Preventing corrosion in mast lights?

RhythmDoctor · #1 (**permalink**) 03-05-2011

Late last season my anchor and deck lights stopped working. I lived without them until dropping the mast last fall, and I got to do some quick maintenance on them now that the mast is down. All three masthead wires failed continuity, meaning that in the ~2 months since haulout, the steaming light had also failed.

I took all the bulbs out and wiped the copper contacts a bit - I did not have any polish or cleaner, just some WD4 on a rag. Two of the three lights then passed continuity, so it was just corrosion and/or looseness of the contacts that caused it. The deck light bulb still didn't work. Although its filament looked pristine, there must have been some corrosion in the bayonet base, because the bulb itself fails continuity. I will replace it. While I am at it, I will also replace the bayonet-type anchor and steaming lights. I have already ordered in the bulbs.

Here are my questions:

In the next couple of weeks I will do a thorough cleaning/polishing of the contact points. For the bayonet-type bulb anchor and steaming lights (dimples on the ends), I plan to burnish the copper contact points with emory cloth. I would like to seal the tips off to prevent corrosion, but I am afraid if I try to use any type of grease as a barrier that it will get too hot in the sunlight and run down to the bottom of the fixture. So I am thinking of hitting the contact points with a little dab of 3M Marine Silicone Sealant. That will crosslink in place and be heat resistant, and could be removed a few years down the road if the bulbs burn out.

Can anyone think of a reason that I would NOT want to do this?

centaursailor · #2 (**permalink**) 03-06-2011

Don,t know the 3M but I,v always used Vaseline Petroleum Jelly for low voltage connections. Lasts well, gives good contact and prevents corrosion.

Safe sailing

Minnewaska · #3 (**permalink**) 03-06-2011

How about battery terminal protector that sprays on like paint?

landmineop · #4 (**permalink**) 03-06-2011

Use No-Ox anti-oxidation grease. Holds up great. First used it in power plants. If it is good enough for commercial power plants and phone company power plants it's good enopugh for me. Look it up on line.

RhythmDoctor · #5 (**permalink**) 03-06-2011

Maybe I did not emphasize this enough: This is for masthead lights (anchor and steaming) which are exposed to sunlight and heat 12-16 hours a day. Others who tried vaseline, axle grease, and similar products have reported to me that the heat caused them to run down to the bottom of the fixture, creating a terrible mess. So if you're recommending something, I'd appreciate it if you tell me whether you have actually used it successfully in an anchor light.

landmineop · #6 (**permalink**) 03-06-2011

Again, try No-Ox. I have used it on my Harley for over 20 years and on my Morgan OI 28 for 3 years.

fryewe · #7 (**permalink**) 03-06-2011

No-ox paste is the way to go. It is specifically formulated to prevent oxidation of aluminum in outdoor electrical systems.

cruisingdream · #8 (**permalink**) 03-06-2011

another product used in the automotive industry is Dielectric grease. It protects electrical connections and wiring from salt, dirt and corrosion and is a nonconductive grease, so no stray current.

Minnewaska · #9 (**permalink**) 03-06-2011

According to the MSDS for NO-OX-ID, the melt point is 140-150 degrees F. If the connections are inside a fixture, I suppose it is possible to get that hot with sunlight on a lens. I've not been able to find the MSDS for any of the popular battery protect sprays (EZ-Red, Permatex, CRC), but suspect the ones that go on like paint have higher melt points. However, some are vaseline based spray grease and woudn't help. Track the MSDS for the battery sprays down if you can. Here is No-Ox:

http://www.cdtechno.com/msds/asset/14-320.pdf

RhythmDoctor · #10 (**permalink**) 03-07-2011

Quote:

Originally Posted by Minnewaska

According to the MSDS for NO-OX-ID, the melt point is 140-150 degrees F. If the connections are inside a fixture, I suppose it is possible to get that hot with sunlight on a lens...

A year ago I would have thought it wouldn't melt. But last summer my fire alarm went off in my house. The firemen came and measured 150°F in my attic, which set off the heat detector there. So I think it's possible. While I was leaning toward No-Ox, I think I'm going to go with something that makes a rubbery film, like maybe CRC.

I'm also considering a dab of hot melt adhesive from a glue gun. The copper strip that holds the festoon bulb is very flimsy, so the adhesive might help maintain contact.