Intro: Backpacking Stove From Aluminum Flashing
First, let me give props to atman and nabilahmad for their intrepid stove designs. I have been experimenting with homemade stove designs for quite a while, everything from cat-food cans to altoids tins to pepsi cans to sobe cans.
I wanted to come up with a design that fixed what I thought were shortfalls that the tin-can designs didn't allow me to do. Namely, I wanted everything to fit snugly inside my cook pot, including stove, pot stand, windscreen and fuel (for at least two nights).
The overall design of the double walled pepsi can stove worked for me, but I wanted it to be a bit bigger to hold my fuel bottel (I use a 4 oz nalgene squeeze bottle for most weekend trips)
So... I set about to come up with something... went through many iterations with many problems (Durability, fuel leaks, etc) and came up with this.
This is my first instructable, I'd certainly welcome any feedback that anyone might have.
What you need to get busy on this project:
Aluminum Flashing (I got 10' x 6" flashing from the Home Despot for like 6 bucks or so
Alcohol. (I use that stuff in the big cans that is used for thinning stuff...DKT? SLK? S-L-X Denatured Alcohol (Thanks, Google!)
Matches (Fire... Fire...FIRE!!!)
Homemade Sharpie Based Compass (See instructable within an instructable!)
Needle Nosed Pliers
Bicycle Spoke (I recommend these over coathangers, as the coathangers just aren't in it for the long haul when repeatedly heated to a few hundred degrees)
Dremel Tool (Not required, but fun)
Step 1: First... the Instructable Within an Instructable... Homemade Sharpie-Based Compass!
I got very sick of constantly looking around the shop to try to find the right sized round object to trace....
First: Get a bicycle spoke... bend it into a vaguely compass-like shape... see the picture for more.
Then, sharpen the end that you would not be putting the sharpie into. Um... pretty self explanatory, right?
Finally... use a zip-tie to make that important second connection to the sharpie. I found that in practical use, the sharpie tended to flop around a bit when only held in place by the spoke.
This is an infintely adjustable little handy-dandy way for making circles.
Unfortunately I cut mine a bit short... you'll see more as we go through.
Step 2: The Base
I started with a template... Then of course I threw it away when I was done making the first incarnation of this stove
So step 1 for me was:
Dig the template out of the trash, un crumple it... and prepare to document the instructable.
I measured the diameter of the bottle I wanted to fit inside. It was somewhere around 1 7/8" (inches). I figured a 2" center hole would work for me.
That being said, I had the final design already in my head, so I knew that the center hole would be surrounded by a burner ring of about 1/4" thickness, and I wanted the sides of the stove to be about 1" high.
SO... to make a long story short, I needed an outer circle of about 4 1/2" diameter, and an inner circle of about 3 1/2" diameter for the base. So that's what I drew. On the template. With my pencil compass. (Not pictured)
You see where this is going, right? I transferred the dimensions to the new Homemade Sharpie-Based Compass and drew these circles right onto the flashing. Using the scissors, I cut along the outer circle and voila...(Or viola... if you're musically inclined) I had a circle. With a circle in the middle.
DISCLAIMER: PLEASE USE CAUTION WHEN CUTTING THE METAL. IT'S SHARP. DON'T CUT YOURSELF. PLEASE.
Now comes the fun part:
I eyeballed this, because I didn't have a protractor handy, and I didn't think it would make a heck of a difference anyway. Make the outer circle into 12 partitions with your spare sharpie, and your straightedge. See the pics for clarification on this if necessary.
Step 3: Cutting, Folding the Base
First, take the scissors and cut along the lines you made. Cut just up to the inner circle.
Next, take the straightedge and score (just score... don't cut all the way through. You're just looking to give the metal an idea about where you want it to fold, here) along the inner circle. Go from the intersection of one line to the next, in a straight line. What you'll end up with here is a dodecagon (12 sided polyhedron) when you're done folding.
Then, using the straightedge as a guide, fold each of the sides up. Start with one, and work your way around the circle. When you get to the last one, tuck it in to the center so they're uniformly positioned all the way around.
Now we need to flatten this out a bit so nobody cuts themselves walking by while you're cooking dinner.
The easiest way to do this is to take your sharp knife and score along the inside of each side at the point where it intersects the next fin. Then, using your thumb to push out, and your fingers to push in... fold the outer edge of the fin down to the point where it's resting along the fin next to it.
Easier to view than to describe. See the pictures for details on this step.
Step 4: The Top
You're going to want your top to stick out a bit over the edge of the base, to allow for improved adhesive capabilities.
Draw three concentric circles on the flashing:
Outer circle: about 2 5/8". I drew that with my handy-dandy Homemade Sharpie-Based Compass.
