SEM 39673 Black Self Etching Primer - 15.5 oz.

This primer is the easiest to use self etching primer I've found so far and it adheres as well or better than anything else I've used for painting bare aluminum. It has a fine spray that goes on far more evenly than most rattle can paints. The primer dries quickly (three thin coats five to ten minutes apart are recommended) and can have the color coats applied after only an hour or so. While the can doesn't specify any temperature range for applying the paint, I have used it in 65-80°F temperatures without any problems. Obviously, the paint will dry faster at higher temperatures. Lower is better since the primer has to be liquid to etch the surface. The can does not recommend applying color coats directly to this primer (SEM doesn't specifically say so but a conventional primer should be used over the self etching primer), which is consistent with other self etching primers I have used which recommend using a regular primer over the self etching primer before applying color coats. I found that Krylon's Dual, a combination of primer and color coat, will work well when applied directly to this self etching primer, which reduces the overall number of coats of paint needed (the Krylon dries very slowly, though, although coats can be applied around 30 minutes apart). As always, proper surface prep is needed. I wet sand the surface with 320 or 400 wet/dry (which one depends how smooth a surface I want), then, after rinsing the piece with hot water and letting it dry thoroughly, I wipe it down with an acetone saturated cloth to degrease the surface (denatured alcohol or lacquer thinner also work well). While degreasing the work and handling it afterword, I wear disposable nitrile gloves to protect my skin and keep skin oils off the surface of the work. The price may seem high compared to other rattle can paints but is actually competitive with other self etching primers when you consider this comes in 15.5 oz. cans instead of the usual 12 oz. cans.

SEM black etching primer covers well and is automotive shop quality. Although not the cheapest it is the best brand I have found. Many body shops I know use SEM products because of the quality they can count on. I have used both the black and the green etching primers from SEM and both work excellent. They also cover much better than others I have tried with disappointment.

A close match to OEM paint on older Kawasaki master cylinders.

Finish really sticks. Looks like iron oxide finish after three coats.

I use this as my go to for touching up frames and suspension components under the car before and after winter. Leaves a nice factory looking satin finish and is a thin coating for going right over bolt heads without issue later on