Announcement

Collapse
No announcement yet.

Resistance Soldering carbon probes - are you experienced?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Resistance Soldering carbon probes - are you experienced?

    With many, the majority perhaps, of resistance soldering rigs, one side of the work is connect to one side of the circuit, and connection is made to the other with a carbon probe permitting a low voltage high amp current to flow. I grabbed a gouging rod and could hack apart some batteries....but wonder exactly what the roll of the carbon is

    The carbon probe has the advantage that it won't solder or weld itself to the work. It also gets hot, red hot sometimes, because of its resistance.

    My question is, does the heat of the carbon rod do anything, or is carbon just used because it won't attached itself? if you made one with the plan to connect both sides of the work solidly and controlled duration with a switch (vs touching off with the carbon rod) would it work as well?

    Thanks for any insight.
    in Toronto Ontario - where are you?

  • #2
    Originally posted by Mcgyver View Post
    With many, the majority perhaps, of resistance soldering rigs, one side of the work is connect to one side of the circuit, and connection is made to the other with a carbon probe permitting a low voltage high amp current to flow. I grabbed a gouging rod and could hack apart some batteries....but wonder exactly what the roll of the carbon is

    The carbon probe has the advantage that it won't solder or weld itself to the work. It also gets hot, red hot sometimes, because of its resistance.

    My question is, does the heat of the carbon rod do anything, or is carbon just used because it won't attached itself? if you made one with the plan to connect both sides of the work solidly and controlled duration with a switch (vs touching off with the carbon rod) would it work as well?

    Thanks for any insight.
    I think you should conduct an experiment, and show the findings to all of us.

    Comment


    • #3
      Originally posted by RB211 View Post
      I think you should conduct an experiment, and show the findings to all of us.
      I'd guess heat from the carbon does very little as the rigs do work without. The post was because I'd rather heed the voice of experience than make every mistake first hand
      in Toronto Ontario - where are you?

      Comment


      • #4
        I understand, but making mistakes is how one learns. For the record, I know nothing about this subject, other than my CF drone heating up due to a short

        Comment


        • #5
          http://resistancesoldering.com/site/faq

          https://www.micromark.com/Instructio...ering-inst.pdf

          http://www.raymondwalley.com/misc/tools/rsu.html
          1601

          Keep eye on ball.
          Hashim Khan

          Comment


          • #6
            Originally posted by RB211 View Post
            I understand, but making mistakes is how one learns.
            Not this one. I'd prefer to only learn by mistakes when necessary. Aren't you a pilot?


            Geez Jerry that was almost an OT.....lol....but I confess that last link was one I missed and quite good, thanks
            Last edited by Mcgyver; 11-30-2017, 05:10 PM.
            in Toronto Ontario - where are you?

            Comment


            • #7
              Originally posted by Mcgyver View Post
              Not this one. I'd prefer to only learn by mistakes when necessary. Aren't you a pilot?


              Geez Jerry that was almost an OT.....lol....but I confess that last link was one I missed and quite good, thanks
              The important thing is that you don’t repeat mistakes, the ones you survive


              Sent from my iPhone using Tapatalk Pro

              Comment


              • #8
                The Carbon Rods are not there to heat up, but to provide a large cross-sectional "low resistance" area.
                The low resistance should not develop heat--normally, the concept being that the two metals you are joining will have more interface resistance, and thus more heat- enough to melt lead solder ( ~ 350-600 F ).
                I use either EDM rod or Carbon Arc rod in my resistance soldering unit.
                Yes, D cell batteries have a carbon rod core, but they also have other metals/alloys that most likely have a higher resistance than pure carbon- and as such will grow hot in use and may not give you the Amps needed ?

                For those not familiar with Resistance Soldering, its a great concept.
                You have a super heavy Low voltage/ high amp transformer that is connected with heavy flexible wire. one wire to a plate of copper and the other to a hand tool ( mine is made of wood). You lay your work pieces on the copper (or steel ) plate and clamp them if necessary ( not a requirement) The hand tool can have a carbon rod or a pointed piece of stellite or carbide.
                The pointed piece is for very small work ( jewelry ie) and the carbide gets hot . SO that hand tool will have cooling fins
                For larger work, the carbon rod is to be placed flat on metal pieces and the Carbon/metal juncture has lower resistance than the metal/metal juncture and so the metal/metal juncture gets hotter ( per OHM'S Law)
                On my unit, I can push 1.8 Volts, 2.0 Volts or 2.2 Volts at 50 Amps +

