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

The Cycling Adventurer
How To...	Paint a Bike Frame — Step 5

Setting up for spraying

Cleanliness is supposed to be next to godliness, and it certainly applies to painting if you want a quality finish.

First of all, the area you intend to use for painting should be clean and free of dust and drafts that can pick up overspray and blow it back on to the frame. An extractor fan on the opposite side from which most of your spraying will be done is a good idea.

If you have a limited area and you think overspray might get on things in your workshop/living room/shed, then set up a "booth" made of plastic sheet suspended from the ceiling or at least covering valuable items.

If you intend to spray in winter, get a heater going to bring the air up to what you would consider comfortable room temperature. Do not use fan or element heaters because of the thinners. Oil-filled column heaters are best.

Paint does not set, cure or dry quickly in cold weather — everything slows down. I remember in my car modelling days that placing a can of spray paint in warm water was advised to improve the "run" of the paint through the nozzle.

It's not something I do now, but for the trike project, done in workshop temperatures close to freezing, the frame and paint were left inside the warm house until the last moment; the frame then was brought back inside after being sprayed to hang and dry in an inconspicuous corner.

You need to consider how you are going to support the bike as you spray it. The best way is to insert a dowel in the headtube and fix the dowel in a stand so the frame is at least at face level.

Not many of us have access to such an arrangement, so the next best (and really only effective) way is to suspend it from the ceiling. The one problem that remains with this is that the frame is likely to rotate as the paint spray hits it.

A handle fashioned from a coathanger and placed through the bottom bracket to the ends are well up the vent holes for the down and seat tubes will help keep your fingers away from the frame itself.

Make sure that you have room to walk around the frame, and that it is at a height so you don't have to bend too far to get the spray on to tubing that faces the ground. If you have to bend too far, you aren't concentrating on aiming the spray at the right places, and your passes are likely to be too short.

Once you have all that organised... take down the frame because you've got more work to do on it.

Your frame has to be meticulously cleaned. Use soapy water to wash it down and rinse off with clean water. You don't need to drench the frame, or else you will be waiting for water to finish dripping out of the vent holes in the chainstays and seat stays.

You can use a cloth lightly soaked in a solvent such as methylated spirits or acetone if you wish to do the cleaning or to speed drying of the water.

Essentially you are trying to remove all traces of dust, so a lint-free cloth is required. Pay special attention again to nooks and crannies, and the corners and edges of lugs.

Carefully inspect, too, all areas above your worksite. I made a mistake in setting up the tubing from which to hang the trike — there was some gaffer tape on the end and the adhesive had dried off so that every time I touched it, small flecks fell off and onto the paintwork below it.

You should wear rubber gloves to do the final clean so you don't get any grease or sweat on the frame that can cause the finish coats to bubble or distort. Use a clean cloth on the workbench to sit the frame while you do any masking and make a final inspection.

The main frame of the trike hanging from a length of chromed tubing wedged under some weighy boxes
on a shelf. The frame is about the right height to
get at all the bits. I held the axles to keep the
frame steady while I painted. The galvanised
"headset" has been masked with tape.

Components such as bottom bracket cups and spindle, and the headset races, don't all need to be taken off the frame. It does help though — masking these items with tape is not something I have been very good at doing because of the curves. Removal of the components makes the task easier, because you just bypass the masking process.

But if for some reason, you don't remove those components and you wish to keep using them, carefully mask; it's probably better to leave the masking tape shy of the frame so you get a bit of overspray on the parts, and this can be carefully removed later by scraping. If you overmask, you have to deal with bare metal being exposed on the frame itself, the possibility of corrosion, and a tatty appearance.

A better idea is to insert old bottom bracket cups so that the threads are protected from overspray and there is no need to mask off this area. However, the fixed cup on the right side (the chainring side) should be screwed in only a couple of turns (anticlockwise) so the paint gets to cover the vertical surfaces of the BB shell.

If you don't have BB cups, another method to mask is to roll up some A4 sheets of paper into a tube and insert them into the BB, the seat tube and the head tube. They tend to uncurl to stay in place and provide full protection of the insides of each tube and the BB threads, yet allow full paint coverage around the external edges.

Now, having masked off everything you need to, hang the bike back up on your stand or from the ceiling, turn on the heater (if the ambient temperature is low) and go have a coffee.

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