countylawdog

I have finally decided to powdercoat my plenum, tubes and valve covers on my 89 L98. I have found a respected pc'er to perform the task, however I have a question or two:

1] do I pc where the part butts up and bolts against another part or should that area be clean of pc'ing?

2] is there any internal parts inside the plenum I need to worry about?

3] how does the pc look on the magnesium valve covers if they are not smoothed out. I have seen pics of the vc smoothed out and pc, but not the other way.

Anything else I need to know, besides doing an exceptional job of cleaning and preparing everything.

Thanks

shakedown067

1. The metal should be clear of any paint where it mates to a gasket/metal

2. Yep. Everything should be masked so the powdercoat doesn't get inside to disrupt airflow unless you port and polished afterwards while it's off.

3. No clue on this one..

AGENT 86

Powder coating won't hide flaws. If you want your mag covers to look great, fill flaws, pock marks etc, with lab metal and sand covers to a smooooth finish.

vinnies87

as agent said, PC is only as good as the prep... also have your PC put a Clear Coat (gloss or Satin) as the final, definately help save the PC and improves the look

jhammons01

You need to mask the surface under the areas where the bolt/nuts will contact it. The reason being when you turn it ti tighten the Powder coat will chip or peel

cv67

Only problem Ive heard with PC'ing magnesium is the outgassing afterward.

AGENT 86

I masked no bolt/nut landings, just masked gasket-ed areas a tad smaller than gasket and plugged threaded holes. My Super Ram is powder coated top to bottom, no problem with torquing all fasteners.
Applied correctly, powder coat is super tough.

countylawdog

Now, when you say "masked" are you using just regular masking tape??

Thanks for all the other tips

AGENT 86

No, special tape is required. The stuff I have is a clear green.



Whats cooking in your oven

Midnight 85

Outgassing is a problem if the part is not pre-heated to around 400 degrees for 10 or 15 minutes. Once the part is pre-heated there should be no more outgassing.

99-ss-vert

Depending on the quality of the powder and the application equipment, the part may not have to be preheated. If the coater maintains ground from the time the parts are sprayed to the moment the part enters the oven, the paint will stay on the part. Outgassing can occur on any substrate and is usually due to under curing (not enough heat or dwell time or a combination). Preheating the part causes the paint to gel on the substrate prior to putting it in the oven and can screw with under or overcuring the paint. Lawdog, if you have a good powder coater, you should have no problems.

KevinRR

I do some powdercoating for myself and a little for my customers as well. Most of my work is on aluminum manifolds, and as such I always preheat to try to outgas and wind up with a better end product. I also like the wrinkle colors because they hide casting flaws and material texture very well and still look awesome. The wrinkle colors are semi-gloss which is nice for an engine bay, because full gloss colors look awesome to begin with but they show dirt, grease, and water spots very easily. Also the rest of your hoses, trim, wiring, etc. are going to be a dull black, and so putting a super gloss black beside it kinda makes everything else look blah. Putting a semi gloss wrinkle black beside it doesnt look so bad.

It is of utmost importance that any mating surface is masked/capped/plugged. It is painstaking work on something large and intricate like an intake manifold but it smooths reassembly later and is a requirement for a proper job.

Here are pics of my setup I just did. Wrinkle black and chrome.

Midnight 85

Well,, I'm glad your happy with it. Wait until it gets dirty and you try to clean it, let us know what you think of it then.

Midnight 85

I would like to know where you got this info. Do you do powdercoating?
If I read correctly you are saying that gasses that are in the metal will not escape under heat if the piece is grounded??

jhammons01

Kevin! Hey there Brotha

Bump for stand up person! Welcome to the CF

KevinRR

Hey man, I figured I'd bump into you over here at some point. I dont post much here but do some reading here and there. I'm working on restoring/repairing my old man's 85 slowly, and trying to avoid the corvette tax on parts.

KevinRR

I've never slung mud all over the parts and then tried to remove it, but I don't see any real issues with it during normal use?

jhammons01

Out gassing the part does not necessarily mean applying powder while the part is hot/warm.

But a Bake out period will get a part to out gas to a degree that will help with powder.

jhammons01

I was surprised to see your name but I welcome you.

The Tax can be avoided on many accounts but you have to dig in here to find out where/what to buy. Sure there are some Vette only parts that cost you, but trust me, on my car building budget, I have saved thousands from using this forum. Your the same way I am, You'll dig into an electric motor and find the broken gear to replace rather than buy a new electric motor......so you'll save a ton of money over here.

99-ss-vert

First, let me correct myself on one point, outgassing is NOT caused by under or over curing a part. It IS caused by air entrapment in the casting. Preheating the part can help keep this from occuring however there are powders that are designed to allow the part to outgas. These are typically higher quality powders.
Second, what I was referring to with regards the subject of grounding, you are probably aware that powder is designed to be applied electrostatically requiring the part you are painting to be grounded. If you don't have a good ground, the powder won't stay on the part. You can cheat this by heating the part before you paint it. This causes the paint to pre-gel and stick to the part.
Go to www.powder-coaters.com to see more.

Finally, I am NOT a coater, but a supplier.