Powder coat/anodize new mast step?

[00X]

I recently had a new mast step machined from aluminum in preparation to replace it this season. Im wondering if there would be any significant advantage having the bare aluminum anodized or powder coated to help with corrosion?

I had it made from 6061 Aluminum (extruded/hardened).

[neilpride]

Anodized to me its better, but if you dont suffer any kind of corrosion or if the step is dry and no disimilar metals around or in contact with the mast step then bare alu its ok to.

[hlev00]

Deck stepped? Salt water?

If deck stepped I would not powder coat it. I have had a few different powder coated parts (Lewmar windlass and Highfield dighy) not fair well at all in the salt environment. Even keel stepped it is likely to get scratched at some point which will provide a place where salt water will get in and cause failure of the coating.

Harry

[00X]

Thanks for replies. Keel stepped.

The bilge is mostly dry (dripless) except for occasional freshwater rain or occasional salt water. I usually mop up any standing water so step wont sit in water for more than a week or so on the rare occasion it gets wet.

The keel bolts are some variety of stainless. I believe #304, and they will contact the step in three places. Also, there is a panting rod that gets attached to the step that is stainless as well. Im guessing #316.

Other than that, just the aluminum mast will sit on it. The mast step does have a bonding wire that connects it to the lead keel as well.

[hlev00]

Oh. Seems unfortunate they will contact the keel bolts as you are asking for corrosion on some very critical parts. It also sounds like a stress point as described. Can't you machine / file the part enough to keep it off the bolts? What will that do to your ability to remove a keel bolt for inspection? But if contact can't be avoided be sure to use plenty of TefGel. Powder coating would wear through anyway.

Harry

[00X]

Originally Posted by hlev00

Oh. Seems unfortunate they will contact the keel bolts as you are asking for corrosion on some very critical parts. It also sounds like a stress point as described. Can't you machine / file the part enough to keep it off the bolts? What will that do to your ability to remove a keel bolt for inspection? But if contact can't be avoided be sure to use plenty of TefGel. Powder coating would wear through anyway.

Harry

Maybe. The bolts sit in slots cut into the step to allow the entire step to slide for and aft. The bolts are 3/4" dia. and i did cut the slots slightly oversized at 1" width, however i will need to put stainless washers over the bolts, and these will sit on the aluminum step.

This was the reason i got interested in a coating, mainly to act as a barrier between the washer/bolt and the aluminum step, but if it offered extended step life, thats a huge bonus. This mast step is fairly large and a tad complicated to get installed so really dont want to have to do this again for another 20 years if possible.

[RaymondR]

I usually put nylon washers under stainless washers when I'm bolting down aluminium.

[s/v Jedi]

Originally Posted by 00X

Maybe. The bolts sit in slots cut into the step to allow the entire step to slide for and aft. The bolts are 3/4" dia. and i did cut the slots slightly oversized at 1" width, however i will need to put stainless washers over the bolts, and these will sit on the aluminum step.

This was the reason i got interested in a coating, mainly to act as a barrier between the washer/bolt and the aluminum step, but if it offered extended step life, thats a huge bonus. This mast step is fairly large and a tad complicated to get installed so really dont want to have to do this again for another 20 years if possible.

Isolate the bolts from the aluminum. Nylon washers under the stainless washers are possibly too soft. You can simply make fiberglass washers from thin fiberglass board https://www.amazon.com/UXELY-Fibregl.../dp/B08P5QNQ1T

Around the bolts you can use nylon bushings to isolate, but the slots need to allow the room for those. You can also wrap with good quality gaffers tape.

Then there is an antiseize that works really good around aluminum. Most on CF only use Tefgel but Loctite LB 8023 is better https://www.amazon.com/gp/product/B00B74AB5C

[RaymondR]

Nylon 6 has a compressive strength of 8,000-12,000 psi.

[neilpride]

Originally Posted by RaymondR

Nylon 6 has a compressive strength of 8,000-12,000 psi.

Dont work with a keel bolt torqued to specs, they tend to crush under compression.

[s/v Jedi]

Originally Posted by neilpride

Dont work with a keel bolt torqued to specs, they tend to crush under compression.

Indeed. Also, I wasn’t impressed with the quality of nylon washers they sell, but who knows what kind of nylon they use…

[team karst]

Delrin washers and hard coat the Al.

[RaymondR]

Originally Posted by neilpride

Dont work with a keel bolt torqued to specs, they tend to crush under compression.

Pretty well depends on the area of the washer. Whatever one uses needs to retain it's electrical insulating properties by not taking up moisture.

[neilpride]

Originally Posted by RaymondR

Pretty well depends on the area of the washer. Whatever one uses needs to retain it's electrical insulating properties by not taking up moisture.

I see a huge beautiful mast step keel bolts backing plate there, aluminium in this case , wrong material of choice in my opinion.

He can make a sacrificial washer with aluminium to, or like Jedi point out, FG, but nylon, delrin, or any kind of plastic used there can compromise keel bolts in the long run, i would have made the foot of the mast in stainless steel, more expensive but easier to isolate the foot of the mast from the mast step in stainless steel than the keel bolts from the aluminium.

The plastic tends to crush leaving a gap between the nut and the plate, it could appear that the bolts are tight when in fact they are loose.

[dfelsent]

As mentioned by many above:
Bushings on the bolts
Fiberglass washers
Hard coat anodize
Anti-seize

Even though it’s below deck corrosion will be an issue without insulating the bolts and nuts.
Although hardcoat anodize is an insulator it is susceptible to scratching.

You could use any tin walled tube as a bushing. Heat shrink would probably work.
Fiberglass washers are available from supply houses like McMaster-Carr.
The machine shop that made the step may have anodizing contacts.