should I paint bronze?

The supports under my swim step appear to be bronze. Can I just leave the bronze unprotected, or should I paint them, and if so, with what?

Should be fine unpainted.

Ted

Some folks paint them with anti-fouling or the stuff people use on propellers. I did the former and it helped a tiny bit. Does your marina get a lot of growth?

All fittings on our boat are unpainted bronze circa 1981 and there appears to be no ill affects.

Enjoy the patina!

LaBomba said:

All fittings on our boat are unpainted bronze circa 1981 and there appears to be no ill affects.

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Well that all depends on the situation where the boat is.

Is the bronze in the the water at rest? If it is, it will get growth on it if not painted with antifouling.

The bronze itself should not need painting except any parts that are actually in seawater. Immersed metal, bronze or not, will often get growth although the copper content will slow the accumulation, but not stop it.

A good bottom paint would be in order.

Historically bronze was painted or polished , never left to go green.

Unnecessary to paint bronze. You can inspect it far better without the paint but, it is your boat, your bronze, paint it if you wish.

C lectric said:

The bronze itself should not need painting except any parts that are actually in seawater. Immersed metal, bronze or not, will often get growth although the copper content will slow the accumulation, but not stop it. A good bottom paint would be in order.

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I think the lowest part of the supports are typically submerged at rest. I'll add some bottom paint down there, and leave the rest untreated. Thanks.

Make sure it is grounded into the bonding system. Let's hope those are stainless nuts and bolts and washer too.

I, and others I am sure, love the look of unfinished bronze. And, btw, bronze fasterners would really set it off nicely! When my stainless fasterners started to fail on a couple of bronze shaft logs, they went to Si-bronze.

Do you paint your bronze hull valves? I hope not.
The key is a good bonding system.

Bolts should be silicon bronze, not SS.

I disagree about the bonding of those supports. If already done then fine but there is absolutely no reason to bond them. In fact good quality bronze often does better not bonded. Bonded can make the bonded part suffer from corrosion it would not otherwise see.
Once bonded those parts , if there is any electrical leakage, can become part of the circuit. If not bonded then there is no way for that to happen.

C lectric, you do not bond your hull valves?

I do bond those. Reason being that I cannot determine positively that all the material are the same bronze. I may change that but too many other things on the go.

But in the case of the O.P. the swim grid supports are not a mix. The bolts appear to be silicon bronze so close enough they shouldn't need bonding.

However, if you are not comfortable without the bonding then do it. Just be aware that any electrical leakage can then affect those items.

"I think the lowest part of the supports are typically submerged at rest."

"Let's hope those are stainless nuts and bolts and washer too."

Many folks that have placed SS bolts underwater would not agree.

Why take chances when bronze bolts are at the same chandlers?

I had the same supports under my swin grid. They had been painted with antifouling every year for about 25 yrs. I added 13" to the inside of the swimgrid several years ago. Those supports were 13" too short, so I had new ones made up of SS. When I removed the bronze supports, I found that many of the bolts holding them onto the transom were corroded, almost to nothing at all. Those were the bolts under the waterline at rest. I don't recall what material those bolts were, but I know they weren't SS. Something brown.

I still have 4 of the bronze supports. I melted one down to cast supports for my boarding ladder. I have enough left to cast a cannon, but that project is still on the drawing boards.

I painted my stainless brackets where they are below water. They had been previously painted. I removed the paint to inspect the welds.

I bonded my brackets when I discovered the stainless was corroded between hull and bracket, despite bedding. Several of the original stainless bolts were corroded through.

This was all part of the project to replace our swim platform and to replace the rotted backup blocks in the lazarette.