Gouge in 631 steel frame

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hazboss
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Gouge in 631 steel frame

Postby hazboss » 28 May 2019, 9:17pm

Hello all,

I am getting my Dawes Galaxy's 631 steel frame powder coated. After cleaning it and looking it over I noticed a rather nasty looking gouge in it. It is slightly dented, and it looks more like a compression rather than having had a lot of material removed.

Can this be patched up a little before the new coat goes on, or is it nothing to worry about with a steel frame?

Any opinions much appreciated!

1111.jpg

1112a.jpg

1113a.jpg
Last edited by hazboss on 28 May 2019, 10:58pm, edited 1 time in total.

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Lance Dopestrong
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Re: Gouge in 631 steel frame

Postby Lance Dopestrong » 28 May 2019, 9:34pm

Fill with plumbers solder and carefully file it smooth, should withstand the heat of a powder coat oven.
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hazboss
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Re: Gouge in 631 steel frame

Postby hazboss » 28 May 2019, 10:53pm

Lance Dopestrong wrote:Fill with plumbers solder and carefully file it smooth, should withstand the heat of a powder coat oven.


Thanks! Would that assume that this is just a cosmetic ding?

Valbrona
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Re: Gouge in 631 steel frame

Postby Valbrona » 29 May 2019, 1:55am

Jesus Christ, a lot of frames break at exactly that point. So, are you sure it is a gouge? meaning, do you know how it got there?
I should coco.

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Lance Dopestrong
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Re: Gouge in 631 steel frame

Postby Lance Dopestrong » 29 May 2019, 6:55am

hazboss wrote:
Lance Dopestrong wrote:Fill with plumbers solder and carefully file it smooth, should withstand the heat of a powder coat oven.


Thanks! Would that assume that this is just a cosmetic ding?


I'd want to examine it closely to be more sure. It also depends on the frame material - some fine quality Reynolds or Columbus frames can have a tune wall thickness as little a 0.4mm...towards the tube centre. This is at the end when the tube is likely more like 1mm, so much more meat.

I think you're probably fine, but get the paint stripped and eyeball it very closely to be sure. If you're a careful rider who does their pre ride checks then you're going to spot advance warning of failure anyway.
https://themediocrecyclist.home.blog
Self employed MIAS L5.B Instructor.
Warwickshire Lowland Rescue Bike lead.
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Cyctech C2 hammer and crowbar bodger.
Lapsed CTC Ride Leader, amateur hour stuff from the fun old days.

hazboss
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Location: Manchester

Re: Gouge in 631 steel frame

Postby hazboss » 29 May 2019, 8:49am

Thanks for the suggestions, both.

Valbrona wrote:Jesus Christ, a lot of frames break at exactly that point. So, are you sure it is a gouge? meaning, do you know how it got there?

I should have said I "re-discovered" a nasty-looking gouge. I didn't think much of it at the time. I was travelling somewhere with the bike in the back of my car, the wheel must have rotated too far and the brakes got stuck... they're aftermarket brakes so presumably slightly too high :oops:


Lance Dopestrong wrote: If you're a careful rider who does their pre ride checks then you're going to spot advance warning of failure anyway.


I'll certainly be keeping an eye on it. In fact, I'd rather they just clearcoated that section so I could keep an eye on it...

JakobW
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Re: Gouge in 631 steel frame

Postby JakobW » 29 May 2019, 9:19am

Valbrona wrote:Jesus Christ, a lot of frames break at exactly that point. So, are you sure it is a gouge? meaning, do you know how it got there?


That's a bit dramatic, isn't it? It is a fairly highly loaded area of the frame, but the breakages I've seen have mostly started at the shifter bosses or the lug. If worried I'd try and take the paint back with some wet and dry and see whether there was a fatigue crack there, but I wouldn't be too anxious - just be aware and keep an eye on the area. I might (with a tip of the hat to Brucey OTP) consider respraying in a light colour so potential cracks are easier to spot, but again I'd not worry too much - in a steel frame you're likely to feel the handling change before tube failure.

bgnukem
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Re: Gouge in 631 steel frame

Postby bgnukem » 29 May 2019, 12:41pm

Maybe try to find out if the ding is in the thicker butted portion at the end of the tube or within the thinner area towards the centre. You can try tapping the tube and listening to the noise.

If the former, then less to worry about. Could you estimate the depth of the defect maybe using a straight edge placed across the area from adjacent undamaged areas? Also check if it is material removal (worse) or just indentation (better).

