Fire - Tin can stove success

I decided to make another tin can stove with the new design, but this time I thought I'd make it work.

A major design flaw of the first attempt was not actually the bit where the tin ripped in two, but was actually the bit where I was thinking upside down.

The previous version had grooves that would only reach the bottom.

That was never going to work.









This time I made the grooves in such a way as they would still be grooves when they reached the top.

Much more likely.

So, the top (open ended) half of the can is bent like this, and made to sit into the bottom (still with the base on) of the can.

All up this process takes only 5 minutes or less.

The zig-zag bit is placed zig-zag down into the half on the left.

It doesn't even need to be a snug fit.

Just drop it in place.





The result is, that when you light the alcohol and wait a few seconds for the device to heat up, it vaporizes the spirit within the zigs and the zags of the two walls created by the can halves, and is emitted as gaseous fuel through the top of the (now inverted) zig-zag bits.

Like this.

Perfect!

And quick.

A quicker, more durable ethanol stove.

A total success.




Much better than the last attempt.

Thanks to whoever first thought of this method of making a little spirit stove, that enable the happy camper to knock out a stove within a few minutes of dumping a can's contents into a pot.

Now all I need is canned food that actually tastes good.

And perhaps the ability to make a tin can.

I have no idea how to make a tin can.

But I'm not going to make a can as a "Thing" because nothing good ever came out of a can.





120 Things in 20 years - No can was hurt in the making of this post.



And sweetened condensed milk comes in a can, and that stuff is delicious.

But I still don't want to learn how to make a can.

Fire - Quicker, more durable ethanol stove

A while back I made a pretty convincing ethanol camp stove out of a coke can.

It worked well and looked like this when it was running.

I've used it a bit since then and it's definitely a practical addition to any backpack.

The problem is it's starting to show signs of aging. The can expands and contracts, and there is now a crease where extra gas flows giving an uneven flame.




In my model (also not my design) I used an inner sleeve with holes at the top to let the gas out. The result is that the trapped ethanol (spirit/alcohol/methanol) between the outside wall, and the inner wall boils the spirit, and creates a gas jet that looks a lot like a normal BBQ burner.

One of the problems was trying to get the top of a coke can to fit into the bottom of a coke can. It's tricky because (of course) they are the same size. It can be done, but involves gently stretching the outside one and it takes a lot of messing about.

Now I'm being pretty fussy here. The little burner works really well, but it did tend to leak fuel around creases that formed in the join between the top and the bottom sections.

Someone on a Stirling engine forum pointed me towards a different method of making one. This method involves no holes, but it just encourages those creases that mine developed by itself, and I think it might be a winner.

Their's also used a drink can, but I think it might make a more robust version if I used a tinned food can.

So, to start with, I peeled a normal, every day food tin.

The first step was to trim it to size.

I needed the top to fit into the bottom, so the first thing to do was punch a hole in it to enable a cutting tool to get in there.

I used that mystery tool that pocket knives have.

Probably a leather working tool or something.

Who knows, just punch a hole in the can.

Next jam in some tin snips or something to make a nice cut to separate top from bottom.

My tin snips are stupid, so I ended up using scissors.

This isn't the best way to use scissors, so don't do this at home unless you actually own the scissors.





One very good method of cutting a tin can, is to just tear it by grabbing a ragged tail of tin with a pair of pliers and twist. If there's a groove to follow, it actually makes a pretty straight cut.

As I said, I ended up using scissors to trip everything to it was nice and neat.

I made the inside sleeve (the one on the left), slightly taller than the other so the pot could sit on the rim and let the gas escape from the gap between the outside sleeve.

I bent a series of grooves in the base of the inner sleeve so that they would allow the flow of gas, and also allow the inside sleeve to fit inside the outside sleeve.

This was simply a case of grasping with pliers, and twisting them to the left, and slightly down toward the centre.

Next I inverted the inside sleeve and carefully positioned the outside sleeve over it so that I might press the two together by stamping down with my foot.

Which failed completely.

Fire - Home made ethanol stove

In a previous attempt to make a ethanol stove I ended up using a potato instead of the bottom the coke can I was working on, and you can see a lot of the build in the post called Fire - Ethanol potato cooker. Because I've already covered most of the build in that post I wont be repeating it here, so read that potato cooker post first.

Sorry for the terrible photo. it hurts my eyes as I try to force it into focus. Hopefully that's just something about me, and it wont actually hurt anyone else.

After some more research I thought I'd try making a proper drink can burner. This time I spent a lot more time on slowly scribing the line with a blade to get the cuts nice and clean. Rather than putting on a lot of pressure, I pressed gently, and rotated the can under the blade holding the blade in my right hand and the can in the other. Eventually a few small holes appear in the line, and at this time you can either cut it with a little more pressure, or just press it out (I used a pen because I wasn't sure how sharp it would be, but it wasn't all that sharp).

