Join Date: Mar 2001
Location: Suisun City, CA
PPG's DPLF is a VOC compliant successor to their DP. Both products are an epoxy primer with self-etching properties claimed by PPG, although others debate the self-etching ability of these products.
The PPG tech sheet on this product describes it as a primer. The tech sheet states that ALTERNATIVELY, the product can be thinned and used as a sealer. PPG sells a different product specifically manufactured as a sealer. I've used a system of, successively, DPLF epoxy primer, NCX 280 primer surfacer, PPG sealer (forget the product code), DBU base coat, 2002 clear coat (all products from the PPG line of products).
For body fillers I use all-metal or metal-to-metal when repairing immediately after working the body dollies to smooth out a dent or pound down a high spot, followed by Evercoat brand fillers - standard lightweight filler followed by a polyester glaze type filler to fill pinholes and laydown a microfine, smooth working surface.
The DPLF can be sprayed and either base coat or NCP 270/280/285 primer surfacer can be painted over it any time up to one week from application of the DPLF - per the PPG spec sheet. If the DPLF is left uncoated longer than one week, it is to be sanded, a new coat of DPLF applied, then it can be painted over with base coat/primer surfacers.
Basically, any PPG primer can be sanded, although my PPG dealer says dry sand, not wet sand. One of the beauties of the primer is that runs, sags, drips, and debris can be sanded out. I've actually block sanded over the DPLF, prior to laying down filler, then more DPLF, then primer surfacer, then more block sanding, filling etc. I've used the DPLF as a sealer and I've also used PPG's specifically formulated sealer.
I have to reluctantly and respectfully disagree with your characterization of DPLF as a sealer and not a primer, and the conclusion that it is not to be sanded. On the other hand, perhaps I misunderstood your parenthetical. Thanks for your comments and support.
Rebuilding a classic mustang is a reality check on your individual state of perfection.