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Hi CNKS, As far as I know, the AU is "supposed" to be better all around than the AE with hardener, although I have never found the AE w/hardener to be poor in any respect. I have quite a bit of experience with AE/h over the years and only a little (more recently) with the AU. The one thing that troubles me a bit with AU - at least the OMNI MTK - is that it seems to result in an extremely brittle film. This is just a passing observation and I have no real proof or careful study of it. It just seems to chip a lot more easily than the AE/h I am more used to. I have noticed this when installing painted bolt and screw heads. I have also noticed it where the hand crank occasionally rubs on the front sheet metal on my AC-B and the paint is actually chipped off in a small area rather than simply rubbed away. I am not sure if this is caused by poor adhesion for some reason or is due to the brittle film. I just have not noticed similar chipping with AE/h. Yes, I think the PPG Delstar AE (which I can't get anymore in my area) is a step up in quality from the OMNI AU (MTK), after having used both. So is DuPont's Centari AE, which is also field-mixable as an AU (no semantic trick here). The Centari is significantly more expensive than the MTK however and I suspect the Delstar is also. Two years ago when I did much of the sheet metal on my AC-B, I used the MTK. I wanted to paint the headlight housings black. I had black in Centari left over from something else so used that instead of getting it in MTK. Noticeable difference in spraying. I think it has a higher solids content than the OMNI, which would explain the higher cost. It also flows out very nicely and is somewhat less susceptible to runs than the OMNI AU. I have had good luck with the MTK (except for that chipping thing) but if I had my druthers, I would use the Delstar or the Centari. I wouldn't be too concerned about the possibility of repair work with AE/h. As long as the hardener is used, it can be sanded and recoated, even machine compounded. It may not be within hours as with the AU but certainly can be done in a few days at reasonable temperatures. I have done it successfully in the past. In other words, for me at least, the possibilty of having to do repair work would not be a deciding factor in moving from AE/h to AU. I think next summer I may try some OMNI AE (MAE) with hardener to see if that is as chip-prone as the MTK. The MAE and the MTK seem to be the only paints that I can get AC persian orange (early shade) in at the present time.  Rod
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