Wheels [JB] Welding some double wall aluminum rims??

Discussion in 'Bicycle Repair' started by sparky, May 12, 2011.

  1. sparky

    sparky Active Member

    So... yesterday I was on this sidewalk, right...

    And I took the opposite way back, and wasn't expecting this minor tectonic plate shift in the sidewalk, right...

    So I barely see it, slam on my brakes, slow down good enough to me, hop over it with my front....

    And then BONK, the back rim hits it fairly hard. It keeps riding for a few revolutions and then the back wheel became extremely difficult to pedal, then locked up.

    I had a fairly big dent in the rim, but the kevlar tires were still holding air (Best. Tires. EV. AR. -- Shadow Undertaker Kevlar, 20")!!!

    Took that side's brake pads off and kept riding no problem at all. Rode some more today, no problem. Eventually I realized I just couldn't deal with just one brake, no matter how RARE this dual-freewheel hub is. So I started beating on it, even tho everybody said I couldn't do it.

    I did it. It's almost back in shape!! The rim did crack, but I think that I could weld it. I remember somebody saying something about how they used the 2-part JB Weld and it held some plane parts on. I think that might be far better than heating up the aluminum rim, and should be slightly easier to sand the brake side off.

    My questions are...

    (1) JB Weld over regular weld?

    (2) Getting the brake-side surface flat is my only real objective, right? Leaving some weld lumps on the inside of the rim shouldn't affect balance incredibly much on a 20" rim at 25-30 mph, should it?

    (3) Should I get the one bent spoke corrected before or after welding, sanding?? HMMM?

    My logic isn't working properly in answering this question... because I've never adjusted spokes and a guy who does adjust them says "it wouldn't matter anyway, because it's so bent". It's not really all that bent anymore, but the crack is a problem, for sure... which I think JB Weld might handle just fine!

    (4) Anything else I should worry about?!? :thinking:
     

  2. olow

    olow Member

    im a firm if u need a new rim u need a new rim after all ur gonna ride on it better be safe then sorry
     
  3. sparky

    sparky Active Member

    Well... to answer my own questions without any experience yet...

    (1) JB Weld sounds great

    (2) An even braking surface seems about the only real objective here.

    (3) I guess I'll take the rim to the LBS one more time and ask whether I should get the one spoke replaced befor or after JB welding.

    (4) Only thing else I need to worry about is make sure the JB Weld is 2-part, and make sure that I prepare the metal properly before applying it!!
     
  4. srdavo

    srdavo Active Member

    IF your LBS suggests a another wheel or at least a new (or used -unbroken) rim laced to your hub.... they are only interested in your safety.

    JB Weld is glue.

    But it could affect how your tire seats on the rim.

    Ultimately.... It's your decision & your skin.

    I vote Replace the rim or wheel.
     
  5. sparky

    sparky Active Member

    Thanks, srdavo! I really do appreciate the concern, but I don't expect any problems and am definitely not going to go over 15 mph over the next couple weeks.

    LBS Guy #1 said that it was beyond repair, "because it was to far bent out of shape".

    Gotcha, but I bent it back. Sure it has a seemingly minor crack... but I am really not expecting the regular ol' 2-part JB Weld that dries overnight to have any problems "being the glue" that holds this minor crack together. It said something like 3950 psi, so I think it should be able to handle it!!

    Only problem is that when I showed the wheel to LBS Guy #2, he *did* remind me about braking forces, which I was not really thinking about before!! I was only trying to get the brake surface flat to not rub the brake pads, but... I still think after overnight drying, and a good sanding.. this thing will still be able to hang. :helmet:

    He said that the bend in the spoke was no deal, we'd just need to tighten it. Guy #2 wasn't quite as dramatic as to saying it couldn't be done after he saw it back in shape. It's not perfect, but perfect is the enemy of the good!
     
  6. Turtle Tedd

    Turtle Tedd Member

    Soarky...JB WELD WILL NOT WORK...get another wheel or get ready for a trip to the hospital
     
  7. olow

    olow Member

    one thing u dont want is the rim to break and fold in2 as some rims ive seen that were in good shape but if u do well god bless and good luck
     
  8. sparky

    sparky Active Member

    I think it will!!!

    I think 3950 psi is good enough for the size crack that it is, and the shape is already back to normal, minus what I can sand... so I don't see the problem just yet.

    I found this comment in another forum...

    I think it just might work....

    The thing was working just fine with the big dent... I don't see how the brakes are going to overheat one little section of the rim enough to re-crack it, but we'll see tomorrow.

    Gotta set it overnight to get that 3950 psi tensile strength!!
     
  9. sparky

    sparky Active Member

    Mmmkay...

    I took it by the LBS after it dried, and the guy puts it on the truing station thingy. He tells me that it is slightly bent, which i already knew, but it was "within tolerance". Sounds good!!

    He told me that even tho the spoke is bent, it's got the proper tension, so there was no benefit to tightening that one spoke. Also sounds good!!

    Put the tire on, used the hand pump and rode it around for a bit without brakes. Rode back up to the shop to get some pads. Everything's looking great!

