[abracadabra]

Hello folks

My 1st post here although I've certainly lurked for some time.

I'm a part time clarinet repairer, really it was a hobby that turned into a part time job. I focus on Albert system clarinets and have refurbished/overhauled a good many at this point.

I pick up tools and techniques as I need them. I haven't run in to too many broken keyed instruments and when I do just had another tech to the work.

I thought it was time to try my hand at silver soldering! I mean next to buying a lathe and stand alone buffer there aren't too many things I haven't learned to do with my tools and bench motor.

Now I read up on this, LOTS! I've got the Reg Thorpe book which I've had for years and have read over the section on soldering in my old Brande manual too.

Then I looked online, various forums including this one, and I thought well it seems hard but I should try it.

I bought this torch: (although for $60 at home depot)

http://www.thecollegetoolbox.com/tuoxtokitox.html

I did this because it was a kit and because I heard MAPP was a decent choice for silver soldering. Also I noticed Ferrees sold the torch and mentioned silver soldering so I said what the heck.

My 1st repair was to an old register key, the kind you see on almost all the old Albert clarinets, it wraps around the instruments. The key cup and arm broke at the hinge tube, the touch piece still attached.

I cleaned it up really well with wire brush and files, jigged it up (an old Brande jig), put some flux on (Ferrees), then lit up the torch.

Now, here's where I'm not sure about things. This torch puts out a flame that seems pretty big for this work. How long of a flame should you use and how much of the flame should be blue (oxygen)??

I heated up, tried, tore it down, cleaned it, jigged it up again many many times and I could not get any results. I'm not sure if I got the area hot enough, and also ended up getting the key all black (although this comes off).

I guess I just would like to hear if this torch is okay, and info on the flame etc.

Otherwise, if its clean as can be, and fits together nicely, and heated to the right temp using the right flux and solder (both from Ferrees) it should work right?

I'm not so worried about it looking great for my 1st time, but I can't even get it to hold together in the first place!

Hopefully I can figure this out and not feel like I wasted money on a torch I can't use.....

thanks in advance for any help folks!!

mark

 

[hornfixer]

Welcome to the forum.
your flame should be blue with a nice point to it.
You should get the key red hot.

 

[abracadabra]

Okay, blue flame.

So less gas and more oxygen I suppose.

mark

 

[abadcliche]

I would suggest trying it on a key off of a parts horn first- or just some small chunks of brass. The heat from silver soldering can melt/deform keys if you are not careful (not to mention blister plating)- particularly on small parts where the heat travels fast and has nowhere else to go, particularly with a large flame. Finesse is the name of the game.

 

[abracadabra]

I guess I just wonder if I have a decent setup right now with the MAPP/oxy torch.

For small soldering like this I've read that you can get by with a small butane torch like a Blazer, but others say it isn't hot enough.

Also I've read some people use just straight MAPP, no oxy. Which would be a simpler setup, I don't really like the two cannister setup with the little wonky stand they provide to prop the bottles up.

mark

 

[Jorns Bergenson]

Abra,
I have several torches for silver soldering/brazing, but I have used the same Bernzomatic setup for repairing keys in the past. Adjusting the gas and oxygen while keeping the flame lit is a bit tricky with that setup. You want to get the bright blue portion of the flame very small, around 1/4". I've never had good results trying to use just MAPP gas.

Here's what I do:

1. Clean the parts completely. Degrease them and then use sandpaper and/or a file to expose "new" brass. You don't want an air-tight fit, but close. Some folks recommend filing a very slight "V" in the parts so that the solder will flow somewhere other than just on the outside of the parts. Clean the solder as well. I use sandpaper and then wipe it down with alcohol.
2. Coat the area to be soldered in flux. Coat the tip of the solder in flux. I use a small, clean paint brush to coat the parts.
3. Use a jig to hold the parts in place. The cheapie soldering jigs from Harbor Freight may work for one or two uses, but in general, they can't stand the heat from hard soldering. Reapply flux if you lost any in the mounting process.
4. Heat the joint keeping the flame moving across the joint. You don't want to melt the brass by concentrating the heat in one tiny spot. You can tell when the metal is close to being hot enough when the flux stops bubbling and turns from white to clear plastic-looking and the joint is glowing red.
5. Touch the solder to the joint remembering that the solder will want to flow towards to highest heat and will also want to flow downhill. Don't melt the solder with direct heat from the flame. I alternate between "dancing" the flame across the joint for a couple of seconds, pulling the flame away and touching the solder to the top of the joint. If the solder melts, I bring the heat to the bottom of the joint to get the solder to flow down through the joint.
6. If the solder doesn't melt, pull back on the solder and heat a little more.
7. If the solder melts but just rolls off, something is probably contaminated: the part, the flux or the solder. Let it cool, clean everything again and start over.
8. You want to make sure the solder flows uniformly through the joint. It takes practice to get a feel for when you should stop heating the joint. Too much heat for too long will melt your part.
9. After the part cools, the leftover flux will be hard as a rock. You can clean your part by pickling or by scraping or filing.

Some other notes:

• You can use a hollow brass tube to hold the silver solder wire.
• You need something behind your work that can take the heat. I use a couple of ceramic floor tiles with a 2600 degree soldering pad on top. I also put a ceramic tile behind the work so I don't catch my workbench on fire.

That's the jist of what I do for a simple key repair. It would be best if you could practice on a junk key a couple of times.

 

[abracadabra]

Jorns

Thanks for the rundown.

You mentioned keeping the flame small on this one is tricky....1/4" blue flame.....is the whole flame 1/4" or just the blue? So basically just using the oxy to get the blue and then cutting back on the fuel to make a smaller flame?

