(From the Theatre Organs
List)
Don B in Hawaii asks: Can anyone tell me the correct method to
solder organ pipes?
Al’s Response:
Greetings Don:
Soldering pipes is
easy after you destroy a few in the learning process. Therefore, I would not recommend on-the-job training using
Wurlitzer pipework. One must remember
that in essence, "You are soldering solder."
Hoyt Metal is almost all lead with a light
coating of tin to make it look nice and bright. The melting point of the lead in the Hoyt Metal is about 600º
Fahrenheit while most solders begin to melt at 380º F and a modern electric
iron can reach 1000º F while idling.
The trick is to have enough heat to melt the solder so that it will weld
the two pieces of Hoyt Metal together without having too high a temperature so
that the iron melts down through the Hoyt Metal and spoils the pipe. Where most apprentices and amateur organ builders
get confused is the difference between the amount of heat and the
temperature. (A bathtub of lukewarm
water has more heat than the head of burning match.) Instead of an "iron" I learned with a
"copper." A large soldering copper may hold a lot of heat and do a
nice job soldering a seam while still having a temperature of only 540º F. You heat the soldering copper up in your
gas-fired oven (yes, I still have one) until it gets just to the point of
melting a 90% lead & 10% tin alloy rod used for testing. Then you let it cool
a bit while cleaning the end off with sal ammoniac (ammonium sulfate) and
tinning with fresh solder. The clean
copper tip is used to pick up the solder from a solder pot or a firebrick with
a shallow well in the surface where 50/50 or 60/40 solder is placed. The choice of solder alloy depends on the
work and sometimes even the very low melting point eutectic solder (63/37) at
370º F is needed for very thin high tin strings. The area along the connection line to be soldered has been
cleaned with a sharp scraping tool so that it is a "V" shape. A special knife is used. Whiting compound has been painted around the
seam on both sides during preparation and when the "V" was cut there
remained sharp borders between the whiting and the metal seam. Sterine candles are sometimes used as flux
to keep the metal from oxidizing until the solder flows into the "V"
channel and makes the weld. The first
blobs of solder are placed at several points around the connection as solder
tacks to hold the metal in position for the full seam to be done. Once the tacks are cool enough, the solder
is picked up by the copper again and run down the entire length of the
seam. If the solder starts to show that
the copper is cooling too much then back into the oven it goes. This is the traditional method of soldering
pipework. Because of the lead fumes do
not breath while doing any of this.
Today with the advent of power variacs or lamp dimmers that may adjust electric soldering iron temperatures, and large electric soldering irons with clad tips, the job has gotten easier. The iron temperature can be slowly brought up to soldering temperatures and a massive 1000 Watt iron will not melt through the pipe wall if kept below the pipe wall melting point. Again remember this is because the *amount* of heat is NOT the same as *temperature.* Still, the preparation work is the sticking point for most people. The purpose of the whiting (a compound containing gum arabic, the world market currently controlled by none other than Osama Bin Laden, no kidding) is to prevent the heat of the iron from conducting to the pipe walls. This makes the only location that the hot solder blobs can find a surface to transfer heat to and alloy with are those inside the "V" groove of the joint. Capillary action, surface tension, and flow characteristics of the molten alloy make it hug the groove walls. The person applying the solder leaves just a bit extra so that the top of the groove is filled and curved to give what is called a "fillet." Literally the "V" walls have melted and alloyed with the solder so that only one piece of metal now exists. There is no rocket science here and any grammar school child can be taught to do the work with a little practice.
Lastly, to do the
work yourself means buying tools and materials you may never use again. Which would be more cost effective? Doing-it-yourself or sending if out?
To reiterate:
"Practice makes perfect" but it is not a good idea to practice on
Wurlitzer pipework! Isn't Terry Schoenstein still doing work in the Hawaiian
Islands? You might give him a call.
Al Sefl
Who has the burn
scars to prove that some lessons really are painful...
And now knows you
shouldn't lick a soldering iron to clean it...
PS: Some people have been using masking tape
instead of the whiting compound and done correctly it will work on some jobs.
PPS: Don, just had another great idea. Send me a ticket and I'll come over to stay
with you and repair the pipes for free.
It shouldn't take more than a couple of months to fix them.