Polyurethan Paint Heat Resistance

[wdhewson]

Gents: Prettying up my 1981 KZ550A2, I've used black hi-temp engine enamel on the cam cover, and from past use on other bike's cylinders' I'm confident it will take the heat. But, for the black background of the KZ550's ignition cover and alternator cover, I used regular black polyurethane. Do you think the regular polyurethane will take the heat on the covers? Or will it turn grey and peel off? Any experience to share? Thanks.

[MFolks]

I use the PJ-1 engine paint on my cooling fins and exhaust system, except for an occasional touch up now and then, it's lasted a long time.

I think it's called "Fast Black" I believe they also make a wrinkle paint if you want that look. Motorcycle Chemicals & Lubricants - Motorcycle Paints - PJ-1 Satin Black Engine Paint - 11 oz. - CBXManMotorcycles.com

PJ1 Gloss Black Barrel and Engine Paint :: Spray & Touch Up Paint :: Solo Moto Parts

[herk]

Originally Posted by wdhewson

... But, for the black background of the KZ550's ignition cover and alternator cover, I used regular black polyurethane....

So, you've painted the parts already? Well then, you'll soon know.
Just curious... why didn't you use the stuff that has been proven to work?
I painted my engine cap covers w DupliColor hi-temp engine enamel - it has worked well.

[wdhewson]

Gents: I have painted the covers already with polyurethane. The engine enamel is a spay can and I can't seem to find it in a can for brush work. I tried spraying the brush then painted with the fine tipped brush, but this was clumbsy and the spray cured too fast for this tedious work. If the polyurethane is killed by heat, I'll keep experimenting.

[StarGate]

Originally Posted by wdhewson

The engine enamel is a spay can and I can't seem to find it in a can for brush work.

Been in that boat before. My solution was to take the spray can, a rag, a nail, and a hammer. Use the rag to wrap around the can and nail, then knock a hole in the top of the can. It releases all the pressure. While some paint will come out at first (thats where the rag keeps you from getting sprayed), most of the paint was left in the can. After all the pressure is gone, make the hole larger and then pour the paint into a suitable container for brush work. It's not the best solution but the only one I could come up with at the time.

[kawpaul]

Why would you want to brush it on? Could you not mask where you did not want paint?

[herk]

Here's how I sprayed mine.

Clean & polish the cover. Don't polish the black area, of course. Haphazardly mask the perimeter w masking tape. Apply a light coating of bearing grease to the raised lettering etc by lightly patting the grease w your finger then applying the grease to the cover by lightly patting the lettering. Then spray. After the paint dries to the touch, wipe off the raised areas & remove the masking tape. Then wipe off any overspary if necessary. The paint should come right off the greased & polished areas.

[wdhewson]

Gents: The small little detail brush seemed less work than the grease, and a whole lot less work than making the detail with tape. De-pressurizing the spray can makes some sense, especially as it nears empty anyway. But I might do that with 6 pumps on my Crossman.

[PatsPOS]

A couple years ago, I used the virtually the exact same method that herk described, except I used Vaseline as the "masking". And I got virtually the exact same results as he posted in his picture above, except I didn't polish the aluminum nearly as well as he did (sure wish I did now! ).

This method MIGHT take all of two minutes to accomplish...you just have to be a little careful to keep the grease/Vaseline from creeping off the lines and letters. Although I never would have thought of punching a hole in an aerosol can, it's not a bad idea.

Pat

[herk]

Do whatever you want. My method was simple & fast.

Edit: In case you misunderstood I only masked the outer perimeter of the alternator cover. I did it real quick in a haphazard manner. I did not mask the lettering or any other raised areas. I applied the tape first, then the grease. Then sprayed. Fast & simple.

...

...

[kawpaul]

I would pull the cover, mask around the shiney part, grease the letters and fake fins, and spray away. But I am just simple like that. It takes very little paint so why ruin a whole can?

Oh and I would use a q-tip to spread the vaseline.

[Polar_Bus]

I used this paint on my GS1100's engine, it's great stuff:

Amazon.com: VHT Clear Coat High Temp Polyurethane Wheel Coating: Automotive


And i've also used this paint for a semi-flat black engine base paint:

Rust-Oleum High Heat Spray Enamel - BIC Warehouse


The hi-temp Rustoleum is a reall good paint that lasts a long time. Remember, the difference between a pi$$ poor paint job and a professional looking paint job is the quality of the preparation.

[wdhewson]

Polar: Thanks for the recommendations. The high temp paints are pretty good these days. My latest experience is with the cast iron cylinders on and old Triumph Bonneville which stayed intact and glossy.

[herk]

Something else I do is to bake the parts in a low temp oven to cure the paint: muffler brackets, brake caliper, wheels, etc. I paint the hidden side of chrome parts w bar-b-que grill paint to deter corrosion: headlite bucket, muffler heat shields, fenders, etc. I topcoated the underside of a rear fender w 3M rubberized undercoating. Not sure how the heat would affect chrome, so I've never baked one of those parts.

[kawpaul]

Anyone try this stuff?
Krylon: Products: BBQ & Stove Paints

The local wallyworld carries it and I though about using it on my engine.

[wdhewson]

Not sure, but I think these BBQ and stove paints are somewhat flat finished. I like the gloss because it is easier to clean and looks good to those of us with "Crow Syndrome". The "old quality" gloss heat resistant paints used to turn a bit gray and flat, so I hope the modern ones are improved in this regard.

[wayno]

After recently finishing a spray can overhaul on a mates motoguzzi, i can tell you all that the best way to mask off large areas is to cover everything that you dont wont painted in aluminium foil.Yes thats right, the roll that everyone has in the kitchen.Its cheap, quick to apply,it covers everything, & is easy to remove.Use masking tape when you need a fine line. or just spray with a piece of cardboard in hand & spray against it.Make sue that everything is cleaned down with degreaser,or mineral turps.A light sanding & dry off, then paint.It will stick.For how long depends on the application.I use engine enamel on all things hot.VHT exhaust paint on exhaust pipes after sandblasting. And it all looks great good luck. wayno 1500 drifter

[kawpaul]

Originally Posted by wdhewson

Not sure, but I think these BBQ and stove paints are somewhat flat finished. I like the gloss because it is easier to clean and looks good to those of us with "Crow Syndrome". The "old quality" gloss heat resistant paints used to turn a bit gray and flat, so I hope the modern ones are improved in this regard.

I don't know, looks pretty shiny to me. I believe the paint I saw in the store was a satin finish, which I prefer to gloss for engines anyway.

[herk]

Originally Posted by wdhewson

Gents: I have painted the covers already with polyurethane. The engine enamel is a spay can and I can't seem to find it in a can for brush work. I tried spraying the brush then painted with the fine tipped brush, but this was clumbsy and the spray cured too fast for this tedious work. If the polyurethane is killed by heat, I'll keep experimenting.

Have you had a chance to run the bike yet?

Something I forgot to mention is that a way to paint by hand using rattle cans is to spray the paint into a small plastic container until it puddles, then use a brush to apply it. This way gives plenty of working time & doesn't waste much paint - I've done it to do touch-ups.

[wdhewson]

Herk: I've not run the bike yet. It is pretty well in large restored lumps in the basement. I'm just setting the valves and trying to get the engine in good shape. My target maiden voyage date is July 2010. Meanwhile my 1978 SR500E will have to pull me around. Late Fall has the Canadian riding season coming to a quick close.