Crack in paint or...

[rst72]

Cleaning bike and found this. It runs along the seam (where the bend begins) where it was crimped for chainring clearance so thinking it’s likely just paint...Columbus Life tubing. Thoughts?

https://flic.kr/p/2iHTCCh

https://flic.kr/p/2iHVdkr

https://flic.kr/p/2iHTCxY

[AngryScientist]

is that steel or ti?

Personally that would bother me not knowing. i'd remove the paint and get to the base metal and see.

[rst72]

Yeah I figured I’d have to sand it down.

It’s steel

[fa63]

If you tap around that spot, does the sound change?

[mflaherty37]

it looks like a crack for sure:banana:

[charliedid]

I'm going with cracked frame :-(

[ultraman6970]

Since is steel doubt is a crack, sand it down.

The other thing, steel creaks right away and probably is not creaking, right?

[David Kirk]

Take the rear wheel out and use your hand to squeeze the rear drops toward each other and watch the area very closely. Next pull the drops apart and watch. My guess is that it's all done.

Sorry.

dave

[rst72]

No creaking or change in sound when tapping.

[blantonator]

that's a crack, but ya you got to sand it down. It can probably be repaired if it's a nice frame.

[rst72]

Take the rear wheel out and use your hand to squeeze the rear drops toward each other and watch the area very closely. Next pull the drops apart and watch. My guess is that it's all done.

Sorry.

dave

Yes...after doing this I think it’s a crack. Bummer.

[ultraman6970]

Steel always make a sound if areas like that are problematic.

[fmradio516]

Yes...after doing this I think it’s a crack. Bummer.

sorry to hear. is that a Max frame?

[unterhausen]

has anyone here actually sanded down a cracked frame? Good way to hide a crack in my experience. Unless you have a microscope.

Cracks are very small when unloaded

[David Kirk]

has anyone here actually sanded down a cracked frame? Good way to hide a crack in my experience. Unless you have a microscope.

Cracks are very small when unloaded

Exactly.

It's sad to say that 99% of the time when there's a crack in the paint it's because the stuff the paint is stuck to has a crack. I've seen super rare cases where there was bondo and it dried and shrunk and then when the whole thing flexed the paint wasn't elastic enough and it failed in the form of a crack.

Sadly - nearly every time the paint is cracked so it the area it's applied to.

---------------

The only long term way to fix that stay is to replace it. People like to flow some braze in there of tig weld it and it will be OK for a short time but it almost never holds. If you take the short route and fix the crack don't waste your money on getting it repainted as you'll just need to do it again soon.

Sorry.

dave

[AngryScientist]

has anyone here actually sanded down a cracked frame? Good way to hide a crack in my experience. Unless you have a microscope.

Cracks are very small when unloaded

what, you dont have a dye penetrant kit at home? i do :)

[homagesilkhope]

It's sad to say that 99% of the time when there's a crack in the paint it's because the stuff the paint is stuck to has a crack.

When you say "stuff," are you speaking narrowly of metal or have you got carbon in mind, too. I value your opinion on this, thanks.

[unterhausen]

what, you dont have a dye penetrant kit at home? i do :)

if you have die penetrant, you don't need to remove the paint.

Anyone can put oil on the inside of a frame and wait for it to seep out. Or even apply it to the outside, let it sit, wipe it off, and see if more comes out.

[David Kirk]

When you say "stuff," are you speaking narrowly of metal or have you got carbon in mind, too. I value your opinion on this, thanks.

Yes...."stuff" could be carbon or metal.

Good paint doesn't just crack on it's own. It's not very elastic and if you put it in tension, compression or shear over a crack it will fail for sure.

I've never seen a tube or joint fail without the paint failing...and I've almost never seen paint fail without the stuff under it failing. The two things are hooked together and the crack in the paint is evidence of relative movement.

dave

[rst72]

Thanks Dave for the insight.

[muz]

Yes...."stuff" could be carbon or metal.

Good paint doesn't just crack on it's own. It's not very elastic and if you put it in tension, compression or shear over a crack it will fail for sure.

I've never seen a tube or joint fail without the paint failing...and I've almost never seen paint fail without the stuff under it failing. The two things are hooked together and the crack in the paint is evidence of relative movement.

dave

Not always true for carbon, where the clearcoat can crack (with the paint) even though the underlying carbon is fine. I have seen this around bottom brackets or seat tubes (cutouts for pinch collar) on carbon frames. But definitely true in the middle of a chainstay.

[Toeclips]

I used to fix cracks in bathtubs
I would identify a crack with a sharpie
Sharpie over the crack and then wipe off the excess and the marker stays in the crack

Good luck