Engine Enamel vs. Powder Coating

[JFunkadelic]

So, what do you guys think of spray can engine enamel? I have a friend that worked in a powder coating / wet paint factory that said he could get me a good deal on powder coating the frame and perhaps the engine, but it'd still be a lot more than anything coming out of a can. How well does that stuff hold up? Any recommended methods, brands, or techniques? Thanks.

[Re-run]

Powder coat holds up well but it is not for engines. Use a high temp paint on the engine and powder the frame.

[shinyribs]

Not all powder coat is created equal. There are some powders made for exhaust systems that I have personally seen hold up very well.

Most standard powders bake on at 450*f for about 15-20 min. After cured, they hold up at that temperature fine.

But unlike paint with rust inhibiting primers, powder goes directly on your bare metal. So you must have a 100% rust free surface or the rust will eventually creep back to life.

The way the exhaust ports are made on these engines the pipes see all the heat, not the surface of the cylinder head itself, so any powder will live just fine. Epoxy powders have fantastic resistance to gasoline but some may fade if stored in sunlight for many years. Flouro**** ( can't recall the name right now) powders have awesome UV resistance, but have less abrasion resistance than epoxies and are a bit more pricey.

For what it's worth, we use epoxy powder for everything. Never seen it fade yet. Gotta set of fenders on a military truck that have lived outdoors for the past 7-8 years. Never been washed even. Still look new.

Powder is awesome, but remember, touchups are impossible.

[Re-run]

The reason I say no on engines is that powder is thick and does not allow heat to dissipate very well. How much heat it holds in, hard to say. Will it be an issue, maybe not. Will the bake process cause aluminum parts to warp? Hard to say, most people stick with paint though for the engine or get it bead blasted and clear coated for the natural look. At least with our engines.

If you do decide to powder, make sure the place doing it is good enough to get into the fins all the way.

[shinyribs]

Good point about the fins. Faraday effect IS tough to combat sometimes. It's the sole reason I'll pay Red to pc my jugs when (if ever) I get the bored. He's supposed to have the correct gun for this.

Holding heat is no worse than any other coating. Besides ceramics,of course, but that's typically reserved for exhaust, so that's not an issue really.

Warping is not as bad as you'd think. Especially on large, cast pieces such as engine cases. Since the entire piece comes up to temperature as a whole ( as opposed to heating one area with a torch,for example) it all ''grows'' and ''shrinks'' at the same rate. Now, thin pieces of sheet metal? Total crap shoot on those.

Outgassing is something else to think about when pc'ing aluminum. the bare part needs to be brought up to temp and held there for a period of time to help push out any contaminants (grease, oil,gas...) that the cast metal has absorbed. Sometimes it takes two ot three bakes before it stops outgassing. You know when it's done. You can see the crud ooze out. More cleaning between every bake,too. Steel doesn't do this,just ally.

I hope I'm not sounding argumentative, just putting out there what info I've gained from personal experience.

[JFunkadelic]

Thanks guys.

 First of all, when I said engine enamel I meant the cheap shit out of a can, which I don't think I'll be going with. I was talking to another guy today, and he said he painted the case, engine, etc. with a 2 stage high temp paint he bought off of… eastwood? (Can't remember the name correctly). I got a friend that can do all this painting with me, so I think that's the plan for the engine itself.

 I like the idea of powder coating, it sounds so resistant, but I don't think I'm game for the cash. As for the frame and front forks, I think I can get this same guy to have someone powder coat it at about half price. What do you think a reasonable price is for powder coating a frame? One place gave me a frame estimate at $300-400! Is that good, bad, outrageous? Anyways, he thought his friend would do it for about $200. I suppose I'm willing to part with that sum.

 Thanks for the input guys. And any good spots for these types of paints?

[shinyribs]

My buddy does bike frames, provided they come to him completely clean, for $300. Price can vary depending on the powder being used.

[johnb]

Here's my 750 engine powder costed and my SL 350...which was done close to a year ago...Personally, I'd go powder coating.

[TOOLS1]

Those look great! Have you powder coated one while it was assembled? I have had one done while it was in pieces, but would hate to take a perfectly good engine apart just to powder coat it.
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P.S. I would like to see some more of that SL. I have 3 CB 350s, and 1 CL 350 that I have collected. I plan on giving one to each of my grandchildren when they turn 16.

[Re-run]

That does look really good. I do have to admin that I have seen warped heads from powdering BUT it was years back. It is completely possible that old issues with powdering an engine no longer exist. Kinda like all the old issues when synthetic oil first came out.

[shinyribs]

johnb wrote

What model engine is that? It's not a 79-83,but that's all I know. I wonder if those carbs are easier to tune than the stock 79-83 CV's ? Also curious is the spacing is correct or if they would fit in stock carb boots. Maybe those carbs and boots will find the early twin cam engines...actually I have lots of questions!

Great looking bike though. Definitely a compact engine compared to the earlier ones.

[shinyribs]

Did some quick research. I'm not up at all on the F2's and F3's. Now I know.

[TOOLS1]

shinyribs wrote

Did some quick research. I'm not up at all on the F2's and F3's. Now I know.

That is not an "F-2 or F-3" It's an 84+ nighthawk. I love that narrow engine. Maybe someday I will have one.
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