Painting engine...want it to stick!!!

[Dano383]

Hi guys,

I'm finally getting ready to paint my assembled shortblock after a few months of being away from it. It's your typical iron-block 355 SBC going with your std. Chevy Orange.

Since it sat for a little, the outside of the block has gotten a little flash rust in some areas where There wasn't any oil on it. All of the inside of the engine is still nice and oily. I'm worried that the paint won't stick or come off later in these spots if I don't clean it well.

1. My question is what do you guys like to use to chemically clean off flash rust before priming/painting anything?

I'm thinking of getting the POR-15 kit that comes with Marine Clean (their degreaser) and Prep & Ready (their rust dissolver), along with the paints.
http://www.por15.com/ENGINE-PAINTING-KIT/productinfo/EPKA/

Anybody use this kit? Or at least their Prep & Ready? If so what do you think?

Any other options for doing the rust removal?

How 'bout Eastwood's Rust dissolver?
http://www.eastwood.com/rust-solutions/removal/ew-rust-dissolver-gallon.html

2. Also what brand paint do you guys typically like to use?
I've use Plasticoat, Dupicolor, and Ground Up's brand...can't remember the name off the top of my head. All were rattle cans, but I liked Ground Up's the best.

Thanks,
Dan

[nicks67camaro]

I am interested as well. I am going to be pulling my engine soon and the current paint is not holding up.

[1969CamaroRS]

1. My question is what do you guys like to use to chemically clean off flash rust before priming/painting anything?

I'm thinking of getting the POR-15 kit that comes with Marine Clean (their degreaser) and Prep & Ready (their rust dissolver), along with the paints.
http://www.por15.com/ENGINE-PAINTING-KIT/productinfo/EPKA/

I solvent tanked my block for a about a week. I still then had to use Por-Strip and a wirebrush a few times to get the remaining crap off. Probably could use Aircraft paint stripper too. If you plan on using Por-15 then you need to get as much off the block clean as possible. I would follow Por-15's instructions to the letter and then use Marine clean a few extra times.

That's what I did to get this:
https://static1.pt-content.com/images/pt/2008/08/Engine001z-1.jpg
https://static1.pt-content.com/images/pt/2009/01/Engine029-1.jpg

Even then I had to go back and touch up around the oil gallery plugs because some grease had remained. Even the slightest amount of oil/dirt/grease will cause Por-15 to peal, so you need almost perfect prep or don't' bother.

However with the prep comes a great paint job that you can wipe down with Lacquer Thinner or hammer on (I did both to this block, cleaning up some stuff and hammering in freeze plugs.). I'd definitely use Por-15 again on any engine block I was doing.

No experience with Eastwoods Rust dissolver thou I like their other paints and especially their powder coating system.

[manicmechanic]

^ Just courious as to why your left areas unpainted? The bolt holes for the mounts and the rear trans face just to mention a few, these will all start to rust if not covered with something. If your afraid of getting paint in threaded area you can roll up some masking and stick into the holes to prevent that. Also most will paint right over the freeze plugs to help provide a seal and help to prevent small leaks. Overall does look good, as for prep good old sandpaper and elbow grease goes a long way and a little cheaper than Por-15 and the likes. Also think about shooting a single stage paint if your worried about it coming off.

[1969CamaroRS]

My understanding is mated machined surfaces you don't want to paint. It had no paint (and no rust) from the factory either.

Freeze plugs are polished and cleared and I thought looked cleaner that way. There is certainly cheaper paint out there but few I doubt beat Por-15s durability. Try wiping down a block with lacquer thinner or hammering in freeze plugs and see if the paint isn't damaged. I wanted to paint the block once and not have to worry about it again.

Por-15 is a nice paint but I wouldn't use it for everything but if durability mattered its right up there with powder coating.

[Derek69SS]

I always grind off the sharp edges of casting flash, as that's where the paint starts to crack and peel first.

[Dano383]

Thanks for the advice so far! What paints are your favorites?

What do you guys like to use for chemically removing rust?

[Stoker420]

I like phosporic acid, spay on wash off

[Tincup]

Use the Duplicolor engine paint "With Ceramic" awsome stuff.

