Any tips on putting together two pieces of flextrack on a curve?
Not much to it, Kevin. It's best to do it before forming the curve, but not that much more difficult if one piece is already in place. Remove a couple of ties from the ends of both pieces of track, then cut them into individual ties. Save them for later. The moveable rail on the flextrack will slide as you form the curve, so you'll need to position it or remove more ties as is suitable in order to have a "tie-free" area under the rail joiners. I've never bothered to worry about whether the sliding rail is on the inside or outside of the curve, nor about whether to stagger the rail joints or keep them even. I usually solder four or five sections of track together at a time, keeping them reasonably straight and the rail ends even, then form the curve roughly in the area where it is to be installed, all the while removing more ties as required to accomodate the sliding rail joints. To do this, use a utility knife to cut the web which joins the ties to one another, then a chisel blade in your X-Acto to shave off the spike heads on the side of the rails that will be away from the viewer. This will allow the ties to drop free of the rails. Cut them apart also, into separate ties, and save them for later.
The actual soldering is very easy. I used a piece of 500 or 600 grit wet/dry sandpaper (use it dry) to clean the sides and bottoms of the ends of all four rails, then slip both rail joiners in place and the second section of track too. Solder the non-sliding rail of the new piece to the existing track section first, so that you can be sure that the gap will be small. The other rail can be slid into place as required.
With the track sitting flat on the workbench or layout, rail side up, place a metal heat sink across both rails of both sections of track approximately over the location of the last ties still in place. I use a couple of steel machinist's blocks, but any substantial metal object, such as pliers or a hammer will work equally well. You can also use wadded-up wet paper towels or tissues. Using a clean, tinned, and hot soldering iron of sufficient wattage (I use either an 80 or 200 watt iron) place the tip on the top (running surface) of the rails, right over the joint, so that both rails in the joiner are being heated at the same time, then place the end of your small diameter resin-core solder against the area on the side of the rail where it meets the top edge of the rail joiner. I make all solder joints on the outside of the rails, to ensure that no overlooked "blobs" will effect the running of trains. As soon as the heat reaches the solder, it will be drawn into the area between the rails and the joiner, making both a solid mechanical connection and a positive electrical connection. As soon as this occurs, remove the iron from the work, to prevent melting the ties.
After you have all of the joints soldered, and enough ties removed to allow you to form the curve, tack the track in place. Now, using all of those ties that you save, slide them under the tie-less rails, working from the normal viewing side. In areas free of the rail joiners, simply slide them into place, with perhaps a little white glue to maintain the proper spacing. (Don't forget, all of these separate ties have had the spike heads removed from the far-side of the rails - you'll need to lift the near rail slightly, using a small screwdriver, to allow the first spike head to slide under.) For areas that fall under a railjoiner(s), I use a small file to remove a bit of thickness from the top of the tie in the area where the joiner will sit. You may also have to shave a bit off the inside face of the remaining spike head(s) in order to accomodate the thickness of the joiners.
This would've been easy to tell with photos, but I don't have any spare flex track laying around.
:-D
Wayne
