nymarine paint prep and clean up

[jimmy]

Hi,

I’ve ordered Alkyd Enamel paint from nymarine for a Johnson restoration, and was wondering what others are using for preparation and cleanup. Peter recommended "base coat reducer" as a final step to de-grease the parts, and either the reducer or "gun wash" to clean up my spray gun.

I saw on some other restoration site that he just used lacquer thinner to prep the motor. Would this be okay? And the gun wash comes in 5 gallon drums, which was a bit of overkill for this size project. Again, would lacquer thinner be ok to clean the gun? There is a local Finish Master where I hope to buy whatever else I need. Are there specific brands I should look for?

I do have access to a full spray booth with fresh air supply, but my friend usually sprays automotive urethanes. I just want to make sure I’ve got everything I need to work with this paint.

Any other tips from those who have sprayed this paint are greatly appreciated.

[nj-boatbuilder57]

I am by no means an expert on metal finishing, but there’s one thing that I’ve learned over the years: painting aluminum is harder than most other surfaces.

Aluminum alloys oxidize immediately on contact with air….can’t be avoided. So you’re never really painting "aluminum" as much as you’re painting aluminum oxide….and paint really doesn’t stick to oxides very well. Sometimes it won’t adhere at all.

Yes, cleaning with a solvent of some sort to remove grease etc. is essential….no doubt. (I like naptha first, followed by acetone). But all the cleaning & degreasing in the world isn’t enough; the really critical part is choosing the proper prime.

Aluminum etching primers like zinc chromate or zinc phosphate are what work the best, as they’re chemically designed to cleat into the oxide and create a suitable paint base. If you take Peter’s paint and simply "go for it", you may be unhappy with the results, and Peter & his paint are NOT the problem.

[jimmy]

Hi NJ,

Good points, I’ve also got NYMarine’s self etching primer on order.

[nj-boatbuilder57]

AH….good!

Then I guess all you need to do is clean it. Lacquer thinner will work as a cleaner, but is pretty expensive, for what it is (a blend of acetone, toluene, alcohol & amyl acetate). For what you’re doing, naphtha & acetone are cheaper and work just as well. Naphtha loosens & removes any grime; acetone really cleans the surface of oils.

Wear nitrile gloves…..the oil in your fingerprints can undo all the degreasing work you do.

EDIT: Hey…are you the same JimmY that built the Glen-L Squirt? I’m Mark-NJ that built the Ski-Tow….

[jimmy]

Hi Mark,

Yes, I’m the same JimmY. Your handle here makes sense now!

I can get lacquer thinner for $5/quart, which is a bit better than buying a gallon for $35.

[Mumbles]

Up here, gunwash is about the same price as lacquer thinner so I use the lacquer thinner to clean the guns. You’ll be using lots of it for cleanup so make sure you have lots on hand. Any leftover will get used down the road.

After lightly sanding the self etching primer, a dusting with clean and dry air and a light wipe with a tack cloth should be enough prep for the paint coats. Don’t wipe the primer with reducer or thinner or you will be starting the job all over again as it can melt the primer. You might want to read the small print on the primer can to as some primers are non-sanding so the surface has to be fully prepared before the primer goes on.

Just remember, if you can feel anything thru the primer, you are going to see it thru the paint so double or triple check for flaws and fix them before considering it ready for paint. Following this step will help give your paint job a professional look!

[Author]

Posts