[Dano383]

Yeah, I've used the Duplicolor with the ceramic. It's pretty good.

I was looking at VHT's system recently...
http://www.vhtpaint.com/engineenamel.html

Has anybody used this? If so what do you think?

[Stoker420]

G2 engine paint is some pritty hard and resistant stuff goes on easy and last a long time, it's a two part epoxy paint you can either brush or spray on.

wicked gloss to it

[Northeast Rod Run]

I always wipe down my blocks with lacquer thinner then use a can of etching primer followed by regular old high temp engine paint and my stuff always sticks.

[Dano383]

yeah, I thought about using some etching primer after getting the block as clean as possible...anybody else use etching primer? How's it hold up (to the heat especially)?

By-the-way, I'll just be using it on the block itself. I have aluminum heads, of course no paint on those.

[67rstbkt]

Here's a dumb question, maybe.....
Why no paint on the aluminum heads? I'm building a Pontiac motor with aluminum heads and was thinking about making it look really stock by painting the heads. Is there anything wrong with that?

[Dano383]

Here's a dumb question, maybe.....
Why no paint on the aluminum heads? I'm building a Pontiac motor with aluminum heads and was thinking about making it look really stock by painting the heads. Is there anything wrong with that?



Nothing wrong with that at all. You build it they way you want it! After all it's your money.

[BonzoHansen]

I always grind off the sharp edges of casting flash, as that's where the paint starts to crack and peel first.


I always wipe down my blocks with lacquer thinner then use a can of etching primer followed by regular old high temp engine paint and my stuff always sticks.

I agree with both of these. Except I just used engine primer. My engine was a mess and needed all new gaskets. I actually dragged it down to the local self wash, hit it with engine cleaner and degreaser and washed it there. Then I brought it home and took down all the flash & such with a cookie on a die grinder. And scrubbed the hell out of all of it with lacquer thinner. Not one scratch in it 4+ years later.


Here's a dumb question, maybe.....
Why no paint on the aluminum heads? I'm building a Pontiac motor with aluminum heads and was thinking about making it look really stock by painting the heads. Is there anything wrong with that?

Do it. I'm working on a new mill right now and i might do it too, even the intake. total stock look.

how it was
https://static1.pt-content.com/images/pt/2010/12/48864377-1.jpg

current look:
https://static1.pt-content.com/images/pt/2010/12/48862454-1.jpg

I like the OE look & feel, so new aluminum heads might get painted too. Aluminun corrodes anyway and looks crappy. So I need to decide about painting the heads, and the intake. And a new aluminum water pump. Anyone have thoughts on painting the intake too? It will look even slower yet pick up 200 hp, lol

[1969CamaroRS]

Nothing wrong with that at all. You build it they way you want it! After all it's your money.

x2, my Brodix heads looked nice unpainted so I left them that way.

[67rstbkt]

Awesome, I was just concerned that the paint would not hold up the same for some reason. It's getting all the good stuff on the inside; forged, stroker, but I want it to look as stock as possible.

[aronhk_md]

My understanding is that paint does not stick well to aluminum unless you use the proper primer. For example with outboard motors if you dont use the primer the paint peels off your aluminum lower unit, and I think the powerheads too. Same with aircraft....there is a special primer. I know if you call a marine supply place they have the primers. Anyone have experience with this?

[ckessel]

Deffinetly get every thing clean, clean, clean. I've had the best luck with using epoxy primer and color from a gun. Use PPG's DP40 or equivalent from another manufacture. This stuff is self etching, sticks like you can't believe and if you top-coat with your color within a couple of hours, you don't sand it. The gun paint, single stage urethane or catalizes acrylic enamel, puts up with heat and harsh chemicals much better than buzz can material. Another way to do it is buy self-etching primer in spray can from an auto body supply if you don't want to use a gun. This works well too. Some of the auto body supply shops can also put a single stage urethane in a spray can for you. Custom colors anyone? This works well like the primer. These materials stick better and last longer. Alot of the usual buzz can stuff does not contain much paint pigment in it so you use up more to get coverage. It also does not witstand heat and chemicals as well. I also like to use Rust Oleum for accent stuff like blacks. It covers good and doesn't bleed through like others when you are trying to cover up overspray or other issues. Use the self etching primer under your other small buzz can projects too for better adhesion. Lacquer based or enamel based primers don't bond, if at all, to whatever you are painting. If you are painting plastics, wash them down with rubbing alcohol then spray them with a "Adhesion Promoter" which you get at the paint shops. This is what will make the paint stick to plastic and not flake off. One other piece of advice I would like to hand off. When I was managing a body shop, we learned that you should store all of your aeresol cans containing solids like paint, undercoating, grease etc, upside down. This will keep the can from plugging up when you go to use it. Your brakleen, carbclean etc can be stored normal.

