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CNKS
03-03-2004 19:04:36
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Re: PAINT PROCESS CONFUSION in reply to PWB, 03-03-2004 13:32:29
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Everyone has their own opinion, often based on their own experience, which is fine. If you do a good job, your tractor will look BETTER than it di in 1935 because the paints are better. I will give you my suggestions, and others can give you theirs. If you are using PPG, get copies of their spec sheets (P-sheets) and follow the instructions to the letter -- they will tell you the proper ratios, how much reducer, etc, you don't need to guess. On the cast (the numbers are for Omni, if you use delstar or whatever, use the compatible products on the p-sheets)--MP 170 epoxy primer, followed by MTK acrylic urethane or MAE acrylic enamel. Same thing on the sheet metal except use MP 182 surfacer over the 170. It can be sanded smooth and applied 2 or 3 times to cover minor imperfections. Do your sanding on the 182, not the 170. Then MTK or MAE -- Simple (until you try it). I use two coats of 170, 2-4 of 182 and 3 of MTK. The spec sheet says one coat of 170, No paint or primer I have seen will cover in one coat -- due to my lousy technique. Other comments: I have not as yet tried clear coating, as I don't believe it to be necessary, I reserve the right to change my mind if I do try it. Forget synthetic enamel, it is old paint technology, it is used because it is cheaper (not that much), acrylic enamel and acrylic urethane are better and do not fade as rapidly as synthetic enamel. Others may disagree, but I see no reason for self etching primer, particularly if you have sand blasted. I do use a phosphoric acid/zinc product for rust protection (it also etches the metal) on bare metal called Picklex 20 -- a thread about this and other products is below. I use it primarly so that I don't have to prime each piece as I do them. Lacquer primer-surfacer does not use hardener, and can shrink into sanding scratches, the hardened surfacer most likely won't shrink, at least not as much as the lacquer version. The scratches often do not show until after you have applied the topcoat. Do NOT use either of these on bare metal, as adhesion will not be as good as with epoxy primer. Always use epoxy first. Hardener makes the paint flow out better, and adds gloss, and the finish is more resistant to gasoline, etc. Hardened paint cures rapidly by chemical reaction, in only a few days. Unhardened paint cures as the solvents evaporate, may take 3 or 4 months. My opinion, others can expand as they see fit.
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