bark_eater 

I'm on my way to pick up a $75 1985 Schwinn Tempo, and on his own the seller just knocked the price down to $50 and sent a full disclosure shot of the sweat rust on top of the top and down tubes. I've pretty much decided to take it on as another project in the pile, and since its a black bike I'm more likely to be happy with a touch up job an a bike I'm going to keep for my self.
My more general question, Is how do you value or devalue a bike that will need a paint job to be "whole"?

Chombi1 

Yes, quite a lot as people who are willing to pay good money for old bikes, really like to go after originality and best confition. And it's understandable as it is one of the main reasons people like to own and collect C&V bikes.
Even the top of the line bikes are affected by such in a big way, proportionally....

himespau 

it depends on how much rust there is.

Kabuki12

Total investment about $200, value? Who knows!
After spending a year, off and on, with my rusty old ItalVega, I can comment on this subject. I purchased the bike for $100 because the Campagnolo, 3ttt, Zeus parts were worth that. I got it home and realized that it would be cool to scrape the rust off and ride it as a patina bike or rat bike if you will. As previously mentioned, the value of the bike isn't what motivated me to do what I did. The original idea would have been , I guess , profitable , but I opted to feed my curiosity and just kept going back to the frame and scraping and polishing until I had the desired look of patina. The bike rides very nicely and I am glad I did it. The deciding factor was , when I tore it apart , the bearings and inside of the Columbus tubing were in excellent condition. That , plus the fact that it is an Italian bike (my first) makes it worth it to me. Again , not a money thing! Joe joesvintageroadbikes.wordpress