Vehicle based camping stove

I'm in the process of building my 1st rocket stove. I want to take it camping so size and strength are important. Ideally I wanted to be used to cook and as a heater.

A friend has welded a 4 inch, 100mm square tube into an L its 12 x 16, 300mm x 400mm (long side) and 8 x 12 200mm x 300mm (short side)

As yet I haven't insulated it and I was wondering if I can get away with just insulating the corner of the L where the combustion takes place, thus leaving the rest of the riser to radiate heat. I realise this will be less efficient but I am hoping I will still get high combustion temperatures.

After reading some posts I was concerned that my riser is to tall, 1.5 times the diameter was suggested mines 3 times.

Thoughts??

It's difficult to have a riser that is too tall. The taller it is, the more time the gases have to burn before reaching the top.
You have an L shaped system, right? You definitely want as much insulation as you can get around the riser, as that will affect the combustion efficiency. Since you want to take it camping, you would probably be well served by surrounding the 4" square tube with big tin cans, and fill the space with insulation. Rockwool would be durable and heat-resistant enough, but might settle over time with moving. It might be the simplest option. Fiberglass might be able to resist the temperatures you generate with this small metal unit; if you have some on hand, try it and see. Perlite would be a superior and waterproof insulator, but you have to contain it so it doesn't spill in transit. Adding and mixing a small amount of clay powder to a damp mix of perlite will make it stiff and spillproof.

Thanks Glenn

I have Perlite to use as insulation. I presume more is better but how much is needed each side of the stove to get the temperature high ie is 2" the minimum, 3,4 etc.

One of the design constraints is to not make it too big as there is only so much space in the 4wd otherwise I would just put it in a 60lt drum and fill it with perlite.

A short, heavy steel tube is not likely to get really high temperatures in any case, as it will rapidly conduct heat away from the hottest zone toward the ends. For portable cooking and heating use, I think you will get good enough results with a minimum of insulation, say tin cans that are large enough to clear the corners of the tube, filled with perlite.

Cheers

I just finished putting the L tube in an 8" x 11" metal box full of perlite. The burn was much better.

There was quite a bit of heat thrown off the exposed riser and top of the box. Good for a heater, bad for efficiency.

Next I will insulate the rest (8") of the riser and see what that does. Need to find the right sized tin.