The logic behind the candle and can is the timing of the reaction. The candle heats the sand quickly to start the reaction, if shaking or stirring did not. As the candle burns, the temperature increases at a steady rate generating nano scale "phase one" and "phase two" stages of the reaction. As the life of the candle is coming to an end, so should the reaction.
The problem with candles is that they tend to burn out, do not burn well, etc. When the basis of your reaction is controlled distribution of heat within a certain time frame, any variation is a potential failure. If you are not familiar with the reaction theory/process and visuals to look for, having to 'lift a hot sand filled soup can containing a test tube or cigar tube topped with balloon containing HI to put a new candle in which may or not burn better than the last', can be very distracting.
Substitutions:
As Shorty mentioned, you can substitute the candle for a hotplate. However, do your reasearch. Be aware of the temperature you must gradually obtain to convert the pseudo. In one hour. It can be done.
As biotechdude mentioned use a small spice bottle or something equivalent in size. This reaction does not do well in anything larger than a 50ml flask, if quantities are adhered to. Put this in moist sand. Turn your balloon inside out to alleviate powders and such. Tape it well and watch it. You do not want to have to deal with a leaky balloon. With this reaction, there is not a large margin for error.
You can produce meth. You will produce tweaky meth. This IS a "short hot cook".