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Discussion in 'Trumpet Discussion' started by kctrumpeteer, Feb 16, 2011.
Monel or stainless, as long as it's plated in nickel!
Thanks Ivan - yes, I'd overlooked that part of the process.
Annealing temperatures for stainless steel are over 1000 degrees C ( Stainless Steel - Heat Treatment ). Brazing temperatures are generally several hundred degrees cooler ( BT - Brazing and Welding 304L Stainless Steel ). You could mess stainless valves up if you kept them too hot, too long, while brazing, but the damage done (chromium diffusion) couldn't be described as annealing -- and it sounds like the damage would be quite obvious: The valves would start to corrode around the brazing.
Perhaps an almost heard it right sort of thing? Like everyone on TM...and the web in general I believe absolutely everything I read. It is in this spirit that I will offer the addendum below. If it is correct it is quite interesting, and of course it was on the web, sooo:
http://books.google.com/books?id=J1...q=stainless vs monel vs nickel-silver&f=false
He is actually the principle brass / woodwind repair Tech at the largest music store in Wi., went to school for metalurgy also, and is the president of the organization of instrument repair people for the US. (sorry, I don't know what the name of that organization is). This was his answer when I inquired about the "Monel / SS " question based on the beginning of this post. Also I've been working around exotic metals and metalurgists myself for 30 years, so I know just enough to be dangerous : ) In other words don't buy and airplane that I designed.......thats why I asked the expert.
I was aware that the manner in which I worded my statement, (after reflection) may have seemed less than neutral...and besides, since I read the statement at first as if it was stated that Monel was a foundational element of stainless steel I decided to look for a bit more info to clarify my thinking. I had changed my response hoping that the edited version was the one read. In any case it is directly above...#64 I believe. All is well.
There appears to be some misunderstanding on this. Stainless Steel valves are fabricated from a tube of stainless steel with brass elbows and a brass spring box. I am not aware of any problems with Stainless Steel valves caused by temperature variations.
SS is not 100% SS, there are always trace elements in SS that cause it to act certain ways in certain environments, this is why there are many types and grades of SS, so engineers can choose the type that best fit their application. All metals are this way. You can clarify this yourself in the "ASTM Standards" for Metals and their properties". It breaks metals down in 6 basic groups which are derived from the metal densities and their frequency, then sub-groups expand from there. When you get to the type metal you are looking for it gives the % of the major metals and the trace elements that make up it's specific characteristic. It would be interesting to know what type SS is used in valves. Whatever it is it works perfect for the application, but I'm sure this is a trade secret at each manufacture. I don't profess to be an expert in metals, this is what I know from spending many years working with them, and I'm for sure not knowledgable about valves as you are trumpetsplus, all I know is to oil them, clean them and press on them thousands of times a day : ) I do enjoy reading your posts and your knowledge in trumpets though !!!
I have seen rusty stainless steel valves. In my experience monel or nickle plated has the best wear. I've never seen a worn monel piston but rather its' hard as diamond material usually wears air pockets in the casing. Remedy was new oversized pistons being lapped in. I've had Kanstul do this for me on a couple Kanstul horns. I've also always said why have a hard metal against a soft metal?? Why not have both surfaces be hard metal, which I got a response of "we need to sell horns you know?" haha.
Early on some baritone horns made in England had copper alloy valves running in brass casings. it is easy and inexpensive to replate copper with copper. If kept clean and oiled i don't see why that method is not still employed. If one gave it a quick dip in the copper plating solution I'm not sure that any honing would be needed. If a copper valve was a bit tight it probably would quickly work itself into a nice fit.