Before painting it I'd be inclined to lightly dress the affected area using a needle file or fine abrasive pad to remove any sharp edges or corners (but aim not to remove any material from the base of the defect) which could create stress concentrations, as this appears to be the underside of the down tube which is a relatively highly loaded part of the frame. At least it's not at the bottom bracket end of the tube.

Keep an eye on the area in future to check there is no cracking growing from the defect. Light-coloured paint would make this easier to detect.

Valbrona
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Re: Gouge in 631 steel frame

Postby Valbrona » 29 May 2019, 1:30pm

JakobW wrote:
Valbrona wrote:Jesus Christ, a lot of frames break at exactly that point. So, are you sure it is a gouge? meaning, do you know how it got there?


That's a bit dramatic, isn't it? It is a fairly highly loaded area of the frame, but the breakages I've seen have mostly started at the shifter bosses or the lug. If worried I'd try and take the paint back with some wet and dry and see whether there was a fatigue crack there, but I wouldn't be too anxious - just be aware and keep an eye on the area. I might (with a tip of the hat to Brucey OTP) consider respraying in a light colour so potential cracks are easier to spot, but again I'd not worry too much - in a steel frame you're likely to feel the handling change before tube failure.


Why bother posting that after the OP has explained that the gouge was caused by the front brake caliper striking the tube? Meaning, it is a gouge and not a break in the tube forming.
I should coco.

hazboss
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Re: Gouge in 631 steel frame

Postby hazboss » 29 May 2019, 1:33pm

Thanks for the advice, this is really helpful.

bgnukem wrote:Maybe try to find out if the ding is in the thicker butted portion at the end of the tube or within the thinner area towards the centre. You can try tapping the tube and listening to the noise.

If the former, then less to worry about. Could you estimate the depth of the defect maybe using a straight edge placed across the area from adjacent undamaged areas? Also check if it is material removal (worse) or just indentation (better).


JakobW wrote:If worried I'd try and take the paint back with some wet and dry and see whether there was a fatigue crack there, but I wouldn't be too anxious


Through tapping with my hand I think it's in the thicker part of the frame. I took the paint back with some wet and dry and no cracks to be seen. I think it's an indentation but a little hard to tell - imagine getting a (very blunt) flathead screwdriver and giving it a tap with a hammer. It looks a bit like that.

bgnukem wrote:Light-coloured paint would make this easier to detect.


Plan is to turn it yellow!

hazboss
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Re: Gouge in 631 steel frame

Postby hazboss » 29 May 2019, 2:45pm

Speech bubble shape is because I was rubbing down where the other scratch was (appears to have just been a paint scratch)

aa1.jpg

aa3.jpg


I think there has been a small amount of material removed (scratch) but the rest is just an indentation.
aa4.jpg

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Lance Dopestrong
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Re: Gouge in 631 steel frame

Postby Lance Dopestrong » 29 May 2019, 3:08pm

That looks quite reassuring.
https://themediocrecyclist.home.blog
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Warwickshire Lowland Rescue Bike lead.
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Cyctech C2 hammer and crowbar bodger.
Lapsed CTC Ride Leader, amateur hour stuff from the fun old days.

JakobW
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Re: Gouge in 631 steel frame

Postby JakobW » 29 May 2019, 5:05pm

Valbrona wrote:Why bother posting that after the OP has explained that the gouge was caused by the front brake caliper striking the tube? Meaning, it is a gouge and not a break in the tube forming.


Because one does not preclude the other? Fatigue cracks generally start at some existing defect or stress concentration.

Looking at the photos of the cleared ding I'd not worry overly, especially if it's in the butted area. I'd build it up and ride it, just checking the area at intervals.

bgnukem
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Re: Gouge in 631 steel frame

Postby bgnukem » 29 May 2019, 6:02pm

Looks like mainly indentation with some material thinning at the scratches as you say. If it's in the thicker-walled part of the tube I'd be tempted not to worry about it too much. Maybe just check occasionally

The scratches are relatively open/large radius of curvature which will tend to reduce the stress raising effect and the material at the base of the indent will have work hardened slightly.

Ultimately it could, potentially reduce the fatigue life of the frame depending on how hard you use the bike, but i) this may take many years and ii) another area of the frame might be more critical from a fatigue failure perspective, e.g residual stresses and/or defects in a weld.

mercalia
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Re: Gouge in 631 steel frame

Postby mercalia » 29 May 2019, 6:28pm

I had a would be thief try and steel my dawes Horizon that has a 531 steel frame , he/she/it then decided to destroy the frame with a supermarket trolly as it found the bike was locked up too well. The pont of all this I was surprised how thin the steel tube was, so I am a bit wary of dents and such like in steel frames.