replacing section of seatstay?
 

Hi folks,
I recently picked up a very early Bertrand (small framebuilder from the 80's working out of Hull, Quebec), and my "good deal" turned out to have a good deal of problems. When I stripped down the frame and started cleaning what I thought was surface rust, I discovered that the seatstays were not adequately set up for drainage, and have rusted through on the drive side. It is pretty localized, and doesn't seem to go beyond what's in the photo.

I'm not in too deep financially, and I thought I'd try my hand at a repair. (As far as tube replacement goes, it could be worse.) Has anyone had success with a partial replacement of a seat stay? I was thinking about cutting out the section of tube from just south of the brake bridge to the dropout, and replacing it. I'd use a small sleeve or a plug to link the two ends at the top end of the repair.

The other options is to replace the whole tube, but I'm thinking my first idea would minimize alignment concerns, and perhaps issues in replacing the brake bridge as well.

Any thoughts? Will this approach seriously compromise strength and ride quality?

Thanks,
Neil

http://i101.photobucket.com/albums/m...e/IMG_0401.jpg

I would replace the whole tube

Having said that, there is no reason why you couldn't replace a section. You probably don't have to replace all the way up to the brake bridge. The trick is going to be matching the taper and getting the dropout ends domed

Thanks unterhausen,
I thought I would use calipers to measure the appropriate place to cut on both this frame and the donor stay. Then, I would measure to the dropout, and prep the end.

I'll see how it goes and take some pics if it works. If it doesn't, I can always take out the whole stay later.
Thanks again,
Neil

I would replace the entire stay... it is rusted through in one spot and there is probably more rust than the eye can see.

Thanks for the input SF. I appreciate your perspective, and I may end up going that route in the end. To start, I am going to see what sort of state the inside of the tube looks like when I cut into it, and go from there. If the metal looks clean in the top half of the stay, I'm going to take a chance - as much to see if I can do it as anything.
Cheers,
Neil

if it really was a keeper, you probably would want to replace both seat stays so they match. Although people seem to have more luck finding weird old tubes than I would guess. I have a single seat stay in my collection for some reason I really don't remember. I think I may have bought it from a lapsed framebuilder.

We have lots of salvaged parts at our shop for those odd jobs and if the bike warranted the work, replacing both stays would be the nicest option.

When I replaced the rear triangle on my Phillips I sleeved the new old stays (from a donor bike) to the existing ones because grinding out the old Tig welds was not a place I wanted to go and it was a morning's work to do this.

When I first started getting into the idea of building a frame, I used my torch to dis-assemble an old damaged bianchi frame. Kind of a waste of acetylene now that I look back on it, but I did end up with some frame bits that I tucked away. One of these is a seatstay that very closely matches the Bertrand in profile...expect it's about 1/2" too short. The dropout end is finished in much the same way though.
Anyway, in my opinion, it's not a frame that warrants the attention you and sixty fiver talked about above. Then again, if I completely botch the job, I may change my mind!

My suggestion depends on what this frame means to you, and perhaps the collectable value. If you have a high opinion and want to retain as much of the resale then replacing BOTH stays in their complete lengths is what I would do. If you're ok with the down and dirty approach, and the resulting loss of value, then replacing the lower section of both is quite a resonable solution. Andy.

If you replace a section from the dropout up would you use an interior sleeve to braze/join the new section to the old? thanks, Brian

Hey Andrew. The bike cost me less than $100 complete, and needed a bunch of other work anyway. While it's a somewhat rare marque, it's not the best specimen. Translation: down and dirty is all I'm prepared to do.

calstar: I am planning to do exactly that. Here's some pics of how far I got today. Need to finish cutting the new tube to size, and get an appropriate piece to use as an internal sleeve/plug.

http://i101.photobucket.com/albums/m...d/IMG_0407.jpg
http://i101.photobucket.com/albums/m...d/IMG_0405.jpg
http://i101.photobucket.com/albums/m...d/IMG_0408.jpg

Down and dirty it is! Drill a few holes in the SS to show your filler flow along your sleeve. I might tack the drop out the align the stay stub before brazing the sleeved portion. Returning to the dropout to finish the brazing. Will you do the LH side too? Andy.

