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Some clearcoating solutions (adv.) pointer   


Q. I am inquiring about polished aluminum, specifically the polished engine case pieces of 1970s motorcycles. I like to fix up these bikes as a hobby. My problem is identifying the clearcoat applied to these polished aluminum pieces. The clearcoat is so unobtrusive that a lot of enthusiasts do not realize it is there. In some cases the original Japanese factory applied clearcoat has turned to a yellowish color. Commercially available "Aluminum Clearcoat" products have proven unsatisfactory. What is the secret to coating polished aluminum with an extremely clear, long lasting protective application?

Many thanks,

Michael Waugh
- Decatur, Alabama


Q. I am trying to find the best way to keep the aluminum parts on my motorcycle their mirror finish a long time and make them EASY to clean. I have tried many different things and I'm now ready to do whatever it takes to make them look show quality but very easy to maintain. I have heard of people using UV resistant clear coats. Any recommendations?

Joe Mergl
polisher - New Jersey


A. Hello Joe; hello Michael.

Remember that there are countless grades of aluminum, and some are optimized for clearcoating while others aren't. If the part was originally clearcoated or clear anodized, it's probably a good alloy for brightness; but if you stripped paint off of it, it's probably an alloy that wasn't intended to retain brightness and doesn't do as well.

It isn't easy picking a clearcoat either. If one coating was manifestly superior to the others in broad ways over a broad spectrum of conditions, the other 999 would have been off the market in short order :-)

Bright dipping plus anodizing isn't for the do-it-yourselfer, but it is what was done on aluminum bumpers, and tens of millions of streetlight reflectors, and may be what was done on those bikes originally -- it is available from plating/anodizing shops. Good luck.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


A. POR-15 Glistenamazoninfo, amazing stuff.
You can buy it online too; it's pricey but worth it. Clear powder coating can be good too, but its can be too thick a coating sometimes.

R Malm
- Ottawa, Ontario, Canada

March 28, 2008

A. The POR-15 Glisten PC has worked VERY well for my polished and brushed aluminum pieces. Is is very durable.

Understand, it is not 100% clear, so the metal takes on an ever-so-slight haze.


Adam Streubel
- Appleton, Wisconsin

Por-15 Glisten Clearcoat

November 23, 2008

A. I've been researching this for a while. I've tried the Glisten PC --^, and yes it does add a haze. It's also prone to runs.

I've heard raves about Permalac and Imeron. Eastwood has Diamond Clear.

VHT is said to have a good clear (VHT Clear Coatamazoninfo), and then there's always Zoopseal.

I'm looking to clear coat some polished brass, and will likely go with the Permalac for that. We'll see how it goes.

Adam Streubel
- Appleton, Wisconsin

Ed. note: According to a plausible posting on, ZoopSeal no longer exists, and its inventor replaced it with ShineSeal [link is to product info on Amazon].

September 15, 2009

A. I used a product called Everbrite on my polished aluminum valve covers, applies easily, no runs, & has held up very well. I have no affiliation w/them, just great results.

Fred Ryder
- Haines City, Florida

Will chromate conversion coating stop black spots on powder coated sanded aluminum?

June 13, 2014

Q. I have a 6061 aluminum extrusion that we are sanding and applying a clear powder coat to, It looks as if sometimes the heat from the powder coat oven bakes something out of the extrusion and leaves black spots under the clear coat. Would Alodine help seal the part and stop this?

Jeff Hodgson
precision manufacturing - Champaign Illinois

June 2014

A. Hi Jeff. It's hard to confidently say that chromate conversion coating will help the black spots specifically -- but it should be done anyway for better adhesion, corrosion prevention in the event of a scratch or pinhole, deterring filiform corrosion, etc. Powder coating should not go directly onto bare metal, but onto pretreated metal. Good luck.


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

June 19, 2014

A. The Black spots are obviously contaminants.
I would think that they are possibly soot particles from incomplete combustion in your cure oven.
You can tune your burners to reduce or eliminate the problem from recurring.
You could "paint" your oven walls with odorless fish oil to decontaminate what is already swirling about.
Otherwise it could be just powder contamination from prior jobs in which case the "painting" option is still a winner.
Hope this helps.

William Doherty
trainer - Soldiers Pt., Australia

June 20, 2014

There is also a possibility that it is coming from the extrusion lubricant that has become imbedded in the metal.
I would run a test sample of wrought aluminum to see if it the oven or the aluminum.

James Watts
- Navarre, Florida

December 12, 2014

I have built a teardrop trailer and clad it with sheet aluminium. I wish to apply a clear coat to the surface and need advice. Thanks.

Ken Howes
- Windhoek Namibia

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