Scratch in bicycle frame down to raw aluminium - problem?
05-11-16, 02:28 AM
#1
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Scratch in bicycle frame down to raw aluminium - problem?
Noticed a small gash on the paintwork on my frame after it slid along a wall - nothing significant but the aluminium underneath is definitely visible. Could this pose a risk of developing structural damage? As I am aware that aluminium is prone to corrosion.
I read that nail varnish can possibly be used to touch up small flaws like this?
I read that nail varnish can possibly be used to touch up small flaws like this?
05-11-16, 02:57 AM
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There are many different aluminum alloys. Some are more damaged by corrosion than others, but in general, they resist the elements much better than steel.
Are you particularly exposed to salt? Road salt in the winter? Marine environment?
If not, I wouldn't worry about it, although there are some individuals who's sweat is also damaging to frames.
Paint over it if you wish, even clear enamel. But, your frame will likely get more scratches in the future.
Are you particularly exposed to salt? Road salt in the winter? Marine environment?
If not, I wouldn't worry about it, although there are some individuals who's sweat is also damaging to frames.
Paint over it if you wish, even clear enamel. But, your frame will likely get more scratches in the future.
05-11-16, 03:04 AM
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From what I know, aluminium oxidizes on the surface that is open to air. However, unlike steel, the surface oxide acts as a protective layer against further oxidation - almost as good as painting over the scratched part yourself. I wouldn't worry.
05-11-16, 06:07 AM
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Originally Posted by Slaninar
From what I know, aluminium oxidizes on the surface that is open to air. However, unlike steel, the surface oxide acts as a protective layer against further oxidation - almost as good as painting over the scratched part yourself. I wouldn't worry.
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05-11-16, 07:58 AM
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The only concern is that surface oxidation can end up allowing moisture between metal and paint in the area around a gouge. This is why it's imperative to touch up any scratch down to metal in a car. Though as mentioned previously, this shouldn't be anything more than a cosmetic concern under normal conditions. The drivetrain would probably rust first anyway.
05-11-16, 08:01 AM
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Clean it dry it and throw some clear coat on it to seal it. As others mentioned aluminum is not as prone to rust that pentrates the surface. However it is a point were paint will be weak, and begin to chip. Cover it up with some clearcoat to seal it.
05-11-16, 08:04 AM
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Originally Posted by dcwldct
The only concern is that surface oxidation can end up allowing moisture between metal and paint in the area around a gouge. This is why it's imperative to touch up any scratch down to metal in a car.
05-11-16, 09:07 AM
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Find a nail polish that closely resembles the colour of your frame and add successive layers until the thickness matches that of your original paint.
From a distance of a few feet, or in motion, no one will ever know.
From a distance of a few feet, or in motion, no one will ever know.
05-11-16, 10:57 PM
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Originally Posted by rpenmanparker
That is correct unless the area is further exposed to corrosive agents like sweat or acidic solutions that dissolve the oxide and re-expose the bare metal surface. A little clear or colored touch-up paint can't hurt. Yes nail polish can be used, but automobile touch-up paint from the auto parts store is even better, especially if you are trying to match a color.
I ride a 1996 steel frame MTB. The frame is full of scratches. Ride it in the winter, with lots of water, snow and salt. No rust destroying it yet.
I've also had a few aluminium frames. But never had an alu frame for more than 4 years to be able to tell if rust would destroy it. However, all my bikes are full of scratches - I fall down a lot and don't bother to be too careful about scratching a frame - never had any rust problems. No paint chipping etc.
05-11-16, 11:20 PM
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Originally Posted by rpenmanparker
Yes nail polish can be used, but automobile touch-up paint from the auto parts store is even better, especially if you are trying to match a color.
I've also gone to hobby stores for unusual colours. I had an old steel Merckx frame that was an odd yellow. I found a train caboose colour from olden times that matched perfectly.
05-12-16, 12:03 PM
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Originally Posted by Bob Dopolina
Find a nail polish that closely resembles the colour of your frame and add successive layers until the thickness matches that of your original paint.
From a distance of a few feet, or in motion, no one will ever know.
From a distance of a few feet, or in motion, no one will ever know.
I have used this method on my aluminum frame and it works very well.
05-12-16, 12:50 PM
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Originally Posted by Bob Dopolina
Have you looked lately? It's amazing how many colours of nail polish there are!
I've also gone to hobby stores for unusual colours. I had an old steel Merckx frame that was an odd yellow. I found a train caboose colour from olden times that matched perfectly.
I've also gone to hobby stores for unusual colours. I had an old steel Merckx frame that was an odd yellow. I found a train caboose colour from olden times that matched perfectly.
Mentioning the auto touch up paint was just a reflex reaction. I have been using that stuff for so long, it is what I just naturally think of. But it is getting to where the nail polish may offer easier matches.
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05-12-16, 12:58 PM
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05-12-16, 05:05 PM
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Here why I like the liquid paints for this.
Orient the scratch on the frame in such a way that it is parallel to the ground.
Then place a small drop of paint on the bare surface inside the scratch or chip and let it FLOW to the edge of the original paint.
Don't brush it over the edge and onto the original paint. Let it flow until it MEETS the edge of the original paint.
Let it dry and do it again until the depth of paint matches up.
Orient the scratch on the frame in such a way that it is parallel to the ground.
Then place a small drop of paint on the bare surface inside the scratch or chip and let it FLOW to the edge of the original paint.
Don't brush it over the edge and onto the original paint. Let it flow until it MEETS the edge of the original paint.
Let it dry and do it again until the depth of paint matches up.
