Yes it can easily be done with any torch, even propane. My experiance is only with high carbon and not stainless steels. I dont think it would do much on a blade that was differentially hardened because the spine should already be a mixture of pearlite and martensite and much softer than the edge. However if you did a full quench on a high carbon steel, you can temper the whole blade at whatever temp you choose for the edge, then put the edge in water and bring the spine up to whatever temp you would like to temper it at. Quench plates would probably work but a pan of water allows you to keep the edge under the water and if you feel that you are getting to hot on the spine you can give it a quick dip to cool it off.