                Rich
                Last edited by Rich Carlstedt; 11-30-2017, 08:17 PM.
                Green Bay, WI

                Comment


                • #9
                  I can imagine that when the carbon rods get hot, that will help to heat the junction and melt the solder. The joint itself needs to melt the solder, so you don't apply it to the carbon tips- that's a common mistake with any soldering. Many people tend to melt the solder with the iron, then apply that to the junction and end up with a cold solder joint. I like to melt a small amount of solder with the iron to assist heat flow into the junction, but then apply the solder to the junction until it wicks in. And the intermittent 'touch and go' thing is bad too- you need to apply the heat and keep it on until solder flows, then pull the iron away.

                  I have a resistance soldering pen, runs on AAs. Think about how few amps are going to flow, several perhaps but certainly not 50 or even 20. I think in this case the heating of the tips is helping to do the job. They call this a cold soldering pen- probably good for making cold solder joints I never use it.
                  I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                  Comment


                  • #10
                    I built my resistance soldering unit some 30 years ago. It uses a typical 1/4" carbon rod that is copper coated. The current flows into the work between the carbon rod and the ground. The reasons for a carbon rod is that it conducts heat and electricity nicely and after the current is shut off when the joint is made, if held in place, it will cool the joint very quickly.

                    I used a 10 amp center-tapped transformer for mine. It was formerly powered with a Variac, but the one I used burned out after many years so I switched to a large light dimmer with good results. I also used a foot pedal to start and stop the current.

                    There are some units that utilize tweezers that have both the power and the neutral or ground side but I'm not familiar with those.

                    I've used my unit on my model railroad primarily for soldering small brass parts together. It works beautifully.
                    Last edited by GNM109; 11-30-2017, 09:43 PM.

                    Comment


                    • #11
                      I too built my unit using a transformer intended for scratch marking on metal, tools, etc. Very low V and high current.
                      The electronics manufacturing plant I worked in had the American Beauty units. I copied the design of the handpiece
                      tweezer at first using D cell carbons, but they were too soft. Installed copper coated arc rods and still have them
                      after over 30 years. Great for soldering large electrical contacts and small metal assemblies. It allows a clean job as
                      no contact is needed with the actual solder area. It's a combination of high current thru the part soldered and heat
                      at the carbon contact tip which is usually a rounded point. I have silver brazed small assemblies as well. There are
                      or were metal alloy tips available for small work.
                      RichD, Canton, GA

                      Comment


                      • #12
                        Originally posted by Mcgyver View Post
                        Resistance Soldering carbon probes - are you experienced? .
                        No. Sorry Mak. No experience that I have.

                        Look, a question asked and and answered. JR
                        My old yahoo group. Bridgeport Mill Group

                        https://groups.yahoo.com/neo/groups/...port_mill/info

                        Comment


                        • #13
                          Originally posted by darryl View Post

                          I have a resistance soldering pen, runs on AAs. Think about how few amps are going to flow, several perhaps but certainly not 50 or even 20. I think in this case the heating of the tips is helping to do the job. They call this a cold soldering pen- probably good for making cold solder joints I never use it.
                          That sounds like the "Cold Heat" soldering system. Their web page says that it generates heat in the tips, not necessarily in the joint that you are soldering. I believe that means that it's not resistance soldering.

                          Interestingly, the cold heat system does work OK in many cases. Handy for fixing broken wires in hard to access spots.

                          Dan
                          At the end of the project, there is a profound difference between spare parts and extra parts.

                          Location: SF East Bay.

                          Comment


                          • #14
                            You guys have this all wrong. NONE of the heat comes from the joint resistance. ALL the heat comes from the carbon resistance. The joint is an extremely short conductor with very low resistance so the voltage drop across that resistance is also very small. Therefore Watts = Current x Voltage drop is almost nothing. Hence the high resistance of the carbon is what is generating the heat. If this were not true a copper rod would work much better and all you get with a copper rod is a dead short.

                            Comment


                            • #15
                              If you look at some of the pics and videos, the carbon tip is often red or orange hot.......
                              1601

                              Keep eye on ball.
                              Hashim Khan

                              Comment

                              Working...
                              X