Marks on raw brass Duo Gravis

[scottcb]

I’ve purchased this King Duo Gravis and I’m keen to get some views on maintenance.

Mechanically it's in decent condition, but aesthetically it's seen better days! The lacquer has been intentionally stripped off the bell at some point and it has quite a few marks.

Is there anything I can do to remove these marks or make them less prominent? Would polishing the brass remove them? They look and feel kind of permanent but I'm no expert.

Thanks in advance!

Duo Gravis (3).jpeg

Duo Gravis (1).jpeg

Duo Gravis (2).jpeg

[BGuttman]

Those look like moisture spots resulting from droplets of water being left on the raw brass. They are probably copper oxide. Depending on the depth of the spots you may be able to polish them off with brass polish. If they are really deep you may have to resort to sanding, which can have deleterious effects on the bell.

Once you clean up the brass a bit, you should treat it with a good hard shell wax (I like Turtle Wax) which will preserve the finish a little longer (but not as long as lacquer).

Note that too aggressive a polish can partially obscure the engraving, so try to leave as much of the engraving as intact as possible.

[scottcb]

Thanks very much for your advice! I will get my hands on some brass polish and see if I can tidy it up a bit.

Most of the water spots seem pretty benign. The one mark that concerns me is the one pictured below. It’s got a reddish tinge. Any thoughts on whether this is red rot or is it something more harmless?

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[BGuttman]

To know if it's red rot you would have to polish it out. Red rot won't polish. But I've never seen a ring shaped red rot. It usually rots from the center out. My best guess is it will just polish out because it's not that deep.

[scottcb]

Great, thanks for your help. I’ll polish it up and see how it goes!

[boneagain]

Great, thanks for your help. I’ll polish it up and see how it goes!

Maybe before you do a lot of polishing you might want to see how quickly the horn spots up with YOUR playing.

To me the patina looks remarkably even.

If you polish it then get tired of polishing over and over, the next round of patina might not be as even.

OTOH, if you are really good about wiping down every time you play, it could get a MORE even patina...

I'm lucky. I have the silver bell model. Lasts a lot longer between polishing. Tarnishes fairly evenly. But I DO have to wipe moisture off the bell or I WILL get spots on the gold wash.

I have found that "between polishing" got longer and longer as I found myself choosing between practicing and polishing.

Just a thought.

[MTbassbone]

I would just leave it alone. As a previous post mentioned it will get that patina all over and not look so different. It does not change how it plays. If you to sell it someday and want to make pretty then polish it. For now just appreciate it for what it is and play it.

[MrHCinDE]

I had a similar looking bell which was purchased fit onto a 70s 3b/f. The marks were a bit smaller and fewer on mine and I believe it had never been lacquered as it had been kept as a spare part in a workshop for decades. I got a brushed finish applied by a professional at the same when the bell was fitted onto my horn and quite like how it's turned out. The inside of the bell is deliberately not brushed. So far it seems to be holidng up ok with a regular wipe down after playing and a monthly waxing with renaissance wax.

I'm not normally a huge fan of the King gold lacquer from that era but next to a low-key finish I think it actually looks pretty nice, especially with a nickel silver slide. It looks like you have a similar lacquer on the valve section etc. and I like how your horn looks as it is.

If you decide to polish, perhaps give renaissance wax a try after polishing?

[scottcb]

I might even just polish the red ring to start with to make sure it's nothing that I need to be concerned about (eg. red rot).

It sounds like leaving the water spots inside the bell won't cause a long-term problem other than a cosmetic one?

[scottcb]

I couldn't help myself. I wanted to see what was underneath and make sure the red marks weren't red rot, so I polished and waxed the DG. It's looking pretty damn good. Will probably leave it to develop a patina now that I'm comfortable it's in good condition.

[greenbean]

Nice! You could wax it...

[afugate]

I couldn't help myself. I wanted to see what was underneath and make sure the red marks weren't red rot, so I polished and waxed the DG. It's looking pretty damn good. Will probably leave it to develop a patina now that I'm comfortable it's in good condition.

Nicely done. Was this all done by hand?

--Andy in OKC

[MrHCinDE]

Excellent work, tri-colour!

[Mamaposaune]

Water marks sometimes happen when it's stored in the case if you set it bell-end down. Make sure there is something in place to catch moisture that drips out of the bell connector, same with the slide.

[scottcb]

I couldn't help myself. I wanted to see what was underneath and make sure the red marks weren't red rot, so I polished and waxed the DG. It's looking pretty damn good. Will probably leave it to develop a patina now that I'm comfortable it's in good condition.

Nicely done. Was this all done by hand?

--Andy in OKC

Yeah, went through quite a few rags!

[scottcb]

Water marks sometimes happen when it's stored in the case if you set it bell-end down. Make sure there is something in place to catch moisture that drips out of the bell connector, same with the slide.

Good tip, thanks for sharing

[ryebrye]

It's been a couple of years now - so I'm curious about the follow up.

The biggest downside to polishing raw brass that I've heard of is keeping it shiny requires maintenance (but using some forms of wax can make it last longer)

What's it been like since you polished it? If you had to do it over again, would you still polish it?

(And what did you use to polish it in the first place?)

[tbonesullivan]

You can look into "Renaissance Wax", which is a micro crystalline wax that is really good at protecting things. It was developed to protect items for British Museums.

Another thing you can do is rub it down with anhydrous lanolin, aka old school tuning slide grease. Not a huge amount, but that's what a lot of collectors put on raw brass items to help them get that beautiful amber cover. It takes a few years, but as long as you don't touch the instrument too much it should work.

[scottcb]

What's it been like since you polished it? If you had to do it over again, would you still polish it?

(And what did you use to polish it in the first place?)

I polished it about two years ago with Blue Magic Metal Polish Cream and finished it with Renaissance Micro-Crystalline Wax Polish.

I haven’t polished it again since then and it still looks great. The only spots that have really tarnished are the places my hand touches incidentally. That being said, I’m a casual player and don’t play every week let alone every day.

If I had my time again I would definitely do the same thing.

[ryebrye]

What's it been like since you polished it? If you had to do it over again, would you still polish it?

(And what did you use to polish it in the first place?)

I polished it about two years ago with Blue Magic Metal Polish Cream and finished it with Renaissance Micro-Crystalline Wax Polish.

I haven’t polished it again since then and it still looks great. The only spots that have really tarnished are the places my hand touches incidentally. That being said, I’m a casual player and don’t play every week let alone every day.

If I had my time again I would definitely do the same thing.

Thanks for the follow up. Your horn turned out great - not needing to polish it again for two years is a pretty great endorsement of Renaissance wax!