    I get back home, then decide to let the air out of the tube and then air it up with the compressor to a higher psi (these tires say something like 120 psi max!).... I put the brake pads on, then start to ride. Instantly, I could tell something was wrong. I look down and the rim had already cracked.

    I'm going to try one more time at this, then I'll brake down and pay the estimated $150 for a new rim to be laced with this hub!!

    I don't think that some of my jb weld mix was good enough, because some parts were more like rubber than the rest, which was more like steel. Today, I made sure to mix the 2-parts together extra well! I shoved it in between the cracks, which I was unable to do yesterday because I'd already hammered it back together. There's definitely a mixture IN the cracks now. Did everything else the same.

    But tomorrow, I'm going to apply a second coat of jb weld to the inside of the rim, right behind the crack.... I think that will even hold the higher PSIs!!

    I'm almost willing to bet money that it will work this way. But we'll just have to wait 'til Monday!! :whistling:
     
    Last edited: May 14, 2011
  10. Elmo

    Elmo Member

    Keep fooling with a trashed rim until you wind up in the hospital.
     
  11. sparky

    sparky Active Member

    Why wouldn't I keep fooling with it??

    The bike shop won't be open for another two days!!!

    I might as well give it the second layer tomorrow, since I've still got plenty of JB Weld left, and then give it a test ride on Monday before making my mind up... don't ya think?

    10 minutes per day for FREE -vs- 3 days or so of waiting, in addition to shelling out ~$150??

    Hmm.....
     
  12. sparky

    sparky Active Member

    I mean.... as soon as I use the air compressor on the tire, I'll be able to see how the rim handles it.

    I'll be able to see the result before even installing the wheel this time!! Either it works, or it doesn't!
     
  13. Turtle Tedd

    Turtle Tedd Member

    Make sure you spread a good layer of penut butter over the jb weld area...Not the cheep stuff..use Skippy .... a little scotch tape wont hurt either
     
    Last edited: May 15, 2011
  14. Skyliner70cc

    Skyliner70cc Active Member

    did you stop drill the crack?
     
  15. sparky

    sparky Active Member

    Hah... OK!! :dunce:

    No I did not. Didn't think about that, and that'd be too much work for me since someone recently "misplaced" my screwgun.

    Soo... I've ridden approximately 7 miles over many bumps, and it actually seems to be holding!!!

    I actually put two extra layers on yesterday. One layer near the center of the crack, then expanding an eighth of the rim in one direction, because I could see a hairline crack in that direction. I checked it last night and saw that there was actually a hairline crack in the opposite direction, so I put another layer on THAT eighth of the rim (opposite direction). Soo... basically, the inside of a quarter of my rim has a good bit of jb weld at the first "step" on the inside of the rim, which just so happens top be where the crack is.

    Anyway.... two days of drying, two whole layers, covering an eighth of the rim... seems to be holding!!

    If it can make it this far, I think it should be able to last a few months, at minimum... but I don't know if it will last FOREVER!!! It will be interesting to see how permanent this will actually be, but 7 miles at 20mph with over 80psi in the tires... is looking pretty good, IMHO.

    P.S. - thanks for the idea that jb weld would actually hold skyliner. Think it was you that talked about using it on an airplane!!
     
  16. Skyliner70cc

    Skyliner70cc Active Member

    Yes, used it on a 4500 hp helicopter turbine that had a cracked engine case. It was an illegal repair but got us flying and completed our mission.....we did, however stop drill the crack to relieve pressures before using jb weld
     
  17. sparky

    sparky Active Member

    I think this should hold for a good, long time!!

    Made it back. So 14 miles so far. No problems at all. I'm only applying about 33% power to the rear brakes and about 66% to the front brakes. Need to tighten or replace those front brakes too, actually.

    But the next time I take the wheel off, I'll try to remember to take a picture.

    Nothing much to it, really, tho. Just have to put it on the inside quarter of the rim if you're smart. :idea: :helmet:

    Also, makes sure to mix EVENLY and CONSISTENTLY, plus LET DRY FOR 1 DAY PER LAYER.

    And I wouldn't recommend this for everybody, either. I'm slightly crazy. But you've heard Skyliner's story, also!!
     
    Last edited: May 16, 2011
  18. sparky

    sparky Active Member

    One more thing...

    You just might be absolutely dumb as dirt if you do this to your front rim!! But I hope not.. ?? :cool2:
     
  19. rustycase

    rustycase Banned

    Glue on a cracked case is plugging a pesky, leaky hole.
    Strength of the casing was relayed to the remaining good metal.
    Would you use glue on a cracked rotor?
    Nevermind... Don't answer that.

    A wheel rim is THE critical element of a bicycle.
    Glue is NOT an effective repair. Never has been, never will.
    I would be suspect of a weld. The effect upon the HAZ could not be determined without Xtreme test equipment.

    It's just a bad idea, no matter how much hot air you want to blow at it.
    rc
     
  20. Turtle Tedd

    Turtle Tedd Member

    Rustycase sums it all up ..very well put..Wear your helmet Sparky ..its been over one year since my front wheel collapsed (it was not cracked or damaged just cheep Chinese aluminum (al+pot metal)...Traumatic Brain Injury , 20 days in a coma , still have problems and issues
     
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