After all that talk about the DIY Compass... I ended up making the darn thing a bit too short. It doesn't make circles less than about 2" in diameter. So... in order to make the inner rings of the top, I went...yup, hunting around the shop for the proper diameter round things to trace.
Turns out that the top of a baby food container (you've definitely got those in your shop...right?) is the right size for the middle circle.
The smallest of the three concentric circles really only needs to be about 1/2" diameter smaller than the middle circle. We're just using it as a guide for cutting tabs to adhere to the center ring so it's not critical. Which is why you'll note in the pictures that I just traced around the outside of a lamp bulb holder thingie that I replaced recently, and eyeballed the middle circle.
You're going to want to cut out the inner circle with your sharp knife. Score once around carefully, then come around again, cut through at one point, and you should be able to press the inner circle out. just kind of run the knife around the edge, and pull up on the outer circle.
Cut the tabs as shown in the pics.
Now you're going to want to poke your burner holes. The merits are debated all up and down the internet about thumb-tacks vs. push pins vs. pin drills... I'm fond of the old needle and pliers method, as I believe the smaller holes help to get the gasses pressurized. Who knows. 32 holes seems to be the standard. Thus, I poked 33.
Now take the tabs you cut earlier, and then fold 'em all down (or up... depending on your preference. I folded the first half down, then flipped the whole thing over and folded the rest up. I'm crazy like that)
Step 5: Inner Wall
Damn this thing is getting long for such a simple stove!
Now we need to build the inner wall. Basically I took that leftover bit of flashing from the first couple of cuts (you didn't throw that away did you?) and cut a 1" strip from that. I scored with the knife along the straightedge and folded it to cut...but you can go ahead and use your scissors if that's what floats your boat.
Curl the strip into a ring as shown below. I work it a bit like one of those fancy sheet metal benders.. pushing and curling and such, but with my fingers. Nice.
Figure out how big the inner wall of your top is where the tabs are all poking down. You could use some math and do the whole Two-pi-R thing, or you could just fit that guy in there and mark where you want to cut. You'll want the inner wall to overlap by about an inch or so.
Once you've got it sized, it helps to find some way to keep that wall in place. I cut a couple of little tabs and fold 'em over, one on the top and one on the bottom. I've found that to be the easiest way to go about this without using adhesive.
Step 6: Let's Make Epoxy!
Who doesn't love JB Weld?
Mix up a big ole batch of that stuff. Don't be shy. I estimate that on most of my stoves, fully 50% of the final mass is due to JB Weld.
We're getting close to done here.
Fit the inner wall inside your top.
Liberally coat the inside seams of your base with JB Weld. Don't be shy. Get up a good glob of glossy grey gooey goodness and smear it all in the seams. Do the same with your tabs that you cut into the top of your stove. Go nuts with the JB Weld, it'll save you from having to fill in holes later.
Run a ring of JB Weld around the outer edge of the top of your stove, and stick that bad boy down onto your base. Devise an intricate weighting system to keep all the varioius edges stuck down and let it dry overnight.
Step 7: Pot Stand and Patches
You were wondering when the bicycle spokes were going to work their way in, right?
Spokes are good for more than just Homemade Sharpie-Based Compasses.
Take one (you should only need one) and line it up with one of your outer slits. Nice and aesthetically angled, no? About an inch above the top of the stove seems to be a good spot for your pot of water, so that's where I make a bend. Put a 90 degree bend into the spoke with your trusty pliers and cut off the spoke about 1/2" from the bend.
I like a cutter wheel attachment for my dremel for this task, as I use it to deburr and round off the edges of the cut spoke so as to avoid puncture wounds.
Once you've cut one, use that as a template to make two more just like it.
Now, pick three slots for your pot stand to come up through. I like to cut a few little notches at the top so my spokes rest flush. Eliminates the need to fill in the gap with JB Weld, which adds to the structural integrity of the pot stands.
Mix up another batch of JB Weld, and before you go sticking any spokes to your stove, use it to fill in all the little holes around the top of your stove, both on the outer and inner circles. Then stick them spokes up there, let 'em dry and you're done!
Step 8: Find Your Own...
For a windscreen, I use a piece cut from one of those disposable aluminum cookie sheets you can get at the local supermarket for a buck or so, with a paperclip to hold it into a circle. Cut some holes in the bottom with a paper hole punch and fold over the top edge to stabilize it. Mine has lasted me for three backpacking seasons so far.
Please, please be careful burning any flammables in enclosed spaces. Don't blow yourself up. If you do, don't blame me :)
There are so many ways to make stoves for burning alcohol. Explore, experiment, have fun.
If you come up with any unique designs, let me know. Post pics here.