, 17:39
can't see how the heat's going to get to the middle 'bucket' to heat your food though ?

spamel
30-01-2008, 17:39
Jamie, the lad I used to bushwhack with in Germany, asked the same questio a tear or so back. He ended up cutting the inner and outer pieces to try and get two billies, but the inside of the second one wasn't quite as nicely finished. Saying that, he could have used both of them with no problems at all.

Shewie
30-01-2008, 17:45
can't see how the heat's going to get to the middle 'bucket' to heat your food though ?


That`s what I thought too, but wouldn`t it still get hot due to radiation fom the outer layer, after all it would be over a fire.

Maybe it`s just a crap idea and it would take 3 hours to boil a brew :rolleyes:


Rich

Eric_Methven
30-01-2008, 19:57
The problem lies in the air gap between the layers. Drilling holes will lose you the vacuum and the insulation it gives, but remember you'll only have liquid in the inner section. The outer section will have no liquid to keep it at a manageable boiling temperature, so the outer is going to glow red hot, and it'll only be a matter of a short time until it burns through. The only reason normal billy cans don't burn through is the water keeps it at 100 deg. Let it burn dry and you know what happens.

Eric

andy_e
30-01-2008, 19:59
I suppose if you drilled a series of decent-sized holes, say 1/4 inch, around the outside at the top and cut a big hole in the bottom, hot air circulating in the space between two layers might concentrate the heat from your fire and cook/boil the contents faster.

bushscout1
31-01-2008, 14:55
I can't imagine that it would work as a billy, as per the comments listed already, as for heat radiating its not that efficient & neither would be a convection current of hot air. I would expect that the heat from the flame would spread around the outside of the unit & radiate into the open air - rather than conducting it across to the inner 'billy' containing the water.

Have you considered adapting it for a hobo stove, rather than a billy?

Perhaps a series of holes around the bottom outer unit would let air in, with a number of holes in the base of the inner unit to let the air into the fire chamber. The air gap would stop the outer getting hot and should protect the ground beneath from damage ?

Just a thought.

In Wood
31-01-2008, 15:06
I was thinking along the same lines as Andy e. What if you cut the bottom off the outer, would thet then concentrate the heat into and onto the inner surface for faster boiling?

Beer Monster
31-01-2008, 15:07
Have you considered adapting it for a hobo stove, rather than a billy?

Perhaps a series of holes around the bottom outer unit would let air in, with a number of holes in the base of the inner unit to let the air into the fire chamber. The air gap would stop the outer getting hot and should protect the ground beneath from damage ?

Just a thought.

That’s what I was thinking. Maybe a homemade Bushbuddy stove (www.bushbuddy.ca). Drill holes around the bottom on the outside the holes round the top on the inside. That way air is drawn in the bottom then preheated as it rises between the 2 layers and as it comes out the top holes it has a secondary combustion. It’s meant to be very fuel efficient. I think Pablo did a review of one on his blog.

andy_e
31-01-2008, 16:50
That’s what I was thinking. Maybe a homemade Bushbuddy stove (www.bushbuddy.ca). Drill holes around the bottom on the outside the holes round the top on the inside. That way air is drawn in the bottom then preheated as it rises between the 2 layers and as it comes out the top holes it has a secondary combustion. It’s meant to be very fuel efficient. I think Pablo did a review of one on his blog.

That's a good idea. Would convection be enough to draw air in for secondary combustion though, doesn't the bushbuddy need a fan?

Beer Monster
31-01-2008, 17:56
That's a good idea. Would convection be enough to draw air in for secondary combustion though, doesn't the bushbuddy need a fan?

Not as far as I'm aware. On their webpage (http://www.bushbuddy.ca/index1.html) here they say no batteries required so I suspect not. I have seen another that does ..... can't remember it name ..... and never really saw the point to be honest!

gilly0802
31-01-2008, 18:31
i made a simeler thing out of 2 paint cans, and they work well enough without the fan

authough they are brilliant when you put a chimny onto it :)

andy_e
31-01-2008, 18:50
Not as far as I'm aware. On their webpage (http://www.bushbuddy.ca/index1.html) here they say no batteries required so I suspect not. I have seen another that does ..... can't remember it name ..... and never really saw the point to be honest!


Ah right, I was thinking of the Wood Gas stove http://www.woodgas-stove.com/

Beer Monster
01-02-2008, 11:22
Ah right, I was thinking of the Wood Gas stove http://www.woodgas-stove.com/

Yup that was the one I was thinking of.

I wonder what would happen if the holes at the bottom where bigger than the ones at the top. As the cold air enters the bigger holes at the bottom, heats up and rises to the top it would be forced through the smaller holes at the top creating more of a "jet" effect ...... might be improved by making the air space wide at the bottom and narrowing towards the top? I gave up physics at before my GCSE's so no idea if the principle is sound?!? A small stove maybe to small scale for it to work.

Another of my highly technical drawings :lmao: :-

http://i25.photobucket.com/albums/c62/beer_monster/Plan.jpg

andy_e
01-02-2008, 11:34
Another of my highly technical drawings :lmao:

Simple, effective, nice use of colour BM :D

Shewie: you didn't mention which store you found these in, I quite fancy giving this idea a try if I can.



Edit: just spotted something you've missed in your pic BM - holes on the inside at the bottom to provide air for primary combustion.

Draven
01-02-2008, 12:06
Yup that was the one I was thinking of.

