Bronze plaque tarnishing

[Jean Shimp]

We installed a bronze plaque a little over a year and a half ago and it is starting to tarnish on the raised bronze parts. Because we are about a mile from the Atlantic ocean the manufacturer says the salt air is causing it. Can we sand off the tarnish and recoat with clear coat. How often should it be re=coated? Any suggestions? The size is about 2'x3' so it would have to be done in its location on a stone wall.

 

[Boudica]

It's just patina. I don't think you need to sand it - just wipe it down with some Brasso?

 

[unclebun]

How was the plaque finished originally? If you got it from Gemini the refinishing would be covered under their warranty. You'd just send it back to them. I can't believe it could have any clearcoat on it if it was showing oxidation in less than two years.

Brasso requires more than a wipedown. It would be rubbed with Brasso until the oxidation is gone, then buffed with a dry cloth.

 

[John_Smith]

Jean - You know that I came from St.Marys/Kingsland and I did a lot of brass and bronze projects for the community and the Navy Base.. Most were factory-sealed with a two-part urethane automotive style clear and others were left to oxidize and weather in place naturally forever. Seasonal cleaning with a fine wire brush is all that is needed most of the time.
Leave it up to the owner as to how he/she wants it to be displayed. Once you start cleaning and clearing it, it will be a maintenance job for "someone" forever. YOU don't want to be "that one". Could we by chance see a photo of the sign? With a close-up shot of the lettering.
Keep us in the loop as how you proceed.
John

 

[Jean Shimp]

The plaque has been up 1 year and 7 months. I really don't want to take it down off the wall. It is very heavy, and I don't know if removing it will damage the wall. It would be better to fix it in place if possible. My main concern is that I don't want this to be an ongoing maintenance job like John suggested. (thanks for your reply John) I am waiting to hear back from Gemini. The plaque was clear coated but apparently the clear coat wasn't adequate. I don't know if Gemini does a two part automotive type clear. I got the impression that because the plaque is subject to salt air, they are saying this problem will continue to happen.

 

[CanuckSigns]

Gemini uses Matthews paints and clear coats, so it should hold up longer than it has. Gemini does have a warrantee and will fix it at no charge, however you need to get the plaque to them first, they should pay shipping both ways, but you would be responsible for removal, crating and re installation. Because it's only happening in the bottom corners I wonder if something has hit the plaque to cause the clear coat to chip off in those areas?

 

[weyandsign]

I would take it down and send it back. I don't think being a mile from the ocean should be their excuse for this. Tell the club to have someone remove it for you if needed.

 

[unclebun]

Yes, I would take Gemini up on their warranty and have them refinish it. We've had them do refinishing on things in the past and it took care of everything. I agree that the oxidation happening on the corners is not from salt air but from damage to the clearcoat. Paint is very vulnerable on sharp edges, so it would have been very easy for the clearcoat to have been rubbed through by sliding the plaque even across cardboard, or bumping it when setting it down.

 

[Jean Shimp]

Gemini told me they will have to continue to refinish it whenever it tarnishes since it is a lifetime guarantee. They said the salt air is tarnishing it. So they are expecting me to take it down every year and a half, box it up, ship it, get it back and re-install it? What planet does that work on? I'm waiting for a call back from Gemini, hoping I can get a better answer from someone else who has a reasonable solution.

 

[James Burke]

I'm going to go out on a wild limb here and call out the manufacturer for creating a botched alloy.

From the looks of the untarnished portion, I'd say there's a disproportionate amount of yellow brass. And the first clue is the bright green in the lower righthand corner. And if you look at the brushed border, it's also starting to get out of control.

There's absolutely no way that a well-alloyed BRONZE should be doing that...even if it were installed in a location directly on the beach front.

Plain and simple...somebody didn't mix the recipe correctly.

JB

 

[James Burke]

Gemini told me they will have to continue to refinish it whenever it tarnishes since it is a lifetime guarantee. They said the salt air is tarnishing it. So they are expecting me to take it down every year and a half, box it up, ship it, get it back and re-install it? What planet does that work on? I'm waiting for a call back from Gemini, hoping I can get a better answer from someone else who has a reasonable solution.

This is absolutely uncalled for. Hop in your car and look for other bronze installed in your area. Bronze has more of a golden hue...not yellow.

I have a sneaky hunch the others aren't having the same issues.

JB

 

[JBurton]

I'd see if their facilities guy had the building pressure washed at some point, based on the bottom being the worst. Take Gemini up on their warranty this time, see if it doesn't hold up longer.

 

[John_Smith]

WOW - That is a new one for me. I am very familiar with brass and bronze plaques on the S. Georgia and Florida Eastern Shores. This is probably the worst I have seen to have been installed for such a short period of time. Just from the photo, it "appears" to be a total failure of the clear coat.
Several things can go wrong with 2k urethane products: Incorrect amounts of the required products and/or emulsification of the components is #1.
Seeing the latest reply above by JBurton about power washing and maybe hard water or "reclaimed" water from the ground sprinklers may be worth looking into.
"Last Resort" if you reach an impasse with Gemini, is to work with the property owner and see if removing (sanding off) the clear coat and let the graphics weather naturally into the brownish-green patina would be an option. Which would be maintenance-free for everyone involved. (especially you). And, if that happens, you can sand off the clear and apply the appropriate acid products to "hasten" the desired patina in just one morning and call it a day.
And, if you (or anyone else here) get a request in the future for such a project, you can put more research into where it will be installed and what environmental impacts it may be exposed to.
Excellent post, Jean. This may be an eye-opener and learning example for anyone who is considering a bronze project in their neighborhood.
Edit: Last, Last and Last resort would be to go sand off existing clear on the raised portions, clean thoroughly, and have your local "trusted" automotive shop spray it with their "top-of-the-line" clear that would last at least 10 years. And, maybe, it will last 5 years before it needs to be done again. (and again, and again).

 

[CanuckSigns]

Yes, I would take Gemini up on their warranty and have them refinish it. We've had them do refinishing on things in the past and it took care of everything. I agree that the oxidation happening on the corners is not from salt air but from damage to the clearcoat. Paint is very vulnerable on sharp edges, so it would have been very easy for the clearcoat to have been rubbed through by sliding the plaque even across cardboard, or bumping it when setting it down.

I agree, if you do end up sending it to gemini for repair, ask them to break all sharp edges before they re-coat it,it will help reduce the chance of the clear coat chipping in the future.