7 in the morning and I'm out behind work spray-bombing the fork on a sample bike so we can use it in a video. Who needs coffee when you have paint fumes?
If I want to use a rattle can to spray paint my frame black (currently white), should I strip the old paint and spray the raw aluminum, or just spray over the old paint? Advantages/disadvantages?
If I want to use a rattle can to spray paint my frame black (currently white), should I strip the old paint and spray the raw aluminum, or just spray over the old paint? Advantages/disadvantages?
Sand the old paint with 100 grit sand paper. Use a coat of primer then color coat. Stock paint is usualy quite durable. If there are deep nicks and scrathes in the original paint these may show up. Thus the primer coat. Sanding the paint is to give the new paint a good grab on the frame.
If I want to use a rattle can to spray paint my frame black (currently white), should I strip the old paint and spray the raw aluminum, or just spray over the old paint? Advantages/disadvantages?
Sand the old paint with 100 grit sand paper. Use a coat of primer then color coat. Stock paint is usualy quite durable. If there are deep nicks and scrathes in the original paint these may show up. Thus the primer coat. Sanding the paint is to give the new paint a good grab on the frame.
So sanding it is preferable to using paint stripper and going down to bare aluminum?
I'll give a quick nitty gritty rundown of proper SOP of a paint job.
If the current condition of the bike is ok (no big gouge or scratches) then sand with 400 grit sandpaper and apply new color on top in either single stage (directly glossy color) or basecoat-clearcoat. Anything courser sanding than that will likely show the sanding scratches through the paint. Always apply lighter coats to start as opposed to big heavy wet coats.
If the bike does have some imperfections, sand with 220 grit. Fill big imperfections with body filler or glazing putty and sand smooth with 320 grit. Apply 2 to 3 light coats of primer and sand with 320 then 400. Then paint. Again, lighter coats preferable to big heavy wet coats. The worst thing you can do is to rush a paint job. All of these steps will take some time in between, and the more steps required to fix imperfections will mean a much longer time until the job is finished. Using a wax and grease remover to wipe on and dry off between steps is greatly preferred, as is a tack cloth to remove any last dust/dirt before each step.
Saved an old Hardrock frame destined for the dump as I already had extra parts for it. Sanded it, primered, layed a Rustoleum 2X Gloss White rattle can base, went to town with some paint pens, and clear coat protected with two-part rattle can 2K Max Clear Gloss. Glass hard cured. Assemebled and done.