[MonzaRacer]

Heck surface rust as in flash rust doesnt even need removed. Spray the engine down with carb cleaner then some brake clean, while scrubbing with wire brush or stiff paint brush.
Heck most of my engines got painted with Wal Mart el cheapo paint, spray a coat, hit with propane torch, when tacky do it again. Several coats and a day or two later its totally dry and last well, heck my 402 bbc is still mostly black, except where it has mud on it. Unfortunately it had to spend time sitting under a tarp and rolled over in the dirt,,,, but for the most part its still painted, and that engine in going on 17 yrs old. My truck engine is painted the same way and other than dirty its holding up pretty good. doesnt shine but then I daily drove both and never cleaned them so with cleaning they would probably have looked ok, depends on how much shine you want.

[aronhk_md]

Ok, getting ready to paint my block. As recommended I will try to get some PPG40 etching primer, and then put HOK Galaxy Grey color on. I believe its a urethane? But I need some help here.


Kosmic reducer - this is supposed to be mixed in 1/3 to the colors 2/3 for my airbrush. But it comes in slow, medium and fast. Does this depend on temperature? Right now its reaching high 40's in my garage during the day, but by 2 weeks from now it could be freezing again or in the 50's 60's here in Delaware. Advice? Is the reducer the activator?
One post said that if using the PPG40 and spraying color within a couple of hours that no sanding is required. So how long do I actually wait to spray color after the PPG40? How long before a 2nd coat? Do I need more than 2 coats? How long after to spray clear?
How many coats of clear? How long in between? Does the HOK clear require an activator.....or does it use the same reducer the color does?
I've done some smoothing of the block, especially on the front, but it still has the casting grain along the sides, and back near the distributor, etc. Once the clear is dry....how long to dry actually? Do I attempt to sand and then polish the clear even though the block surface isnt really smooth like sheetmetal? Seems like it would be kind of tough, but will the clear look crappy if its not sanded and polished?


Thanks for the help!

[chevelletiger]

hok epoxy primer works well for engines but dont lay it on heavy then paint and clear.john kosmoski does a step by step for a harley engine in one of his books,or give ther tech line a ring there super cool to work with.

[aronhk_md]

Contacting HOK may work as you mentioned. Just wondered if anyone here had advice. Many people here have lots of experience.

[BulldawgMusclecars]

I mostly smooth the block, give it a light coat of filler primer, then base it and clear it. As long as its good and clean, its as durable as anything else you can do, and you have a lot more choices for color (such as matching the car, stripe color, etc). BTW, I would be hesitant to paint Pontiac aluminum heads...with the exhaust port being cast the way it is, even the best paints can burn off. I haven't ever tried it, though, so I can't say for sure.

[aronhk_md]

Paint burns off with stock iron heads, but it MIGHT live with aluminum heads because the aluminum runs cooler on someone elses engine. BUT, in my case theres the heat build up from backpressure the turbo creates. Regardless, I'm almost halfway through the painful task of polishing the heads and intake. What fun! I just want to do something fun with the block and hopefully since these paints have more solids than the canned stuff it'll last longer and look better. Think I'm going to scuff the freeze plugs well before painting, and yes I'm smoothing the block and timing cover too.

