Which mettle is going to be best

[hardee]

Which mettle is the best choice for use on the C-Dory, in primarily salt water use?
a. Aluminum with a powder coating finish
b. Aluminum with an anodized finish
c. Stainless with a brushed finish

The goal is to have a surface that will stand some salt spray, and tolerate a freshwater wash down after each trip and be sturdy. Most of all, not need replacement in 6-7 years.

I am still working on replacing my ScanStrut radar tower that is aluminum with a powder coating finish that has failed after 6 seasons. I have not found a production product similar that will meet what I need, ( 12” rise with a forward lean ), and am looking at having one built, so I can pick what it will be made out of. I do want it out of mettle.

Harvey
SleepyC

[B~C]

what failed on your stand? if it's the finish you may be able to just have it powdercoated again.
I've been looking at radar arches and pondering what material, the polished stainless sure looks nice but is so expensive. If you only got six years out of the powdercoated pedestal, maybe the stainless isn't such a bad price

[potter water]

Stainless regardless of finish. I like mine polished bright.

[journey on]

I'm surprised that an aluminum radar mount corroded out that fast. For example, Our Journey had a powder coated aluminum mast, which was drenched regularly and it's still going strong after 20 years. It seems to me that a radar support on a C-Dory would be more protected than a sailboat mast.

Where I did have trouble was putting 2 dissimilar metals together: Aluminum and stainless will corrode each other, right through any powder coat. Found this out the hard way. So please say where the support is corroded. If it's where the stainless bolts touched the arch, you can avoid that with plastic washers.

As mentioned above, a stainless radar arch is bulletproof. The one the factory mounted is still good. You might contact the OEM fabricators to see how much one for your boat would cost.

Also, ScanStrut offers a stainless tower and a composite one. The composite plastic one looks neat, will not corrode and is about the same price as an aluminum one. The stainless tower isn't much more expensive.

Boris

[thataway]

The "mettle" of stainless steel metal is going to be the best for your radar support. There are some very high quality anodizing which will last for many years--but it is very rare to find these preparations on most consumer grade applications. (Long Beach Ca. Marina has anodized aluminum railings which are about 50 years old, and still look fairly good--but that is the exception)

There seems to be a lot of difference in the durability of powder coated aluminum. It may be the alloy, the technique or materials used. If I wanted to redo the old strut, I would completely remove the coating, then properly acid etch the bare metal, apply two part epoxy chromate coating and final good two part LP paint. I have had that last over 10 years on masts. Bori's comments on dis-similar metals is very important, especially if not properly separated.

Of course the $10 "commode" mount will not corrode at all….

[Will-C]

If it's metal your speaking of, get out the dollars and do stainless steel. I got a partial credit on my failed aluminum powder coated radar pedestal and went with polished stainless steel. Game over. Pictures in our album
D.D.

[rogerbum]

You have to have the right mettle to use the right metal.

[BrentB]

Another suggestion is use Deft 02-Y-40A zinc chromate epoxy primer (Mil Spec and used on the fighter aircraft landing gear and very tough) then use Awlgrip 545 and color it to match gelcoat

m2cw

[hardee]

I kind of messed up that "mettle" thing didn't I.

Sorry.

To clarify. I'm not sure if it is corrosion, but it is for sure powder coat adhesion failure. It is on the base, and appears to have started at on of the bolt holes. The Scan Strut tower is aluminum, and is bolted down with stainless bolts. The failure looks more like failure of the PC to stay attached or bonded to the aluminum, and may be due to the stainless bolt, or that bolt penetrating the coating in the drilled hole, or possibly the wrench making a gouge in the coating when used to tighten the bolt. The powder coating has flaked off of most of the base by now.

Boris, I have looked at the Scan Strut options, and actually have a Stainless tower from them that has a beautiful mirror finish, but it is not tall enough and the rake is aft, not forward, which I prefer, and then it is also too short for what I need. I like the idea of the composite, but really wanted the stainless.

I would love to find a 12" stainless with a forward rake and that beautiful finish, but have been unable to. At the Portland boat show, I talked to a fellow from a Tacoma company that does Aluminum tubing, (biminis, and fly bridge etc) out of aluminum, large bore, (2" up to maybe 3"), anodized with a bright finish. it looked really nice, but I was concerned if it would be sturdy enough.
They assured me it would be a lifetime finish.

I looked through the album for Will-C and the corrosion that it looks like your tower had is more like a true corrosion. Mine looks like the PC is just flaking off. The metal is still intact.

Ken, From what I have been able to find, it was probably a lack of good preparation for the PC, (Although ScanStrut denies that, unless I send it back to them to analyze --ah that would be back to UK I will pass on that. I liked the white tower, but I do not want to go through taking this one off, getting it re-done and then having to do it over again in 5 or six years.

As to the spelling, It came from looking at the name on a beautiful, Armstrong cat, based in Port Townsend, except I swapped the "L" and "E". And yes I know the difference, but was not concentrating on what I was doing at the moment, and my spell check didn't catch it. Oh well, thanks all for reading my mind, and for the great comments. I would be open to thought on good custom fab shops, probably stainless, and yes, potter-water, I like the shiny stuff too.

Thataway, I agree, the WC stand would be corrosion free, but i have a thing about wanting the forward rake, and could not figure out how to make that work with those parts. The current ScanStrut will probably go thorough that process after I get it off, and then be sold to a Brat down the line.

Harvey
SleepyC

[Sea Wolf]

Regarding Harvey's problem with the PC radar tower:

When bolting down powder coated metal structures with bolts, would it be advisable to use nylon washers to avoid having the powder coating crushed between two metal surfaces (which are a much harder material) and would seem to initiate fractures in the powder coating, and then lead to further delamination ?

Seems logical to me, anyway. What do the manufacturers recommend?

Joe.

[thataway]

Maybe I am missing something--but the strut you have now is satisfactory, except for the powder coating. If so, remove all of the powered coating. Sand it by hand until completely bright, use progressive dinner grit sand paper down to about 600. Then wash with soap and water. Blow dry with non oily compressed air. Then brush on Alumiprep33, coat with Alodine 1201, Let dry, coat with epoxy Zinc or Strontium Chromate primer, and then apply your top coat color paint of choice. If properly done, and then installed, this paint job should last longer than the powder coat did. (and if it gets a bit dull, just touch up with new paint.

[localboy]

S/S, polished. No other choice IMO. But it will cost. Also, DO NOT USE TANNER MFG! I cannot stress this enough. I had a lousy customer service experience from them and will not use the EVER again. Ask around who does good work besides them.

[redbaronace]

Have you considered having one fabricated for your boat. By doing so, you can achieve the height, and angle you are seeking. Cost might be a bit more, but at least you get what you want.

Im having an awning made locally (Seattle) and going custom was the only way to get the proper look I was after.

If you want a referral, I got someone.

[journey on]

hardee, that stainless tower would have a forward rake if you turned it around 180 deg. I believe that the mounting surfaces are parallel and the member that joins them is a truncated cylinder so the geometery is correct.

Just a thought, your choice

Boris

[hardee]