Powdercoating my first engine case...Tips appreciated.

[Tremelune]

As part of my '68 CL350 motor rebuild, I am preparing to powdercoat the engine casings once I get them back (blasted and cleaned) from the shop. I have:

- My (hopefully) trusy Eastwood Dual-Voltage HotCoat gun
- Some Eastwood HotCoat 10103 black satin powder
- A giant Oster TSSTTVXLDG countertop oven
- High-temp masking tape
- Silicone taper plugs
- Fucking coat hangers
- Just enough know-how to make a mess of things to start a fire.

The plan is to heat each piece to 450 degrees for 30-60m so aluminum can off-gas, rub it down with acetone until the rag stops collecting dirty, mask everything internal to the motor (plus all bolt holes), hang it, spray it at 15kV, and follow Eastwood's directions for curing:

- Preheat oven to 450 F.
- Moving suspended piece into oven.
- Turn oven down to 400 F for 20 minutes once all the powder appears to gloss over.
- Crack oven door and let the piece cool slowly.

I will try some test pieces first, as this is my first time with powder. I'm not terribly concerned about the finish (orange peel, etc), but I am concerned about durability and not getting powder where it doesn't belong. I bought these silicone plugs in the hopes that I would be able to keep powder out of bolt holes. Anyone ever use them? I've seen folks use balled up masking tape, but it seemed like it wouldn't work out well. I also found this video that shows a nifty technique for masking the mating surfaces:

http://www.youtube.com/watch?v=k3-3c30jpxU

This seemed like a good place to bring questions up and track my progress, as the info I'm finding doesn't take certain motorcycle-motor idiosyncrasies into play. If anyone has experience with powder and motor bits, feel free to drop some knowledges on me.

 

[SONICJK]

Sounds like a good process. Sandblasting or really thorough cleaning and sanding should be in there somewhere though....

My other suggestion is to avoid that eastwood powder. Get some from powder by the pound, or columbia coatings. I find the eastwood stuff harder to spray and it requires more like 500 degrees to properly run out. Your mileage may vary.

Play with some test pieces first. If you don't have a sandblast setup or soda blaster be prepared to spend a lot of time getting things clean.

 

[AlphaDogChoppers]

Blasting should be done with aluminum oxide, or some similar abrasive. Soda blast and bead blast are no good as prep for powdercoating. Not enough tooth, and the coat can chip.

Clean all holes and passageways in the cases multiple times. I mean it! The blasting media penetrates EVERYWHERE, and a single particle of aluminum oxide in your engine is too many. It can embed itself into an engine part, and stay there perpetually, causing wear. Clean the cases again and again and again to be sure no screw hole or oil passage has a speck of abrasive in it. Chase threaded holes with a tap. Blow things out with carb cleaner and compressed air. When you think you have it completely clean, do it again.

The pre-heating you are planning is a good idea, although I have had little trouble with outgassing on Jap castings. British castings, OTOH, are like a fucking sponge. Takes hours of baking and re-sandblasting to get all the oil out of them and get a decent finish.

I put acetone in a spray bottle, and spray off pieces. Do it outside. Even though acetone has relatively low toxicity, it will stink up the whole house if you do that in the garage. Wiping with acetone on a cloth is not a good idea. It will leave crumbs of lint on the surface that will cause flaws in your finish.

The pictures below are a CX500 engine that I powdercoated. I used silver vein, which is a textured finish that disguises surface flaws nicely. I followed it with clear in order to make it easier to clean.

 

[hunterkey]

That cx engine looks great! Better than new!

 

[AlphaDogChoppers]

The bike came out looking pretty good, too.

 

[Tremelune]

Excellent, thanks!

With regard to blasting, the machinists doing the valve job are doing it, so it's kind of out of my hands. They know I want to powder coat it, and they know I cannot clean it once the media gets in there, and I've been told it will be returned to me ready to go. I'll hit everything with compressed air and brake cleaner to double-check, but at some point, I gotta have some faith. There will always be tasks I can't do myself, and I'd like to have a relationship with my local vintage shop, as they seem like good, knowledgeable people.

