Soldering brass.

[Tins]

In yet another fit of stupidity I bought a saxophone. No, I can't play. I want to though.

This sax is around 80 years old, beautiful Italian thing, but it looks like it spent the last few years in the toddlers room at a creche. Ok, I reckon I can deal with most of the damage, but it needs some of the key posts reattached. Solder seems to be the go, the brass is too thin to cope with the heat of brazing. Trouble is, there are too many conflicting opinions on the internet ( NO! ) as to what to use. Lead free solder, various forms of silver solder, etc... Now, I can solder ok, but this needs a torch, which I have. I guess my question is, does anyone here have real world experience with soldering thin brass, for instrument repair or maybe jewellery? Right now I'm focussing on disassembling the thing, with all its bent rods......

Once I fix it I will have another way to annoy the long suffering neighbours.

[austastar]

Hi,
301 Moved (https://share.google/rKIrJy540byqvMlCo)

May be able to help. He lives locally, (Hobart) but may respond to email or phone call .
Cheers

[JDNSW]

In my experience, thin brass is easy to solder (with a soldering iron) - except that it is an excellent conductor of heat. Preheating with a heat gun I have found helpful, a torch would work as well. The advantage of using a soldering iron is it is easier to get the solder only where you want it, which depending on what part you are soldering, may be fairly critical, if only because the solder is a different colour.

As to what solder to use - depends on what bit you are soldering, but my guess is that for most bits which have low stress on the joint, it will not be critical. If it is a previously soldered joint, I suspect that in view of its age, the original was probably traditional lead/tin solder, although today I would suggest lead free, if only from a workman's health perspective.

[BradC]

I use a leaded solder with silver for really thin brass. It's a Sn62Pb36Ag2 composition.

I've found a couple of really good youtube channels over the years on musical instrument repair. I have a "Smith Little" torch I use with Oxy/Propylene for a teeny pinpoint flame.

Never done a brass instrument, but I watched a lot of instrument repair videos to get a technique I use for soldering brass shim-stock.

One trick I learned is to get an old pair of socks. I soak them and wrap them either side of the bit I want to solder to stop the heat spreading too much. That and I use a 2B pencil to draw around (dirty up) the area I'm working on to stop the solder spreading too far.

Take some pics. Love to see some before and afters.

[Tins]

I use a leaded solder with silver for really thin brass. It's a Sn62Pb36Ag2 composition.

I've found a couple of really good youtube channels over the years on musical instrument repair. I have a "Smith Little" torch I use with Oxy/Propylene for a teeny pinpoint flame.

Never done a brass instrument, but I watched a lot of instrument repair videos to get a technique I use for soldering brass shim-stock.

One trick I learned is to get an old pair of socks. I soak them and wrap them either side of the bit I want to solder to stop the heat spreading too much. That and I use a 2B pencil to draw around (dirty up) the area I'm working on to stop the solder spreading too far.

Take some pics. Love to see some before and afters.

Thanks very much for this, Err, Brad... . Especially the tip about the socks. I was wondering about some sort of thermal bandages but that's much simpler.

[Tins]

Oh, and there will be pics. It's the only way I will be able to put the thing back together.
I have also found a couple of channels for instrument repair. But in my case it becomes another rabbit hole to get lost in, which is why I asked here.

[Tins]

This guy is interesting to me, well at least this series is. Makes it approachable.


https://youtu.be/HJQq9JhlLpY'si=XjEOH21i6rX6SeoC

[123rover50]

Watching with interest. I have a single barrel shotgun I want to put a front sight on. I will use a brass bush made to fit the OD then solder on the bits to make the sight. I have a little coil of silver solder but dont know if it has its own flux.(label gone) if not will have to buy one. Was going to try first, so now I will wait for your trial.[smilebigeye]

Keith

[Tins]

Watching with interest. I have a single barrel shotgun I want to put a front sight on. I will use a brass bush made to fit the OD then solder on the bits to make the sight. I have a little coil of silver solder but dont know if it has its own flux.(label gone) if not will have to buy one. Was going to try first, so now I will wait for your trial.[smilebigeye]

Keith
I did that once on a little .410. Didn't trim the end inside the barrel. First shot and I had to do it again

[Tins]

I use a leaded solder with silver for really thin brass. It's a Sn62Pb36Ag2 composition.



