rubrail questions

[Lunasea]

I recently purchased this boat with a solid metal rubrail trimmed with a stainless steel strip. I am unsure what the rail is, I am thinking that it is aluminum, I tried using a magnet with it attaching. but as you can see in the pictures, there is some form of degradation behind the stainless. So I need to remove the stainless and find a repair for the rubrail? I am obviously worried about breaking possibly every screw that attaches the rail and trying to figure out how to drill them out. plus, do I just paint or cover the exposed metal?

it almost looks like I need a grounding strap to the rub rail?

 

[kchace]

It's hard to tell from a picture, but it does look like aluminum corrosion. with stainless screwed to the aluminum and salt water contact, the aluminum will always lose. This is galvanic corrosion and grounding will make no difference. The only thing you could possibly do and I don't know how you'd do it in a practical sense - is electrically isolate the stainless from the aluminum.

Ken

 

[DHeckrotte]

Yup, looks like aluminum anodized black. Are there separate, concealed screws that hold the aluminum (I think I see them in the top pic.)? And the second set of screws holds the SS? Unless you are an exemplary human being, you'll break most of the screws holding the stainless and not a few of the ones holding the aluminum to the hull. This is an assembly that's basically a battery and almost guaranteed to fail as you see. Sailboats often have this sort of assembly and they take great, but usually unsuccessful over time, efforts to electrically isolate the SS, the SS screws, and the aluminum with insulative goos and gaskets sold for the purpose.

You have some choices: clean it up and touch up the black, remove the SS and isolate it and its screws from the aluminum, remove and replace with a vinyl/SS, or a wood/SS rubrail. Might as well put a bigger (thicker) one on while you're suffering.

 

[RT Firefly]

Greetings,
Mr. L. I agree with Mr. kc. Are the SS screws machine screws or sheet metal type screws? In either case, you may find an impact driver will aid in removal after soaking with a penetrant.
Impact Screwdriver Set with Case

 

[kartracer]

TACO metals has that rail if need some.

 

[kchace]

This is an assembly that's basically a battery and almost guaranteed to fail as you see

Battery, I like that term and quite true in this case.

 

[Lunasea]

well that is disappointing. I do not want to remove the aluminum rail, it seems fine despite the exterior damage. Maybe remove the stainless and repair the exterior rail? Should I try to repair the damage IE bondo or fiberglass? maybe weld repairs over every screw hole? Or just remove the stainless and paint the aluminum rail?

 

[Lunasea]

could I find aluminum flat rail to replace the stainless pieces to retain the look? plus it would cover the damaged black aluminum

 

[koliver]

well that is disappointing. I do not want to remove the aluminum rail, it seems fine despite the exterior damage. Maybe remove the stainless and repair the exterior rail? Should I try to repair the damage IE bondo or fiberglass? maybe weld repairs over every screw hole? Or just remove the stainless and paint the aluminum rail?

I have had some success and some failures with aluminum that I have painted.

Better preparation and using a primer works best, then a black topcoat. Refasten the SS and you will be good for at least a few years.

 

[DHeckrotte]

Well, then Lunasea, just scrape the worst of the mess off the aluminum and touch-up paint it dull black. Some time down through the years, the SS screws may cause enough corrosion in the aluminum to pull out. Replace 'em as necessary with larger ones gooped up with sealant. I've painted silver anodized aluminum with ordinary aluminum paint; looked fine (even where the paint was adjacent to the anodized surface). I've painted a previously painted aluminum mast where corrosion was creeping out from under (non-life-threatening) fittings using Procon Primer and Brightside Polyurethane; still giving good service after about 10 years.

You'll lose nothing but the effort. You'll always be able to bite the bullet later and replace the rubrails with something less subject to corrosion. It won't come apart happily now or later and you'll just do the demolition with a cut-off wheel in an angle grinder.

 

[Benthic2]

West Marine has a variety of Aluminum and Vinyl rub rail inserts here:

https://www.westmarine.com/rub-rail

 

[mike50]

Highly recommend using Tef-gel on SS screws into Al.

 

[AusCan]

Highly recommend using Tef-gel on SS screws into Al.

Great stuff!

Smear it on the aluminum wherever it contacts the stainless.