If that is what it says in the tech sheets that is right. When it says something to the effect of "maximum allowable dry before topcoating" or "Dry to top coat", Or "dry to sand or topcoat" That is the terminoloy they may use. Then there is usually a note such as "Must be sanded and recoated after XX hours" or "Must be recoated after XX hours before top coat or other undercoats can be applied"
I tell you this because sometimes the language is not always clear.
Sometimes they are very clear "If XXXX is not top coated within XX hours, it must be sanded" that sort of thing.
There are many products like etch primers, epoxies, urethane primer/sealers and even basecoat colors that have a window of even a week. While other VERY similar products may have a very strict recoat window of as short as 4 hours!!
So it is very important to follow these recommendations for the product YOU are using not what someone says because they used something similar.
Buy the way, I use to sell a lot of product to fleets. Tractor trailer, fleets of all kinds. Including national accounts like COKE and UPS. The systems that were used on these fleets were all none sanding systems. Etch primer over bare metal, epoxy or urethane primer/sealer and then urethane top coat, not sanding what so ever.
In fact, I gained a lot of accounts because I simply showed them a way to paint in less time with BETTER results. I had one account that they had been sandblasting equipment like "blades" (commonly called "graders") then priming them with lacquer primer (
) then painting IMRON polyurethane (very expensive) top coat. They were SANDING THESE HUGE PEICES OF EQUIPMENT after the lacquer primer !!
They were thrilled with the SYSTEMS I had to offer them. The funny thing is thier DuPont rep could have taught them the same thing using DuPont systems if he had taken the time. But I got the account because I went in there and showed them. Etch primer, epoxy primer, then a urehtane top coat. No sanding, the products total cost was almost the same because IMRON was so high. And best of all the labor was WAY,
WAY less to do it. They ended up with a FAR superior product which meant they didn't have to paint the trucks as often (this particular place is on a coastal town and the shop was about 200 yards from the ocean!) and that saved money.
I also had companies who manufactured hundred thousand dollar pieces of equipment like machines to manufacture auto componants or that sort of thing. These pieces of equipment were painted the same way. But the epoxy was skipped. It was simply etch primed and then top coated, no sanding. You can't do this will all etch primers, but, again, if you read the tech sheets you find out what you can do.
I only go thru these stories to show you that this is something that is done all over the country and is recommended by the manufactures of the paint to do so.
