Dent repair strength?
11-24-19, 05:10 AM
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Dent repair strength?
I've been checking out the Yellow Jersey website and I had a question about the dent repair process. Looks to be that you roll the frame to diminish the dent, then fill it with brazing, sand, and paint.
Once that's completed how has the ultimate strength been affected? I know deformation and the rolling back would weaken the tube, but then you'd have some extra material on the braze patch. Of course the tubing would be heated in that process too.
Would it make a difference if the tubing were 531 or chro-mo? Initial dent size/depth?
I know this is all dependent on a lot of factors, but can any generalities be made?
Once that's completed how has the ultimate strength been affected? I know deformation and the rolling back would weaken the tube, but then you'd have some extra material on the braze patch. Of course the tubing would be heated in that process too.
Would it make a difference if the tubing were 531 or chro-mo? Initial dent size/depth?
I know this is all dependent on a lot of factors, but can any generalities be made?
11-24-19, 09:14 AM
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It's a lot more complex than you're making it to be. Of course, some of these issues are not easy to grasp. I assume filling with bronze makes a difference with a heat treated tubing, but shouldn't with chromo or 531. Rolling might put microcracks in a tube, but it's not going to weaken it unless those cracks coalesce into a macro crack. A dent makes a tube more likely to buckle, but it doesn't really weaken the tube at all. In general, it's a pretty solid repair.
11-24-19, 02:05 PM
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There's some work-hardening that results from rolling out dents. Filling low spots with lead solder rather than brass or silver requires less heat.
11-24-19, 08:23 PM
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I'll add that most dents are in the less stressed mid sections of tubes. So the after repairs are subject to less forces then the tube ends where undercutting (from heavy handed filing or poor welding) and overheating can be found. Dent repairs take a real toll on the paint and often don't add any benefit but cosmetic. Andy
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11-26-19, 05:12 AM
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Thi
s seemed like a place to mention this; only works on seat tubes. Had a dent half way down the seat tube (DB 531) No sharp edges, paint nice. Made the tool in the pict on the lathe .002 bigger than seat post dia, drove it down tube after cleaning out tube and lubing with moly paste, pulled it out with slide hammer. All but a couple thou of dent gone. YMMV
s seemed like a place to mention this; only works on seat tubes. Had a dent half way down the seat tube (DB 531) No sharp edges, paint nice. Made the tool in the pict on the lathe .002 bigger than seat post dia, drove it down tube after cleaning out tube and lubing with moly paste, pulled it out with slide hammer. All but a couple thou of dent gone. YMMV
12-01-19, 11:42 AM
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Thi
s seemed like a place to mention this; only works on seat tubes. Had a dent half way down the seat tube (DB 531) No sharp edges, paint nice. Made the tool in the pict on the lathe .002 bigger than seat post dia, drove it down tube after cleaning out tube and lubing with moly paste, pulled it out with slide hammer. All but a couple thou of dent gone. YMMV
s seemed like a place to mention this; only works on seat tubes. Had a dent half way down the seat tube (DB 531) No sharp edges, paint nice. Made the tool in the pict on the lathe .002 bigger than seat post dia, drove it down tube after cleaning out tube and lubing with moly paste, pulled it out with slide hammer. All but a couple thou of dent gone. YMMV