On the workbench, flip the flextrack over and
carefully remove 2 or 4 ties depending on the particular Gapmaster you
are using (alternatively you can do this in-place on your roadbed).
Clean the underside of the rail only, with fine 0000 steel wool
Turn the track right-side-up, and place the Gapmaster
under the rails in the open area. You may elect to tape down the track
and Gapmaster to your workbench
Apply heat to rail head using a soldering gun; a 100W
setting is generally sufficient for rail up to and including Code148.
Apply a small amount of silver-bearing solder to the joint between the
rail base and the Gapmaster metal top. Do this to all joint areas. Note:
many modelers have had great success with resistance soldering units.
Clean with steel wool. Cut gap(s) using a razor saw held firmly
(preferred), a Dremel tool, or a jeweler's saw. Clean up burrs with a
file and scratch brush after.
Install on your roadbed