Aluminum Swingarm Damage: Smart Fixes for Acid Blemishes

Summary for aluminum swingarm damage Discussion

Aluminum swingarm damage from battery acid is usually not something you can truly “clean out” and make disappear. In the thread, Toni explains that the sulfuric acid removed the aluminum oxide layer that gives the swingarm its dull aluminum appearance, so the only way to restore a uniform finish is to remove the swingarm from the bike, take out bushings/bearings, and have it stripped and re-anodized by a finishing shop. Toni says the mechanical removal work is the hard part, not the refinishing itself. A second answer offers a less exact but easier option: if the discoloration is minor and a perfect match is not essential, a self-etching primer in aluminum color may adhere well enough to blend the spot. The best choice depends on how visible the damage is, the bike’s age, and how perfect the rest of the finish needs to be.

Q. I had my battery leak acid all over my swingarm (piece of aluminum that holds the rear wheel in place on my motorcycle) So now the swingarm is discolored where the acid hit. How would I be able to remove these blemishes while having the finish match (original finish is a dull aluminum color)? I need a list of what to use so I can do this job, what works best and easier.

Thanks,

Antonio Reis
– Union, New Jersey
2001

A. Toni,

When the battery acid

⇦ on

eBay

or

Amazon [affil link]
(sulfuric acid solution) leaked on to your swingarm, it removed an aluminum oxide layer, which provides the “dull aluminum color” to the part. The only way to bring the surface metal of said swingarm back to some degree of uniformity is to remove it from the bike, then remove any bushings/bearings, etc., then have it stripped and re-anodized at a finishing shop. It’s really not that big of an operation for a facility of this nature. You or your mechanic would be doing all the knuckle-busting stuff. There is a company in Union that I know would help you out either through their services or their recommendations. The internet yellow pages are a wonderful thing.

randy fowler
Randall Fowler – Fowler Industrial Plating, LLC
Cleveland, Tennessee, USA
2001

Lead Setter’s Note: Please also visit our Shops directory; several of our advertisers specialize in automotive refinishing for the hobbyist.


Q. I read the response on how to restore the aluminum look on the swing arm. The same situation just happened to me. The question I have: Is there any other possible alternatives than to disconnect the entire swing arm to re-anodized just the small section where the battery acid

⇦ on

eBay

or

Amazon [affil link]
came in contact with the aluminum. I’m selling the bike and would like to try to fix it up with the least amount of work. Thank you.

Ryan Kazmark
hobbyist – Binghamton, New York
2005


Self-etching Primer Spray

self_etching_primer_spray

on Amazon
or


eBay


(affil link)

A. Hi Ryan. It obviously depends on how good a job you need, which in turn may depend on the age of the bike, how perfect the rest of it is, and how big the discolored area is. Self-etching primer in aluminum color should stick to aluminum satisfactorily; and if the discolored area is actually minor, it should probably be okay. Good luck.

Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha

finishing.com – Pine Beach, New Jersey



Need quick confidential answers? $25
Need project assistance? $100/hr.