The real test will be what they do with that rubber ball I left in the case by mistake. I'm hoping they'll say "We noticed the oiling ball you left in there. It does this--be sure you put it back in. Here it is" as opposed to giving me a case with no ball and no words.

My other suggestion is to avoid that eastwood powder. Get some from powder by the pound, or columbia coatings.

Sounds good to me. You can't cook a great steak with bad meat (you can, of course, fuck it up either way). Columbia Coatings looks like much better stuff, based solely on the quality of the website…I'm going to go with some Low Gloss Black Urethane, as Semi Gloss Frame Black Epoxy doesn't seem to like sunlight.

After gazing at all of the options, it seems a shame to just go with regular-ass black, but this is a long-term bike/project, and black will surely look good to me in a decade. Part of my goal for this bike is to not be noticed when parked on the streets of Brooklyn. Understated look, magic internals...I hope.

The pictures below are a CX500 engine that I powdercoated.

This is the exact motor I was looking for last night. I remember it clearly from the masking and I was trying to figure out how it was done. The tape I bought is translucent and green (in 1/2" and 3"), so I assume it is similar stuff. Did you just tape it and break the edges with a razor like in the video? It looks excellent. What did you do with the bolt holes?

 

[AlphaDogChoppers]

They know I want to powder coat it, and they know I cannot clean it once the media gets in there, and I've been told it will be returned to me ready to go. I'll hit everything with compressed air and brake cleaner to double-check, but at some point, I gotta have some faith.

Hey, I don't know nothin'. You can choose to explain away my excellent advice if you want. Good luck with your "faith."

The tape I bought is translucent and green (in 1/2" and 3"), so I assume it is similar stuff. Did you just tape it and break the edges with a razor like in the video? It looks excellent. What did you do with the bolt holes?

Threaded holes were all covered with the tape. Non threaded holes are less critical. Some get plugged with silicone plugs/caps/corks.

Stick the tape in place, burnish it down with your fingernail, as it doesn't stick all that well. Trim with Exacto knife.

Don't mask before your outgassing pre-cure. The tape will just shrink and pull loose and you will have to re-do it. I made that mistake. I had to mask the cases three times. Once before the pre-heat. (mistake) Once before the silver vein, then again before the clear.

 

[AlphaDogChoppers]

Trust me, no amount of blowing out passages with compressed air will remove all of the glass bead that will have found its way into passages. There are traces of oil in those passages, and the bead will find its way into them and stick to the oil. It doesn't matter how carefully passageways and openings are closed off, the glass bead, (most likely what the machine shop used,) WILL find it's way into every little nook and cranny, driven by 100 psi air.

That shit is death to your engine. You can be lazy and ignore my warnings, and probably ruin your engine, or you can listen to the voice of experience and do it right.

No shit, man. Fuckin' listen!

One of the biggest blunders inexperienced bike builders do on this forum is ask for advice from more experienced builders, then fuckin' argue with them if they don't like the advice.

 

[SONICJK]

I think he was saying the machine shop will handle the cleaning, but I agree he should definitely doa thorough follow up job as if it hasn't already been done.

You'll be much happier with columbia coatings powder. I use These Guys and their flat black is just plain great, sprays easy as pie and I never get any flaws even when I do shitty prep. (honestly, unless its an engine case, I blast it, blow it off with compressed air and coat it then and there with no more prep, works great.

 

[Tremelune]

Oh quite the contrary--I'm taking this advice to heart. They told me they would clean the motor after blasting to be ready for powder coating (after I was pretty clear about my inability to clean the parts after), and I'm going see how true to their word they are. Since I'm doing most of this in my bedroom and a storage room in the basement of an apartment building, I'm limited in what I can do myself (specifically, the mineral spirits parts cleaner I have stinks up the hallway and is pretty much off limits). Basically, it's Simple Green, brake cleaner, and a wire brush on my balcony for cleaning parts, so I'm hoping there isn't much left for me to do when I get the bits back. If it's not ready, I'll get it ready.