The end result was a very neat, clean cut that needed only a light sanding.

Actually it didn't really need a light sanding at all, but I did it anyway.

I also employed the method of putting a blade in a book. This time I clamped it down with a G-clamp, and pressed the top (really the bottom) of the can down with one finger while I rotated the can with my free hand.

I used the blade and book to mark a line for the base.

But the second cut of the can required scissors as there was no "top" of the can to press down with one finger.

But scissors cut it very cleanly.

So here are the three finished sections.

The one on the left is the top with all the holes punched through with a drawing pin

Centre is the inner sleeve cut out of the middle section of the can. (see previous post)

And the bottom is on the right.





The bottom bit was stretched* by pushing a full, un-opened can into it a wriggling it around for a bit.

It's difficult to describe the motion, but if you jam it in the move it around like a ball and socket joint (like your shoulder) the lip of the can is eventually stretched. It's very easy to get off the can as there is a perfect seal, and the air pressure inside pushes the small section off.

Put your base on something flat.

Press in a full can.

Wang it about a bit**.

Success!

Now, with the inner sleeve roughly in place, you can slide the top and bottom parts together. As long as you make them meet as close to evenly as you can (ie not one side first) it will fit.

I made my base section the outside, but I'm not sure if there is an advantage either way.

It looks like this when it's lit.

And this when it's not.
















120 Things in 20 years was  overheard to say "On the subject of fire and home made ethanol stoves,   I personally didn't have any blood fall out, but I would say that although this is a great project to do with kids,  if you like them I'd make sure there was an adult around to stitch them back up, and put the fires out".




* Thanks for the tip Jabro

** If only someone would come up with a way to rapidly display pictures one after the other to give the reader the illusion of a "moving picture".

Fire - Ethanol potato cooker

I was thinking about my Murray River epic adventure, and thought I might need a small emergency stove for when I find myself in a storm, or otherwise unable to make a fire. The difference between being miserable and content often boils down to a hot meal.

So I thought I'd make a ethanol stove. There are a few on the market, and they work by boiling the ethanol within a small chamber with holes around the top. The ethanol turns to a gas, exits at the holes, and burns like a nice gas stove. Lots of heat, light weight, and perfect for what I need.

There are quite a few examples of home made versions on the net, so after quite a bit of research, I thought I'd have a go.

I failed.

I found it impossible to squeeze two halves of a drink can that were the same diameter over each other.

Stupid physics.

So I thought I'd convert my failed project into a potato cooker.

It looked a little something like this...

I started with a can.

I poked some holes around the near top of it with a drawing pin.

I cut the top off with a box knife.

The best way to do this is to lightly score it, round and around, until you gently wear through.

I didn't do that, and I nearly cut all my fingers off one after the other in a series of ever more lucky near misadventures.

Lucky.

To cut the next bit, I originally set the can upright with the blade held at the correct height by placing it in page 321 of Stephen Hawking's book "God created the integers" which was exciting, because I finally found a use for it.

It didn't work as well as youtube told me it would.

Neither did the box knife without Steven Hawkings' help.

Eventually I used scissors. 

This pic is me cutting the planed base that the top was meant to firmly slide over.

I threw that bit away in the end, and used a potato instead.

I cut a strip from the can, and made a cut first half way through one end, and then half way through the other side of the other end.

Then used the opposing slots to make this inner sleeve.

I also cut a little v in it to allow the flow of fuel.

I sat the inner sleeve inside the outer, top bit with the holes in it.

I sliced a potato top and bottom to make a nice stable base, rested it over the top, and gently pressed it down onto the device until it was firmly stuck in place.

It looked like this and appeared to make a pretty good seal.

I added fuel up to the holes, and lit it.

At first the inner section burns and heats up the fuel between the sleeve and the outer section.

At this stage you just leave it alone for a few seconds until it warms up.

Quite suddenly and with a pleasant pop reminiscent of lighting a gas stove, the fuel turns to steam and the burner ignites at the holes.

Total surprise. 

The thing actually works. 

I quickly found a pot, and put one metric cup (250ml) of cold tap water on the heat.

As soon as you do this it snuffs the centre section, but because the holes are down a bit from the top, they continue on perfectly. 

I had a proper boil at around 5 minutes, and a slight simmer at just shy of four minutes.

Much better than I expected. This was a total success.

The entire project from the time I looked at the soft drink can to the time I could make a cup of tea was around an hour and a half, but most of that was attempting to make it without the potato. I think I could knock one of these up and have water boiled in 10 minutes with nothing but a drawing pin and pair of scissors.

Way cool. Thanks to everyone on the net that did stuff like this and gave me all your tips. My only contribution was the potato.

120 Things in 20 years - Ethanol stove - Potato cooker. Boiling water! Yum!