I cannot recommend recoating MAE at all until it is fully cured since PPG indicates there is no safe recoat period. I am assuming by "recoat period" you mean some period after the initial dry of your topcoats. Your coats should all be done at the same time with flash time (measured in minutes) between them as indicated in the tech sheet CNKS linked for you. After the initial dry and before final cure, many enamels used w/o hardeners are in a sensitive state that can wrinkle and lift when recoated due to the solvents present in the recoat. The time for the film to fully cure is undefined and could be weeks or months later. I suspect it is highly temperature dependent. The recoating of MAE w/o hardener is not addressed in the PPG tech sheet for it. I had asked PPG technical service (via their web site) about the matter a couple of years ago. What follows is my question to them and their answer.
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Comment/Problem Description:
What is the safe recoat period for OMNI MAE acrylic enamel (w/o hardener)?
There is nothing to indicate any recoat sensitive period in the tech
sheet. It used to be that uncatalyzed enamels were sensitive to lifting
upon recoating after a short dry time and before full curing perhaps
months later. I have noticed that DuPont's NASON FastDry acrylic enamel
(uncatalyzed) indicates recoating after 48 hours. Can MAE (w/o hardener)
be similarly recoated without danger of lifting?Thanks,
Rod Thompson
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Rodney, Thank you for your interest in PPG products. There is no safe recoat period for uncatalyzed MAE. We do not have any recommendations for recoating uncatalyzed MAE. The best recommendation would be to put a waterborne primer over the uncatalyzed MAE and then recoat with MAE, still there is no guarantee it will not lift. If further assistance is required, please contact us at the Technical Service number listed below. We have established an automated faxing system that allows you to fax
yourself product bulletins 24 hours a day. The PPG FaxBack number
is 800-450-2654. If you order document number 24747 from our FaxBack system, this document provides the instructions on how to use the system and the indexes that are available. PPG Technical Service office is open Monday - Friday, 8:00-6:00 EST. This office can be reached at 440-572-6111 or FAX 440-572-6772. The
E-mail address is - reftechserv@PPG.com. You can also find us on the web at www.ppgrefinish.com Before using any PPG Refinish products, be sure you understand the
warning messages on the labels of all components, since the mixture
will have the hazards of all it's parts. Spray equipment must be
handled with due care and in accordance with manufacturer's
recommendations. Spraying of any material can be hazardous. PPG
recommends the use of a fresh air supplied respirator with the use of
any of our products. PPG REFINISH MATERIALS ARE DESIGNED FOR
APPLICATION BY PROFESSIONAL, TRAINED PERSONNEL USING PROPER EQUIPMENT
UNDER CONTROLLED CONDITIONS, AND IS NOT INTENDED FOR SALE TO THE
GENERAL PUBLIC. Technical Service/LS
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