MRT2

I just watched an episode of the show Air Disasters, that dealt with an analogous situation, a crack on the wing of a very old sea plane. The maintenance crew tried repeatedly to repair the crack over a period of months, maybe years, but the analysis of the show was, their efforts just covered up the cause of the damage. Anyhow, the plane made several flights a day until one day, the wing failed catastrophically. Now, a catastrophic failure to a head tube likely won't be as disastrous as the failure of an airplane wing, but the attitude of the airline ("We haven't lost a sea plane yet") is sort of the same thinking as you.

Reynolds 

This is how a proper wire wrapping should look:

kennj123

I know that series and i really like it. The one that really give me the shivers is the passanger plane that went down in Brazil when an American flight clipped it. The passenger plane immediately went into a high speed rotation like a blender until it aerodynamically failed. They did a computer simulation and when the plane broke apart what looked like confetti came out. Air craft vibration really causes a stress on aluminum that would be tough to fix with epoxy. But what am I? 1/6 hp? I think reinforced epoxy will stand up to me.

Miele Man

That's the truth.

****.

Cheers

kennj123

what about rebar in concrete? Rebar will stretch but the concrete doesn't. Since the rebar is embedded in concrete and rebar has all those little ridges on it, it can't stretch because it can't move independently of the concrete. Same issue with my twisted wire embedded in epoxy.

jyl

Concrete, whether with or without rebar, is not used in tension.

Miele Man

If the rebar rusts enough it can increase in diameter enough to CRACK the concrete.

Cheers

tgolden

Again, you're totally wrong. Your intuitive understanding of reinforced concrete doesn't directly correlate to your epoxy/wire head tube "repair." Rebar can slip in poorly designed or poorly constructed reinforced concrete structures. Certain criteria needs to be met to ensure it doesn't. Your epoxy/wire "repair" completely avoids any professional knowledge of materials or loads. It's judgment like yours that resulted in the requirement for engineers to be licensed. I'm convinced you're a troll.

unterhausen

if we can keep the OP posting, then he will not ride the bike and he will not die. So who is going to take the first shift?

kennj123

whats with the capping? i know about rust, thats why I applied quite a bit of epoxy over the top of the wire.

FBinNY 

Though I posted various (IMO) better options regarding this, including doing nothing at all, I can't see that the OP's solution represents any great risk of injury due to failure, so I am not one with those who insist on picking on him over this.

As for who the troll is (or trolls are), IMO the "dire danger" posts are more trollish.

Miele Man

Caps are for emphasis of that word.

The problem you have just like the rebar in the concrete is two dissimilar materials that expand differently and that can lead to cracking.

It's beyond obvious that you're not unhappy with your, ahem, repair and that you refuse to see anything bad about it. Therefore I'm finished with this thread.

I just hope that when that headtube cracks further or even splits that you don't get injured. Remember that failures usually occur at the worst possible moment.

Cheers

FBinNY 

Please don't take this personally, but IMO the entire rebar comparison is meaningless. There's a difference between the use of reinforcing material within a structure and use of reinforcing wrapped around a structure.

In this case, expansion from rusting of the headset inside the tube led to expansion and hoop stress cracking the tube. By the same logic, if steel wrapped around the outside the aluminum tube rusted, it would cause increased tension in the steel, but compression of the tube, which is this case would be somewhat desirable. So, rusting of steel surrounding the tube is a non issue.

kennj123

Anytime concrete is used without something directly underneath it, its in tension. I've been in Italy and Brazil and its amazing what they are building out of nothing but rebar and concrete. Actually a better example of my case would be wire mesh in concrete, used in concrete floor so it won't crack. thats the same situation with my stranded wire around the head tube, its just i didn't need reinforcement lenghtwise.

kennj123

caps are shouting. single quotes or italics are for emphasis.

kennj123

Your saying nothing factual here. its just an emotional outburst. you sound like Elmer Fudd.

jyl

You actually think his haphazard wrap of epoxy, fiberglass mat, and wire is going to make any difference, one way or another, to the future progression or not of that headset crack?

kennj123

I was thinking about trying to wrap the wire around like a shoe lace and make it look all pretty but decided just to get it done fast before the epoxy set. Are you saying if it looked pretty it would work better? Like I said, it all depends on how well the epoxy adheres to the aluminum. I'm pretty optimistic because surface prep worked pretty good.

FBinNY 

No, and I believe my first post on the thread reflects that. I don't think it'll help much, though it might a bit. As I posted earlier, as the proud owner of 2 bikes with the same problem, I've elected to do nothing at all (for now). The OP's method may be better than my do nothing approach, or it may not. But I'm pretty confident it won't do worse.

However, I don't criticize people's DIY solutions on their own bikes, unless I feel obligated to warn of a clear and imminent danger. It's their bike, and their own decision about what makes sense, and they're the only ones the decision affects.

So, let's take your premise that the crack will continue despite his repair. So, what will happen? and why all the criticism on this thread? Even if we assume that the totally split tube is some sort of safety issue, the fiberglass windings may act as sort of a safety net, so it's not all bad.

In summary, while I'm not in the OP's camp regarding his repair, I'm more for him than against.

jyl

I'm not in any camp regarding "this repair", because I think the crack hasn't been repaired and it doesn't matter whether it ever is repaired - it's a cheap beater bike, if the head tube splits there will be no dangerous result, the bike will just get replaced sooner rather than later.

What I find sort of alarming is that OP might someday use this approach to "repair" something that actually will have a dangerous result.

FBinNY 

If you read my post (no.32 in this thread), you'll see what I think of the repair (though I don't mention it directly), but I'm not invested in what the OP or anyone else does to their own bikes. I see quite a bit of nonsense here on BF, but generally just let it slide by. Otherwise I'd go nuts worrying about stuff that doesn't matter.

I also don't see any reason to apply "gateway" logic to this and assume he'll use similar methods in more critical applications. However, if you're concerned, you'll just have to find a way to live with it because I doubt the OP is going to change anything based on this thread.

BTW - Actually, I think the OP was dumb, not in his choice to repair it this way, but in opening himself to unwarranted criticism by bringing it up here. FWIW - it might be generational, or just me, but I've never understood the impulse to drop one's pants in public and ask people what they think.

tgolden

I agree that it's the OP's bike and his ultimate decision, but it's important to point out the facts or valid criticisms so that others reading this thread with a similar head tube condition don't get the impression that this epoxy/wire "fix" is a valid or an effective solution. It's really just a bubba attempt at a "fix" and could easily be confirmed as totally ineffective with testing or engineering analysis. There's enough good information included in this thread so that anyone looking for an effective head tube crack fix should be pointed in the right direction.

kennj123

If thats the case why don't you have somebody put in the sticky a warning that any DYI solution is unacceptable on this site. If its not prior art is doesn't belong here.

PS: The site moto should be 'Anyone that thinks outside the box will be put in a box, permanently'.

cobba

bigbenaugust 

I just read the whole thread. This is almost Foo-worthy.

Did OP die in the last hour and a half?