soldering question for the repair guys

[dave]

I have an original Stewart Stand for my euphonium that I have used a lot, to the point where the velcro has stretched and the bottom post moves around inside the velcro (if you are not familiar with the original design of the Stewart Stand, it has an adhesive-backed velcro that attaches to the horn, is in a double layer with the post for the Stewart Stand attached to a 20 ga. piece of stainless steel strap that is sitting between the two layers. The strap curves around the tubing and has a hole punched in it for the post assembly of the stand).

So my thoughts are to get rid of all that velcro and just solder the stainless strap directly to the horn (after trimming it to a small circle). I might just throw the strap away entirely and make a base that is a bit heavier (1/8" thick, 1 1/2" dia.) on a metal lathe and solder that to the horn (silver-plated Hirsbrunner).

How easily does stainless steel solder, using regular 60/40 tin/lead solder? I'd rather not use high temp silver solder due to the possible damage to the silver plating. Is there a better choice of solder for this than 60/40? Is there a special flux needed or is this just as easy to solder as brass?

Dave

[Dan Schultz]

How easily does stainless steel solder, using regular 60/40 tin/lead solder? I'd rather not use high temp silver solder due to the possible damage to the silver plating. Is there a better choice of solder for this than 60/40? Is there a special flux needed or is this just as easy to solder as brass?

Dave

I might stand corrected here, but I think stainless steel and what we generally refer to as nickel are one in the same. I found this when I executed a search for "soldering stainless steel":

Recommended procedure for soldering stainless steel:

· 1. The steel surfaces must be clean and free of oxidation.

· 2. A rough surface improves adherence of the solder, so roughening with grinding wheel, file or coarse abrasive paper is recommended.

· 3. Use a phosphoric acid based flux. Hydrochloric acid based fluxes require neutralising after soldering as any remnant traces will be highly corrosive to the steel. Hydrochloric acid based fluxes are not recommended for soldering of stainless steels.

· 4. Flux should be applied with a brush, to only the area being soldered.

· 5. A large, hot iron is recommended. Use the same temperature as for carbon steel, but a longer time will be required because of stainless steel's low thermal conductivity. (This is a quote from the original web site. A torch that is used for soldering brass should do fine).

· 6. Any type of solder can be used, but at least 50% tin is recommended. Solder with 60-70% tin and 30-40% lead has a better colour match and greater strength.



NOTE... 60/40 solder is the choice for soldering to silver plated finishes. 70/30 is not recommended.

[Jeff Miller]

There's no reason on earth other than hidebound tradition, given the location and function of the piece to be added, why you wouldn't want to do this one with a decent glue. Either "Goop", or an epoxy.

Isn't removability a decent reason not to use glue?

[Dan Schultz]

There's no reason on earth other than hidebound tradition, given the location and function of the piece to be added, why you wouldn't want to do this one with a decent glue. Either "Goop", or an epoxy.

'cept brass repair guys get shot at sunrise for the mere mention of epoxy! However, I agree that it might be a viable alternative to solder in this case.

[Chuck(G)]

Why not just get some new velcro?

[Chuck(G)]

You some kind of troublemaker?

Okay, okay, he should have the bracket spot-welded to his horn.

You guys happy now?

[dave]

OK, Dale says it won't work, its a metallic property of stainless not to solder well; Dan gives an acid flux method that might be worth looking into; Dave says use a hose clamp in a piece of clear tubing; Chuck says new velcro; Henry says epoxy, then Joe comes in with his usual. Guys, thanks for thinking outside the box, I really do appreciate the effort.

I'm not going to go the velcro route, it was nothing but a pain to deal with. You are trying to hold a 20 pound weight by the shear strength of a piece of velcro that was never designed for that. I think I will avoid the issue of soldering stainless entirely. Anybody have some German Silver pieces, 1/4" thick, 1.5" dia.? Or I will make the bases out of brass and get them silver plated at Andersons.

Dave

[dave]

I finished the project, thought I would share the results. I made two posts out of brass to replace the metal strap and velcro on the original Stuart Stand. Since I don't have silver plating locally, I just tinned the two parts then soldered them to the euphonium. My soldering is a bit messy (whats the best way to remove solder from silver), but it is good and functional.

-Dave

[Chuck(G)]

(whats the best way to remove solder from silver)

On modern (i.e. thin) silverplating, it's darned difficult to do without removing some of the silver too. This is where you need to ask before doing. There is stuff called "resist" or "solder repel" that you can paint on the areas where you don't want solder to stick. About all you can do now is dress it up a bit by scraping it down smooth with a piece of sheet brass or similar metal that's softer than silver but harder than solder) and leave it alone. If you try to buff the remaing stain off with rouge, you stand a very good chance of taking the plating with it--and then it'll look like hell.

[dave]

Chuck wrote:

On modern (i.e. thin) silverplating, it's darned difficult to do without removing some of the silver too.

I called Ferree's and asked the same question (how to remove lead stain from silver plate). The guy I spoke to said to use pickle solution (i.e. 1/8 nitric acid, 1/4 sulphuric acid).

[Chuck(G)]

I called Ferree's and asked the same question (how to remove lead stain from silver plate). The guy I spoke to said to use pickle solution (i.e. 1/8 nitric acid, 1/4 sulphuric acid).

Good luck--and remember that your silver plating's about 9 microns thick.

Tell us how it comes out.

[dave]

If I had some nitric and sulfuric acid I would. Its not easy to locate a supplier who will sell any chemicals to an individual, and I would not want to buy a gallon bottle of each any way. I used to teach HS chemistry, so I had access to reagent grade acids, but not any more.