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Paul, "I have parts primed with 182 that have been sitting on the shelf for anywhere from 1 to 6 months. Does 182 have a recoat window like epoxy primer?" No, there is no recoat window. "Should I Scotchbrite them before topcoating?" No. Just sand with 400 or finer grit prior to topcoat if you haven't already done so. You should also do a final cleaning with DX330 or equal and tack rag off immediately before topcoating. "Should I apply a fresh coat of 182 after Scotchbrite and then topcoat?" No need to apply additional 182 if the surface is nice and smooth. As noted above, my preference at this point would be the 400grit paper instead of Scotchbrite (for sheetmetal, not castings). "I'm planning on OMNI urethane (solid coat, not clear)with hardener for the topcoat. So I don't make a similar novice mistake when I go in to buy the paint and hardener, what topcoat products should I be getting?" The OMNI single stage urethane is called OMNI MTK. If your code (color) number is XXXXX, then you want OMNI MTK XXXXX. It requires the hardener. Unlike the MAE enamel, it cannot be used without it, since it would not cure properly. There are three different hardeners and four different reducers to be used, depending on the temperature at time of application. See the tech sheet here. The tech sheet doesn't give you actual temperature ranges. Here's my own interpretation:
MH167 - Fast Hardener - 60-75 deg F
MH168 - Slow Hardener - 70-85 deg F
MH169 - Very Slow Hardener - 80-95 deg F
MR185 - Fast Reducer - 60-70 deg F
MR186 - Medium Reducer - 70-80 deg F
MR187 - Slow Reducer - 80-90 deg F
MR188 - Very Slow Reducer - 90+ deg F "Do you typically use a smaller orifice set (HVLP) with topcoat vs primer (182)?" Either CNKS or Butch or someone else can help you out here better than I. I think the answer is probably yes, providing you are talking the 182 surfacer rather than a straight primer like the 170 epoxy...however, I am not a fan of HVLP and have no experience with using different tip sizes. The couple of times I used the 182 without a pressure-fed gun I had to use the same tip size as used for the topcoat. It worked but was not as fast or as good as what a larger tip would have provided. I suspect one tip size larger would have been better.  Rod
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