[bug67]

My first paint job went very well (used acrylic).

For my second paint job, since I've heard that urethanes were harder to handle, could I shoot an acrylic color and then shoot SS urethane clear over it?

[willys36@aol.com]

Don't know why they said urethanes are hard to handle. Get all the paint for a specific system and bc/cc urethanes go on like a dream.

If you are determined to cc acrylic, the answer is yes you can. You can clear coat anything w/ urethane. I spray all my model chrome trees with it B4 starting the model build and that seals the chrome from rubbing off like it is prone to do. Solvents in urethane seem pretty mild compared to acrylics and lacquers which will attack a lot of plastics and other paints. Just make sure the acrylic is totally dry before clearing and you must sand the surface w/ 600wet or dry before spraying to insure the clear will adhere properly. Incompatibilities between the solvents can really mess up the job if you spray before the acrylic is dry. Don't ask how I know that.

[cyclopsblown34]

I was told years ago, you can urethane clear over acrylic, just don't use the hardener in the acrylic. This was by a benchtop chemist who had been painting for several years and had turned out some nice looking work. I just wasn't brazen enough to try it. I try to use the same system from etching primer to clearcoat.

[bug67]

Thanks a lot!

[BarryK]

Originally Posted by cyclopsblown34

I was told years ago, you can urethane clear over acrylic, just don't use the hardener in the acrylic. This was by a benchtop chemist who had been painting for several years and had turned out some nice looking work. I just wasn't brazen enough to try it. I try to use the same system from etching primer to clearcoat.

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Anytime you plan on using a urethane clear over either an Enamel or an Acrylic Enamel you must activate the enamel to the manufacturers recommendations. Most enamels are 8:1 and if that is your case you must activate.

A common rule is you can then spray your clear in 4-6 hours, however you are always further ahead if you let the enamel set overnight and then clear it in the morning just to be safe.

Reason for this extra caution is enamel activators are not all created equal and the content of ISO's in that pint can can range from 35% to as high as 80% depending on brand and type be it for spot repair or allover use.
DFX80 and 793, (PPG and Dupont) are some of the best at about 76-80% for those numbers. Worth the money to put those in any enamel system as the activator is the most important part for durability, gloss and long term hold out.

[cyclopsblown34]

I never had the cojones to try that, so I just used Chromabase and Chromaclear. If I sprayed Centari, I used the Centari Performance Pack. I sprayed a couple of lacquer paint jobs and then found base/clear and never looked back at least on my own stuff. I did use Centari single stage on friends vehicles though.