(0)SCHOLARSHIP REPORT by Jim Myers
SILVERSOLDERING CLASS
INSTRUCTOR-TOM McCARTHY
September 2010
My reason for selecting Silver Soldering as a scholarship subject was that I had been having
trouble with brazing joints and felt that brazing and silver soldering were quite similar. The class
was a jewelry soldering class, silver solder on silver sheet and bar silver. Really small scale to a
blacksmith. Nothing to do with brazing of sheet steel, but I hoped to see what techniques I could
carry over into sheet steel brazing. In the end I am happy I made this choice.
This was a weekend class. On Friday night it was all discussion of silver soldering theory,
practices and our questions. Saturday morning actual soldering of a "sweat joint". My first shock
was the torch. It was Air-Acetylene. No oxygen line. A lot less heat, but plenty for the job. My
second shock was that I was expected to hold the torch in my LEFT(off) hand. After a short while I became a convert to this. Saturday afternoon was making a "Tee joint" and setting up a "Butt
joint". Saturday night we finished the Butt joint and had a long question and answer session. To
this point it had all been jewelry silver soldering. Sunday morning we all did our own thing. My
thing was about silver soldering on sheet steel, and Tom gave me a lot of help .
I have become comfortable with soft soldering. This takes place at about 430 deg. F. The solder
flows easily by heat transfer from the work to the solder wire. After learning how to heat the work
and finding a flux that I liked, I can use it as a common process, but it is a WEAK joint. Brazing
with a brazing rod gave me real problems. I regularly burned the flux before the brazing rod flowed and instead of running out flat, my brazing rod made blobs. Stubborn little blobs that did not like to flow.
When you jump up to silver soldering and brazing at 1100 deg to 1400 deg you are no longer in
the soft solder world. As Dorothy said in Oz, "Toto I don't think we are in Kansas anymore." We
did no brazing, but, with silver solder, we were just below that temperature range. Clean joints are a necessity. Sanding was the answer to this. Close fitting joints are a necessity as the silver solder flows by capillary attraction. Flux is a necessity as it keeps the metal from forming oxides that kill the bonding of the metal to the silver solder. Our flux was a borax paste applied with a brush. Into the flux we placed small pieces of silver solder AT THE JOINT. On heating the base metal the flux first liquified, then boiled the water out and then dried out, locking the silver solder bits in place. THEN THE FLUX MELTED. This was a very visible happening and it WAS AN INDICATOR THAT THE BASE METAL WAS AT 1100 deg. This is close to having the silver solder flow. Heating the base metal further we WATCH FOR THE FLOW OF THE SILVER SOLDER. When that happens we pull the heat immediately. If all has been done correctly the joint is made.
A tightly fitting joint, as silver solder does not like to bridge gaps. Fluxing the area where you want solder to go. Placing the solder right at the joint. Heating the base metals and keeping the flame off the solder. Bringing both pieces to be joined to soldering temperature at the same time.
THESE ARE THE BASICS. There is also the fact that the solder RUNS TO HEAT. On my Tee
joint I had flux applied to the vertical member at one place and in heating the joint I got too much
heat on the vertical piece and the horizontal piece not hot enough and the solder RAN UP the
vertical piece instead of into the joint. It was a great learning experience.
On Sunday morning I got to work with silver solder and sheet steel. My past problems were, that
because steel is such a poor conductor of heat, in my attempt to get the steel hot enough I would burn the flux. Careful heating would be a requirement. The flux we were using was not a
specifically "high temperature" flux, it was just the paste flux we had been using. To help, we
switched to "Easy Solder" which is the lowest melting temperature silver solder, and I sanded
clean an area on the sheet steel and FLUXED THE HECK out of the area, dropped my silver
solder bits into a small circle and started to heat the perimeter of the pile. When the flux had
melted I continued heating that perimeter and suddenly the solder ran and flattened out into a
beautiful (to me) flat spot.. I knew that silver soldering with steel was possible for me. It now
becomes a matter of practice.
I am aided in the knowledge that there is a higher temperature flux available (not locally, but on
special order) and that this might work on brazing rod cut into small bits. I am fearful that my
higher temperature Oxy-Acetylene torch may require a lot of learning to keep the Heat localized
where I want it and the temperature lower than I have used it in the past, but BRAZING this way is on my to-do list.
Again I would like to say that if you are able to take the time off for scholarship classes and do not participate in the drawings you are missing out. My own experiences have all been at John C. Campbell Folk School and all good to very good. My philosophy has been to try to get really good instructors. Some GOOD smiths can't TEACH. Some will take an interest in answering questions and some won't. Some have "Pets" among the class students. I ask around about an instructor in selecting a class.
