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Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

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Old 01-02-09, 05:58 PM   #1
Mike552
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JB Weld and ugly TIG welds

Hello fellow BF'ers:

I am in the process of refurbishing my Jamis Aurora touring frame. It is made of Reynolds 520 (aka:4130) and it is TIG welded. I have been taking some JB weld to a couple of small dents in the TT, and the results came out better than expected.

One thing that always bothered me about TIG frames is that the weld spots are visible where the tubes meet. I was wondering if I could cover those weld spots by applying some JB weld and sanding it to a smooth finish.

My only concern is that there would be too much compressional/tensional stress being applied to the tube ends, and that it would crack the coating of JB weld.

I do not want to repaint this bike a second time if I can avoid it.

Does anyone know for sure if this is ok given that it is a TIG frame?
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Old 01-02-09, 07:45 PM   #2
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You can dress the TIG welds with a rat tail file as long as you don't dig down too much and remove a bunch of material. Keep off the tubes as well - I can't stress this enough.

I did this to a poorly welded frame one time and when it was done it looked like mini fillet brazed joints - looked really nice.

If there are any noticeable low spots in the welds after filing, fill them with JB Weld, it won't fall out or anything.

Just don't go too heavy with the filing; smooth out the top of welds and stop when you get the rough top surface smoothed out.

Good luck.
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Old 01-02-09, 08:11 PM   #3
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Thanks Nessism. I'd love to hear some more views on this if anyone else has a similar experience.
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Old 01-02-09, 08:13 PM   #4
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How does JBWeld make the welds look better? It's clear, right?

- Mark
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Old 01-02-09, 08:31 PM   #5
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How does JBWeld make the welds look better? It's clear, right?

- Mark

JB Weld cures a gun metal gray color. Looks like raw steel.
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Old 01-02-09, 08:32 PM   #6
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How does JBWeld make the welds look better? It's clear, right?

- Mark
From the J-B Weld website:

Q: What color is J-B Weld when it cures? Is it clear?

A: J-B Weld cures to a very dark gray (steel-like) color. We're still working on a clear version that's just as strong as the original.
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Old 01-02-09, 09:25 PM   #7
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I don't care for the color. I just wanted to smooth out the TIG welds so it would look similar to a fillet brazed job. I am painting the whole bike anyways. Thanks for the replies... I will post pics when I am done!!
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Old 01-03-09, 02:05 PM   #8
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I don't care for the color. I just wanted to smooth out the TIG welds so it would look similar to a fillet brazed job. I am painting the whole bike anyways. Thanks for the replies... I will post pics when I am done!!
If you're painting afterwards, I'd thnk there would be better fillers than JBWeld which is an all-puropse repair epoxy and not designed for this application - you want something that bonds tenaciously with the metal, yet remains somewhat flexible and takes paint readily. There are a ton of body filler products other there. I don't know which would be best, but making repairs to frames with filler is something a frame painter does all the time and they would know. Perhaps something like this:

http://www.evercoat.com/productDetail.aspx?pID=37

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Old 01-03-09, 08:22 PM   #9
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Keep the fillets small and as tight to the welds as possible. I use devcon or WEST 5 minute epoxy mixed with a fairing compound. This softens the epoxy making it less likely to crack. Bondo may seem like crap to some, but it actually holds up to this kind of use. I like the adhesive qualites of epoxy, and while I would normally use something better than a quality 5 minute I tried a patch with it once and it lasted really well, on some architectural stuff that is outside 24/7. For a fairing compound something like talc, 410, soft microballoons should be fine. I would even try baby powder mixed with some 5 minute. Don't mix it so dry that the glue won't get a hold. 5 minute does not hold up unless painted. The 5 minute used needs to be decent stuff that is a thick clear liquid, if it is too paste like to start with then it won't be able to absorb the filler. Don't worry about mixing up your own stuff, a lot of the better things out there are user mixed.
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Old 01-04-09, 12:33 AM   #10
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I've used JB Weld when filling nicks and such on a frames before. It sticks to the metal just fine. Bondo will also work, and is specific designed for the purpose.
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Old 02-18-09, 03:19 PM   #11
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is it possible to use JB weld to fill bottle holder holes? I want to file mine down and fill the remaining whole with JBweld.
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Old 02-18-09, 10:49 PM   #12
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It depends what you mean by holes. The mounts I have have a threaded sleeve in the tube with a flange outside the tube. If the flange were filed down it's possible the remainder will fall into the tube eventually. JB weld put into the threaded sleeve will hold up well. If you conpletely remove the insert, then the JD weld has nothing much to adhere to. I have a technique for that that works well in golf culbs. You make up a stiff mixture of the epoxy and use a syringe to inject it in the hole, then pull the syringe, and tape over the hole, and hope the epoxy slumps into enough of a mass that it adheres well to the inside of the tube. Works great in golf heads, and they take a beating. Still always a risk it would detatch and rattle around. Always the worry the tubes are oily inside, etc....

Regardless of what you do you would be lucky for the patch not to eventually print through the paint. Of course it would be a lot less visible than a hole.
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Old 02-20-09, 08:33 AM   #13
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I would go with this for small holes a little bits of filler like your tig welds.

It requires no hardener and dries to a better sanded finish than bondo with hardener.