Bit of looking, I can find that as a paste, which I can get from Mouser, and others I suspect. Is paste what you mean?

[BradC]

No, I have it as rosin cored solder wire.

I have this (which is current) :
Access to this page has been denied (https://www.digikey.com.au/en/products/detail/kester-solder/24-7150-9710/7565174)

And I managed to grab some of this before they ran out of stock :
Pro's Kit 8PK-033A-L Premium Silver Solder (2%) (https://hobbyking.com/en_us/solder-wire-w-63-sn-250g-dia-1-0mm.html)
I believe it's still made, I just don't know where to get it. The cost difference was significant. The difference in use is pretty much immeasurable.

I generally only use leaded solder where I can get away with it as it's just so much more forgiving, and I've used all sorts of different alloys over the years. Those two are just mint to solder with.

I have 2 rolls of this lead free stuff :
Stay Brite(R) 8 Lead-Free Solid Wire Solder - 3mm (https://dealer.harrisproductsgroup.com.au/product/73639-stay-brite-8-lead-free-solid-wire-solder-3mm)

It's fussy and needs external flux but bloody strong for a soft solder. I got it for more mechanical work where I wanted a robust solder but not at silver solder temperatures.

For silver solder I have a whole array from 5% to 56% for use with the oxy. But frankly for most small or delicate stuff this soft solder is just brilliant.

[V8Ian]

John, we'll have to start calling you Lisa (Simpson) [wink11]


https://youtu.be/B8gKnuP8eNE'si=PHfirwBNREIpL8rr

I'm expecting more doh, than Baker Street. [biggrin]

[Tins]

I prefer leaded as well, especially when removing or reflowing. Lower melt temperatures. But that's on electronics. This is a whole new world.

[Tins]

I know the question I asked referred to soldering, but I may get some tips here. Soddering can't be that different, right?


https://youtu.be/axM19M6OEgA'si=CTOousRRdslo3i7f

[Tins]

The sax. Tipping it's nickel plated, and I guess I'll need to remove that to fix it properly. I suppose reverse plating it would be the go. Still got to take it to bits... obviously.

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Replating it will be a challenge, at least for this novice.

[BradC]

Jane Kits do an "electroless" nickel plating bath (I have 5L of it here). Nasty stuff and you'll want to do it outside on a gas stove/BBQ but it works and gets into all the bits you can't reach with an electrode. I bought it to plate the hole inside a bit of drilled copper (making a new desoldering tip) because solder being sucked through it was eroding the copper. Turns out solder sticks to nickel plating like **** to a blanket, so while it didn't erode the copper it kept blocking up. Live and learn.

I've had fantastic results soldering to nickel plated steel. Actually, nickel plated anything to be fair. If you were after structural strength you could abrade the plating off the bit you want to solder to in order to get to the base metal. I suppose if you solder to the plating there's a chance it will peel off when subjected to mechanical stress.

I've never seen a plated sax. Only flutes, so this is a first.

[JDNSW]

I am pretty certain (but could be wrong) that soldering is effective on nickel plating - but not on chrome plating. Normal preparation in cleaning the surface mechanically would probably remove the nickel anyway.

[BradC]

Just another thought. You could remove the coating locally and then "brush plate" when it's done to restore that bit.

[Tins]

Jane Kits do an "electroless" nickel plating bath (I have 5L of it here). Nasty stuff and you'll want to do it outside on a gas stove/BBQ but it works and gets into all the bits you can't reach with an electrode. I bought it to plate the hole inside a bit of drilled copper (making a new desoldering tip) because solder being sucked through it was eroding the copper. Turns out solder sticks to nickel plating like **** to a blanket, so while it didn't erode the copper it kept blocking up. Live and learn.

I've had fantastic results soldering to nickel plated steel. Actually, nickel plated anything to be fair. If you were after structural strength you could abrade the plating off the bit you want to solder to in order to get to the base metal. I suppose if you solder to the plating there's a chance it will peel off when subjected to mechanical stress.

I've never seen a plated sax. Only flutes, so this is a first.

It's Italian, and possibly 70-80 years old. Pretty sure the plating is original. I'm not wedded to it, but it would look great all cleaned up. Of course it would need to be repaired where the plating has lifted, unless I want to treat it like a Series and keep the "patina".

[Tins]

I am pretty certain (but could be wrong) that soldering is effective on nickel plating - but not on chrome plating.

