Hi Ken, If you have a fresh air respirator, then by all means use a hardener in an enamel or use a urethane paint. The durability and chemical resistance (think gasoline spills) is much better with such paints. Plus the possibility of quick repairs of any errors (yes, they do occur, even with the best of painters) make the use of hardened paint worthwhile - but only if you can use such materials safely - with a fresh air respirator. There are many different possibilities for equally good paint choices and "systems". I say systems because I think it best you select one such system from a single manufacturer and stay within the products of that system for all components - e.g primers, surfacers, hardeners, reducers and topcoats. Unless price is no object, there usually has to be some compromise in the issue of price vs quality/performance. Everyone has their own idea of where that compromise occurs. Mine happens to be with an "economy" or "value" line of an automotive paint for use on overalls such as tractors. I happen to use PPG's OMNI line in acrylic urethane because I have used PPG products for quite a while and have been satisfied with them. They are also readily available locally. That is not to say that other similar lines such as DuPont's NASON or NAPA's Martin Senour "value" line equivalent is inferior. I just haven't used them. They are competitors and I have no doubt that they are of similar cost and quality to the OMNI. My personal preference for a primer is a two part epoxy, such as PPG OMNI MP170. For a surfacer on sheetmetal it would be OMNI MP182. For the topcoat it would be OMNI MTK acrylic urethane. Other manufacturers provide similar products. Note that the MP182 and the MTK are urethane products that require an isocyanate additive (hardener/activator/catalyst, whatever). The additive is what makes a fresh air respirator necessary. The additive for the epoxy does not contain isocyanates and therefore a chemical cartridge respirator is satisfactory for that product. If you are interested, check out the on-line Manufacturer's Safety Data Sheets (MSDS) for all ingredients of any paint mix for the proper respiratory protection. Any thing that contains "diisocyanate" or anything similar is a dead giveaway for the need of fresh air protection. This info is readily available from all the key auto paint companies. I would use the epoxy primer over everything - bare metal as well as any old paint, provided all have been cleaned and properly sanded. I would use the surfacer on the sheet metal to fill any sandscratches left over from sanding. On sheetmetal a final sand of the surfacer with 220 then 400 grit. Then a final cleaning wipe with a specialized cleaner such as PPG's DX330. For the sheetmetal do a quick swipe with a special tack cloth to catch any remaining dust particles and then spray the topcoat. Get technical data sheets for all the products you are going to use well before any purchase and study them as to compatible products and usage. Do not rely on the salesman's word of mouth. Talk is cheap. The best and most reliable usage information is in writing from the manufacturer. These data sheets are available on-line from all the large automotive paint companies so they are readily available. Don't worry about sounding like a complete idiot. If you study the tech sheets beforehand you likely will be more knowledgeable about the products than the salesman is. Be in a position to tell him exactly what you want to buy - not necessarily what he might be offering to sell you. Of the three jobbers I can purchase paint from, only one of the three "salesmen" do I trust to give me good information and advice. Same goes for safety measures. That's not a good track record. Be forewarned. I assume in all this that you are not thinking of any metallic type of finish or trying to match a panel repair on a fairly new automobile. The situation there would be quite different. One suggestion. Once you have settled in on a line of materials, do a little practice painting (using all of 'em) on some junk sheetmetal before tackling the tractor. It will be time well spent. I always do a sample sprayout when I use a different paint product. I don't like surprises and it's a great confidence builder. Rod
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