850 Trek freeze crack

[AL_BUNDY]

I left my 850 out side one to many times when I thought my riding days were over. It got water inside the chain stay and froze. there is a small bulge on the bottom of the stay with a 1/2" long crack running lengthwise. Can any good welder with a heliarc repair this. I do have a frame builder 15 miles away but he may not want to do it. I just had a bike shop do a overhaul on it and they didn't mention it until the work was done so I have a good dependable ride with a cracked frame.