 

[o1marc]

Here's my experience as a Professional coater. DO NOT go by Eastwood's cure directions unless you want your powder under cured. Cure times should always be monitored off of the part temp (part metal temp PMT) It depends on the thickness and mass of the material to get to 400*. You want to cure for 10 minutes at PMT. If you wait til the powder starts to flow and then just go 20 minutes your engine case may never get to PMT in that time and you will be under cured. You should be using an IR temp gun to monitor the temp of the actual part. When the part hits 400* start your 10 minute timer then. NIC Prismatic powders make some of the best and freshest powder on the market. Columbia Coatings sells NIC products but don't stock many of them so if you order an NIC powder from them they just send the order over to NIC in Oregon and let then drop ship. Shipping time can be an issue. Columbia Coatings also sells a house brand of manufactured powder that is less than the best quality and I would stay away from it.
AlphaDog, I love that Silver Vein powder, so much so that the motor in my CRX has the cylinder head, oil pan, oil filter, all brackets, suspension knuckles and more coated in. My motorcycle frame is also done in it. It's also a good base coat for candy colors which I have done a bunch of.

Eastwoods powders are good quality but they are too proud of them and they are extremely more expensive than anywhere else you can get them. I think most of their powders are Tiger Drylac products. they also don't package them in DIY friendly quantities.

 

[o1marc]

I'm pretty sure the machine shop will hot tank the cases a couple of times to clean them. They are, if they are a reputable machine shop, aware of what blast media residue will do to an engine. when mine was done they hot tanked it, then opened the washer up and hit all the oil galleries with a pressure washer and compressed air and then did the whole process a second time.

 

[o1marc]

Powderbuythepound is okay but, for example, their Mirror Black sells for $13.84/lb. I deal a lot with Powder365 out of Ga. They are all ex employees of PBTP and have taken customer service to a level PBTP refused to do. P365 sells the same Mirror Black under the name Midnight Black and it's only $9.99/lb. The sample pic for Midnight Black is from a set of wheels I did.
www.powder365.com
www.Prismaticpowders.com

 

[AlphaDogChoppers]

AlphaDog, I love that Silver Vein powder, so much so that the motor in my CRX has the cylinder head, oil pan, oil filter, all brackets, suspension knuckles and more coated in. My motorcycle frame is also done in it. It's also a good base coat for candy colors which I have done a bunch of.

I'm fond of the vein colors in general and enjoy using copper vein and gold vein, also. I first got the silver vein specifically as a base for candy.

I had a little fun with the candy red and silver vein in the engine and tank badges for that CX500. I didn't do the candy over the silver vein in this case.

 

[JRK5892]

alpha motor looks great!

OP: you can blow out any media that gets in there and/or plug it up man... just take your time masking

soda and bead are not a good surface for cases, as stated alum oxide is the way to go, here are some engine parts we have done in gloss

 

[Powderfinger]

All good advice you are getting, one other thing you can do as one of the final steps is go over the parts with a small propane torch. This will burn off any stray pieces of lint.

 

[Tremelune]

Very exciting stuff. I got a few small pieces coated with great results following this procedure:

1) Spray the sucker.
2) Preheat oven to 400 F (which for my oven was best achieved by setting the oven to 425 F, according to my oven thermometer).
3) Transfer piece into the oven.
4) Check the temp of the piece with an IR thermometer in various places.
5) When it broke 400 F, set a timer for 10m.

The only problem I had was finding out that the Eastwood HotCoat 10103 black satin powder is way closer to flat/primer than gloss. The finish is even and durable, but just too flat. So, I'm going to spray paint these suckers the same as my frame (Rustoleum 7777830 Satin Enamels), buy some satinnier powder, and see how it goes with another small piece before doing the tricky case bits.

 

[SONICJK]

Yep satin is one step up from flat. That frame looks more semi gloss maybe?

 

[JRK5892]

PBTP satin black is going to be a much closer match buddy

 

[Scratcher09]

Lots of solid advise here.

I also am a fan of silver vein. I had done the case covers and many other parts on my mostly blacked out SV650 with silver vein and it got a lot of compliments.