Its just bondo glazing and spot putty...
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Old 02-20-09, 11:01 AM   #14
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If I were dealing with 'ugly' tig welds, I'm not sure I'd be completely at ease riding the bike. That hints at severe undercutting or lack of penetration. If you have a problem with seeing a tig weld in general, then you've got weird mental issues. A nice tig weld is a thing of beauty and I can't understand why you'd want to cover it. Filing hurts the grain structure and is a no-no even if it ends up smooth. It may not make it break, but it will make it weaker.

If you absolutely have to cover the weld, body filler(Bondo brand sucks, but would work) and/or spot putty is probably the way to go.

If JB Weld is the answer, then it was a stupid question.
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Old 02-21-09, 12:01 AM   #15
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If I were dealing with 'ugly' tig welds, I'm not sure I'd be completely at ease riding the bike. That hints at severe undercutting or lack of penetration. If you have a problem with seeing a tig weld in general, then you've got weird mental issues. A nice tig weld is a thing of beauty and I can't understand why you'd want to cover it. Filing hurts the grain structure and is a no-no even if it ends up smooth. It may not make it break, but it will make it weaker.

If you absolutely have to cover the weld, body filler(Bondo brand sucks, but would work) and/or spot putty is probably the way to go.

If JB Weld is the answer, then it was a stupid question.


Many of the cheaper steel frames have functional but lumpy TIG welds. Taking a rat tail file and dressing down the chunks sticking up is a perfectly safe thing to do. There is no harm that will come of it as long as you don't go very deep into the weld and stay off the tube itself as much as possible. Undercutting is something that happens on fillet brazed frames when the builder cuts into the tube too much while dressing down the fillets. Needless you don't want to do this. And the grain structure will not be altered by dressing the welds.

After dressing down the lumps, filling any valleys with JB Weld is a good idea; it's just a cosmetic dressing so no worry. JB Weld itself is pretty good stuff. Lots of framebuilders use it to attach carbon stays since it's strong and not brittle.
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Old 02-22-09, 10:36 PM   #16
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Many of the cheaper steel frames have functional but lumpy TIG welds. Taking a rat tail file and dressing down the chunks sticking up is a perfectly safe thing to do. There is no harm that will come of it as long as you don't go very deep into the weld and stay off the tube itself as much as possible.
Really? I believe you, but I haven't seen any cheap steel frames lately. Are you sure they aren't MIG'd? That would make more sense from a cost perspective if they were going cheap and high production rates. I'm just surprised that bad TIG welds are an issue. Generally, if someone has the equipment to TIG, after a while they'll have the skill to do it well.

Ya, I agree you can use something like JB Weld for spot filling. I wouldn't use it structurally, though. There are _much_ better adhesives available.
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Old 02-23-09, 02:12 PM   #17
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One possible advantage to using JB weld is that it can be powdercoated.
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Old 03-02-09, 01:53 PM   #18
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I acutally contacted a powder coating place and they told me that JB Weld could not withstand the heating process involved with powder coating.
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Old 03-02-09, 04:17 PM   #19
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I have heard people say that JB weld works with powdercoating, and that it doesn't. There is a fairing compound designed for that purpose, and you can get it from Eastwood I think, basically any place that supplies auto body products. You can also use a metal filler, even solder. I think Eastwood has a powdercoating forum, there is one out there somewhere that I have used.

"Generally, if someone has the equipment to TIG, after a while they'll have the skill to do it well." There is a lot of turn-over in weding. In a production setting you can tell they literally grab some guy off the street and tell him to start welding. I am thinking mostly of stuff that comes from China, like engine hoists, totally scary. But the welds are similar if better on the average, say 400 dollar retail frame I see also. Lumps, not so much examples of bad stuff like undercutitng, but then you never know for sure what is down there. It is certainly possible they are using MIG. A lot faster, and it puts out a lot of bead, which is normally overdone on the average bike. Also, TIG isn't just TIG. I would wonder what the average rig looks like over there. Still possible to do good work with a simple set-up, but it is more difficult.
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Old 03-04-09, 10:24 PM   #20
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If you're painting afterwards, I'd thnk there would be better fillers than JBWeld which is an all-puropse repair epoxy and not designed for this application - you want something that bonds tenaciously with the metal, yet remains somewhat flexible and takes paint readily. There are a ton of body filler products other there. I don't know which would be best, but making repairs to frames with filler is something a frame painter does all the time and they would know. Perhaps something like this:

http://www.evercoat.com/productDetail.aspx?pID=37

- Mark
This stuff is the jam. It has excellent adhesion, and doesn't shrink like the crap in a tube that dries without a hardener. Plus, the stuff out of a tube is NOT intended for anything deeper than sand scratches; use it at thicknesses greater than 1/16 of an inch and it will never dry. Metal-To-Metal is the way to go.
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Old 03-05-09, 05:17 PM   #21
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I've powdercoated a few things with JB weld, and it worked OK at the 375 degree cure temps I used. The only problems I had were getting the powder to stick, but it did eventually with some fiddling with the gun settings. Eastwood also sells stuff called Lab Metal, but it's pretty expensive. I'm sure there is something better, but it was all I had at the time and others on the Eastwood forum had suggested it.
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Old 03-10-09, 09:58 PM   #22
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When you are done, and you end up with JB Weld all over your fingers and it won't wash off, use some vinegar first. Cuts sticky JB Weld like nothing else.
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Old 03-29-09, 07:34 PM   #23
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A nice tig weld is a thing of beauty and I can't understand why you'd want to cover it.
Please post a picture I don't believe you
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Old 03-30-09, 11:11 PM   #24
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How about this by the guy that made the jig in the background? Even some of the same colours.
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