Soldering Tips and Procedures

Soldering is most likely the most difficult craft to master. A good

solder joint should hold up for the life of the horn. Cleanliness is the key

to good solder joints. Materials selection can help make the job easier and

produce a stronger joint. There are also a few tools which are necessary to

do the job well.

  1. Selecting Solder
  2. Materials Selection
  3. Tools
  4. Scrapers, Clamps
  5. Re-Soldering
  6. Flux Formulas

Selecting Solder-

Solder is made up of Tin and Lead. When you purchase solder you will

notice on the label the Tin and Lead content(ie.40/60). Below are two

examples of commonly used soft (also known as "Quick Solders") solders-

The most commonly used solders in brass musical instrument work are60Sn-40Pb,

70Sn-30Pb. It is up to you to try these and see which works best.

You effect the strength of the soldered joint by the amount of lead or tin content.

For example, although you will be able to make 60/40 solder flow easier, it will not

have the stength of 70/30. Over time, the tin will crystalize weakening the joint. Tin,

more than lead, is effected by a wide variety of chemicals. Temperature can also have a

detrimental effect on the adhesion of tin to the joined surfaces.

As you have probably seen, some joints just seem to come apart for no reason.

Usually this is due to an unclean joint but can also be attributed to high

tin content in the solder. I like to use 60/40 since it is fairly strong and

flows evenly. If I am soldering a tuba bell brace, I will use 70/30 for added

strength. 70/30 solder requires higher temperatures which will burn lacquer

and create alot of clean-up time. In the US there is a movement afoot to

eliminate all lead solders due to a general hysteria over lead exposure.

Because of this, solder manufactures have come up with a new solder using a

low temperature silver. This solder will mealt at about 440 degrees F. This solder

is known as Tin/Silver Solder and is composed of 96% Tin and 4% Silver.

I have this in the shop and use it periodically to get used to it. At some point in

the future it will be all that is available. It works good if the joint is

completely clean and you can get the job done in one pass. If you need to

reheat the solder joint after applying the solder, the dross(dirt and residue

from metal) will inhibit filling any voids. For now, purchase 60/40 or 50/50

solder and get use to the amount of heat it takes get it to flow.

Materials Selection-

You will need a torch which can be regulated and is very flexible. In

most cases, I recommend a propane torch. You can purchase a twenty pound RV

tank with regulator for very little money. A twenty pound tank should last

you about a year and cost you about $20 US. I have natural gas and propane as

well as oxigen and acetylene for all applications. Propane will allow you to

soft solder as well as braze joints. The torch should have a flow regulator

and peizo ignitor.The Bernzomatic TS7000 is a good choice. This torch will be

expensive, relatively speaking, but you will get years of service out of it

and come to realize its usefulness. You will have to attach the torch to the

tank with about 5 feet of tubing. All this is available at your

local hardware store. If you can't get the fittings at the hardware store, go

to your local RV (recreational vehicle) supplier. I also have a torch which

is made in Great Britain and performs well. If you can't locate the

Bernzomatic let me know and I'll find a supplier for you. The cost is around

$70 US.

You will need solder flux to clean the joint during soldering. NEVER USE

ELECTRICAL SOLDER PASTE! This can cause severe corrosion in a very short

period of time. Flux can be several different combinations of chemicals.

Usually, Zinc Chloride, Ammonium Chloride or Hydrochloric Acid are used as the

base for most soft soldering fluxs. Every manufacturer of flux uses different

combinations. To simplify things, simply purchase liquid flux intended for soldering soft alloys.

Hardware stores do not always have this in stock so you may have to order

this from one of the suppliers listed. Check the label when you buy it

and make sure it is not intended for aluminum or for brazing. You can also

get alot of help at jewelry supply stores. They specialize in this sort of


A trick used in the profession for years to keep the solder from

"running" is to draw a black line with a majic marker close to the joint

before soldering. This creates "dirt' which the solder cannot flow past.

You'll want to try this after you get started.

RECAP- 60/40 solder,Propane Torch, Lead Solder Flux


The main tool you'll need after you have soldered a joint is a scraper.

If you look in the Ferrees catalogue you'll notice that there is a big

selection. I recommend a slightly curved scraper for use on most jobs. This

tool is used to remove any excess solder around the joint. It is a little

tough to get used to using one of these but I am afraid you'll have to figure

it out for yourself. You want to scrape along the brace and surface at a 90

degree angle. It is only important if you have caused excess solder to

accumulate at this point. I hold the scraper, handle in my palm, index finger

under the curve, thumb pushing on the top. This last sentence will not make

any sense until you try it the first time. Since I have been doing this for

so long, I don't normally have to scrape the joint but I always do if there

is any excess. Sadly, most repairmen don't care if the joint looks sloppy.

