Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
-----
Clear coat sealing aluminum for outdoors
Q. What is the best way to protect a solid aluminum sign I will be hanging on the exterior of my building. I would like to retain the look of the natural aluminum so something clear is important.
Tija Patrick- Los Angeles, California, USA
2003
A. Hi, Tija. I'd suggest that you have it clear anodized, although a good clear coating is an alternative. Best of luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003
Q. I would like to give a gloss clearcoat on polished aluminum wheels and forks of my motorbike. Is there something I can apply, or is anodising the only solution?
Stephen Spiteri- Santa Venera, Malta
2005
A. Hi Stephen. Clear chromate conversion coating followed by a clear coat should be fine. Just make sure the clearcoat is UV resistant so it doesn't turn yellowish too soon.
Luck & Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. We have a solid cast aluminum table top that is used OUTDOORS on Restaurant patios. We have a good powder coated surface, but water spots, and oil from fingerprints and food leave "spots" in the paint that cannot be washed off. The paint also can be scratched easily when metal objects are dropped onto the table or pulled across it.
I understand a Clear Coat would help us eliminate the spotting and scratching issues. My question is what product is best to use for OUTDOOR environments? And will not yellow or crack over time, and if intentionally scratched (keyed or screwdriver used to vandalize)or burned (cigarette butts), what method can be used to repair the scratched or damaged surface? Also, is there a "powdered clear coat" that can be applied over the colored powder coated paint? or will a 'wet' system provide a better finish?
Buyer - Franklin, Tennessee
February 28, 2008
adv.
Hi Doug,
I have a chemical called Sharkhide Metal Protectant. Sharkhide⇨
is a wipe on chemical treatment that's fast drying (60 to 90 sec.), and is completely UV stable. It's water proof, and not affected in the least by the elements.
To repair things like scratches you would simply swipe a new coat over the old. Sharkhide is self etching, so the new coat momentarily melts, then flows into the base coat. For extreme damage, you would wipe off the old coat with lacquer thinner
⇦this on
eBay
or
Amazon
[affil links] Warning! highly flammable!
and a paper towel, then re-apply a new one over the area.
I hope this helps,
O'Fallon, Illinois
Ed. note: Readers -- to the extent possible, please suggest technologies and types of products rather than brand names or sources (huh? why?)
Multiple threads merged: please forgive chronology errors :-)
Q. Dear Sirs
We are currently manufacturing & installing signage outside in Dubai, UAE. In summer the temperature can reach more than 45°C with high humidity. The metal surfaces are highly polished architectural grade Stainless steel, copper & brass sheet metal. Although ornamental [thus no mechanical wear & tear in expected], the extreme weather exposure will cause these pieces to tarnish quickly. What gloss finish clear coating would be suitable to maintain a the mirror polished finishes? We have previously used Urethane spray on coatings, but this tends to blister & perish after a few years. Please advise.
Regards & many thanks.
- La Lucia, Durban North, Kwazulu-Natal, South-Africa
March 27, 2008
adv.
Hi Chris,
We use Sharkhide Metal Protectant on all sorts of polished items⇨
On commercial items such as polished tank trailers, we can expect several years of protection from a single application. Since your items don't see the abuse a trailer does, you may see up to ten years or more of protection per application.
I hope this helps,
O'Fallon, Illinois
Ed. note: Readers -- to the extent possible, please suggest technologies and types of products rather than brand names or sources (huh? why?)
A. Hi, Stephen.
Yes, a clearcoat can offer some protection from corrosion. There are many pretty good ones. If you have an automotive spray gun, you can try 2-component automotive clearcoat. I've recently heard of two-pack clearcoat in some special rattle can which apparently mixes just before or while you spray it.
but I haven't tried it. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 30, 2010
Q. I just recently purchased some 6061-aluminum angles for a residential interior guardrail application. I want to polish the angles to that I can get the stamped text (ASTM info, etc.) off as well get it to a fairly decent shine (not mirror finish). What is the best way to go about doing this? Also, when is it necessary to consider anodizing or doing something to protect aluminum from corrosion in an interior application? Do I need to take them somewhere to have them treated or is there a way a can do this myself? Thanks,
Princeton Porter- Voorhees, New Jersey
2003
A. Hi Princeton. You can buff the aluminum with a power buffer and compounds made for aluminum. After buffing, you may want a scratch-brush look (which is done with one quick "scritch" with sandpaper. But aluminum must always be protected from corrosion and if you want to maintain the natural color without continual rebuffing, even inside. Your choices are anodizing it or clear coating it. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
by Stephen F. Pollard
on AbeBooks
or Amazon
(affil links)
Q. I recently purchased an old sailboat with some "well used" aluminum spars (boom, mast, etc.). I would like to clean them up. I can wet sand the parts to get a nice smooth surface. Doing so looks like it will remove the anodizing. Given the marine environment and winter (garage) dry storage I am setting myself up for rust problems down the road. It is my understanding that Aluminum has a thin natural oxide coat. Is this sufficient? Do I need to re-anodize the parts? Given the fact that the mast is 25', I am afraid that trying to find someone to do this may prove difficult and expensive. Moreover, a 25' tank is outside of the hobby kits? My questions are:
1) Do I need anodization for this application at all?
2) If so are there any cheap options to get this done?
3) If not, are there any kit type processes where I could do this at home without killing myself?
4) Are there any other options that will look okay?
Rustbullet
⇦this on
eBay or
Amazon [affil links]
? Rustoleum? etc.
Thanks. I apologize if this is a duplicate question. I couldn't find anything on point.
Timothy Nathan- Monroeville, Pennsylvania, USA
2004
A. Hello Timothy. The natural oxide film on aluminum will not protect it in this environment. Architectural aluminum is anodized in tanks of 40 - 50 foot wide every day, so finding a shop to do it at isn't totally out of the question, although it probably wouldn't be cheap. But if you want to do it yourself, paint is a good alternative you can do for yourself, clearcoating probably won't be as durable. Maybe see if the marine store has an aluminum primer ⇦this on eBay or Amazon [affil links] and a good quality marine paint in your choice of color. If you or someone can pretreat the aluminum with Alumiprep 33 ⇦this on eBay or Amazon [affil links] and Alodine ⇦this on eBay or Amazon [affil links] , the corrosion resistance and adhesion can be further improved.
But don't go near aluminum with "bottom paint", as the copper content will cause aluminum to corrode rapidly. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. I have a boat with a tower and some of the anodized aluminum is rough, the anodizing has worn away or scratches in the finish have left those areas rough. Are there any system to make these repairs? I was a finisher of wood for over 20 years so if you could suggest a system I could follow and materials I could use that would be appreciated. Capt. Joe
Joseph Branzetti- Danvers, Massachusetts
2006
A. Hi Captain. The "roughness" and oxidation must be corrected mechanically by sanding and power buffing as needed. You could try simply power buffing with something like Mothers Mag & Aluminum Polish ⇦this on eBay or Amazon [affil links] but it may not be abrasive enough to remove the roughness in a practical amount of time -- you may need something coarser for the first step.
After it looks pretty good you can clear coat it or send it out for anodizing. These towers are sometimes anodized after fabrication, so you can inquire of a local tower builder whether they have a lead on a place to get it done in your area.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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