Thursday, January 31, 2013

Super Cat Stove with Wind Screen/ Twig stove

 Super Cat stove project.  
 A guy named Jim Wood created a stove from a cat food can in about 2005.  It has become very popular in the ultra light backpacking world.  You just punch about 30 holes like I did above in an aluminum 3oz cat food can, put about an ounce of denatured alcohol in it and you have a stove.  Most single hole hand paper punches do a great job making the holes.  In about a minute the alcohol sort of boils.  A pot seals the top and the gas becomes somewhat pressurized shooting hot blue flames out the side.
Most backpacking cooking involves just boiling about two cups of water to mix with dehydrated food and this stove does a great job at that in 4-6 minutes.  I have been making a lot of Ramen noodles "testing" the device in my shop each night.
 The stove works so well I have used it a few times for other purposes like making coffee in my Cona vacuum brewer.
Heat sources have been a problem with this brewer in the past but no more.  

Wind is the big issue with most backpacking stoves and this is especially true of alcohol burning stoves.  Most wind won't blow the fire out but it will take the flame and all heat away from your pot.  To use the stove outside an integrated wind screen is essential.  The pic below is a competed wind screen I made. 
The wind screen has a few essential features.  
It has one rectangular hole in front on the bottom to let air in, the supercat stove is elevated inside to prevent incoming air from effecting it and it has a cut out for the pot handle to keep them cool.  The cup I will use with this wind screen is a Snow Peak titanium trek 700 mug that holds between 3 and 4 cups of water.   You can easily make a screen to fit any pot you have.  
This version of mine is very close to Jim Woods original version.   He deserves the credit for most of the ideas here.   
 6 inch aluminum roof flashing.  It weighs very little, cuts with scissors and isn't super sharp like sheet metal often is after cutting it.
 Measure it around the pot you are likely to use with the wind screen.  Leave about a half inch around the pot.
 Air hole is an inch high and one and a half inches wide.  In the pic above I have cut the air hole sides with scissors then by just folding the metal up a couple of times it will snap off cleanly.  I don't cut corners.  The handle hole should be cut in a way to keep the pot handle of your particular pot out of the fire.  Each pot will need a different size and shape hole.
 I am using three holes and some stainless screws and nuts to keep it together.  Pop rivets are a good permanent solution, wing nuts would be easy to take it apart for travel.  For some unkown reason I have the wind screen upside down in the pic showing the screw heads.  I used a drill to make the holes.  The metal over laps about 5/8ths of an inch.  I used an awl in the metal first to make sure the drill started where I intended it to start.
 The stove needs to be elevated above the air hole.  I found some aluminum gutter cover mesh in the garage and it works great as a platform for the stove.
 The bike spokes go through the wind screen about 3 centimeters up to hold the mesh material that holds the supercat stove.
 Here it is in place.  See below how the spokes are going through the wind screen under the mesh.  You could use titanium tent stakes or an old coat hanger instead of spokes.  Part of the fun of this project was using what I already happen to have at home.
 Note the little holes up higher.  If you put additional spokes in those you could build a little twig fire or put an esbit tablet on the aluminum mesh grate and then have your pot on the top spokes.  It just takes a hand full of  small twigs to boil some water.
 Here is how the stove sits in the wind screen.

 Pour in and light an ounce or so of denatured alcohol or alternately Heet fuel treatment (but use only the kind in the yellow bottle).  Wait about a minute for the fuel to get hot and cook away.
It is hard to see but I also made an optional heat reflector/ground protector out of some of the sheet aluminum to sit under the wind screen.
 In addition to the alcohol stove you can use this wind screen set up to cook over a  twig fire, use fire starters or Esbit tablets for fuel.  Lots of versatility in a stove/wind screen that weighs just a few ounces.   


Heath said...

Spokes are a nice touch to your fine stove.

queasyfish said...

very nice work