Will 2k clear coat survive on an engine?
(Urethane with hardener, sprayed from a gun)

Should I expect yellowing or similar issues?

I’ve had good luck with single stage enamel and urethane, did my latest in urethane SS, it looks good, but was thinking about adding a few coats of clear for a deeper appearance.


TIA

I used to use 2 stage. Really not necessary. Been using single stage for motors 20 years. Don't be afraid to grind casting flash and bumps. No Indy logo here. Yup its bondo. 10 years.
Doig

There is the trick of adding a little clear into the final coat of a single stage paint that is supposed to boost the final gloss and depth.

Doug no concern about paint under the head bolt face?

The paint has never bothered anything. To be honest it would probably be better to clean it off. 15-1 with Cometics for 10 years.
Doug

The paint and body folks on other platforms all told me to go for it.....thought I'd throw it out here.

Definitely appreciate the friendly advice although conflicting, it makes life interesting, everyone's got different experiences.



Not many would guess

After a good scuff I'm going to give the idea a whirl over this cured single stage urethane, and see how it goes.
It looks great as is, but I would like a few more mils on it, and wouldn't mind a little more depth to the appearance.

At the same time/partial planning for future efforts I'm also going to experiment with 2k urethane clear shot over
cured/scuffed rattle can paint as a basecoat. Have seen many reports of success and long life, and I think this approach has potential.
I have a test part shot (A 5.7 exhaust manifold I had laying around) with some MP turquoise and some VHT hemi orange ready for that,
when the time comes, to see how it looks.

Taking a guess that... if the clear ingredient that is already in SS Urethane does not appreciably yellow, then a good quality
clear on it's own hopefully also would not yellow and will hold up.

Might be awhile before I get to this as I've been replacing metal on the car for the past couple years but am getting close
to the next stage. When I move on to bodywork and blocking, and am spraying more regularly, I can get into this without too much hassle.

Zippy.... i have been in the body shop business for 40+ years as well as selling it for the last 21 years. IF you need anything/advice let me know..(as well as Al Alquire is in this business also)

Thanks!

If you'd like to weigh in on this topic, I'd appreciate it.

I hoping that...as long as the single stage was well-cured and scuffed, the clear shouldn't cause any problems.

Gold scuff pads.....3m07745 some type of scuff soap Presta 130732 or 3m06013 or spies 7081 then wash it well and clear away.... USC makes a great 2k clear in a spray can, works great.

Thanks.

I have a gallon kit on hand intended for jamb/trunk/engine compartment and will probably use that.

Been spraying a little more often lately, and snuck this in.

Here is a follow up just to say this worked really well.

Since I'd decided my initial paint job was a little too thin and I wanted more mils, I shot one more coat of PPG 3116, then
3 coats of budget Acme FC720 clear over it.

It's got plenty of time to cure while I continue working on the car....but for now it definitely achieved the look that I was after.

It looks good Zippy, I've never used anything but single stage, the last couple engines I've added a little hardener.

While the big motor is really great and all, what interested me just as much was this test part I threw in on the side.

(It's a scrap 5.7 LX manifold drilled and tapped for instrumentation, circa 2007).

Can 2k clear work over rattle can basecoat? Yes.

The basecoat is from spray cans.
The Turquoise is Mopar Performance, the orange is the VHT brand formula for street hemi orange.

The clear coat is the budget Acme FC720 again, from the same gallon I got for general use/to experiment on stuff like this.

I really like the look of this test part, and the rattle can basecoat is a good cost save.

I would not expect this strategy to be quite as durable as the hemi with single stage urethane + clear as both the base and clear has a hardener, but it just might be comparable.

I want to try rattle can base/2k clear on a complete engine next, one of these days, to see how I like it.