I use a 50/50 mix of Acetone/Naphtha, when the temp is in the mid 60's to mid 70's. Just as the primer can says, acetone works great to reduce for general spraying. To accelerate the drying time Japan drier can be added. The recommendations on the Japan drier can should be followed to prevent wrinkling. I have also had very good luck using a synthetic enamel hardener with this primer. It drastically cuts down the drying time, and allows the top coat to be applied that same day. I red scotchbrite the surface before top coat. I have had great luck with the tractor supply hardener. Mix at 8:1, or 1 gallon of primer to 16oz. (pint) can of hardener. Remember the ratio can be explained as 128oz (gal. primer) divided by the 16oz. (pint hardener) this gives you 8 as in 8 parts primer/ 1 part hardener. Or 32oz. (quart) to 4oz. hardener.
Either the primer by itself, the primer with a splash of the Japan drier, or the primer with the hardener all work very well. The Rustoleum primer sold at home depot does not contain any fish oil. Although, Rustoleum does offer a primer with this added ingredient. This is just a good old quality medium alkyd resin with added oil most recently refined soy bean oil (Soya). If you are planning to brush this on then at the most I would use the Japan drier. The hardener will just make a mess if you are not familiar with the product. Also the 8:1 ratio is only relevant to the hardener. This does not mean that a recommended primer to reducer ratio does not exist. It all depends on your spray gun, the surface temp, and the surface being coated. As with any painting the more you clean down the surface the better it will hold down. I have been a painter for more than 18 years, and have worked with and applied a wide variety of finishes. You always get back exactly what you put in to it and onto it.
Either the primer by itself, the primer with a splash of the Japan drier, or the primer with the hardener all work very well. The Rustoleum primer sold at home depot does not contain any fish oil. Although, Rustoleum does offer a primer with this added ingredient. This is just a good old quality medium alkyd resin with added oil most recently refined soy bean oil (Soya). If you are planning to brush this on then at the most I would use the Japan drier. The hardener will just make a mess if you are not familiar with the product. Also the 8:1 ratio is only relevant to the hardener. This does not mean that a recommended primer to reducer ratio does not exist. It all depends on your spray gun, the surface temp, and the surface being coated. As with any painting the more you clean down the surface the better it will hold down. I have been a painter for more than 18 years, and have worked with and applied a wide variety of finishes. You always get back exactly what you put in to it and onto it.