# JB Weld or other epoxy vs. TIG



## Entrenador (Oct 8, 2004)

I'm sure readers are getting ready to fire off "You've got to be kidding, right?" type messages, but if you have experience on the matter, please read through before responding.

I have recently purchased a seriously over built 1989 Santana tandem with a stuck, decrepit captain's seat post. After trying a laundry list of other methods, I resorted to cutting it out. It's out now, but while cutting it out, I cut a 3", blade-wide slit in my seat tube:


















This hole is far enough below the top tube junction that it will not interfere with my new post, and my gut says that since the seat tube is supported in 3 spots (top tube, down tube, and the center brace tube -- see second pic), that this slit is of no structural concern.

I'm ready to get this patched up, and very likely going to send it out for a repaint when it's done. My questions:

1) Can I use an epoxy like JB Weld or something else, to fill the hole, and if I do, will it withstand the sand blasting and powder coating process? Will the PC stick to it?

2) If it needs to be welded, can you recommend someone in the SF Bay Area to repair it? If this were a more critical repair, I'd only go to someone with lots of frame building experience. As it is not, I should be safe going to any good welder for this. Agree or no?

Epic Fail was previously noted, so no need to state it again. All thoughtful experienced responses are welcome.

Thanks much mtbrers!


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## mtnbeer (Jul 2, 2007)

What you've done is created a stress concentrator of humoungous proportion. 
At the ends of the cut the average stress in your seat tube will be multiplied by a factor of something like 5X to 20X. The stress in will cause the cut to progate as a crack. Maybe slowly maybe really fast. 

You need a full penetration weld to fix that or maybe a brazed on Gusset will do.
Then the inside of the seatube will have cleaned up after a full pentration weld. Otherwise a seatpost won't fit back in there. 

Go to a framebuilder for the repair.


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## mrchow (Jan 18, 2006)

that it will not interfere with my new post


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## TimT (Jan 1, 2004)

Yep bring it to a frame builder. Brazed patch or TIG weld the tube should be reamed after the repair. There will be distortion. JB weld won't take powder coat.

Tim


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## jimmyjammoto (Sep 16, 2005)

x 3 for the gusset welded over it. Have a cool looking one water jetted out ala headtube badge.


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## smdubovsky (Apr 27, 2007)

x4. just tig it. will look like its never happened.


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## HomeGrownSS (Jan 18, 2006)

TimT said:


> JB weld won't take powder coat.
> 
> Tim


i have no experience with it, but i was told that JB weld does take powdercoat.


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## dbohemian (Mar 25, 2007)

I agree, a framebuilder should fix it.

But a few fixes should work. It is a tank and a cruiser so I don't believe it will be extremely stressed. If you can strip it entirely (paint too) and then either a TIG bead or some bronze filler should do. 

Let me tell you what I would want.....I hate repairs where they bring the entire bike (wheels, parts and all dirty) I can't do anything with that, so strip it and make sure it's clean. If you want you could even go farther by stripping the paint in preparation for refinishing which would make a framebuilders life way easier. If you could put some solvent on a rag and really try and clean out the inside of the tube around the repair that would also be really helpful. If that is done than a quick weld job is all it is. Otherwise it sucks up an afternoon .


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## Entrenador (Oct 8, 2004)

Thanks y'all.

Patched, on the cheap, by a frame builder, and reamed by the LBS:









The patch is basically a steel band aid, and nearly the same size as a band aid. So, thinking about getting a small bottle of flesh tone paint. 

Powdercoated, and nearly assembled:









Fresh set of decals arrived from Santana today. The white walls are fun to look at, but will be replaced by more functional Serfas Drifters. Should be completed in the near future. Very glad I posted here and skipped the epoxy experiment. Thanks again for the zinger-free advice.
105mm


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## Yogii (Jun 5, 2008)

How about fake "stitches"??


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## jay_ntwr (Feb 15, 2008)

105millimetersofpleasure said:


> The patch is basically a steel band aid, and nearly the same size as a band aid. So, thinking about getting a small bottle of flesh tone paint.
> m


That would really be cool looking. I like that a lot. Please post pictures if you do this, 'cause I think that is funny and creative.


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