Right now I'm using the Magic isocyonite harder found at Tractor supply. Van Sickle hardener does well also as it too is an isocyonite hardener. BASF has hardeners that mix well and as far as reducers go I stopped cutting with acetone. Xylol is a bit slow, but I have reduced with it while spraying outside in the sun. Acetone will sometimes flash off too rapidly for my liking and I have had inconsistent results depending on ambient temperature. Rustoleum's Specialty Reducer is my preference and Auto Zone is the only place I know of that carries it. At work we don't have an account with AZ so I often reduce with a medium urethane or xylol in a pinch. Toluene I have had better luck with over xylol indoors, but yet again I have to generally go to another vendor that my employer has an account with for toluene. 4:1:2 is a good mix to start with and adjust from there. My work truck has 2 coats of white Monstaliner bedliner with a couple coats of Rustoleum flat white and SpedoKote urethane clear over that for a bit of UV protection. It's a decent hard paint job. I'll use Rustoleum with a hardener for random interior applications. Flat black with hardener gets almost a satin sheen to it, but if it sees sunlight it will flatten out in a few months time without a decent automotive clear. Many farmers and ranchers add a hardner to their enamel for added durability so the concept isn't anything new. The big thing is you need to stick with an isocyonite hardener. There are isocyonite clear coat hardeners that don't react well with Rustoleum so I would advise seeking your hardener from a farm/ranch supply as this product is generally made to be added to a cost effective paint. I treat gloss Rustoleum like a single stage paint and flats can be used as a base coat. Finish 1 makes a satin clear and I have used U-Pol' satin clear as well. Never over Rustoleum, but if someone were trying to spray something satin-ish black and then wanted to stick said object out in the sun a satin clear might be an option. Then again you could very well end up with more of a semi gloss finish. For matte or satin black finishes Summit Racing carries hod rod paint that costs a bit more than Rustoleum, but is probably the better way to go in the long run. I'm a steel fabricator by day and my automotive paint background is mostly self taught. Rustoleum with a hardener is great for things like bollards and railing when a gloss finish is appropriate. It's the first paint I think of for trailer frames, ratty vehicles and equipment. You'll save a small fortune compared to rattle cans. I've found that you need to have reasonable expectations of this paint. Sometimes it's best to budget for automotive paints or an industrial system formulated to stick to like products. I happen to have certain products on hand, so I might decide to scoop up a $15-$20 quart of oil based paint and pour a little hardener in it because it makes sense. There are plenty of good single stage automotive paints that are affordable as well as industrial products with or without a catalyst. Last thing I will add that I keep forgetting is the Krylon Tough Coat paint works the same. I have gotten that stuff tinted in a satin base and sprayed a bunch of restroom stalls with it. I think on that I cut the hardener down to about half a part and reduced by eye. The stalls came out really nice. Much nicer than seeing the stipple from a roller.
