3. Use an erlenmeyer filled with icewater, and hold it close above the container with the boiling IPA with the dissolved crystals in it. That way, if you hold it a bit tilded, the hot IPA vapours will condense on it's outside, and the fluid will roll off into a small beaker you keep under it.
When the small beaker has collected about 20% of the evaporated IPA, then you take the boiling IPA container off the hotplate. So you have now a superconcentrated solution in IPA, and let it now cool down. The time needed for this concluded when you read on the small beaker that about 20% of the motherload IPA was evaporated.
""Is the use of charcoal neccessary in the recrystallization of MDMA.HCl? Is this charcoal the same kind that you would use to grill some burgers on a Sunday afternoon? It's just carbon, right?""
Depends on the acumulated impurities, mostly roughly appraised by the color by a cook.
No, it's definitely ACTIVATED carbon, like also used in aquarium filters, thus obtainable in 1 liter sacks in aquarium shops, if you want it OTC.
The rest of the procedure is pretty well like you described, however to obtain the highest purity, you should repeat it another time, so 2x recrystallization. It depends also on the quantity of your to be recristalized crystals, the less, the more difficult to gain purity with more recrystalizations. LT/