Broken droput repair
 

Is this how you repair a broken dropout on a steel frame? Is the repair adequate?

The other part of the video.

I dunno if it's adequate, but I surely recognized the various ways he used the Dremel :)

I watched the build video, too. I wonder how well the bike braked afterwards? After watching the way he linked up the rear brake I assume there will be a decent amount of travel at the brake lever. Pads weren't lined up with the rims, either. And that bike deserved a stainless Campy coil housing - with ferrules on both ends - at the RD. Damn, I'm picky ;)

Still and all, a nice video record of a vintage bike build.

DD

Repairing a cracked dropout
 

Exactement...

In the video they used a standard electro-arc welding setup. Using TIG welding gives much better control over the weld quality and amount of material deposited.

A number of years ago, I started cleaning up a 1982 Bertin Reynolds 531SL frame that I bought on eBay in preparation for assembly. I noticed what looked like a crack in the right dropout.

https://cimg6.ibsrv.net/gimg/bikefor...618bdccfcc.jpg

It has Shimano UF vertical dropouts which have a reputation for cracking in that area. I scraped off some paint and sure enough it had a small crack.

https://cimg1.ibsrv.net/gimg/bikefor...9413c259f9.jpg
I removed the paint to prep it for welding and took it to a frame builder friend to have him TIG weld it.

https://cimg7.ibsrv.net/gimg/bikefor...2738e8b00b.jpg

He used a carbide burr in an air grinder like in the video to notch the area to be filled in. As he did so, the crack broke through so he had to notch the inner side too.

He did a clean job and shot it with some primer. Took him about 10-15 minutes. I left the weld bead intact so that a future owner could see that it had been repaired.

https://cimg2.ibsrv.net/gimg/bikefor...97ffe5adbf.jpg

I used some touch-up paint and the repair is almost unnoticeable. It's also probably stronger than new too.

https://cimg3.ibsrv.net/gimg/bikefor...585cc83a1d.jpg

If it were a more severe break I would have had the dropout replaced, especially if it were a more valuable bike.

verktyg :50:

Hi CycleryNorth81, strangely enough I've had a few Pinarello Asolo's over the years and 2 of them had similar cracks in the RH rear dropout as the Colnago in the clip. I cleaned the cracked area up and brazed the dropouts back together without the need to open up the crack even further. I've still got one of the frames and, 15 years on, it's given no further problems.

Ugh. The way he inserted the stem and seat post during the buildup. "Hold up, lemme see how many zig-zags I can put on this thang!"

That is certainly not a very good way to repair that dropout.

1. I would remove a little more paint from the area than they did. Any possible contaminants near the weld area could cause failures in the weld.
2. Stick welding is not an appropriate way to repair that dropout. It will hold ok if you do a good job, but a professional welder would choose TIG welding for thin metal repairs. The other problem with stick welding is that there are a lot of sparks and slag produced during welding. The guy in the video did nothing to prevent these hot bits of metal from damaging the paint on the rest of the frame.
3. Welding outside is a risky process. People around without adequate eye shielding can get arc flashed and there is a greater risk of electrocution when arc welding. The grounding method through a bolt in the dropout was clever but besides that this is a hack job. The fact that he's welding on top of a stack of cardboard is also laughable.
4. There was no attempt to fixture the dropouts such that welding doesn't affect alignment. At the very least use a dummy axle, if not a full-fledged fixture, to keep the dropouts parallel!

I agree that TIG weld is the best choice with v-ground channel prep and that is exactly what Bernie Mikkelsen used to fix a cracked Campy "short DO" for me years back. It hasn't failed yet! But Bernie is one guy who knows what he's doing and minds the little details that make a difference to final results.

Ive fixed a few dropouts, but I used a Mig Welder and the process was similar to this video.

2 Pinarellos and 1 Bottechia and so far they have held up over the years..Its not heart surgery.

That is a smaller rod than I've seen used around here. So, not at all "farm welding".

I agree, it could have used a little more cleaning. But, I'm not hearing any splattering or popping. Everything looks like a good clean weld.

One option that people talk about is wrapping wet rag around heat sensitive areas like the chainstay.

The guy isn't even wearing leathers.

Yeah, a slight fire risk to the pallets and cardboard, but it likely would have been localized and easily extinguished.

How did humans ever survive with the potentially damaging sun in the sky? We should all be blind by age 5!!!

That location looks relatively isolated. The arc flash isn't significantly dangerous as long as people don't look at it for a sustained time.

Wind can be an issue outside, but perhaps less of a problem using flux. Nonetheless, outside is better to avoid welding fumes.

Contrast to this guy.

https://www.bikeforums.net/classic-v...-bikeshop.html


He does some grinding and welding about halfway through the video, apparently without any eye protection. And, wow, those welds!!!

https://www.bikeforums.net/attachmen...hmentid=467441

https://www.bikeforums.net/attachmen...hmentid=467442

TIG Welding Dropouts
 

Ed Litton did mine. He had the job finished while we were still discussing the problem.

The other advantage of TIG welding is that you can control the heat much better than with electro-arc stick welding, especially in this kind of application.

After he finished welding there was hardly any more paint damage than the area that I had prepped.

Before welding:

https://cimg0.ibsrv.net/gimg/bikefor...cc6976312d.jpg

verktyg :50:

I think his welds look like that because he closes his eyes.

BTW, nice bungee bike stand.

...I caught a lawnmower on fire once welding a sleeve patch to the broken handle. Forgot to empty out the gas. True story/ :o

Ahhh... I did upload it here.

My welding jig for the cargo bike.

https://cimg6.ibsrv.net/gimg/bikefor...92388c2856.jpg

https://cimg1.ibsrv.net/gimg/bikefor...ac0886e4f0.jpg

Cardboard behind to protect the car from splatter.

And, didn't even manage to burn down my workshop. :eek:

Note: I now have a fiberglass mat from Harbor Freight that I'll use in the future for similar protection... Probably...