Repair paintwork on Mountain bike frame

  Diemmess 12:49 17 Sep 2009

Student grandson has just finished 6 weeks mountain bike holiday in Whistler B.C.

He saved for two years for this and enjoyed every minute.
His minor scars are healing well, but the bike frame is scratched and scored on its alloy frame.

He believes the frame has powder coating or expoxy paint and at first thought of stripping and polishing it.
He had to agree that his idea of polishing the aluminium alloy would not result in a nice shiny frame and would probably weaken it quite seriously.

So, what should he do?
Would car body filler fill any scoring and then what type of paint professionaly sprayed cound be used to posh the white frame up again?

  Quickbeam 13:14 17 Sep 2009

Bare aluminium will soon oxidise and look a furry mess, so it will need to be lacquered at the least.

Or take it to a painter that does motorbike frames. You can have a plain colour or a fancy graduated paint job.

I had a custom frame for a motorcycle sprinter chromed in about 1980 but it was a real pain to keep looking good.

  wee eddie 14:18 17 Sep 2009

Why should he want to?

Many a Desktop Mountain Biker would relish a few scratches on the frame of his precious bike, many of which have never been anywhere near a Trail, let alone, been put to the Test.

Suggest that he wear the "scratches" with pride and preferably with a story for each one! No, maybe he is too young to be telling of past exploits. Better leave that to old buffers like myself!

  wiz-king 16:26 17 Sep 2009

Getting a colour match would be difficult - there are many shades of white. I would go to a car accessory shop and get the smallest can of brushing touch-up paint that is a near match and use that to protect the bare metal. Wear the scratches with pride!

  Diemmess 17:50 17 Sep 2009

wee eddie - Good point, but G is in final year of an MSc in Mech.Eng.
Its Freshers week next week and he will go back in time to man a stand and hopefully attract other serious M Bikers, so I suppose he wanted it shiny by then.

He is being sponsored at Brum by a Glos. engineering firm but had this sort of interest since he was at school.
This was his second trip to Whistler on the same mountains as the Winter Olympics site.

Wear the scars with pride? His skin is almost healed, but he did need new handlebars and had a cracked rim on the rear wheel at day two, which grew daily but managed to last the holiday.

There is a late photo of his feet sticking out of a bush when he decided mid-jump that he wasn't going to make it and let go of the bike grabbing an obligingly soft young pine as he passed.
His friend was appalled and only pressed the shutter when all was still except for a cloud of dust. On this occasion he was barely scatched.

As he said to his mother on a rare text, he was spending more on repairs than on food.

  Noldi 18:01 17 Sep 2009

If you go to a profesional paint sprayer he should make a small repair and match the colour. If they can do it to avery expensive car I would think a bike frame should be no problem. Dont try to bodge it yourself you will make the repair even more expensive.


  Forum Editor 19:14 17 Sep 2009

there's no chance of an invisible touch-up repair. The frame can be made to look like new, but it will have to be professionally done. There are lots of companies who will grit blast the frame (with aluminium oxide grit) and powder coat it in any one of a hundred or so colours for about £90.

  carver 21:15 17 Sep 2009

If he wants a good job give these people a try click here , he really doesn't want the frame blasting if at all possible, these people chemically strip the items which on alloy is better.

Try them, might not be cheap but they give a good service.

  morddwyd 21:27 17 Sep 2009

Anyone with with a serious interest in mountain biking is likely to be far more impressed with a mountain bike that looks as though it's actually done some mountain biking than a nice shiny pristine one.

Given the normal conditions of use of a mountain bike I wouldn't be surprised if the tube manufacturers have put some sort of corrosion inhibitor in the alloy mix.

  Forum Editor 22:56 17 Sep 2009

Grit blasting is done after the chemical stripping - you can't powder coat a bike frame that has only been chemically stripped - the first treatment after paint removal is a dip into a corrosion inhibitor which contains an acrylic resin. Aluminium oxide grit is used because it's non-ferrous, and won't leave contaminants on an alloy frame.

After that the frame needs a coat of epoxy primer, and then the powder coat.

  Diemmess 17:21 18 Sep 2009

G has seen the thread through, and tells me he is not in a hurry to have anything done at all.

Thinking back he broached the subject with a question of whether I thought he could strip and polish the frame.
e no longer has any illusions about that, and the frame itself will bear its scars either until he can afford it or accepts and ignores.

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