Oct 26, 2013

Catwick Stove

10-25-13 Update:  I broke my GSI collapsible spoon.  Didn't hold up to scraping the bottom of the pot when cooking in the pot.  Also, got food in the "track" that was hard to clean.  Purchased an MSR folding spoon http://goo.gl/QCj8DQ to replace.  It is much stronger.  Also, I have the thought of adding a second Little Friskies can to the setup.  By dropping the second can over the pot stand, I may be about to put the stove out.  Not simmering, but lets you put your dinner in the pot koozie and then reheat it half way through hydration.  Will test soon.


After using Super Cat and Yaas stoves, I wanted to find an alcohol stove design that heated my 700ml Backcountry Ti pot efficiently, without the need of a pot stand.  Efficiency is key.  After reading discussions on the backingpackinglight forums, I read about using a Texport stainless steel lantern globe for a integral pot stand.  After testing I found this just didn't work by itself.  The forum discussion said that you needed a wick to make this work.  I tried a few different wicks, and found a folded fiberglass cloth wick worked perfectly.  I tested the stove for 12 days on the trail, and I am confident that this is a superior stove design.

So here's the design:

Need the following materials:
1. Little Friskies cat food can - free
2. Texport stainless steel lantern globe or similar  $6
 http://www.texsport.net/propane-accessories/stainless-steel-lantern-globe.html
3. Fiberglass bodywork cloth  $6
http://www.walmart.com/ip/Bondo-Fiberglass-Cloth/16927983

Construction:

Based on the Yaas stove design, I cut the stainless globe 1" taller than the cat food can, and long enough to create a cylinder inside the can without overlap or a gap.  Afterword, I think I would cut the mesh in half so I could make a second stove with the screen since the screen left wasn't tall enough for a second stove.  Not sure how much flame gap this would leave, but I'm sure it would work fine.
1.  Create a template with paper to create a cylinder inside the can and 1" about the rim.  See discussion above.
2. Cut the stainless globe mesh to the template with sheetmetal shears
3. Cut the fiberglass cloth the the length of the template but twice the height so that when folded in half, it's the height of the cat food can.
4. Fold the fiberglass and wrap around the inside of the can, fold up.
5. Insert the mesh, trapping the fiberglass wick between it and the inside of the can.
6. Make sure the fiberglass cloth fold is exposed all the way around the cat food can rim and the wick touches the bottom of the can to wick up the alcohol.
7. Done.


Note:
I put the folded edge of the stainless globe up to strengthen the part that the pot sets on.

Use:
I put in 3/4 oz of alcohol for 2 cups of water.  I use a flint and steel to light, lighting the alcohol in the center.  When the flame jumps to the wick on the rim, I drop the pot onto the stove.
If you use a lighter, you can wet the wick by rolling the stove then light the wick.

I use 1 oz of alcohol to cook a Knorr dinner.  I pick up the pot after it boils a put it 3/4 off the windscreen to simmer.  This stove does not simmer.  Only negative.

Windscreen Design

A critical part of the design is the windscreen.  The windscreen should leave a 1/2 gap all the way around your pot.  The taller the windscreen the better, but it is important (for me) that it can be stored inside the pot.

My pot has attached handles, so I like my screen to be just below the handles, but you can notch out a taller screen.  Also, I make sure my handles are fully outside the windscreen so they don't get hot.

Materials:

I use aluminum roof flashing.  Left over from a replacement roof project.

Construction:

1. Score the flashing with a razor knife and bend to cut.  The cylinder should be 1" wider diameter than pot.  Remember it's 3.14 x diameter for circumference.
Add 1/2 inch to the circumference to leave material for a fold to create a "hook" to form the cylinder.

2. Fold the last 1/4" up on one side and down on the other to create a hook to lock the screen into a cylinder.  I used a vice to get a sharp fold.

3. Punch holes around the bottom about 1/2" apart, about 3/4" above the bottom.  (Depth of hole punch)

4. Cut 4 or 5 slots, 1/2" deep, equally around the top of the screen.  Bend one side down to the inside to create a triangular tab that makes sure the windscreen leaves a gap between it and the pot.  See photo.  This is optional, but helps efficient heating.

Here's my complete cook kit:

I use a folding spoon, and put toothbrush, toothpaste, ibuprofen, aspirin, and vitamins in my cooking pot to keep them available at dinner and breakfast.  Current spoons is a GSI, but will replace with a stronger MSR folding spoon.




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