Anybody have any ideas for firm connections other than solder for wiring in the small confines of, say, an HO slope-back tender? In the case of the tender, I need to make wiring connections for the locomotive motor (the motor’s pickup through one side of the tender trucks) and constant lighting components (the lighting circuit module and the locomotive and tender lights) which use small wire (~26 or 28 gauge).
True, soldering allows for good mechanical and electrical connection, but solder joints require some sort of insulation to prevent short circuits which could easily occur in the small space inside the tender. Of course, electrical tape works for that purpose, but over time the sticky substance on the tape can loosen and expose the bare joint. Wire nuts (as used in electrical junction box wiring) is another method, but I haven’t seen ones small enough to hold 26 or 28 gauge wires firmly.
Heat shrink tubing is your friend. I have some that shrinks over 30 gauge wire just fine and stays pretty flexible. It is truly a “miracle product” for anyone making small wire connections.
This pin connector, for instance, has five short lengths of heat shrink tubing. This would be a messy job to attempt with ordinary vinyl tape. There is also a brush-on insulating liquid but I have never had the opportunity to use this.
On the right side of the connector in the photo shows the amber-colored kapton tape. It is much thinner, more durable and the adhesive is more stable than plain vinyl electrical tape. This tape is also a helpful material to have in your model wiring toolkit.
Use connectors for the interconnection between loco and tender. Also use smaller wire - DCC decoder wire is about #30 and very flexible. Within the tender itself - nothing is going to take less room than soldering the connections and using heat shrink for insulation. Just use the proper tool. A soldering station with a fine tip is the best, inexepensive and with a different tip can be used for all sorts of soldering jobs, but lacking such, a small 15-25 watt iron with a fine tip would work for the small wires.
I pretty much go with Ed and use heat shrink for insolating my wiring but I also use Amazing Goop glue for insolating solder joints. It also works for after thought insolating when I forgot to slide the heat shrink on the wires.
The picture below shows the wires soldered to the backup light in a MDC tender attached to the shell.
I just make sure there is glue between the wire and the metal shell. I attached the decoder sockets to the shell with Goop too.
This tender is a mate to a slope-back for my MDC 0-6-0 switcher, I can run it with either the slope-back or the Vanderbilt tender. I also used Goop in the slope-back to insolate and attach the sockets.
Wish I had some pics, but a friend of mine scratch builds locos in N scale. He has some with slop back tenders that contain the motor AND a DCC decoder. And he solders all the wires. Frankly, not even something I would want to attempt. And before anyone says “he must be a young guy” nope, he’s older than I am. And he doesn’t have a fancy soldering iron or anything. Nor is he an electrical/electronic guy - he’s a lawyer. An HO scale one - that’s HUGE in comparison.
Hey, thanks to all for ideas…I’d heard of heat shrink tubing, but didn’t know it was available in very small diameters. The Goop and tape sound good, too.
Re the N-scale slope-back…your friend must have a very steady hand!
Those SIP and DIP connectors are great. I used them on my DC locos for operating MU connectors (MR, Sept. '92). They pass track and constant lighting power between locos, and to passenger cars.
I agree, the SIP Header Connectors are great for my model Railroad. They are rated at 2 amps and very small, .1” centers, the nominal electronic spacing. An LED will plug directly into the female .1” spacing connectors. Compatible with the standard NMRA 8 pin connectors at a fraction of the cost, less than 2¢ per pin.
One thing that really works great for me is with a little bit of effort you can customize them to fit any contact configuration as well connector polarization.
The female will double as a male by reversing it but the male connector has a tigher fit.
They are “breakable” into any number of contacts in single or double row. I find it best to cut them with a razor saw to keep them from cracking and wasting a pin.
I use mini-connectors similar to those which Mel shows…
…and solder them to the wires, then cover the joints with heat shrink tubing…
I also use the round ones, which go together easier, but they also come apart easier, too - sometimes too easily. For those, I usually tin the male connector, which increases its diameter just enough to prevent unwanted disconnects…
I’m using them simply for all-wheel current pick-up on the tenders, as I’m running DC only.