Another great trick is to use braided steel wire similar to the contacts

used on model slot cars to take up the excess solder. By applying a little

flux to the wire and heating it up while touching it to the solder joint, it

will draw off the excess thus saving you from scraping. This takes a little

practice but works good.

The only other tools you will need are clamps. Simply

take an old hanger and bend it in a "U" shape roughly the distance between

the outer most surfaces to be soldered. Of course, you will have to cut the

wire to an appropriate length before bending it. You can adjust these

clamps to hold the braces or parts in place while you solder them. It is

cheaper and easier to make your own clamps rather than buy them from one of

the suppliers. Their clamps are not the greatest quality and can fall apart

in the middle of a job. It's surprising how well hanger wire works.

A traingular scraper is the best tool in the shop for cleaning up a

joint between a ferrule and tube. You may have to order these from a

catalogue. They are used to remove the old solder and oxidation from the

inside and outside of disassembled tubing. Look in the Ferrees catalogue to

see what they look like. Once you have taken a tube and ferrule joint apart

you can use this tool to scrape around the inner edge of the

ferrule(connecting tube) and the outer edge of the inner tube. Doing this

will prepare the joint for re-soldering.

RECAP-Scrapers, clamps

When soldering a joint it is really important to make sure that the

joint is clean. I recommend using sandpaper to clean the joint both inside

and out. After you have scrape and sanded, clean the joint with NAPTHA.

NAPTHA is the chemical most commonly used to fuel lighters (ZIPPOS). You can

get it at the hardware store by the pint or gallon at a fraction of the cost

of lighter fluid. Just ask for NAPTHA. You'll find this very handy for

cleaning just about everything, including the lawnmower.

I missed one thing-wipe the excess solder off the joint after

disassembly by heating it and quickly dragging a rag across the part. This

will save you alot of time scraping and sanding.


When you have cleaned everything up and are ready to reassemble the horn,

always check the fit of the parts. The closer they fit, the easier the

soldering. Put the parts back together and "fan" them with the heat (pass the

torch over them slowly, heating them up a little at a time). When the parts

are fairly warm, apply a small amount of flux. If you have cleaned the parts

properly, there shouldn't be too much dirt appear. If there is alot of

"black stuff", apply more flux to wash it away after applying a little more

heat. This is really touch and go from here on out. You'll have to gain some

experience with this to fully understand what I'm talking about. Don't be

upset if you run solder all over the place, you have to come to an

understanding of the proper amounts of heat to get the job done.

Use the horns you have now to try this stuff out. Soldering is a good

place to start. Some dent work can be done without removing any pieces but

really good work requires the ability to get things apart and back together

in a short amount of time without any noticable difference in appearance.

Good soldering ability will help you do just that!.


It is necessary to use liquid flux with brass soldering since the acid core solder is extremely corrosive. It is impossible to wash away the flux which then begins to eat at the brass. You may want to look in the telephonedirectory to locate a welding supply or jewelers supply. Either of these will have the liquid flux. You can apply this with a acid brush or small eye dropper. Remember that when you solder it is important that the parts fit very closely. The better the fit, the better the solder joint. Flanges (flat brace material) can be burnished onto the corresponding branch with a screw driver or other smooth implement. You may want to overbend the flang so that when you put it in place in will squeeze down flush to the other part. Always clean the parts before soldering. If you are having trouble getting solid solder wire you may want to order it from Ferrees supply althoughit will be more expensive than getting it at home. They also sell containers of flux but I don't know if they'll send it overseas (regulations on toxicchemicals). If you are having alot of trouble with this, I will send you a formula to make your own. The ingredients are easy to obtain. I think if you have the torch, instruments, flux, a holder built, solder, 120 grit sandpaper(for cleaning), and a scraper you should try to see what you can do. You can make a scaper out of a nine penny nail. Heat up the end (red hot), grab it with a pliers and bend it at about a 20 degree angle. Grind the small bent end square and flat at the end. Sharpen the end with a sharpening stone and use it to clean up the solder around the braces. Your thumb will get sore from this but it is the price you pay for repairing! I know this is not really clear but it is always best to try first then ask questions. Tools are always made to work for you alone-make something that gets the job done!

Flux Formulas-

Soft Soldering Flux

U.S. Patent 1,974,436

Zinc Chloride 25oz

Alcohol 20oz

Ammonium Cetyl Sulphate 1/2oz

Nickel or Monel Soldering Flux

Saturated Zinc Chloride 50% in

Hydrochloric Acid

Any question? Drop us a line and we'll try to help.

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