Cycling Adventurer: How To... Paint a bike frame

The Cycling Adventurer
How To...	Paint a Bike Frame — Step 6

We're ready to spray

Reread the instructions on your spray packs. There are variations between brands, so it is difficult to predict how you will approach the actual painting stage in terms of recoating, rubbing back and waiting periods between coats.

Take special note of how long to shake the can. Most have a ball bearing in them to act as a mixer. It may take a few shakes to get it moving, but then shake for as long as recommended, and if there is no recommendation — shake for around three minutes. If the paint is not at ambient temperature, you may need to put the can in some warm water for half an hour.

The paints I have used usually have specified that the next coat be applied within a short period such as 30 minutes, or that the paint should be left for the three days before another coat is applied. Your personal timetable will be a decider for the primer coats, but for the finish coats, I strongly advise patience and do the painting over aweek.

WARNING! Wear a face mask of some sort otherwise you will pick boogies out of your nose the same colour as your last spray job for a couple of days (and believe me, you WILL be picking them out).

But it's not just gratuitous advice. A facemask will stop the stuff from getting to your lungs. You can pick someone who has just finished a spray paint job without a face mask, because their facial complexion is usually very pale, even grey. It doesn't do your lungs any good whatsoever. And you will be amazed at how much overspray the mask collects.

Your spraying technique will be tested by the primer coats. Use thin coats and lots of them applied with a feather spray — in other words, quite rapid passes left to right or up and down, across the tubing.

You will need to note right away how the spray fans out of the nozzle. Some nozzles are adjustable so you can change the fan from being vertical to horiztonal and vice versa.

If you still have a substantial area of original paint left on the frame, spray the areas that have been rubbed back to metal to build up the level of the primer to that surrounding it. Do this coat by coat, rather than one heavy one.

When you are satisfied you have the "patches" done, give the whole frame several light coats of primer. One of the functions of primer paint is to fill the tiny scratches and pits. You will likely sand back the finished primer surface to reveal a lot of the original paint again, but the surface transition from original paint to the patches will be silky smooth.

Start spraying before the paint hits the metal, sweep across, and keep spraying momentarily after the last bit of tubing. Keep the can at right angles to the surface you are painting; don't swivel the can with your wrist because this is likely to produce uneven layers of paint that are thickest in the middle and thinnest on the edges.

I can't emphasise strongly enough to go lightly on the coats. If the paint dries or goes off rapidly, you will be able to build up the requisite coats within 10 minutes. If the paint takes longer to go off — and with primer, than means the shiny surface disappears into a dull or matt finish — then you will have to be patient.

If you start from a completely bare frame stripped of virtually all the previous finishes, the first primer coat may only just cover the bare metal and have a mottled appearance to it. The idea is then to build thin coats that gradually give a depth of colour (a solid grey if you are using grey primer).

You really don't want to have to deal with paint runs — they take ages to set/cure/dry, and the temptation is to wipe them off, leaving a significant scar to deal with by wet-and-dry sanding and spot spraying again.

The most difficult areas to deal with are, again, the lugs, around the bottom bracket, as well as under the toptube, and around the headtube at the top of the seattube where the seatstays join. You do need to ensure an adequate depth of paint in these locations, because they are also water traps.

The trike's main frame is evenly coated a grey primer and is left to air dry for about a day. The surface feels a little rought to the touch, and it
is to be very lightly sanded with a 1200 grit
wet-and-dry paper to make it smooth
and to encourage a glossy finish.

"All I want to be when I grow up is a Giant!" The tricycle's primer-coated seat and fork take
advantage of a dormant handlebar indoors
in cold weather to let the primer harden.

But there is a temptation to just point and spray into these locations to get the coverage. Resist that temptation. You should have the bike hung or positioned so you can easily walk around it and bend under it to reach these places.

Use the same sweeping methods as for the tubing. If you sense that you really do need to point and spray, do so in very short bursts from different angles to get the coverage you want.

With each coat, you will get some overspray on the lower parts of the bike that should be cleaned off before the next coat is applied.

This is not quite so critical for primer coats that are going to be rubbed back anyway. But, because this is also a practice run for finish coats, start each new layer of primer at the bottom-most part of the frame where it hangs, and working upwards.

It's a good case for the frame being hung so it is upside down, so the overspray doesn't collect around the tubes at the bottom bracket.

When you have finished a session with a spray can, turn it upside down and press the nozzle to clear the paint from both the nozzle and the tube inside the can. This will help prevent the paint from hardening and making the nozzle useless — recovering a blocked nozzle is almost a lost cause.

A wipeover with a cloth dabbed in acetone or paint thinners also will help stop a build-up of paint around the tiny hole in the nozzle.

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