“Free,” easy, flat bottom wide-mouth Foster’s can pot, lid, and Esbit burner

[David Gardner]

This post shows how to upcycle a Foster’s can and a cat food can into a super ultralight 33.8g/1.2 oz, 500-700 ml wide-mouth, flat bottomed cook pot, lid and Esbit burner.

You need:
Foster’s can, drained
Unopened 5.5 oz cat food can
1-3 Utility knife blades
Couple little screws
Couple pieces of wood ½” and 1″ thick
Side-cut “safety” can opener

Even better, also:
Couple of C-clamps
Utility knife
Work gloves
Needle nose pliers
Fine tooth flat and round file(s) or several emery boards

The best way to cut both the Foster’s can and the 5.5 oz cat food can is to screw a utility blade onto a piece of wood and wear gloves while you hold down the board with one hand and rotate the can with the other. Don’t press very hard or you will deform the can, just go round and round until it finally breaks through somewhere, then go around the can from that point pressing a thumb firmly on the cut line and the aluminum will shear at the cut line. I’ve tried other methods, but they take longer and you’re more likely to cut yourself.

I use one blade mounted to one board, doesn’t matter which one. I use it to cut at one height, then flip it over and hold it down onto the other board to cut at the other height. Better, screw a second blade to the other piece of wood, especially if you plan to make more than one pot (like maybe a practice one or two before the final one). You can use one hand to hold the board down firmly while you rotate the can with the other, but it is much easier and safer to clamp the board with the blade onto a work bench, table, counter top with the C-clamps. If you use a table or counter top, for god’s sake put some thick paper/poster board on top or you’ll be sleeping on the couch for a long time.

First, cut the unopened cat food can a half inch 0.5″ below the top rim. I’ve cut them before removing the lid with a side cut can opener and after – after is much easier. The can is more rigid and easier to cut with the utility blade before removing the top and contents, and it’s still easy to remove the top with a side cut can opener. Use the side cut can opener to cut off the lid.

This leaves you with the flat bottom for the Fosters can, the support ring for the rim of the can, and the unopened lid from the cat food can to use as a lid for the pot:

Now, before cutting the Fosters can, you want to place the top rim. The first step is to put a thin smear of food grade sealant (available in caulking tube size and sometimes small squeeze tubes). I think something like E6000 is OK for this, because no part of it will be inside the can, but food grade sealant is better. Put the top ring from the cat food can on top of the fosters can, making sure it is parallel to the rim of the Fosters can all the way around, and gently push/pry with fingertips the ring down onto the can until it is about 1/16th inch below the shoulder. Cut off the top of the Fosters can:

After cutting the top of the can and before the glue sets, pull/pry the ring back up above the cut edge of the fosters can a bit more than 1/8th in inch. This part can be a little tricky, so do it very carefully and gently. You don’t want to pull the ring all the way off after the Fosters can is cut, because it’s a devil to get it back on. The 1/8th inch above the top of the Fosters can is so that the cat food can lid will sit down flush with the top ring. After the adhesive has set, use the fine rounded file or emery boards to de-bur the inside edge of the Fosters can cut line.

After you have glued and cut and the top it is time to cut the bottom off of the Fosters can. You could cut the bottom first, but believe me, it’s easier to cut it after the top. Use the blade mounted on the ½” piece of wood. Flip the cut off bottom over and you have a no-drip Esbit burner.

After you have cut the bottom off the Fosters can the next step is to debur the outside edge with the fine files or emery boards. Go around lightly filing parallel to the cut edge at about a 45° angle a few times, until you can feel that there are no burs left on the outside. Use the round file or emery boards to debur the inside, but pulling the file or emery board out for the cutting stroke, again very lightly. Go around a few times until you can feel that it is smooth.

To get the bottom of the cut Foster’s can into the bottom of the cat food can can be a bit tricky also. It helps to press an unopened Fosters can onto the cat can bottom and work it around, pressing firmly, to get a tiny bit of flare outwards. Hold the cut edges towards each other, get one bit of the Fosters can started on one side, and gently rotate the cans while keeping them lined up as closely as possible and only pressing them together with nano-force, until the whole Fosters can slips in just tiniest little bit. Now wiggle, rotate and press in about 1/4″ and stop. Put a thin schmear of adhesive all the way around the lower part of the Fosters can in the 1/4″ above the top of the cat can, and finish pressing all the way in. Rotate the cans about ½” back and forth a couple of times to make sure the adhesive bonds continuously all the way around the seam and doesn’t leak. Let the adhesive set.

Now you need to make at least one small hole in the cat food lid as a vacuum break. It also lets steam out, but the most important thing is the vacuum break. I left one of these rigs with some warm water in the bottom out overnight once without a hole, and in the morning the can had collapsed from atmospheric pressure. I made a few extra holes in the lid pictured here so I could use the lid as a strainer if I want to for some reason. I drill at the rim in front of the pull tab because this is away from where my fingers are when I the hold the pull tab to lift the lid, in the bit of the lid that is outside the seam where the lid is intended to separate when you open the can the usual way.

You don’t have to, but I like to also bend the pull tab up so it will be easy to grasp. You could also use a small zip tie or even one of those little paper/wire thingies for tying bread and fresh produce bags instead. You can bend the tab with your fingers, regular pliers, or needle nose pliers. Regular pliers are OK, but needle nose are best because you want to pinch the pull tab at the bend point to flatten it before bending it will bend easily and not crack. Use fingers on one hand to hold down the part of the tap you don’t want to bend so that you don’t accidentally start popping the lid. Or I guess you could use a popped lid anyway and just press it as nearly closed as you can get it, and skip the drilling step.

The burner fits nicely at the bottom of the pot. Perfect for sitting at the bottom of a cozy to hold it all together for packing.

And there you go. Everything you need except some kind of pot stand and windscreen or cone clone, and a cozy or bag to hold it all together.

Hmmm, now that I think of it…..

[Bonzo]

That’s cool…and it makes me want to try a version of it with one of my spare crowler cans.

[Daryl and Daryl]

Very clever and creative.

Thanks for the tips.

[Craig]

Looks great thankyou – could i please enquire – Why do you want a squared off bottom from the a food can for the base of the stove ?  Why not just use the indented fosters bottom as is  – is it for better access to food in the bottom of the stove?

[David Gardner]

Sure Craig. The advantages of the cat food can base include being lighter than the original bottom, thinner for better heat transfer, flat profile provides better flame spread for better heat transfer, sits better on pot supports, and lets you customize the height and capacity of Foster’s can, depending on where you cut it.

[Craig]

Ahhh.  That makes perfect sense. Thankyou!

[Author]

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