Sealing Aluminum to prevent oxidation?
Some clearcoating solutions (adv.) 
A discussion started in 2003 & continuing through 2017 -- add your Q to bring it back to the Hot Topics page.
(2003)Q. I am a manufacturer of custom machined aluminum parts, both polished and brushed aluminum, and I would like to know the most economical way to prevent oxidization and keep a long lasting finish on the product. All of the parts that I make are for automotive detail/finishing for either engine compartments or interior such as radio trim pieces, speaker grilles, sill plates, radiator covers, etc.
Kyle Williams- Omaha, Nebraska, United States
(2003)
A. Hello, Kyle. The two common alternative approaches would be anodizing or clear coating (which in turn can be one part or two-part, applied by spray or brush, or a powder coating). They are all rather different, and it may depend a bit on the look you want as well.
Multiple approaches exist because there is no one best approach for all conditions. It may be that anodizing is appropriate for some of the parts and different types of clear coating for the others ... but since you asked for "most economical", a one-part spray-on or brush-on clearcoat will surely win by that measure.
Good luck
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
(2003)
A. I've been using a spray clear coating on architectural aluminum for 2 decades with wonderful results.
Bruce Smith
metal refinisher - Hayward, Wisconsin, United States
(2006)
Q. Please tell me more about chemical that can be used for sealing of aluminum material.
Thanks.
- Ho Chi Minh City, Vietnam
May 30, 2008
Q. How can I find the spray on sealer for Aluminum?
Thanks Rob
- Embudo, New Mexico, USA
May 2008
A. Hello, Nguyen, Hello, Kyle.
One-part clear coats for aluminum are available from many sources including Everbrite [a finishing.com supporting advertiser]. Two-part clear coats are available as "automotive clear coat"; these cure by chemical reaction (like epoxy) rather than by drying, so they typically use professional spray equipment, but they can apparently be done with specialized aerosol cans which spray both components at once =>
Good luck.
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
November 17, 2010
Q. What clear topcoat (brand) is best to protect brushed aluminum? I have used Rolite Premium polish and sealant that wipes on and off with some success, but I want to retain that bare, metallic look so am looking for the optimum sealant/protection.
Tom PopeFinisher - Clearwater, Florida, USA
November 16, 2010
A. Hi, Tom. Sorry, but we only talk technical issues here, like comparing types of clearcoats and their technologies, not brands. Unfortunately, the internet is largely anonymous, and the site instantly attracts shills, some even posing as satisfied customers, when there is a commercial opportunity. Brand names have ruined threads here a dozen times and we're finally learning and not comparing them :-)
But Everbrite [a finishing.com supporting advertiser] is certainly a reputable brand.
Regards,
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
January 18, 2012
Q. What can I use for sealing edges of anodized aluminum weldment? I'm trying to seal the unwelded portion. Corrosion is starting to leach out. Clear or dark gray caulking sealant?
armando amoranto- Seattle, Washington usa
January 20, 2012
A. Hi, Armando. The best surface protection would probably be chromate conversion coating followed by a 2-component or powder coated clearcoat on any surface that isn't anodized.
But when you suggest caulk, it sounds like you are talking about a capillary crevice, such as between two sheets in a stack. Sealing in the remnants of acid doesn't sound promising to me, but better rinsing during the anodizing process (hot & cold, and including a dilute nitric acid or sodium bicarbonate dip) usually helps. Alternately, sealing the parts with an anaerobic adhesive before anodizing may work too. Good luck.
Regards,
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
May 19, 2016
Q. What would you recommend for cast/extruded aluminum materials, to protect the powder coating from oxidation or fading?
Paulena Jaks- Toronto, Ontario, Canada
A. Hi Paulena. The substrates must be properly pretreated before powder coating, which probably means a chromate process or tri-chrome process (please see Mil-DTL-5541 [link is to free spec at Defense Logistics Agency, dla.mil] for this). Then a polyester powder coating.
If you can offer full details of your situation, you can probably get specifically targeted advice rather than just truisms :-)
Luck & Regards,
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"
June 5, 2016
Just saying thanks for the info. It really helped.
- Mechanicsville Virginia USA
July 6, 2016
Q. Hi. Just read your responses to the clear coating of aluminum.
I am working on restoring lawn chairs which have tubular aluminum legs and arms. Some I am replacing while others will be re-used. Some of those have marks, grime, pits and stains. I have burnished with 000 steel wool. Is there any recommendations for a layperson? I was wondering if a 'dry lube' could work but would prefer a clear coat?
Your thoughts?
Mike
- Cleveland Hts, Ohio
August 11, 2016
Q. Please advise if there is a product to seal painted aluminum soffit to slow or stop the growth of mildew. I really don't understand what is happening, on the front of my garage, one side of the soffit is clear of mildew but at the seam it starts to mildew and follows that piece the rest of the way across. there are other places that do the same thing. Looking for a solution and thank you for any light you can shed on the subject.
dee moore- savannah, Georgia USA
February 5, 2017
A. Dee,
Your paint supplier can sell you specialty primers and paints designed for this particular problem. A couple of ideas: Check gutters and moisture sources to be sure excessive moisture is not affecting the problem areas. Frequent power washing and scrubbing may be needed. Mildew hates hot dry sunlight so maybe it's time to trim some tree limbs.
Feather Hollow Eng.
Stockton, California
December 20, 2016
Q. Hi,
I recently polished the wheels and front forks, etc., on my 1998 Honda F6 motorcycle and wanted to protect the shine and more so to stop oxidation. The original aluminum was protected by a clear coat which the manufacturer applied. Can I apply a one or two part clear onto the parts? Will it adhere. I have spray equipment.
- Galway, Ireland
Repairing oxidation (and protecting) aluminum garden stools
February 27, 2017Q. Hi,
I recently purchased these aluminum garden stools for outdoors =>
after a few days in the rain, they oxidized and have spots all over them! :(
I didn't exactly think that one through, as there has been a lot of rain in my area recently.
I purchased Star brite Aluminum Cleaner, which I noticed has sulfuric acid in it.
My questions...
- will Star brite (I hope) repair the oxidation?
- after removing the damage from oxidation, I'd like to protect it from further incidents.
I'm planning to use Rust Oleum 280702 American Accents Ultra Cover 2X Spray Paint, Gloss Clear by Rust-Oleum to seal it. Will this work well to protect it during rain, and from oxidizing?
Should I polish it before I seal it, say with Mothers Mag & Aluminum Polish?
Thank you for your help! :-D
Laura
- Huntington Beach, California
Q. I work for a group that travels with horses. Several stalls are partially aluminum and wham the horses run on them (scratching themselves) they tend to get aluminum dust stains. This is lousy before a show on white horses.
What would be a suggestion to safely seal the stalls?
Safe for the animals in case they lick it.
Thank you so much.
Odysseo - Portland, Oregon USA
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