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Surface Corrosion

By Scott Smith, Marketing Manager

Well, here we are, on the back cover of the Action, looking to hit yet another home run with an incredibly informative boat care article. Lotsa pressure. What to write about…this is the difficult part. You know, you look at a boat and you see a lot that needs to be taken care of. I mean, this is your baby, and you want to treat it right, and you want to make sure everything is working.  I’ve got a responsibility to provide a fresh perspective on boat care and to keep long-time Action readers provided with new material­-that’s why I love e-mail.

After racking my brain for a few days, I got this incredible idea to e-mail people right here at Thunderbird and ask them what they thought would be important in terms of caring for a boat. I reasoned that this would force me to look at boat care from many different perspectives. Although I did receive a lot of suggestions completely unrelated to the subject at hand, I did manage to glean enough serious responses. One team member was enthusiastic enough about his idea to send me a series of three e-mails:

  • – “How about a story on how to use corrosion block in the bilge? Benefits, types available, how to apply, safety in application, etc? Thanks.”
  • – (Second e-mail) “Hello, Scott. The article could also go into corrosion block on the back of gauge and switch panels, and breaker panels as well? Thanks.”
  • – (Third e-mail) “Hey, who’s writing this thing anyway? I do not care for WD-40 (in the marine environment) as it tends to evaporate …My favorites are Boeshield T-9 and Corrosion Block. May be some other out there (that work well also). I would warn people that a bit of their engine and equipment shine will be gone, but that is because a film of  there …Yes, turn off the battery switch; do not spray on something hot . I am sure that one should have a respirator on as they may have their head in the corner of the bilge. Thanks. P.S. This is not meant to be the article ready for print!!!!!!”


Mr. S.P., Formula executive and all-around good guy.

Well, I guess it wasn’t ready for print–I just needed to flesh it out a bit. In any case, this is the type of enthusiasm and team mentality that I live for! Actually, there are many points to be well taken in this cluster of e-mails. First and foremost, the fight against corrosion in a marine environment cannot be overemphasized! If anything metallic lives around the water, it’s going to corrode sooner or later if there’s no intervention. I have written in the past about galvanic corrosion (Spring/Summer 1998); however, the focus of that article was on components below the waterline in some sort of electrical contact with the body of water itself. What this loyal Formula team member is alluding to is surface corrosion which is more a localized problem than a full-scale bonding problem. It’s still an electrochemical reaction; however, all the proper bonding and NMMA/AYBC/Coast-Guard-regulation wiring and construction protocols in the world won’t prevent it entirely. Further protection is necessary.

Let’s explore the problem: When two metals of dissimilar electrical potential are connected and an electrical circuit is completed between the two, the instigator is usually an NaCI molecule common to the marine environment. When this battery effect occurs, an electrochemical reaction changes the molecular structure of the metals and, in most cases, causes a breakdown of an installed electrical circuit. In layman’s terms, salt air causes rust and component failure. To prevent this, you must block the corrosive molecule from coming in contact with your stuff! The easiest and best way to do this is to rinse off everything in your bilge (also your drive, trim tabs and steering components) and spray thoroughly with a penetrating agent that displaces water and leaves a tough, sealed film. The same applies to electrical panels, except you should simply wipe them clean after turning the power off to them.                         

It is key to use the proper product for the job at hand. The person sending the e-mail was not criticizing WD-40, for instance (a fine product and penetrating agent in its own right), but a characteristic that makes it good for use in normal household and garage projects is a strike against it in the marine environment: it evaporates too quickly and the corrosion barrier disappears. What you need is something designed to  kick out the salt and the water, then stay there and prevent the metal from oxidizing. That the e-mail author of this message recognized some dulling and its being a sign of a barrier of protection shows experience and understanding that prevention is the best method for long-term protection of your bilge and electrical hardware. A couple of very good products are Corrosion Block® (available in many marine stores, or call 800-256-2548) and Boeshield T•9 (616-355 -6615), developed by Boeing for long-term aircraft protection. Either will provide a tough, lasting barrier on clean metal.

Finally, yes, there are some caveats. Turn off your battery switches, and do let surfaces cool down until you can touch them. You don’t want to cause a fire, nor do you want to burn the protective film off. As Mr. S.P. states, if you’re going to keep your head in an enclosed space while spraying the film on, a respirator may be in order. Avoid your eyes and your ears–just use the same precautions you use when spray painting.

Controlling surface corrosion is a time-honored battle of the mariner. Become a part of the tradition and clean and spray down vital components periodically, and every time you lay up out of salt water for an extended period (winterizing? Hint, hint!). This will help protect your Formula for years to come!