Because of a bad weld and/or lots of vibration (and/or ) one of the mounting tabs on one of my case guards has broken.  The break is usually lined up fine - I pushed it out of position for better visibility:



I've put off having it repaired because I'm not sure whether to have it welded ON the bike or OFF.  (I'm worried about the alignment getting messed up; it's a 3-point guard so everything needs to line up right.)  It finally occurred to me (Duh!) that perhaps I could just fix it with some JB Weld.  But I've never used it before.

What do you think -- is this an appropriate application for JB Weld?

Either way I'll probably have to take the guard off and clean the rust out of there, eh?

No, not a good application for JB. JB et al is more suited for repairs on very porous non-ferrous metals eg aluminum, zinc, sometimes even bronze. I have seen it used as a temporary fuel tank patch that didn't really work all that well, but it definitely doesn't work too well in applications involving heavy cyclical stress such as would be seen on a case guard or an engine mount. Little G is lonely, I miss the forum.

C.......

I have used JB weld for a number of applications.  I have never had any trouble with it.  I keep it with the tool kit on all off-road bikes. I used it to hold the exhaust bolt in on a 1970 kawasaki g4tr.  That "weld" held for the rest of the time I owned the bike.(1 1/2 years) I would assume if it will hold such an extremely stressed piece like an exhaust bolt, it will suit your purpose just fine.  CAUTION: Do not put too much hardener in, mix it 75/25 steel/hardener too much hardener will make it a softer compound, although it will stiffen up much quicker.

So, just get it welded then?

EDIT: Oh!  Sorry SPARK;  we cross-posted.  Any 3rd or 4th opinions?

Yeh, and if the welder knows his/her stuff, they can mig it and it will penetrate enough/as well as if it were off. And the mig won't let that surrounding area get too hot like a stick welder. Oh for a glass of G and to visit more often.

C.......

If you have the time, $$, and resources.  The actual weld would obviously be better, but the quick and cheap answer will work as well.  lay the piece flat. Use 2x as much as you think you will need. file down the excess.  Never failed yet.

Thing to remember when using JB and some of the others is if, for example, you put it into a hole for a thread with a bolt inside of that, it has a "backing" component. Your situation doesn't have that. It's good stuff, but to satisfy your curiosity, take some and "weld" two pieces of steel together, then take some and "weld" two pieces of aluminum or zinc or bronze or even cast iron if it isn't machinable cast, let them dry, put each sample in a vise and just tap it with a hammer...don't even slug it, just tap it, and see which sample holds. G'luck K, wish I could ride, still like the twin forum.

C.......

I'm headed out to the garage right now.

are the tolerance so small you cant weld it off the bike....it would be a pain and impossible to make a good weld with it on....not to mention all the spatter.

One other thing K, when you put the piece back on the bike make sure you don't have to force anything. If it was under stress to begin with it would cause it to break. And from the looks of it it appears you may have had to slightly force the studs/bolts into position. Like it, love it.

C......

Quote from: johncam4are the tolerance so small you cant weld it off the bike.

I don't know.  :dunno:

But like I said, the pieces seem to line up fine by themselves.  So I wonder if just a little more misalignment would be even worse.

Saaay ... I have another idea.  Perhaps the stress on the part was more forward-and-back than side-to-side?  If that's the case then adding a little extra metal into the crack might be a good thing!

If it were me, I would re-align the piece, tack weld it to hold the alignment, remove from bike, and fully weld.  JB weld is only for emergencies and people who don't really care about actually fixing something.  JB does not tend to fare well in high vibration enviornments (like on a GS).  I would let the pros handle it, instead of doing my own band-aid.

That's the best idea yet!  

Thanks everyone - I'll let you know what I come up with.

PS - I'm still holding my breath for your results, SPARKPLUG1977....

Just to look at the problem from a different angle:

That tab vibrated off through a piece of rolled, massive steel.

Do you honestly think that some kind of half-assed pseudoweld (is all that these band-aids are, really) will hold up for long?

Nope. Tack, then weld, that's the way to go.

Have it welded Kerry- But Off the bike. If you want to leave the gap (since its now sitting at the alignment you kinda want). Make some marks with a scribe or something and take it off. Have it welded OFF the bike. No need risking frying any electrical components...(I assume it will be MIG welded...).

Shame you aren't closer...I have a mig welder.

I used JB weld on my exhaust, the last owner did the dremel on the small pipe in the middle. I went to Home Depot bought a brass pipe fitting , some JB and its worked perfectly for me.


But I think for major parts and fixes I would not have gone that route

Quote from: MarkusNThat tab vibrated off through a piece of rolled, massive steel.  Do you honestly think that some kind of half-assed pseudoweld (is all that these band-aids are, really) will hold up for long?  Nope. Tack, then weld, that's the way to go.

I agree: tack, remove, weld.  However, just to defend epoxy: metal will fatigue when flexed repeatedly. Epoxy can be made hard, strong, and takes repeated bending very well (because it is just a plastic).

However, strong, sudden shear forces will cause epoxy to fail, and your case guard joint would probably fail, in with just a hard tip-over.  Epoxy is not strong over larger distances.  So in this case, epoxy is not the right solution.

Quote from: cernunosThing to remember when using JB and some of the others is if, for example, you put it into a hole for a thread with a bolt inside of that, it has a "backing" component. Your situation doesn't have that. It's good stuff, but to satisfy your curiosity, take some and "weld" two pieces of steel together, then take some and "weld" two pieces of aluminum or zinc or bronze or even cast iron if it isn't machinable cast, let them dry, put each sample in a vise and just tap it with a hammer...don't even slug it, just tap it, and see which sample holds.

Quote from: SPARKPLUG1977I'm headed out to the garage right now.

SPARKPLUG?  What ever happened with your experiment?  Inquiring minds want to know....

IT DIDN'T HOLD.

Yea tack in place and weld will work... however this is the problem I am thinking you might have ... the metal is weakest next to the weld... It broke there obviously due to that... hence its going to break again possibly. I'll either replace that plate with a thicker one or brace and bridge it on the top or bottom so there is a thicket plate to take the load.
Cool.
Srinath.