Varnish: (golden) for metal instruments.
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the elephant
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Re: Varnish: (golden) for metal instruments.
No varnish. Lacquer.
There are a number of types in use, but I only have experience with nitrocellulose and baked epoxy. Nitrocellulose is easier to use but is fragile. Baked epozy is more difficult to apply correctly, but seems to be more durable.
The application of the lacquer to metal (via a spray gun or a "rattle can") will fail if you do not do the proper preparation to the metal. That includes a very thorough chemical degreasing prior to spraying the lacquer onto the instrument. You must be absolutely meticulous with the degreasing step or the lacquer will flake or bubble off of the metal.
There are a number of types in use, but I only have experience with nitrocellulose and baked epoxy. Nitrocellulose is easier to use but is fragile. Baked epozy is more difficult to apply correctly, but seems to be more durable.
The application of the lacquer to metal (via a spray gun or a "rattle can") will fail if you do not do the proper preparation to the metal. That includes a very thorough chemical degreasing prior to spraying the lacquer onto the instrument. You must be absolutely meticulous with the degreasing step or the lacquer will flake or bubble off of the metal.
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- Igor (Thu Aug 29, 2024 8:36 am)
Re: Varnish: (golden) for metal instruments.
Thank you for your answer, it helped me a lot.
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- the elephant (Thu Aug 29, 2024 8:45 am)
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bloke
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Re: Varnish: (golden) for metal instruments.
Spraying lacquer on a completely polished and cleaned brass surface - whether clear lacquer or tinted lacquer - requires the person operating the spray gun to be either mighty skilled or mighty lucky. Over the past few years, perhaps I've become mighty experienced, rather than either of the previous (as I've seemed to become more and more lucky). The problem is that tiny runs (rather than simply being little thick areas that dry to barely detectable thick areas) become dark lines, because the dye added to the clear lacquer becomes concentrated in the runs.
Yesterday, I shot a bass trombone bell section with clear (no dye in it). I didn't use any lacquer thinner (which dries in mere moments). because of the high temperature and somewhat high humidity. I wanted to increase the drying time so that any water vapor (possibly trapped under sprayed lacquer) would have time to make it to the surface and disappear - rather than turning the lacquer white. (The white phenomenon is called "blushing".)
Rather than thinner, I used drying retarder which is substitute thin solvent which can be added to lacquer in order to thin the lacquer enough to be sprayed. Since it dries slower, I ended up with a tiny run in the bell interior next to the rim. I knew to stand around and watch it for a while, and - sure enough - that tiny run developed. I had the bell situated horizontally and supported by an appliance which was held in a vice in an air conditioned room. I simply rotated the bell so as the run would run back the other way and disappear. It actually disappeared, but - had I used gold tint/dye in that lacquer - I wonder if it would have left a dark place, even though I managed to get the run to disappear.
Sometimes, I don't add gold tint to lacquer, and I add odd tints - such as bronze, a tiny touch of green, and things such as that (to get my new lacquer - sprayed around the outside parts of tubas - in particular - to come closer to matching the old good-enough-condition lacquer left in place on the interior portions of a tuba). It's the same hazard, because whatever odd color I add can do the same thing as described above, if there's a run.
All I'm saying with all these words is that adding tint/dye requires that the person spraying understand that there's another layer of concern when spraying lacquer (as your inquiry specifically asks about tinted lacquer).
addendum:
"Gold" tinted lacquer is typically intended as a faux lacquer finish to appear as if a yellow brass instrument (or yellow brass whatever) is gold plated.
"Bronze" tinted lacquer (and a few different hues of this tint are available - as well as controlling the intensity simply by adding more or less) is typically intended as a faux lacquer finish to appear as if a yellow brass instrument is made of a higher copper brass allow (such as the commonly-seen 80:20 alloy) or (obviously) bronze (which sports a similar appearance to high-copper brass). The previous should clarify that (unless there is a tint added to clear lacquer - though all lacquer barely does have a color) when multiple colors are observed on a lacquered instrument, those colors are the actual colors of the various polished metals.
The 55-year-old domestic bass trombone that I just shot a day ago features 80:20 brass (bell and bell bow), nickel-brass (connecting and hardware parts), and yellow brass (F-attachment circuit tubing, and F-attachment slide).
Here's (perhaps?) a better picture of color of 80:20 "gold" brass:
Yesterday, I shot a bass trombone bell section with clear (no dye in it). I didn't use any lacquer thinner (which dries in mere moments). because of the high temperature and somewhat high humidity. I wanted to increase the drying time so that any water vapor (possibly trapped under sprayed lacquer) would have time to make it to the surface and disappear - rather than turning the lacquer white. (The white phenomenon is called "blushing".)
Rather than thinner, I used drying retarder which is substitute thin solvent which can be added to lacquer in order to thin the lacquer enough to be sprayed. Since it dries slower, I ended up with a tiny run in the bell interior next to the rim. I knew to stand around and watch it for a while, and - sure enough - that tiny run developed. I had the bell situated horizontally and supported by an appliance which was held in a vice in an air conditioned room. I simply rotated the bell so as the run would run back the other way and disappear. It actually disappeared, but - had I used gold tint/dye in that lacquer - I wonder if it would have left a dark place, even though I managed to get the run to disappear.
Sometimes, I don't add gold tint to lacquer, and I add odd tints - such as bronze, a tiny touch of green, and things such as that (to get my new lacquer - sprayed around the outside parts of tubas - in particular - to come closer to matching the old good-enough-condition lacquer left in place on the interior portions of a tuba). It's the same hazard, because whatever odd color I add can do the same thing as described above, if there's a run.
All I'm saying with all these words is that adding tint/dye requires that the person spraying understand that there's another layer of concern when spraying lacquer (as your inquiry specifically asks about tinted lacquer).
addendum:
"Gold" tinted lacquer is typically intended as a faux lacquer finish to appear as if a yellow brass instrument (or yellow brass whatever) is gold plated.
"Bronze" tinted lacquer (and a few different hues of this tint are available - as well as controlling the intensity simply by adding more or less) is typically intended as a faux lacquer finish to appear as if a yellow brass instrument is made of a higher copper brass allow (such as the commonly-seen 80:20 alloy) or (obviously) bronze (which sports a similar appearance to high-copper brass). The previous should clarify that (unless there is a tint added to clear lacquer - though all lacquer barely does have a color) when multiple colors are observed on a lacquered instrument, those colors are the actual colors of the various polished metals.
The 55-year-old domestic bass trombone that I just shot a day ago features 80:20 brass (bell and bell bow), nickel-brass (connecting and hardware parts), and yellow brass (F-attachment circuit tubing, and F-attachment slide).
Here's (perhaps?) a better picture of color of 80:20 "gold" brass: