How to touch up chips and scratches in your bike's paint
You’ve looked after it lovingly, spent money on upgrades and kept it well serviced. So you’ll want to fix chips and scratches in your bike’s paintwork. It’s a job you can do yourself with a bit of patience and the right materials.
It’s more-or-less inevitable that your bike’s paint will pick up scratches as you use it. That may be from flying road chips hammering the bottom of your down tube, but larger chips can come from the bike falling over or the top tube grazing against a wall. More significant chips and scuffs can come from a crash or damage in transit.
The good news is that your frame can live happily with chips and scuffs. They won’t affect a carbon or alloy frame and even surface corrosion on a steel frame shouldn’t be an issue.
But it’s nice to keep your bike looking its best and touching up chips in the paintwork isn’t hard.
Is the damage just cosmetic?
First up, you need to assess how bad the damage is or get a professional opinion. Even in metal frames, anything deeper than a cosmetic chip to the paintwork needs inspection.
I once had a rear mech break and make a small ding in the seat stay of an alloy frame. I thought nothing about it but a couple of months later it had spread into a fracture across most of the stay, which you could push apart with quite light hand pressure. Fortunately I noticed it and stopped riding the bike before it failed.
The potential for invisible, deeper damage is even more of an issue with a carbon frame, where a bash can delaminate the carbon fibre layers on the inside of the frame, where it’s invisible.
So if your frame has been in a crash or otherwise put under unusual stress take it to a shop and ask them to assess it before continuing to ride and before deciding to start a paint repair.
Match your frame
The next problem is to work out the right colour for your frame and source it. When it comes to retouching scratches in your paintwork, there are advantages to an all-black bike - there’s a good reason why it’s a popular colour!
If your bike has panels of different colours, it’s not too difficult to mask the edges with tape and paint up to them to get a straight edge where they meet. If you’ve gone for a fancy gradient paint job, hiding the scratches may be more difficult, depending on where they’re positioned. Add a glittery, pearlescent finish and you may need to take your bike to a professional to get a repair that matches the rest of your frame.
Assuming you’ve just got one colour to match, you’ll need a paint colour chart - RAL is an industry standard and includes over 200 different colours. The colour chart fan is pretty expensive, so it might be worth trying to borrow one. Check your colour in different lights and get a second opinion. Note down the colour match for future reference - your paint will probably have dried out before you need to make another repair.
It’s also worth asking your bike’s maker if they can tell you the colour used, as they may keep a record.
Source your paint
There are various sources for appropriate paint to match your frame - it’s worth a hunt on the internet to find the colour you want. Enamel paints are likely to give a better looking finished job than acrylic.
Some places sell paint that’s specifically designed for bicycles and some bike brands sell touch-up paint for their bikes. Otherwise car touch-up paint comes in lots of colours and can work well. Modelling enamel is a good option too. Humbrol's comes in several hundred colour/finish combinations. Again, there’ll usually be a colour chart available to help you match your colour.
If you can’t get an exact match, a close colour might be good enough, particularly if the repair is somewhere unobtrusive.
Add the paint in layers
Bike paint is surprisingly heavy - one bike maker has told me that it added an extra 90g to its frame’s weight over lacquered raw carbon. That’s a sizeable chunk of extra weight on a sub-kilo frame and fork - its pros went with the raw carbon finish.
That weight indicates the thickness of paint on a high quality frame like our road bike range, so if you do take a chunk out of it, you’ll probably not find that you can patch it up adequately with one coat.
First off, clean any oils and dirt off the frame, first with detergent solution, then dry and rub the area over with isopropyl alcohol, available from decorating supply shops, chemists or Amazon. You can use cheaper alcohols on metal frames, but these can damage carbon frames.
You’ll now need to add paint in layers and build up enough thickness to cover the scratch, which is likely to take several applications. You want the area of new paint to be thicker than the surrounding frame paint, so that you can smooth it down to blend in. Between each application, you need to let the previous layer dry thoroughly so that it provides a good foundation for the next one, so be prepared to take your time over the repair.
A thicker enamel-based paint will build up an adequate thickness more quickly than a thinner product. Use a good quality paint brush and clean it thoroughly between coats.
Sand down carefully
Eventually, you’ll end up with a layer of new paint that hopefully matches the paint on the rest of your frame and is a bit thicker than it, which you can smooth down to blend in. Make sure it’s well dried first, then rub down with fine emery paper - it wants to be 1500 grit or above.
Wet the paper and use a support like a block of wood to make sure that it rubs the paint down evenly and is less likely to scuff the surrounding original finish. Wipe off the area with a rag and check progress frequently as you work. Don’t go too far - it’s better to have a slightly raised patch than to eat away at the original paint.
Once you’re satisfied that you’ve got the new paint more-or-less flush with the bike’s original paintwork, you can either shine it and the surrounding frame area up with wax polish or apply a coat of clear lacquer if the affected area is larger.
Job done and your bike should be looking like new and ready to ride again.
View: How to choose the right tyres here >
View: How to keep your bike serviced at home here >
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