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

The Cycling Adventurer
How To...	Paint a Bike Frame — Step 3

How-To...

Remove the old finish — or do you have to?

Sanding back the original paintwork on the frame might seems a good starting point. But first, any decals have to come off.

This has become more difficult on modern bikes, many of which have a clear coat over the top of the graphics, so they have to be sanded off. With older bikes, the plastic backing on which the decals were printed, or the lettering itself, can be "peeled" off. But the task is messier and more difficult than it first appears — those promotional bits and pieces were made to stick for a long time!

Heating with a hairdryer can help, but really, I have found acetone (in the form of nail polish remover) and mineral turpentine have been the most useful chemical combattants... plus a blunt knife!

Acetone can also be bought in bulk at hardware stores, either in the paint section, or where the fibreglass supplies are kept. It's highly volatile, so use it with caution — avoid inhaling it, don't smoke around it, and don't run exposed element heaters when you use it.

As nail polish remover, acetone is designed to lift paint off very easily, especially newly applied stuff, so put it and any rags away when you start painting the frame.

There is nothing particularly difficult about assessing the old paint finish. If the original paint is in reasonably good shape, sand down the scratches and chips to the primer or bare metal, a touch of rust coverter to any corrosion on steel bikes, and an all-over light sanding with a fine paper such as 1200 grit might suffice before applying the primer coats.

It is important to do the all-over rubdown on most gloss paints so they are smooth to touch, but appear to the eye to be dull or matt. The very, very fine scratches which cause the dull appearance provide the primer coat with an anchor or keyed surface so it actually does stick. Remember this later, too, when rubbing down between primers and finish coats.

Just about all sanding should be done with wet-and-dry paper... when it is wet. Squirt a small amount of dish-washing detergent into a half-full bucket of water, and you will find the paper runs more smoothly over the old paint, and you won't breath in nasty paint dust. Don't use a sanding block — it can cause "flatting" of the surfacing.

For the tricycle project, I could not be bothered with the water lubrication. The frame was only small, and the finish wasn't overwhelmingly critical. But the primer dust did clog the fine sandpaper.

You may have to improvise to get into sharp angles and strip the paint from around the bottom bracket and headtube, but be patient and pay attention to these areas.

After washing and provided the metal is dried off immediately, there should be no concern with surface oxidation before a primer is applied (which should be as soon as possible after the frame prep).

Aluminium is a little softer than steel, so care is needed not to scour into the metal's surface.

You should include the fork in your assessments. The drop-outs (on the rear triangle as well) will need some work because paint is often chipped off when the axles are dropped in or removed or the quick-release tightened.

The tricycle's seat needs very little work because of the solid coat of paint already on it. The nicks and scars just need rubbing back to remove rust and to
feather the paint edges.

Likewise, the fork needs little work
before the primer coat. It was the
main component in best condition
on the tricycle.

Any work required to straighted or align drop-outs, or cold-set the stays on a steel frame should be done now. Likewise, if you want tabs brazed on, holes drilled in the dropouts for eyelets, or Rivnuts inserted for additional drink bottle cages or rack attachments... this is your last chance to have the work done.

Top of Page

How-To...