Background first, questions later: For those who are not familiar with resistance soldering, it is a lot like 'arc welding' where a current is passed between two electrodes with resulting heat generated in a very small area at a fast rate so as not to heat the surrounding areas. Voltage is only around 6 volts, but current is very high. Either using a 'tweezers' type of hand held unit or a ground clip and a 'probe' type of hand unit. Depending on what is being soldered would determine the type of hand unit. For our application a 'tweezers' type of hand unit should be ideal. You can make one of these yourselves (if you are so inclined since the power unit is nothing but a transformer); http://www.google.com/url?sa=t&rct=j&q=resistance soldering&source=web&cd=6&ved=0CJ0BEBYwBQ&url=http%3A%2F%2Fwww.girr.org%2Fgirr%2Ftips%2Ftips1%2Fsolderer.pdf&ei=j9p-T4XfE4-e8gTXsrTWBw&usg=AFQjCNEC9d3xCIHbYBaBTOpIJGoDpc7GNQ Or purchase one from these two manufactures (both US made); American Beauty and P-L-B. http://www.p-b-l.com/ This site is basically a 'ad' for AB, but is helpful; http://resistancesoldering.com/site/ This is about the cheapest source for the AB 100 watt basic model; http://www.all-spec.com/products/10501.html?utm_source=amazonshopping&utm_medium=feed Of course it's hard to justify the cost to solder a few 'power feeders' unless you are lucky to find a unit used as I did. I was going to go with the smaller 100 watt unit, but I was concerned that it would limit the usefulness down the road for other applications. The 100 watt is fine for just N scale and fine work, but I now find using their 250 watt step up version I'm running the adjustable 'pot' at half current, which means it would have to be at full if it was a 100 watt station. I talked with someone from AB's tech support and he admitted many buy the 100w version only to find it wasn't enough. (this wasn't a sales pitch either) Now the question. Since the 'key' is unrestricted conduction between the two tips, anything the hinders this causes a problem. No electrical path, no heat. The problem is flux buildup on the tips of the 'tweezer' unit using flux core solder requiring constant cleaning of the tips. Would it be better to use pure solder and apply flux to the work first?
I use both methods. I do occasionally have to clean the probe tips. Clamp onto some very fine sand paper an pull. Flip the paper and repeat and I am good to go. Much easier than keeping a conventional pencil tip clean. When building up turnouts I shave slivers of rosin solder to make tiny disks with rosin in the middle. I slide these between the bottom of the rail and the top of the PC board ties. I clamp the resistance tweezers on the rail over the disk and heat. The rail heats up, melts the solder and sticks to the PC board. No rosin ever touches the points.
I use both paste and liquid acid flux at times with solder and just rosin core solder, depending on the project. I only have rosin core solder so it gets used in both. PC=printed circuit. A popular way to make turnouts in N and other scales is to cut strips of phenolic printed circuit board, that has one side clad in copper, and cut these into lengths for ties. After the rail is soldered to the ties, you have to cut the copper foil between the rails to electrically isolate them. This was my first turnout I attempted. It is in Nn3 gauge. This is an N scale turnout I did after I got better at it. I use wood ties to fill in the gaps later.
Thanks, I've never laid my own track and probably never will. The link for the do it yourself can't be posted correctly due to this forum.
I use my resistance soldering unit for soldering feeders to the rails. I use regular rosin core solder and I too have to clean the tweezer tips every so often with some 320 grit paper. The problem is not the rosin flux, but the heat causing oxidation on the tips. A quick polish with the paper takes care of it.
The tips blacken as from flux which is why I figured it was the flux. I try not to get the solder touching the tips, but sometimes it's hard not to.
Older thread, but a current solution, especially if you have many track feeders as I did to solder. I couldn't of done this w/o resistance soldering and the ability to 'hold' the work with the tweezers tips which you surely can't do easily) without. Note that in the attachment.
