Urathane drying time???

I kind of question that 10 min on the MAE tech sheet (for unhardened MAE). When used with hardener, the MAE dust free time becomes 30 min (70F) - at least that's what's on the other tech sheet that includes the hardener. I haven't used it so I have no personal experience. I know the Centari acrylic enamel I use with the Ultra Performance Pak (urethane hardener) dries very fast and has a stated dust-free time of 15-20 min (77F). The unhardened Centari is stated to have a dust-free time of 1-1.5 hours. Which is why I question the 10 min for the unhardened MAE. My personal experience with OMNI acrylic urethane (MTK) would bear out the stated 45 min dust-free time and I do think the hardened Centari is faster but I've never actually compared them that closely. I don't think any difference is particularly significant - at least between the Centari and the MTK. Both have quite fast dust-free times.

I suspect no general comparison statements can be made because of different manufacturer's, different lines and different additives being used, resulting in different dry times. For the products I've used, I can't say that acrylic urethane is significantly different than hardened acrylic enamel relative to dust-free times. The non-automotive products may be very different however. Some of the old enamels intended for brush application are very slow dry and a modern automotive acrylic urethane will easily beat the pants off them regarding dry time (and, of course, performance in general).

Rod

The answer is NO. It would bring no benefits and could possibly cause severe problems. You should always use exactly the hardener, reducer or other additives specified by the manufacturer of the paint and indicated on the can label and technical data sheet. Cross-mixing between brands or even between different lines of the same brand for ingredients is always frowned on, even for the same basic chemistry, and can result in problems. Cross-mixing between chemistries can be worse. Don't do it. The cost of good paint products is too high to risk failure by saving a few bucks on generic or "cheaper" ingredients. If you are using automotive paints from a major paint manufacturer and want to get the best product for your money, stay away from the premium lines and concentrate on the economy ones, assuming that precision color match is not a priority. For example, if you are looking at PPG automotive products, look at OMNI MTK for single stage urethane and not Deltron Concept. The cost difference is very significant.

You also cannot directly compare the cost of specific ingredients such as a hardener because of different mix ratios and coverage abilities of the mixed products. The only accurate way to compare costs is on a mixed "ready-to-spray" basis also taking into account the possible differences in coverage between the products being compared. That assumes the comparison is between products of the same basic chemistry. An additional cost consideration is precision color-matching ability if that is a prime requirement - e.g. in collision repair work. Such additional consideration is usually not needed for tractor work.

Rod

You should do fine with Nason. That's DuPont's "economy" line of automotive paints like OMNI is in PPG. While I have never used NASON, I have every reason to believe it will provide excellent value for the money. NASON has two single stage acrylic enamels - Fast-Dry AE that doesn't use a hardener and Ful-Cryl II AE that surprisingly requires one. They both have stated 30 minute dust-free times. On the urethane side, NASON has Ful-Thane AU and it also has a 30 minute stated dust free time. You should get the tech sheets for all products than you are considering using. For NASON, go to the DuPont website here and log in as a visitor. Once the site loads, follow this path:

products>technical information>Nason to yield a listing of all the NASON product tech sheets in pdf format.

Rod

They do have a nice isocyanate FAQ in pdf published here.

I no longer see any reference to Delstar AE. It was still being carried along on the old site but not available in many areas. It may have finally past into history altogether. Really too bad. It was an outstanding acrylic enamel.

Rod