Hi all, I've been playing with some different 2x4 N scale layouts, trying out different materials and construction techniques. I want to build something bigger, but I want to be sure I've conquered some of the annoyances I've experienced before finding myself in the middle of that project. I'd really like to solder at least some of my rail joints, but I have experienced the problem of melting plastic when I try to do this. I know it shouldn't happen, so I guess I could be better at this skill. I've tried alligator clips as heat sinks, but have really been looking for a new version of the MLR-5004, a small aluminum plate with grooves that not only isolates the heated area but also keeps the track aligned during the process. Any alternatives or words of advice would be appreciated. Second, I want to be able to cut my flex track reliably and squarely, i.e. both rails align very closely in length after I've cut them, regardless of length or shape. Again I've seen tools made for this purpose that are made no longer, so looking for alternatives here. Since metal isn't as important I'm considering making the effort to carefully create something like this in a piece of wood, but wondering if there's something available out there already before I do this. Thanks!
My MLR tool is plastic/resin, but it works pretty well. I also went to a resistance soldering tool . At work I had a small tub of a blue putty that was designed for welding applications, but it served the same purpose of providing a heat sink so it would probably work for soldering as well. Here's the soldering version Nu-Calgon Heat Sink Compound,Putty,12 oz. 4371-38 - Walmart.com . I haven't tried it because I haven't needed to. For cutting flex, I either use a set of Xuron side cutters Xuron 2175 Maxi-Shear Flush Cutter | Premium Pack , Red - Amazon.com or a dremel with a cut-off wheel. Since I'm freqently trying to cut track at odd angles (like curves), the rails will not be equal lengths, so any sort of a jig is pretty useless. If you are just cutting straight pieces, you can simply use a miter box and a razor saw. Excel 55666 Razor Saw Miter Box Set, 3pc, Made in USA — widgetsupply.com
I like the Xuron rail nippers, but the rail always require some clean up with a file. If you pass the file along the base rail on each side it makes it easier to slide the rail joiners on. Soldering rail without the heat affecting the plastic ties can be challenging. You have to be quick. I always use a very hot iron along with past flux. I used the liquid flux in the past but it just does not work as well. I also tin the wire and rail so the solder is already in place when I add the heat. Tinning keeps one hand free to hold the part rather than holding the solder.
I'm using the Xuron. but I find that I always cut a little too much or too little (curves and such). I'm looking for something that will let me draw a cutting line 90 degrees from the tangent so both rails align after the cut. Like I said I might need to make it...
Getting a square cut on a curve is much easier if the curve continues (with the same radius) past the point you wish to cut off, assuming the radius is uniform for as far as the guide needs on each side of the cut. You need two rail contact points (or small wheels?) either side of, and equidistant from, the cut, and a guide for the cutter that is perpendicular to an imaginary line drawn between the two rail contact points. The longer the distance between contact points, the more accurate, but also needs more excess length of uniform curvature (past the point you wish to cut) which may not be available (like when the piece of uncut flex ends barely past the place you need to cut.) If you have a large compass (the drawing type, not the navigation type), or a large pair of dividers, and remember how to construct a perpendicular bisector to a line, that also works on a curve, if your compass pivot points are equidistant from the cut (also easy to find using the compass). If you've ever used a center finder for wood turning, the principle is similar, but usually on a smaller scale than you would need for model railroading. Or do what I do: just use Unitrack! ;^)
Hi For cutting I use a Dremel with a cutoff wheel. You can be remarkably accurate, and you can trim and shape with near-file quality. Several points on soldering- use a low power soldering iron, variable temperature type with a tapered pin tip. Use rosin flux (like Kester 186 or similar, no acid flux). Then set your tip temperature to about 285-290F. Use 60-40 PbSn solder, rosin core, fine gauge- 0.025inch or so. Then, put a little flux on both sides of the joint area. Don't worry about slopping over- you can clean up with a Q-tip and alcohol. Get the iron hot. Clean the tip on the wiper sponge, then add a bit of solder to the tip. Then, go directly to the joint. Hold the tip along the rails for 3-4 seconds, the flux should smoke off. Then feed the solder into the hot area between the rail and the tip. It should flow immediately. If it doesn't flow, then stop. Increase the temperature by 10 degrees (the iron tip is pretty dynamic- depends on how much heat you are extracting into the joint volume.) Then repeat. You should not melt the ties. Do not use one of the big Weller (or similar) 25W irons- 'way too hot! You could try to practice a bit on the work bench. For most joints I use an Atlas metal joiner, then solder it onto the rails. Easy to reverse this process if you need to disassemble- just cut with a dremel cutoff wheel, and small files to reshape the rail.
Good idea, I can't believe I've forgotten to rely on all that high school geometry! Unitrack is awesome, but if I do this larger project it is because I want it to be sweepier and more random than any set track will give me.
