How about black toons? Metallurgist please speak up

[belercous]

I've been cleaning my toons every year with an acid bath. Leaves them pure white. Looks good & I seal them with Sharkhide. Doesn't last, but the Sharkhide helps to slow the algae growth, a tad bit. Every time an acid bath is used it takes off a bit of metal. This can't go on forever.

I cruise the Mississippi & keep it docked there too. The underskining I put on it last year has started turning dark so the water must be acidic. (.032 2024 T3 alclad. The outer layers of 2024 are 1100 aluminum which is close to pure, yet it still turns dark.) Aluminum turning black is a layer of oxidation, same as gun bluing or the dark "scale" (a technical metallurical term) that forms on steel. This is a form of oxidation which prevents further oxidation. Looking to do something similar to my logs so that I don't have to worry about keeping them shiny every year. I'd just like them to be the same color.

A light layer of oxidation will turn my logs black (or very dark), and I'm good with that IF IT WILL NOT OXIDE FURTHER. I will seal the logs after using a treatment (bluing), so that algae doesn't get a foothold so quick. Muriatic acid will turn the toons black real quick, but I'm not sure that it won't weaken the toons by eating away too much metal. After the toons get a "scale" or "bluing" I will seal them with Sharkhide.

I've given up on keeping my toons bright & shiny when it gonna last. Why fight it? I want to go with a protective layer of oxidation & don't mind having everything below the deck dark. I'd just like to keep everything the same color throughout the year. The toons want to turn dark & I'm tired of fighting them.

My questions are: Has this been done before? If so, what is the best method of putting a layer of protective oxidation on my toons? (I don't want something that'll keep eating them, which I fear muriatic acid might do. After I get the logs a uniform color I will seal them.) I can't be the first person this has happened to, nor the first to have raised this question.

Any advice will be most appreciated.

[MH Hawker]

A lot of people mostly in salt water though use a special paints to protect the logs from the salt and barnicals, you can do that.

[Bamaman]

You're right about the oxidation turning the toons black. After toons are cleaned with the acid based cleaners, polishing with a dual action polisher and a quality metal polish is not that difficult or even time consuming.

But getting the black oxide off the creases, welds and slag with lacquer cleaner is double tough if you're wanting to Sharkhide the toons to keep'em shiny. It's many times more work than just polishing the toons 1x or 2x per year.

Leaving the boat in the water all year is the problem. See below for options:

What type of Antifouling Paint should I use on Aluminum?

Trilux® 33 with Biolux is specifically developed for use all surfaces including aluminum boats, outdrives, and outboards. Trilux® 33 with Biolux, unlike other antifouling paints, does not use cuprous oxide. Trilux® 33 uses Cuprous Thiocyanate. Cuprous Thiocyanate is safer to use then Cuprous Oxide. The biocides work together to fight shell fouling such as barnacles and zebra mussels while the Biolux blocks slime and algae. This blend of resins and biocides, when properly applied over primer, offer excellent antifouling protection. While Trilux® 33 has been specifically developed for use on primed aluminum, it can also be applied to fiberglass, wood and other underwater metals on boats. Trilux® 33 is for use below waterline in fresh, salt and brackish water. If you are in Canada use Tri-Lux II.

It comes in 5 colors, and a gallon covers 443 square feet. It's expensive stuff @ $235 per gallon, but it goes a long way. 2-3 coats is preferred, as it works best when a thick coat is applied.

This is probably your only option to keeping your boat looking good if it's kept in the water.

[belercous]

I'm not going to keep cleaning my toons with acid, it's a losing battle & it eats metal away every time it's done. I'd just as soon have them turn black & not have to worry about it anymore. I'm also not going to paint them since sooner or later, the paint will chip or pop off from flexing. Plus painting is a major hassle & gets fairly expensive to keep painting 32' long tubes. Paint is not even an option I'll consider.

I keep the boat in the water for about 5 mos out of the year, but I'm not sure that's the reason for the oxidation since my underskin has also started turning black & it's only wet when the boat is moving. I keep the boat on the Mississippi & God only knows what-all is in that nasty water. Besides a lot of jumping carp.

What I'd like to do is oxide the surface to protect it from further oxidation (such as scale on steel, or the bluing on guns) and get a uniform color. Then seal that in with Sharkhide.

Muriatic acid will turn the toons black, but I'm afraid it might be a bit strong. I expect to have to neutralize the toons after treating them, but am not sure what the best procedure is, for both putting on a thin layer of oxidation & then neutralizing the treatment. On aircraft we'd treat bare alunimum with an alodyne solution which would turn it gold. While this looks good, it'll scratch easily. (Same for electro-chemical anodization, nice pretty gold color, but not durable)

Certainly I'm not the first person to have this problem & came up with this idea for a solution, am I?