Hey boys and girls, let's do chemistry! (Disclaimer: this is theory and hasn't been tested)
Cocaine's MW: 303.353g/mol
Cocaine HCl's MW: 339.813g/mol
Sodium bicarb MW: 84.01g/mol
Equation for freebasing:
Coc.HCl + NaHCO3 = Coc + NaCl + H2O + CO2
so
339.813 grams cocaine.HCl + 84g bicarb = 303.35g cocaine freebase
and this means 1 gram cocaine.HCl + 0.247g bicarb = 0.893g cocaine freebase
assuming you have pure product.
If you are using cocaine cut with non-alkaloid salts (caffeine, baby powder, B vitamins or whatever) you should use only as much bicarb as you have actual cocaine in your stuff. Alternatively, there are methods for purification that will remove these.
A higher percentage of alkaloid salt cuts (ephedrine or whatever) will mean you need to use slightly more bicarb for salts weighing less than cocaine.hcl, and slightly more for salts weighing more than coc.hcl.
On the tpic of "crack" vs "cocaine", they're both the same alkaloid that's going into your head. The only difference is the physical properties of the solid and how effectively it is absorbed by the body. You say "smoking cocaine doesn't happen" but it does all the time, people just colloquially refer to it as "smoking crack".
TL;DR: The best ratio for making crack rocks would be 1 part cocaine to 1/4 part baking soda, assuming pure, dry reagents.
