It might hold out for a while, but the P sheet recomends; " For best adhesion and corrosion resistance, treat all bare metal areas larger than a quarter in diameter with a self-etch or epoxy primer prior to the application of DURA BUILD.: I follow the P sheets. My stuff doesn't fail.
Jus' so ya know, acrylic lacquer primer offers less than zero corrosion protection It always shrank like a motha, and if you didn't seal it prior to goin to your top coat, would sandscratch swell badly On the plus side it wasn't no $175.00 a gallon, you could build it fast, and it had good bite over an old finish. " Meanwhyle, back aboard The Tainted Pork "
I can just hear the collective "The sky is falling", but I use it all the time and like it. Never had adhesion problems. I leave it in a cheap gun and use it for weeks. Its inexpensive and no two part hassle. I like the smell of it too!
Old Old technology. There are so many shop line lower priced quality materials out there that is a shame to use old lacquer primer. If you don't have the facilities or equipment,you an actually roll on your first coat. It just takes a little more effort to work with it. Some of your high volume body shops,not quickie cheap paint jobs,but full fledged production shops prime that very way on 5 or 6 cars at one time. It helps save on a lot of masking and wrapping for the first coat.
I use red oxide dura build mixed piss thin as guide coat. Use a good epoxy primer on really clean metal, you will never be unhappy with it.
Back in the day, that's what we used and it worked. Though it isn't as good as today's etch/epoxy/urethane for adhesion, build or chemical resistance. Cars were done with it for probably 30-40 years. Today I'd definately use a better system than a lacquer primer, even under lacquer paint. For example on an old style custom, whose owner wanted black nitrocellulose, I still used HOK's epoxy primer all the way up until paint. That worked very well.
Though corrosion inhibiting pigmentation can be employed in undercoats, it is safest to assume that metals must be chemically clean and stable then coated with a good bonding non reactive primer. Adhesion and a stable substrate is paramount while corrosion inhibiting pigments will not make up for improper preparation. I decided to evaluate Durabuild primer in the 1990s and as far as I can tell it is still basically the same. Its adhesion is excellent on treated or untreated steel or aluminum. It sands extremely easily,builds well,and most topcoats bond well to it. I recommend a test panel of the same products to be used on the car to evaluate adhesion. I only prime untreated areas of the car that were previously treated then sanded through and not contaminated or left exposed for over a day. In primers of this catagory this one excels in adhesion, as good as you are likely to find and better than many. I find in tests the primer will tear apart without releasing from the surface or topcoat. The primer is porous which I am sure speeds the release of solvents and makes it sandable very quickly,but getting the primer wet or contaminated with a water soluble soil is to be avoided. Avoid wet sanding. Allow wax and grease removers to fully evaporate before continuing. Do not allow primed metal to stay outside if only Durabuild is used. Use only if project can be completed inside once started. It can be softened by the topcoats but if steel is kept to a 80 DA finish or finer and body filler,putties and primer blocking is kept to 180 grit or finer the sandscratch amplification is very minimal. Activated 2K primers vary widely in quality. While most will not soften and move like a lacquer will, some have very poor structural integrity and will pull apart as easily as lacquer. The best 2Ks will provide near factory coating toughness. There are reasons I would use Durabuild. It eliminates exposure to hardeners,a valid concern. Ventilation control is less critical for health and safety, guns don't need to be cleaned several times a day,exposing the painter to cleaning solvents. It is very user friendly and can be sanded very quickly. It eliminates loss of product from activating more than needed. Overspray is easy to deal with in a home shop environment. I would not use it under $500 a gallon paint, balance it roughly with topcoat performance. The best system I used Durabuild with was coated with a 1k sealer,then old DBU basecoat and cleared on a police car and it provided years of service without issue. It can be used over bare steel or aluminum if metal is chemically stable but will not shield the metal if the paint is compromised. Resistance to chipping is poor compared with say K-36 and a K-36 compatable topcoat , but comparable to some cheaper 2K primers. If your goal is to paint a car in a home garage with a low to medium priced system and the car will need extensive priming that will require the gun to be cleaned dozens of times, I consider it an option
The Jalopy Journal
