Polishing a silver trombone

[nogginbone]

I have a silver B&H Imperial 4040 trombone. I don't know what material it is made of. Is it silver plated brass or something else?

Also, more importantly I would like it to shine, but I don't know what to polish it with. At school many years ago we all used to use Brasso, but I've heard that some brass polishes can be too abrasive. What should I polish it with?

[BGuttman]

It's brass with a thin plate of silver. Brasso is too aggressive. Find a good silver polish; preferably one that is not too gritty. Wright's Silver Cream or Haggerty's are good brands in the US.

[stewbones43]

Your B&H Imperial is definitely silver plated brass but it may be bright silver plate or it may be frosted silver plate. For either, do as Bruce has suggested; one will shine but the other will not.
If it is frosted silver plate and you want it to shine then, from experience, you can use Brasso/Silvo and after about a year of polishing weekly, you might get it to shine! If not, repeat and repeat and repeat...........

Just out of interest, your 40-40 is a fairly rare version of the B&H Imperial. Could you measure the bell and bore diameter for me? B&H used various bore sizes-0.487in, 0.500in, 0.523in, 0.547in. I had an Imperial 523 model some years ago, but would like to find out where the 40-40 fits in the scheme of things. It could be a B&H version of the Besson 10-10 which had an 8in bell and a 0.523in bore. Whatever, I am sure it is a pro' quality horn.

Cheers

Stewbones

[nogginbone]

Thanks for the tips. I think it's bright plate. It doesn't look frosted.

How do you measure the bore size? The bell is 7 inches wide. I've been trying to figure out when my trombone was made, but there is not a serial number on it.

The number 537 is stamped on it. That might be the bore size, ie 0.537 inches maybe?

If it is a pro quality horn, I am going to have to up my game. I am not making it sound like one.

[BGuttman]

Best way to measure bore is with an inside caliper somewhere inside of the stockings. Most people don't have inside calipers so measuring the inside diameter at the stocking is about as good as most of us can get. You'll need something more accurate than a common ruler, though. We need to measure to thousandths of an inch or tenths of a millimeter.

[nogginbone]

My friend has some callipers in his workshop.

I’ll borrow them when I can, but it might be a while.

[jtbandmusic]

Every time you polish, you basically SAND OFF the tarnish. Some old horns have a nice thick
layer of silver plate; some new horns have a finish that's three molecules thick; a couple
of polishes and you start to see brass.

There's an easier way; less messy, too.
Got a plastic trash can, probably kitchen size? Or a bathtub works fine.

Put a big piece of aluminum foil in the bottom. Fill the can with hot water;
it doesn't have to be boiling hot. Dump in half a box of baking soda and stir.

Put the trombone in the water so it's completely submerged; make sure both pieces
of the horn touch the foil. Let it wait a few minutes, then wipe. Rinse it off, and
flush the inside with tap water. That's it.

Clean, no black crud, no grit. Best of all, no abrasives.

Oh yeah, DON'T do this with a lacquer horn.

John Thompson

[Doubler]

I maintain silver plated horns with Goddard's Silver Polising Cloth after using cotton balls and Flitz Multi-Purpose Polish and Cleaner. I haven't tried the method suggested by jtbandmusic, as I haven't had the need for it, but I've heard and read only positive comments from those who have.

[stewbones43]

I am pretty sure that your trombone will be a 0.487in bore if the bell is 7in diameter. The 0.500in bore wasn't used until the 1970s/80s as far as I know.
There is a simple way to gauge the bore size of B&H/Besson trombones; take a half inch (0.500in) diameter drill bit and carefully push it into the top of the inner slide at the taper which joins the 2 halves of the trombone together. DO NOT push it into the mouthpiece receiver side!!!!!!
If it is a good tight fit then the bore is 0.500in, if it is a loose fit the bore is 0.523in, if it a very loose fit it is 0.547in or even 0.562in (bass trombone bore. Note there are small bass trombones by B&H/Besson which used a bore size of 0.555in.), if the drill doesn't fit into the tube, then it is 0.487in bore.
Where do these strange, seemingly random measurements come from? They are the modern equivalents of old Imperial measurements expressed as fractions; 0.487in=31/64, 0.500=1/2, 0.532=17/32, 0.547=35/64, 0.562=9/16.

The Imperial models were B&H's pro line after WW II until the advent of the Sovereign range in the 1970s; they were standard supply for the British and Commonwealth military bands and brass bands, along with the Besson equivalents. Because of these large markets, the instruments were made to withstand heavy usage and so are heavier than most US manufactured instruments.

The serial number can be found on the underside of the bell, just in front of the first bell brace. It should consist of 6 digits and probably HP or LP. these are High pitch and Low Pitch-the international standard. Most High Pitch models will have been converted to Low Pitch now.

Cheers

Stewbones

[leafylief]

I go by this video. I modified it a little bit:

[hornbuilder]

Note that the "frosted" solver horns were bead blasted prior to plating, so no amount of polishing will make it "bright", at least not without going through to brass.