HAPPY SMITHING
John Myers
SILVERSOLDERING CLASS
INSTRUCTOR-TOM McCARTHY
September 2010
My reason for selecting Silver Soldering as a scholarship subject was that I had been having
trouble with brazing joints and felt that brazing and silver soldering were quite similar. The class
was a jewelry soldering class, silver solder on silver sheet and bar silver. Really small scale to a
blacksmith. Nothing to do with brazing of sheet steel, but I hoped to see what techniques I could
carry over into sheet steel brazing. In the end I am happy I made this choice.
This was a weekend class. On Friday night it was all discussion of silver soldering theory,
practices and our questions. Saturday morning actual soldering of a "sweat joint". My first shock
was the torch. It was Air-Acetylene. No oxygen line. A lot less heat, but plenty for the job. My
second shock was that I was expected to hold the torch in my LEFT(off) hand. After a short while I became a convert to this. Saturday afternoon was making a "Tee joint" and setting up a "Butt
joint". Saturday night we finished the Butt joint and had a long question and answer session. To
this point it had all been jewelry silver soldering. Sunday morning we all did our own thing. My
thing was about silver soldering on sheet steel, and Tom gave me a lot of help .
I have become comfortable with soft soldering. This takes place at about 430 deg. F. The solder
flows easily by heat transfer from the work to the solder wire. After learning how to heat the work
and finding a flux that I liked, I can use it as a common process, but it is a WEAK joint. Brazing
with a brazing rod gave me real problems. I regularly burned the flux before the brazing rod flowed and instead of running out flat, my brazing rod made blobs. Stubborn little blobs that did not like to flow.
When you jump up to silver soldering and brazing at 1100 deg to 1400 deg you are no longer in
the soft solder world. As Dorothy said in Oz, "Toto I don't think we are in Kansas anymore." We
did no brazing, but, with silver solder, we were just below that temperature range. Clean joints are a necessity. Sanding was the answer to this. Close fitting joints are a necessity as the silver solder flows by capillary attraction. Flux is a necessity as it keeps the metal from forming oxides that kill the bonding of the metal to the silver solder. Our flux was a borax paste applied with a brush. Into the flux we placed small pieces of silver solder AT THE JOINT. On heating the base metal the flux first liquified, then boiled the water out and then dried out, locking the silver solder bits in place. THEN THE FLUX MELTED. This was a very visible happening and it WAS AN INDICATOR THAT THE BASE METAL WAS AT 1100 deg. This is close to having the silver solder flow. Heating the base metal further we WATCH FOR THE FLOW OF THE SILVER SOLDER. When that happens we pull the heat immediately. If all has been done correctly the joint is made.
A tightly fitting joint, as silver solder does not like to bridge gaps. Fluxing the area where you want solder to go. Placing the solder right at the joint. Heating the base metals and keeping the flame off the solder. Bringing both pieces to be joined to soldering temperature at the same time.
THESE ARE THE BASICS. There is also the fact that the solder RUNS TO HEAT. On my Tee
joint I had flux applied to the vertical member at one place and in heating the joint I got too much
heat on the vertical piece and the horizontal piece not hot enough and the solder RAN UP the
vertical piece instead of into the joint. It was a great learning experience.
On Sunday morning I got to work with silver solder and sheet steel. My past problems were, that
because steel is such a poor conductor of heat, in my attempt to get the steel hot enough I would burn the flux. Careful heating would be a requirement. The flux we were using was not a
specifically "high temperature" flux, it was just the paste flux we had been using. To help, we
switched to "Easy Solder" which is the lowest melting temperature silver solder, and I sanded
clean an area on the sheet steel and FLUXED THE HECK out of the area, dropped my silver
solder bits into a small circle and started to heat the perimeter of the pile. When the flux had
melted I continued heating that perimeter and suddenly the solder ran and flattened out into a
beautiful (to me) flat spot.. I knew that silver soldering with steel was possible for me. It now
becomes a matter of practice.
I am aided in the knowledge that there is a higher temperature flux available (not locally, but on
special order) and that this might work on brazing rod cut into small bits. I am fearful that my
higher temperature Oxy-Acetylene torch may require a lot of learning to keep the Heat localized
where I want it and the temperature lower than I have used it in the past, but BRAZING this way is on my to-do list.
Again I would like to say that if you are able to take the time off for scholarship classes and do not participate in the drawings you are missing out. My own experiences have all been at John C. Campbell Folk School and all good to very good. My philosophy has been to try to get really good instructors. Some GOOD smiths can't TEACH. Some will take an interest in answering questions and some won't. Some have "Pets" among the class students. I ask around about an instructor in selecting a class.
HAPPY SMITHING
John Myers
Tags: No tags
