Both of these burners are based on the tuna can. These cans are used because they are large enough to be useful but compact enough for practicality. Additionally their height to diameter ratio is such that they are very stable. Making them hard to tip over. A nice safety benefit. They are also used unlike other cans of this general size they are heavier duty and robust enough to withstand the heat they will be exposed to. To construct the candle version one or more wicks usually 3, 4 or 5 are placed in the can and it is filled with paraffin. While producing adequate heat they are the better method for generating light. You only need to light as many wicks as you need at the moment.The buddy burner on the other hand is more adapted for heat production. To construct newspaper [although most any paper will work] or corrugated cardboard is cut into strips the width of which is the height of the can. The strips are then rolled and placed into and filling the can. Melted paraffin is then poured in saturating the material. Pour until it will hold no more. The paper or cardboard then acts like a very large wick. Both of these can be refueled while in use. In both cases take chunks of paraffin chopped from a bar. For the candle place them in the pool of melted wax and the burner just place them on top. The additions will simply melt and be incorporated. As these will get hot during use if you intend to use them in the interior of the car [and that ’s reason they're there] you will need something to set them on to prevent burning or melting a hole in your seats. A simple trivet woud be a hot pad from your kitchen used to handle hot cookware of course. In my younger days I have cooked meals on a buddy burner with no difficulties. Also they make plastic lids to cover open cat food containers, This just happens to be the same sizes as a tuna can. Thuis way you can close up the can for transportation when it is cooled off. P. S. Don't forget something or better yet several some things and methods to ignite them. Even more important anything that burns uses air. Crack a window without ventilation you could run out and die.
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When in danger or in doubt
run in circles scream and shout
RAH
And always remember TANSTAAFL