Thanks Andy, that's something I hadn't considered, but a good idea! The LH side seems OK - a few specks of rust, but clean underneath when I scraped away the paint. I'm going to drill a hole to help avoid future problems, and we'll see what that looks like. Might be another day or so before I get a chance to try this out, but I'll post an update when I do.
Cheers,
Neil

Who could stay away a couple of days with a fun bike project waiting! I got a little further tonight. Difficult using the ready-made stay, as the internal diameter of the tube made it hard to get a sleeve to work in both upper and lower pieces, so I started over with a different bit of stay closer in tube thickness. Still considering cleaning it up at the dropout. Not super happy with the look at the moment, and I think I can do better. Very happy with the fit at the top end though.

http://i101.photobucket.com/albums/m...d/IMG_0413.jpg
http://i101.photobucket.com/albums/m...d/IMG_0411.jpg
http://i101.photobucket.com/albums/m...d/IMG_0409.jpg

Neil- I just got done with some seat stay work myself about 15 minutes ago.

The top end looks about as good as you'll likely get things. The drop out end almost so. Clean off the drop out paint for about 1/2" away from the stay. The rest will burn off during the torch work, stay away from the fume plume. Consider pinning both top and bottom. The drop out is more my concern. Pinning will stabilize any displacement as well as serve to reduce the gap to be filled.

Keep the photos coming. Andy.

Haven't tried pinning a joint before, but I can see the appeal in this case. Updates to follow!
Neil

check alignment as best you can prior to brazing. Particularly how a wheel sits in the dropouts

For sure. This is just a dry-fit, and I haven't yet measured or otherwise verified that alignment is still OK, but I certainly will before getting to the brazing stage. Thanks for the note though!

OK, long hiatus, mainly due to lack of acetylene, but here's an updated. Finished brazing, and sprayed on some paint. Didn't have my camera handy for a photo of the brazed and unpainted stay, but my brazing isn't that pretty anyway.
http://i101.photobucket.com/albums/m...ps8ecffaa5.jpg
http://i101.photobucket.com/albums/m...ps3ac03645.jpg

Alignment is pretty good. I put a wheel in, and it's maybe 1/8" out at the brake bridge. I can live with that for this project.

If this ever comes up again, I will likely follow advice given early and just replace the entire stay, but it was fun to try it this way this time.
Thanks again to all who gave advice!

Why do you think it ended up .125" out of alignment?

You could have gotten the rear wheel to center perfectly by brazing the two ends of the replacement section separately. Do the 2 middle sections together first making sure in your mock up before brazing that it is a bit long. Now use a true wheel to see if the seat stay length is right (so the wheel centers). Hopefully it is a still a little too long and you slowly nibble a bit of the dropout away (so the distance shortens) until the wheel does center. Do this slowly checking often so you don't go too far. It is possible to pull the dropout out of the seat stay to file it some more. If the chainstay gets sprung too much so it loses contact with the seat stay, it can be bent back up when out of the seat stay. Of course you need to check that the dropouts are the same distance apart from the centerline of the frame with the Park ***-2 Frame Alignment Gauge (or something similar).


By the way there isn't a need to slot the seat stay into the dropout for this repair. It is easier to braze with an open end and extra brass can be added beyond the stay to create the dome (or whatever shape you want). It isn't going to come apart.


In this case I would absolutely have spliced in a piece of seat stay to preserve as much of the original frame as possible. I've done a lot of rust repairs over the years and often a tube is not rusted evenly throughout the tube but just in certain areas and usually near the bottom where water would sit. Once you get the stay cut apart, you can look into the rest to see if it is rusted too much to save.

Hi there...sorry, been away from the site for a while. Thanks for your comments, Doug. We haven't had an opportunity to test the work yet, (still lots of snow on the ground here) so I haven't had a chance to see how the results work. Slotting the end of the stay certainly make things more difficult, as I had to flex the chainstay down to get the dropout in position, which likely caused it to come out of alignment slightly when the joint was set. If this comes up again, I'll keep your idea in mind (re: keeping the end open, even if it's only on one side). Hopefully this doesn't happen again!

Cheers,
Neil