And I agree on practicing on some junk keys, but in this case the key I'm fixing was messed up by someone else, so, I can only make it better by making it work (the plating is marred).

mark

 

[Jorns Bergenson]

I'm sure someone else will chime in here about the flame length, because people have different preferences. I've always gone for a really small, bright blue cone inside the wider flame when working on key arms so that I can keep the heat more localized. When soldering thinner brass, like a keycup, a pinpoint flame can burn a hole right through it.

With the Bernzomatic, at least the first time you try to light it, the flame will often go out as you open the oxygen valve no matter how slow you open it, but it usually will stay lit the second time around. Make sure you always turn the oxygen on last and off first or you'll get a nasty pop.

 

[Stephen Howard]

I guess I just wonder if I have a decent setup right now with the MAPP/oxy torch.

For small soldering like this I've read that you can get by with a small butane torch like a Blazer, but others say it isn't hot enough.

Also I've read some people use just straight MAPP, no oxy. Which would be a simpler setup, I don't really like the two cannister setup with the little wonky stand they provide to prop the bottles up.

The Blazer's a bit small for general use - and if you have to run a torch at its limits you have no leeway. Better to run a larger setup with a smaller flame.

I just use a propane gas cylinder and a set of Sievert guns with nozzles that range from pencil thin for precision work to a 2 incher that will melt brass for casting.
It also powers my bench Bunsen burner.

Regards,

 

[clarnibass]

I have a Blazer and couple of similar ones. I can't silver solder with them except for the smallest part and even that is borderline. The problem is you can't get the part hot enough, not because the flame is not hot enough, it is. Silver soldering requires about 650° and the Blazer torch is 1370° but the flame still can't get the parts hot enough, because it is too small. So you need either a hotter flame or a bigger flame (or both). For example, I once tried two Blazer (type) torches (with a helper) and this worked when one failed, showing the temperature of the flame isn't always the problem.

The torch you linked to seems like it should work, especially if you use it with oxygen. For silver soldering I use a butane or propane torch with a bigger flame. It comes with several nozzles and I almost never need to use any other than the smallest one.

If something went wrong then it's probably an issue seperate from the torch itself or that the flame of the torch is too small for its temperature. Hotter flames can be smaller (like the Little Torch) but also more risky.

 

[Gordon (NZ)]

The Blazer's a bit small for general use - and if you have to run a torch at its limits you have no leeway. Better to run a larger setup with a smaller flame.

I just use a propane gas cylinder and a set of Sievert guns with nozzles that range from pencil thin for precision work to a 2 incher that will melt brass for casting.
It also powers my bench Bunsen burner.

What I use is similar. A huge advantage in using just propane or butane (with a large enough burner to provide heat faster than it is conducted away by the work, until the work is red hot) is that with this lower temperature flame, there is almost zero risk of melting the work.

Any fuel with oxygen added is capable of easily melting the work if the operator is inexperienced.

1/4" would refer to the blue core of the flame. Use the flame just past that pointed blue core. The full length of the flame would be a lot longer.
Increase the proportion of oxygen until there that blue core is short and clearly defined. How much flow of both gasses will depend on the size of your work: Enough gas so that you get the work hot enough within say 10-20 seconds, and not so much gas that you greatly increase the risk of melting your work. It's based on experience.

From post 6:

"7.If the solder melts but just rolls off, something is probably contaminated: the part, the flux or the solder. Let it cool, clean everything again and start over."

Or the work is not hot enough. This may be easier to judge in a darkened room, so that you can see better when it is red hot.

"8.After the part cools, the leftover flux will be hard as a rock. You can clean your part by pickling or by scraping or filing."

Soaking in water, especially hot water, quickly dissolves that flux.

BTW, the type of flux you use must match the rod that you are using. BTW, is your rod 40 - 45% silver? If not, you may have big problems.

 

[Chris Peryagh]

It does help if you're using an insulating or heat reflective block or board (such as Skamolex) as the heat won't be drawn away from the key as fast as it can be if it was suspended in mid air mounted in a jig or resting on a metal block (which you wouldn't do anyway), but this is only best for soldering small or flat components or if you've wired the piece to be soldered together with mild steel wire.

See page 11 for Skamolex blocks and boards: http://www.squirestools.com/12-17.pdf

 

[Henning1]

Welcome mark, unless you've already seen it, this thread about soldering might give some general clues for you.

 

[abracadabra]

Well folks, I did it.

First thing I did was take back that whacky oxy/mapp setup. Way too complicated and I don't like using the oxygen.

I got this: http://www.bernzomatic.com/quickfire-hand-torch.aspx

This was a little cheaper (home depot) and works GREAT. There's just nothing to it and after reading and re-reading up on the procedures I went at it today.

I fixed three keys, the register key I mentioned in the 1st post (old wrap around kind) and two other ring keys.

Funny, the one I thought would be the easiest turned out to be the hardest! And the register key came out great, I got it on the instrument and its one of the nicest feelings ever, this thing didn't work for how many years, now its singing! Its an old Couesnon C Albert.

Anyway the work I did doesn't look great, especially on the one key, but its solid. I know that that I'll improve with each one, just like with all this work. If you keep doing it you just get better and better. I look at work I did a year ago and I feel like its night and day (although I am still in the beginning/apprentice/ stage, I imagine once one gains experience the leaps in quality of work aren't so obvious?)

Thanks for the good tips, it certainly helped a bunch.

mark

 

[Stephen Howard]

That's more like it.

It's worth your while seeking out a specialist supplier of solders and fluxes, you can 'fine tune' your soldering technique by choosing more advanced solders...such as those with better flow or fill characteristics. Varying the melt point is useful, for those jobs where two or more joints in close proximity are required and that can't be done in one pass.
Knowing how your chosen fluxes and solders work is just as much a technique as knowing how to use a flame from a gun.

Regards,