Which leads me to my next question. How do I tell? It's so dull at the moment that colour isn't a giveaway. But it hasn't flaked where it's dented....

[JDNSW]

Find an inconspicuous spot, and see if you can tin it with solder. Clean thoroughly first and, I suggest preheat it (with a heat gun) so you don't have to use a large soldering iron.

[Tins]

Makes sense. Thanks, John. Feeling my way here. I can solder electrical stuff, and have soldered copper pipe, but this thing is a little delicate.

[Tins]

I know there are probably people here that question my sanity. Here's your proof..

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Still a cvouple of screws that are resisting me. I dunno how people did this before smartphone cameras. Soak time. It's filthy.

[BradC]

You should have started this as one of those Youboob "restoration" videos. You'd have made a fortune.

Oh, hang on. No this one is real. Nobody would believe it.

[Tins]

Yes, well, in those vids they always reassemble the thing perfectly, and it looks like new. That's not gong to happen either.

[Tins]

The plating is seriously deteriorated, with pitting and bare patches. I guess I will need to either strip it off completely or clean it up and plate over it, if that would even work. If I strip it off maybe I'll just see what it looks like as polished brass. Decisions decisions.

[Tins]

Those Jane Kits look interesting. Thanks for the tip, Brad. I'll be in touch with them to see if their Jane Clean is ok on brass.

[BradC]

Yeah, that'd be a good idea. Every chemical pickle I try on brass ends up selectively removing zinc and leaving a copper blush on the surface. Looks like crap and needs a ton of polishing to get back to "pretty", so do tread carefully.

[JDNSW]

As Brad says - brass is almost impossible to clean cheically as the large difference in electrochemical potential between zinc and copper will inevitably result in dezincification. Which you don't want on something where the surface finish is important (or anywhere else for that matter!). It will have to be cleaned up mechanically - i.e with polish and elbow grease.

[Tins]

As Brad says - brass is almost impossible to clean cheically as the large difference in electrochemical potential between zinc and copper will inevitably result in dezincification. Which you don't want on something where the surface finish is important (or anywhere else for that matter!). It will have to be cleaned up mechanically - i.e with polish and elbow grease.

That's going to be fun, around all the posts etc.
What about reverse plating?

[BradC]

Most of the fluxes I use are either water soluble (bloody hot water) or will weaken with caustic solutions, so there's no real need to pickle. Prep before soldering would be something like a fine wet and dry, wash up and then acetone to degrease. You shouldn't need to pickle.

Just be super sparing and careful with acid flux if you use that. Bakers fluid is loaded with zinc, so it should be pretty gentle on the brass if you go easy.

[JDNSW]

That's going to be fun, around all the posts etc.
What about reverse plating?

Yes, it will be fun, but a small (12mm) polish wheel in a suitable tool to spin it would make it easier.

I doubt reverse plating will be effective without ending up with some dezincification.

[Tins]

Yes, it will be fun, but a small (12mm) polish wheel in a suitable tool to spin it would make it easier.

I doubt reverse plating will be effective without ending up with some dezincification.

Fortunately I have spent heaps on 'tools ? that have been gathering dust for a while. What I haven't bought is patience [emoji854] Time to learn.

[Tins]

Hi John, Jane Clean is not going to do much to remove Nickel unfortunately.
It is something that will be challenging trying to remove with chemicals, we don't have anything that will do that safely sorry.

Kind Regards,

Guess they agree with you both. Oh well, time to learn some patience. I have surgery on Thursday so I guess I'll be inside a bit [emoji856]

[Tins]

Hmm.. Any thoughts on this? (https://www.caswellplating.com.au/store/store.php/products/nickel-stripper-5l-kit)

[BradC]

Not sure. In theory it's probably ok. If you were going to try it, maybe try it on a nickel plated brass plumbing fitting first? Grab a cheap coupler/adapter from the big green shed and strip the nickel off to make sure it's not going to discolour the brass.

[JDNSW]

I think you will have trouble finding anything nickel plated today. Most, if not all of it, is chrome plated, and you definitely cannot solder that. Nickel plating was used from around the late 19th century into the 1920s, or perhaps a little later, but was replaced by chrome plating, often as a thin coating of chromium on top of nickel.