I wonder what would happen if the holes at the bottom where bigger than the ones at the top. As the cold air enters the bigger holes at the bottom, heats up and rises to the top it would be forced through the smaller holes at the top creating more of a "jet" effect ...... might be improved by making the air space wide at the bottom and narrowing towards the top? I gave up physics at before my GCSE's so no idea if the principle is sound?!? A small stove maybe to small scale for it to work.

Another of my highly technical drawings :lmao: :-
(image)

I quite like this idea. I don't think it would be necessary for the gap to get narrower towards the top, as the air warming up will expand anyway. If it works properly, the hot air rising and being forced out through the smaller holes should be enough to ensure a constant flow; rather like some of the heaters that take air in at the bottom (because cold air sinks) and expell it, warmed up, out the top. The problem I forsee, particularly with narrowing the channel, is that the pressure created may be too much for the "hot air rises" rule to apply; the air may expand, go out the bottom (because the holes are bigger) and cold air will be pulled in from the top. I think it might work better if the holes were equal size and an equal number of them; therefore, it will be just as easy for the hot air to go out through the holes in the top, and the "hot air rises" rule would reinforce that...

I think :cool:

Shewie
01-02-2008, 13:39
Simple, effective, nice use of colour BM :D

Shewie: you didn't mention which store you found these in, I quite fancy giving this idea a try if I can.




They were in "Range" Andy on an clearance aisle end.


Rich

andy_e
01-02-2008, 14:01
They were in "Range" Andy on an clearance aisle end.


Rich


Ah right, cheers Rich, not sure if we have them up here. Will have a scout around at the weekend and see what I can find.

Beer Monster
01-02-2008, 15:43
Simple, effective, nice use of colour BM :D

Edit: just spotted something you've missed in your pic BM - holes on the inside at the bottom to provide air for primary combustion.

I thank you. I don't think I'll give up my day job though :D !

Here are adjustments:-

http://i25.photobucket.com/albums/c62/beer_monster/Plan-1.jpg



I quite like this idea. I don't think it would be necessary for the gap to get narrower towards the top, as the air warming up will expand anyway. If it works properly, the hot air rising and being forced out through the smaller holes should be enough to ensure a constant flow; rather like some of the heaters that take air in at the bottom (because cold air sinks) and expell it, warmed up, out the top. The problem I forsee, particularly with narrowing the channel, is that the pressure created may be too much for the "hot air rises" rule to apply; the air may expand, go out the bottom (because the holes are bigger) and cold air will be pulled in from the top. I think it might work better if the holes were equal size and an equal number of them; therefore, it will be just as easy for the hot air to go out through the holes in the top, and the "hot air rises" rule would reinforce that...

I think :cool:

..... there you go ... someone who knows what they are talking about :D ! I forgot that hot air expands!

I suspect that you would have to either raise the air holes for the primary combustion or if they are lower down put some sort of mesh across the holes otherwise ash etc would fall into the space between the skins of the stove (this might not be a problem initially but might build up over time). Might also be worth staggering the holes at the bottom i.e. so the holes bringing cool air into the stove don't overlap the holes feeding the primary combustion.

Shewie
01-02-2008, 17:42
Ah right, cheers Rich, not sure if we have them up here. Will have a scout around at the weekend and see what I can find.

I`ve checked out their website Andy and there nearest Range to you is in Carlisle, they haven`t quite breached the wall and reached you lot up there yet.


Rich

andy_e
01-02-2008, 17:47
I`ve checked out their website Andy and there nearest Range to you is in Carlisle, they haven`t quite breached the wall and reached you lot up there yet.


Rich

LOL! Cheers for looking - Carlisle is a *little* far to go for an ice-bucket :D I'll keep my eye out for anything similar as I'm sure between us all we could make something interesting.

Draven
01-02-2008, 18:33
..... there you go ... someone who knows what they are talking about :D ! I forgot that hot air expands!

Not really; but Standard Grade was only a few years ago, so some scraps are still in mind :p

It looks like a pretty good design, I can't see why it wouldn't work; but it all depends, really.

The fire WILL heat the air between the walls, so it will expand and it will rise.

However, the effectiveness of this will really depend on just how much air the fire sucks in; seeing as it's actually burning, it will get the majority, I'm sure. If this happens, and little-no air is going up between the walls (unlikely but possible) then that could actually be a benefit; the high pressure between the walls (caused to the air heating) is forcing air out from between them, and the fire is stopping much air replacing it, so the pressure between the walls should be pretty low all tolled - the low pressure "wall" of air will help prevent heat being radiated away, ensuring that the inner wall stays hot, and that heat will therefore radiate up, and help to heat whatever you're heating!

So even if it doesn't work exactly how it's meant to, you should still get benefits from the design. :)

bushscout1
01-02-2008, 21:13
What about using larger diameter holes around the outside at the bottom than the inside holes (primary & secondary air supplies)?

That way there'd be plenty of air getting in.

If I recall correctly then the area of a circle is pi (3.142) x radius squared - which basically translates that a hole twice the diameter will allow 4 times more air through.

ie. if you drilled 12mm (0.5") holes around the outside (say 8 evenly spaced),
and you drilled 6mm (0.25") holes around the inside (top & bottom - 8 each level)
then you'd still have 50% too much air supply if air in = air out
but as the primary supply would draw more in, and the secondary supply would also have a draw (but also be expanding the air to increase the volume further....) :22:

I think I just blew my brains out :togo:

I guess the best bet would be trial & error - but that could get expensive with many holey ice buckets :lmao:

Draven
01-02-2008, 21:36
Nice one Bushscout, I hadn't thought of that :)

andy_e
01-02-2008, 21:44
I'd probably go for more and smaller holes around the inner top to attempt to get a more jet-like effect.