[Happyfunballs]

1. Fast reducer for cold temps, slow for warm temps. Use a fast for those temps. HOK doesn't use an activator for their BC's. It's just a reducer.
2. You can get away with this, but technically you're not supposed to do it. I do it all the time for non-critical parts. You can spray the next coat as long as the first one is dry enough that it doesn't transfer material to your finger when you touch it. That is a very GENERAL rule. For catalyzed parts, I wait a bit longer. I've never had a problem.
3. Two wet coats on a block should be plenty. HOK clear requires a hardener and reducer and uses the same reducer as the base.
4. Dry and cure are two different terms. Dry within hours. Don't buff the block....you'll hate yourself in the morning.



Ok, getting ready to paint my block. As recommended I will try to get some PPG40 etching primer, and then put HOK Galaxy Grey color on. I believe its a urethane? But I need some help here.

Kosmic reducer - this is supposed to be mixed in 1/3 to the colors 2/3 for my airbrush. But it comes in slow, medium and fast. Does this depend on temperature? Right now its reaching high 40's in my garage during the day, but by 2 weeks from now it could be freezing again or in the 50's 60's here in Delaware. Advice? Is the reducer the activator?
One post said that if using the PPG40 and spraying color within a couple of hours that no sanding is required. So how long do I actually wait to spray color after the PPG40? How long before a 2nd coat? Do I need more than 2 coats? How long after to spray clear?
How many coats of clear? How long in between? Does the HOK clear require an activator.....or does it use the same reducer the color does?
I've done some smoothing of the block, especially on the front, but it still has the casting grain along the sides, and back near the distributor, etc. Once the clear is dry....how long to dry actually? Do I attempt to sand and then polish the clear even though the block surface isnt really smooth like sheetmetal? Seems like it would be kind of tough, but will the clear look crappy if its not sanded and polished?

Thanks for the help!

[aronhk_md]

Ok, thanks for the info....basically wait an hour or so in between all coats until they are dry to the touch....and go from primer to color to clear all in the same day the same way.

Now.....HOK of course doesnt recommend using PPG40. They recommend using their bare metal primer, and THEN their sealer.......then finally the color and clear. Any thoughts on this? Part of me says just follow what they say. Another part of me hates to go through another step.

How long after the final coat of clear before its safe to begin really handling the engine for assembly?

Thanks again!

[chevelletiger]

i used u-pol,to valspar dtm primer under hok bases,had no problems.the say to use sealer i did for my ride it allows faster coverage and protects from filler bleed thru,you use less paint too. aron hk on the clear flash time youll know when to spray the next coat when you do a finger touch test to masking paper tape and it does not string up like spider webs.hoks line is not any more$ than ppg.for guys not used to what works and doesnt stick with what the tech manual says,but your good with the primer you have.btw rick if you look at hok 2010 tech book you do use a hardner in bases now,for cali.regulations

[Happyfunballs]

Hardener in bases, in California, go figure. I'll second the fact that HOK can be sprayed over anything. I've use everything in the cost range and is has never failed. Aron, I'm assuming you intend to use DP40 from PPG? Your process should go like this (IMO):
Bare clean block
JP215 Etch (This is somewhat optional, however you can never argue with a good foundation)
3 good passes with DP40 (I would let this fully cure on an engine block)
Sand DP (that wont be fun)
HOK base till coverage is made(new coat can be sprayed when base is dry to touch)
Clear(multiple light coats. Next coat can be applied as Tiger suggested when the previous coat doesn't "string")

[aronhk_md]

Thanks guys, but BOY is this confusing! Everyone has a different way. I thought the PPG DP40 was self etching......but you are saying to use an etching agent too? Also, it was recommended above that if you sprayed the color within a couple of hrs of the DP40 then no sanding would be required.

I dont think its possible to get a good sanding in some of the areas of the block where I didnt grind off the grain of the block. I smoothed the front of the block, and some other areas, but I didnt do it all.

[Happyfunballs]

If memory serves, DP40 is an epoxy, so it isn't an etch primer. You can, however, spray it over bare metal that has been prepared properly. I'm sure PPG recommends an etching primer underneath, but it isn't always necessary. I mentioned spraying color over a not-so-dry primer for non-critical parts. I would consider an engine block critical and it might be more important than not to properly prep everything considering the temperature swings of an engine block. JMHO.

[aronhk_md]

Gotcha....thanks for the info. Post #20 on the first page someone mentioned that DP40 was an etching primer.