Chromium has the advantage that it does not tarnish - which nickel will, and also it is harder. Today chrome is often underlain with copper electroplate. Nickel, even when polished, looks yellowish compared to chrome, which has a bluish tint.

Stainless steel's colour when polished is usually pretty close in appearance to chrome, although it depends on the alloy - most stainless steel includes both chromium and nickel, in varying amounts, depending on the alloy. (And stainless steel is very difficult to ipossible to solder as well.)

[Tins]

Where one post has come off. Guessing this suggests it's nickel then.
194553

[JDNSW]

That certainly looks like solder.

[Tins]

That certainly looks like solder.
Does, doesn’t it? I can’t read a date on it. There is a serial number but I haven’t had any luck yet with finding a reference.
194555

[Tins]

Reverse electrolysis removes the nickel for sure. Now all I need is some croc clips that don’t dissolve ☹️?

[BradC]

They are available in stainless steel, but I seem to recall using stainless on a cathode can leach hexavalent chromium into the bath so it's probably not the best idea.

Pretty much anything you use on the anode is going to dissolve. Might be worth just buying a bag full of cheap ones from Aliexpress. They are available in nickel plated steel, raw copper or brass if you look around. Maybe experiment to see what lasts longer?

[Tins]

They are available in stainless steel, but I seem to recall using stainless on a cathode can leach hexavalent chromium into the bath so it's probably not the best idea.

Pretty much anything you use on the anode is going to dissolve. Might be worth just buying a bag full of cheap ones from Aliexpress. They are available in nickel plated steel, raw copper or brass if you look around. Maybe experiment to see what lasts longer?
That’s the plan. I have never done this before. There are a lot of small parts that I would like to hang from something so I can batch. But I don’t have any idea so far how to dip the main body. I am using glass vessels because they are inert, but I will need something else for the body. Oh well, it’s interesting to do, and I can go on building my M18 batteries with 21700 cells while it cooks. Speaking of AliExpress.

[Tins]

I will be using the solder, Brad. Life has been getting in the way lately.

also have to practice the solo part that my choir wants me to do ????*?

[BradC]

John if you rush the chef you get a lousy meal. Prep and practice are key and good prep takes time. I'm in no hurry to see how it turns out.

I do wonder if you are going to do lots of stripping whether or not you can just hang the things with a loop of copper wire. The copper is going to dissolve but it's cheap and easy enough to get as to be disposable.

What electrolyte are you using?

[Tins]

2:3 hydrochloric to distilled water. 5 volts and 4 amps. I’m starting out with small parts so as not to destroy the whole thing. It’s working so far but I do see what you mean about copper bloom. 194744

[BradC]

Given you only need "a conductive solution" try bicarb or sodium hydroxide instead of HCl. You're looking to pull the plating into the solution. HCl will do that, but it'll also preferentially attack the zinc in the brass. A basic solution should do that less.

[Tins]

It would also have the advantage of being cheaper, and possibly less painful ?

[Tins]

I guess it would also mean that I could use a plastic tub for the big bits.

[BradC]

If bicarb isn't conductive enough, pool pH increaser (sodium carbonate) is the next step. Sodium hydroxide will attack zinc, although it has to be pretty strong.

I've used both for electrolytic rust removal because I keep both around for the pool.

[Tins]

I've done it again... I found an old Cornet in a junk store. It's a Boosey and Co, and the serial number shows it to be from around 1911. Difficult to play by modern standard, but it's been over 50 years for me as well.. This one is silver plated, so i'm lucky it doesn't need soldering! It's in amazing shape, considering. Bit of a clean, and some oil for the valves... Need something gentle to clean it. I have some Simply Green stuff that's amazing on aluminium, but not sure about this. No ultrasonic cleaner on it, at least not yet. I do not want to damage the plating. Thing has two mouthpieces, each of which is worth more than I paid for the whole thing... No wonder I'm broke, though. A sensible muppet would flip it.


There's a Boosey euphonium there as well, in need of rescuing.... sigh. So, along with an OKA, a Series III, a 300TDi D1, a currently non running TD5 D2, and a FIAT 124 Sport project, I was running out of things to not do...

[Tins]

195377195378

[Tins]

Note to self: Don’t leave the acidic electrolysis bath uncovered. Still, I suppose the resulting mess might polish out. Otherwise I might be replating the horn, or taking it back to brass and lacquering it. Sigh. Silly me.