Classic & Vintage - A question about frames

All -

I posted a thread in Framebuilders here (http://www.bikeforums.net/showthread.php?t=314923), asking some questions about a frame I might be able to look at over the weekend; I guess they're having a couple of slow days in there, so I thought I'd ask here, too.

It sounds like it was handwelded/brazed by the seller - It might be made from Columbus SL - and it might be in my size range ( I need to measure the TT ).

What might be some things to look for that could indicate potential issues with the frame? Its painted, so is it hopeless? I don't think there's a BB in the frame, so I might be able to see the some of the guts of the frame through the BB shell.

And, is there a way to tell that its Columbus SL?

Thanks for your time & thoughts.

B

Broadly speaking, Columbus SL is on par with Reynolds 531 and a damn fine tubing. Here is a spec sheet comparing various Columbus models, taken from a 1980s Columbus brochure:
http://www.equusbicycle.com/bike/columbus/columbuschart.htm

And here from the 1970s in which SL is listed directly below SLX, which is described as a "superbutted" tubing for professional frames. http://www.equusbicycle.com/bike/columbus/columbusoldfullcat/big/04columbuscat.jpg


The hierarchy appeared to get a little more complex in the 1980s but the catalog describes SL thusly:
All-purpose, high-performance tube set for road races over even terrain. Double-butted tubes. Cold-rolled fork blades.
Cyclex Steel - Weight: 1925 g

Thanks for the link to the Columbus spec sheet; it sort of confirms what I thought re: the quality level of SL.

are you aware of any external/internal characteristics that are present in a Columbus tubing set that might indicate its quality level? Granted the frame isn't that expensive, but i'd still be curious to know a bit more about it.

Too bad it's painted. You could get a better look at the brazing - but look at the joints anyway and make sure they don't look sloppy or starved. Lug thinning is a good indication that the builder took some time with the frame. Also feel for the ST and DT ends inside the bottom bracket - are they radiused, cut square, or do they feel too short? May help you in determining the builder's care.

vpiuva -

i'm going to take a wild guess that you mean "lug thinning" to mean a gradual tapering of the lug as it lengthens. Is that correct? i know i've seen a couple of photos here of lugs that become slightly thinner vertically as they progress, say, from the the head tube towards the seat tube.

thanks a bunch for the replies. i really appreciate your help.

-b