Crazylegsmurphy

Hey Everyone,

So my folding bike made it to Berlin, but not without a few chips in the frame. I was wondering what is the correct way of fixing these?

I have read a lot about people using model paint and nail polish to fill in the chip, but I would like to know if there is a more "professional" way of doing this. I want it to look like there was never a chip in the first place.

Should I sand it down first? Do you add a clear coat after you paint? Do you use spray or brush?

Any help would be greatly appreciated.

CLM

FMB42

I just clean the chipped area with wax and grease remover, or rubbing alcohol, followed by applying automotive touch-up paint (the kind with the fine tipped brush in the bottle). You can proceed this with an application of "rust converting primer" if any corrosion/rust has formed in the chipped area (on steel framed bikes).

Crazylegsmurphy

Thanks FMB42, but how do you assure that you get a nice seamless finish?

rhenning

You will not get a completely seamless repair unless you repaint the full bike. You can get closer sanding and widening the spots until they are smooth but then you will have bigger repair areas and will have to get color matching spray paint and I suspect you will still see the spot. When you get scratches in cars that is why they repair the complete panel with the scratch in it. Fix it the best you can and live with it. Roger

dsbrantjr

A problem with getting repairs to match is that not only must the color match but the manner of application must be the same also. Otherwise the way the pigments are laid down will be different and the repair will be noticeable. Even spraying, for example, must be done in a substantially same way (gun settings, paint thinning, application thickness) or it will not match. This is why entire panels are done as rhenning mentions; spot repairs will never blend properly.

Just do the best you can and look at them as war wounds or as blemishes on fine leather or a beautiful woman; signs of character and distinction. I mean, it's a bike, it's going to get blemishes unless you hang it on your wall and don't use it.

Retro Grouch 

Yeah. There's "perfect match" and there's "not exactly".

"Perfect match" is hard to achieve.
"Not exactly," in my experience, draws your eye and looks even worse than an unrepaired chip.

FMB42

I agree with rhenning, dsbrantjr, and Retro G.

Practice makes "better" but not "perfect" when it comes to using brush applied touch-ups imo. You can gain practice by starting with the least visible chips first, or on an "unimportant" practice item (such as painted garden equipment and/or tools, etc). Also be sure to follow the paint manufacturer's directions (i.e. surface preparation, paint application, ambient temperature recommendations, etc). You will, of course, want to position the chipped area in an upwards facing horizontal position while applying the paint.

You can sometimes achieve a relatively seamless finish by very lightly sanding just the (painted and thoroughly dried) chip area with extremely fine wet or dry sand paper (i.e. #600). This, followed by polishing and/or "rubbing out" the repainted area can improve the finish. It can also make things a lot worse, so be careful (this is where practicing on a "sacrificial" item really pays-off).

Note: Some paint types require as many as 6 months or more to dry throughly enough for such finish processing. Other paint types will dry enough in just a few days (or hours). An Internet search on "rubbing out a new paint job on a car" will provide much more info on this than I can.

I'll also note that I have yet to bother with "touching-up" the paint on any MTB I've owned. Nice road bikes (like yours) a few times, MTBs never.

FMB42

You might also consider covering and/or wrapping the chipped area with automotive vinyl adhesive graphic "tape" of a suitable color (i.e. chrome, white, black, or even a color that closely matches your paint). Another similar option would be to use a legally required "license identification" label or bicycle related sticker of some type.

Crazylegsmurphy

Cool, thanks guys.

I did get some recommended paint colors from a Tern representative so at least that will help in matching. I have heard about wet-sanding down the area with a fine grit paper before applying a primer. Then spraying on the replacement colour being sure to blend it as nice as possible. I just don't have any idea if this is overkill, or would even work.

I have had to accept the fact that my new bike is chipped, but what I'm more concerned with now is rust. I want to make sure I match the paint as well as I can, while also protecting the chips from further damage.

ultraman6970

You have a use a high built primer to cover the chip 1st and sand to get it even, the hobby shop is your best friend, there is one called like mr ginzu 2000 primer or something like that, is really similar to car paint primer, is expensive too. In 15 mins is ready for sanding.

Then you have to use a toothpick or something and cover the primer, sand again to get it even and done.

onespeedbiker

I would not sand down the chipped area, it usually just expands the damaged area. The first thing you need to know is was the paint clear coated or not (I'll get back to this later). The best way to repair a chip is to fill with paint. If it's down to bare metal you can use a little primer. First scrap the area clean with something like an exacto knife, and then using a fine paint brush dip it in primer, I like to use Rustoleum by spraying a puddle on a throw away surface like cardboard, and than dab it in the chipped area. Give the primer sometime to set up (best if you wait a day) and then come back and start layering thin coats of whatever color paint you have; I actually get great results with fingernail polish if I can find a close color. If the original finish is clear coated, use a clear paint (I again like to use clear fingernail polish) on the last couple of layers to fill up the chip and then add a few layers more. Once you have a layer or two above the chipped area and it has dried, take some 400 grit sandpaper and carefully wet sand over the chipped area so the extra layer of paint or clear is sanded even with the un-chipped surface. Once this is done, take some fine grit rubbing compound and rub over the sanded area until the area becomes glossy. And viola! the chip is gone. Now all you need to do is spray the frame with Pledge and wipe it down; this will even out any difference in gloss. The only issue will be a slight difference in color or shade because there is no perfect match. It's a long process and you need some patience, but it's the best way I know short of re-spraying the frame.

Crazylegsmurphy

Awesome! Thanks for all your replies.

I think this should give me a really good chance of fixing these chips, and making them look good. I'll report back when I'm done (pending finding the materials in Germany).