Having difficulty finding a shop to work with aluminum
I have an old semi-rare aluminum (7005) mountain bike that I love; however, it lacks a disc tab on the rear of the bike. I live close to a handful of both well-known and slightly-less-than well-known framebuilders (I'm just outside of Boston), but researching all of their websites shows that they all only work with steel, Ti, and carbon fiber. I haven't called any of them personally.
Am I seeing a lack of aluminum framebuilding simply because of the lack of demand for boutique aluminum framesets, or is it because of some sort of difficulty regarding working with aluminum? If a shop mostly works with steel, has the equipment for aluminum, but rarely works with aluminum, would it be risky to take the bike to them?
Additionally, are there some sort of certifications I should look for in a framebuilder? Obviously, reputation counts- a shop like Seven or IF is likely to do a good job, but I feel like I'm probably looking for a builder that's a little less high-profile, but still better than some-yahoo-with-welding-equipment-and-a-nice-website.
Anyway, I know its a tiny operation, but the frame is more or less irreplaceable, and I'm hoping to find my way to the best chances of getting a quality job done to it. Any advice is welcome, thanks.