In the Shop

Motorcycle Painting Part 2 of 3

By Bob Wark

(Note: You may use this article on your Website, but it must inlude the following - This article was written by Bob Wark. It is not intended to be a tutorial, rather an overview of the process. You may contact the author at The Warkshop - 740-374-4250 - or at his Website: www.warkshop.com)

The most time consuming, labor intensive part of a good paint job.

Important Note: Just in case you were wondering, this is NOT a "how-to" series! Without the proper equipment and know-how, this is dangerous work. Toxic, flammable, and potentially explosive chemicals should not be sprayed around just anywhere! I have heard too many stories of guys painting in their garage when the hot water heater (also in the garage) ignites the paint fumes ... BOOM! Do not take the risk of shortening your life or your family's life from inhaling this stuff or burning your house down! Sorry to bug you about this but please ... for your own safety "DO NOT TRY THIS AT HOME!"



If the factory paint is not cracked or softened and still has good integrity, it can be painted over. Any prior re-paint will be grounds for stripping at least down to the factory finish and generally all the way, Aircraft stripper is a good start for metal parts. Care must be exercised with ABS plastic and fiberglass parts as they can absorb the stripper. Stripper is very toxic and will burn the eyes, skin, and lungs! Also it is not real environmentally friendly. Proper safety gear as well as correct disposal techniques are a must. Sandblasting is the next step to get all the old paint off. The above cautions about stripper also apply here. Like your Mom said about the BB gun, "You cold put your eye out with that thing!" Metal parts, ABS, and 'glass' parts can all be worked with the blaster, but different air pressure and blasting medium are required for each material. Blasting can easily ruin any part so great care must always be used.

Next, all parts are sanded to smooth out the surface, then they are thoroughly cleaned and dried.

Thank goodness we have this step done!



Wow! Look at all that bondo in that once nice tank! Stress cracks in those 'glass' fenders!

This damage, being under the paint, is often unknown to the bike's owner. I expect to find a certain amount of this and factor it in when estimating. Excessive hidden damage is extra money.

All old filler (bondo) must be removed, then bodywork re-done. Cracks in 'glass' must be ground and filled, either with cloth and resin, or fiberglass filler. If this step is not correctly done, the cracks will re-appear down the road. Sometimes cracks are caused by improper mounting or bent mounting brackets. The painter, of course, can not do much about that. Just be sure upon re-assembly that nothing is under stress and that all rubber bushings are sound. It is impossible for me to describe how I work parts to remove flaws (dents, cracks, repairs): Regardless of what countless how-to articles say, it is a skill that takes lots of practice, not to mention knowledge of all the materials involved. That is if you want it to look professional! After paint, any repairs should be absolutely undetectable with the finish as good or better than factory! Blah, Blah, Blah! Don't I babble on!

Cracks in gas tanks or steel fenders are gas welded using a small tip, then hammered to relieve stress. (The steels not mine! Ha!) While there is a wire welder in the shop, I do not like to use it a lot except for welding up unwanted holes. Heat control and warpage avoidance is trickier with gas, but excellent control of the weld penetration makes it worth the effort. Also, less grinding is needed saving time.



All parts must be clean and dry. Also the shop temperature must be consistently warm. If the temperature is allowed to drop to much at night, your primer will be cold... very bad! Warm parts and cold primer do not make for good companions! Warm parts, primer, and air are all very important, as is dryness. One result of this is that Mr. Painter usually has a pretty hefty natural gas bill! Just one of the costs which are unavoidable when top quality is the goal. Only the best urethane primers should be used. They are dramatically superior to any lacquer products. The cost is higher but increased longevity of the job makes it money well spent. All metal parts should have a light coat of a 'wash' primer. Often this is a zinc chromate rich epoxy or vinyl material.

Three or sometimes four coats of primer are sufficient for 'filling' the surface. If parts have had a lot of work done on them, a first sanding with 280 or 320 grit wet paper should smooth things out and maybe show some pin holes or other small flaws. Clean, dry, then more primer. Finally finish sand with 600 wet to what should now be a flawless finish. Some parts with no repair work won't need but one priming, then the 600.

Note: With urethane materials, it is recommended you paint SOON after sanding for best adhesion. Waiting too long lessens the chemical bond.... Now why would we want to do that?

Next time we will talk about actual painting and 'buff-out'. Read On!


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The Warkshop, Painter Bob Wark, 1955 County Road 9, Marietta, OH 45750 - (740) 538-4746

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