The one that meets his needs. Without more information the question can not be answered further.
the best way to get a good looking/ strong weld on aluminum is using a tig welder it is also possibles with a mig welder but for best results recommend a tig welder with HF
Sober and drug free.
Becoming a welder is very difficult and take a long time to complete the training. The best school in tennesse to start this training is Wyotech.
Best to ask a gunsmith for help. You can request a manual from S&W also.
Your two best options are to find a gunsmith and find a gunsmith. By the time you buy the necessary book(s) you could have paid a gunsmith to do it.
Best to take it to a gunsmith.
Best left to a gunsmith
Best left to a gunsmith
Best left to a gunsmith
Best left to a gunsmith
The best thing you can do is find a gunsmith
Best left to a gunsmith