Engine paint using DP90 primer

[Chuck S.]

Re: Engine paint using DP90 primer

I have to admit it's been awhile since I painted an engine. Paint specs have likely changed to please Big Brother...the result is probably aerosol paint that has less pigment and less "hiding" ability. If your only option is water base paint because of where you live, you are truly unfortunate.

Paint manufacturers want to sell you as many products as they can; therefore, the back of spray cans recommend primer, and now, usually a cleaning product too. Unless I'm finishing bare wood or steel (engine iron an exception), I usually disregard such "instructions" as marketing. I haven't experienced any problems.

Plastikote engine enamel (if you can still buy it), is the exception: their instructions tell you to clean the surface and spray it on directly...no primer. They say it's good to 500 deg. If you're going to use a primer, better use one that's similarly rated. Also...IF you feel you HAVE to use a DP primer (confirm the temperature rating), at least use DP74...it's red oxide color is closer to the final color than black (or gray).

I'm actually not trying to convince anyone not to use primer. But...I feel someone asking the question should be aware of possible consequences if they are having the car judged. My objective was to keep engine appearance as close to factory as possible, and Flint didn't use primer. But, like Gene said, maybe over-restoration is now acceptable as the new "normal", and in that case there are no consequences.

If you are building a custom hot rod engine with aftermarket paint colors...then slicker is better; primer and multiple wet coats are cool.

[Gene M.]

Re: Engine paint using DP90 primer

Unless the primer is tinted to engine orange color (primer tinting possible at paint stores), primer will not help inferior engine orange paint to cover...the "hiding" ability of the orange paint is unchanged by primer. It will take at least as many coats to cover a gray primer as it does to cover the cast iron, plus you'll still have the additional film build of the primer.

Chuck you are wrong. Finish paint has poor adhesion on bare metal with out primer. Primer if it was as you say, there would be no need for it painting anything. Primer does not adhere any less at the peaks than in the valleys of the casting pours as finish paint alone does.

The color of the primer helps if orange or red but sure anything is better than bare metal. Paint coats (both primer and finish) need to be thin so it looks as original.

[Craig O.]

Re: Engine paint using DP90 primer

I'm getting my engine back from the rebuilders this wknd. It has been cleaned and no paint.

I though I read some time ago, that someone has used DP90 as epoxy primer/etcher then Quanta orange engine paint.

I was wondering if the epoxy primer is OK with the high engine heat?

This is a '73 SB,

I also vote for no primer needed on a properly cleaned block, The DP primer comes in 6 colors 90 being the black. once cured it is hard as nails and sands very difficult. I used it on my frame to fill rust pock marks before top coat. It has great adhesion properties on bare steel and after a few coats sanded, the frame looks like new. lots of work though.

[Chuck S.]

Re: Engine paint using DP90 primer

Chuck you are wrong. Finish paint has poor adhesion on bare metal with out primer. Primer if it was as you say, there would be no need for it painting anything. Primer does not adhere any less at the peaks than in the valleys of the casting pours as finish paint alone does...

We've each called the other "wrong" now, so I guess we've even without resorting to worse names.

You can avoid the tendency for the first color coat to "run" on any substrate, and get full coverage quicker, by first misting on a "bond coat" and letting it get tacky before applying your first wet coat. Of course, this assumes you have the proper reducer temp range and don't spray the followup coat too wet. It's a tip I learned from custom painter Jon Kosmoski at a local demonstration of House of Kolor products.

[Bill L.]

Re: Engine paint using DP90 primer

If you want it done as the factory did it the coverage was pretty poor from what others have said.

I can tell you from first hand experience that I love the Bill Hirsch Engine enamel.

It will result in a far nicer finish than original. The orange appears correct or very very close. Once dry and baked on after running the engine it resists gas and oil really well.

The other thing I really love is that you can use a brush for touch ups and the brush marks pretty mush disappear.

I used his engine paint on both my 70 vette and my old ram air GTO. Excellent results both times. No primer.

Just my two cents.

Bill