Dented Chainstay Repair or Replace
 

I have a 2004 Specialized Allez Comp with a Columbus Foco steel frame that has a nasty dent on the drive side chain stay. I have discussed the possible ramifications of the dent over at Bicycle Mechanics: https://www.bikeforums.net/bicycle-m...tastrophe.html and was referred to ask about it over here.

Can the chainstay be repaired or strengthened by welding the dented area or possibly brazing it to prevent further deterioration and cracks from forming? Or would the best scenario be to have the chainstay replaced entirely?

Advice on how to proceed?

https://cimg6.ibsrv.net/gimg/bikefor...3bbba294cf.jpg
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https://cimg8.ibsrv.net/gimg/bikefor...081eefe6f4.jpg
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The biggest concern is the apparent crack over towards the right. Is it just a crack in the primer though? It looks like there's metal behind it. You will get a better idea if you clean some of the paint off. If the metal itself is cracked then you could do a repair (I would use TIG braze) which would be a bit sketchy but probably actually fine. If it's not cracked then it'll probably be fine without anything, although you could still fill it in with a bit of brass and sand it all smooth.

According to Bicycle blue book the bike is worth $300. To have the chainstay replaced and repainted will cost that or more.

I'd ride it as is and keep an eye out for a crack developing or strip the frame and find another frame. Right now it looks like there is no crack, a crack can show rust along the crack.

Are you referring to this area here as the "crack over towards the right?" I had overlooked that until you pointed it out.

https://cimg7.ibsrv.net/gimg/bikefor...314a68a01d.jpg

An important consideration.

No. Not sure what that is. I meant the gashes just to the left of it. I'd take the paint off and see what's what. If you can actually see daylight through it then it's much more compromised.

Gotcha. Sorry thought maybe you were suggesting there was a crack under the paint further on the right. It is kind of hard to see from the photos due to shadows, but as far as I can tell none of the gashes are cracked and there is metal behind them. When I get a chance I will remove some of the paint just to get a better look around the gashes to be sure.

My thought? Ride it till it dies. Might take quite a few thousand miles but the damage will probably lead to the chainstay breaking there, Likely not an issue other than spoiling a ride. My Peugeot UO-8 broke just behind the gusset. Noticed it while riding and just rode easy going home.

Or take it to a framebuilder and have him fill the dented and scraped are with braze. Have him or you file the braze to smooth, take a spray can and do your best to match the paint. Ride it, now until the frames dies for other reasons. (That could take a good long while.) I'd guess a framebuilder would want around $200 for the repair,

So, do nothing and get what you can out of the frame or spend a couple hundred and sacrifice the finish in the area. Or spend a lot more and have both good as new and the looks to go with it.

Ben

those gashes look horrible, but their really isn't much you can do about them. It does occur to me that if you found someone to TIG over them, it might last a little longer. Need to find someone that's good at welding on thin metal though.

Thanks for the advice.

Two questions: Would JB Weld or some other sort of epoxy help at all to strengthen the area? Add low cost reinforcement without damaging the paint. It seems sketchy but thought I would ask, to explore all options.

Anyone know any good framebuilders in Utah?

metal filled epoxy by itself will not do much. The only framebuilder in Utah that I know is Walt at Waltworks https://waltworks.com/

I wouldn't bother with JB Weld. If it looks all right after the paint is off use car body filler, sand it smooth and get some paint on. It's right by the crank so a less than perfect paint job will not be noticeable.

One way to find out if a crack is present is to first clean off the outside (medial blasting works really well and gives a pretty consistent surface texture) then add some dirty ATF to the insides (I suppose one could use any dark penetrant). If there's a crack of any significance the dirty stuff will bleed through. Andy