I went to see this Bianchi some time ago. I knew from the seller's pictures it had quite lot of surface rust, but it was affordable for being a lugged Bianchi and roughly my size, which doesn't come around that often.

To my disappointment I noticed there was more damage than I had expected. The non-driveside chainstay was bulging some 5 mm underneath, paint was peeling around it and there was a roughly 1" long visible crack along the bottom of the bulge. My guess is it has somehow gathered water at somepoint, and left outside the water has frozen and expanded, causing the tube to bulge and eventually, crack.

The seller said he hadn't noticed it being there before, and offered to take it to his friend's car repair shop to be welded. I'm concerned whether it's likely for it to have have rusted through on wide areas, under the paint etc. and that the car guy couldn't fix it properly because the tubes would have too thin walls or too little unaffected metal to work with.

Now, what would it take to make this frame safe to ride? I've figured changing the chainstay by a professional framebuilder (which we don't have many around here) would be more than double the original asking price for the whole bike.
I don't need the fix to look like new or to shave grams, it's fine as long as it will not kill (or seriously maim) me, if you get the point.

I just want a frame to build up with some old thrifted components I've gathered, and affordable, small enough for me, lugged steel frames are few and far between.

Do you think the car repairman could weld this so it wwould be safe to ride? As far as I know, the main triangle (3tubi) is made of Oria Cro-mo and the rest is propably hi-ten, if that makes any difference.


underneath the chainstay



rust on down tube too