Five important tools for decoder installations

Installing mobile decoders, other than the simple plug and play type, requires five basic items. First, you should have a good wire stripper, one that can remove the insulation from the very small diameter wires now being used. These need not be expensive, the one pictured is available from All Electromics for about $4. These are simple to adjust for various wire diameters, easy to use, and are so useful for just about all wiring jobs that I keep several scattered around the layout.

Second, get a roll of double stick foam tape. This stuff is great for holding the decoder, speaker, and wires in place. The fact that it is foam allows it to conform to uneven surfaces well. It can also be used to trap wires in odd places, and it seems to last forever–I have 20-year old installations with the original tape. I have several rolls but the 1″ wide gets the most use and can be cut to smaller dimensions easily. You can find it in most office supply stores. I also use it around the layout to stick small circuit boards to the underside of the layout and to joists. I even use it to stick small accessory decoders directly to Tortoise switch machines.

As I have advised in the past a fine tipped, low wattage soldering iron is essential for getting good solder joints without melting everything in sight. A pencil point shaped tip will concentrate the heat just where you need it. A soldering station like my Weller WLC100 is a good investment that should last you for years and is flexible enough for almost all your soldering needs. Micro-Mark and most electronics suppliers sell them. I recently upgraded from the Weller unit to the pictured Hakko FX888D-23BY which allows me to set the iron to a specific temperature and is protected aganist electrostatic discharges that can fry critical components. I still use my Weller for jobs like soldering rail joiners and feeders to rails.

A good small diameter solder is important–I currently have a roll of .02″ diameter. For this work a 60/40 tin/lead solder works well, either as plain or resin core–do not purchase or use acid core solder or anything other than a non-acidic resin based flux. I buy mine in 1 lb rolls which usually will last me a decade or two. And that includes all the soldering required on my layout. Once I use up the last of this roll of 60/40 I plan to switch to 63/37 which melts and solidifies at exactly 361 degrees, lessening the chances of getting a bad joint. All of the electronics suppliers and Amazon sell solder.Heat shrink tubing is a plastic like tubing that shrinks in diameter once heated and is essential for protecting solder joints and prevents small wires from breaking off. I use a lot of the 1/16th inch diamter stuff. You can order this from places like All Electronics, Digi-Key, or Jameco. Cut a piece long enough to cover the solder joint plus a little extra, slide it on one wire, complete the solder joint, then slide the tubing over the joint. Finally, you need to shrink it. While they make special heating tools to do it, I just lightly stroke the tubing with the tip of my hot soldering iron. A selection of small sizes down to about 3/64″ is good to have on hand.One optional item that I have been using for a couple years is Kapton tape–the thin, orange tape that comes on some plug and play type decoders. This stuff is a good electrical insulator and holds up across a wide heat range. I have been using it in place of black electricians tape which tends to fall off after a few years. The 1/2″ wide tape works well for most of my installations. Most of the DCC suppliers as well as Amazon sell it.


  • Larry my list mirrors yours. I also use a multimeter on most installs to make sure that I get the motor wires correct. I enjoyed both of your articles in the recent copy of MR. I now wished I had held onto my NW2 but at the time could see no possibility of installing a sound decoder in it. Oh well I can always pick one up on Ebay.

    • I just counted 38 of them on eBay so go for it. I have two that I bought when they first came out, one of which still needs a paint job. A really nice model!

  • Three cheers for Kapton tape! I bought a loco that was not DCC ready but a “professional” had installed a decoder. I opened it up to take a look and he had sealed the decoder to the frame with black electrical tape. I was hours removing it and the gummy residue. A small strip of Kapton tape was all that was needed to keep the decoder and wires in place. Less is more when it comes to that. Inherently, DCC decoders generate some heat and need to be able to breathe. A cool decoder means one that will last for years to come.

  • Larry–regarding the decoder install in the KATO NW2. The Dremel cutoff rotary blade- Was it diamond, metal or ceramic?
    Was the cut just a guess or How much extra room beyond the decoder thickness was allowed? Did you use the same cutting tool to make the “V” groove? Where did you solder wire to the trucks to electrify the motor as I am assuming the copper pickups were discarded? Any problems soldering to the motor contacts which is surrounded by plastic?
    I thought it was you who mentioned a person supplying “rounded” sugar cube speakers that
    fit easily to the ceiling of the cab?
    With weight removed, does it pull as well?

    • Joel–the Dremel disc appears to be fiberglass embedded in a resin along with cutting grit. I bought a kit that includes the mandrel and cutting discs for plastic, ceramic, and metal. I placed the decoder alongside the chassis half and outlined it with a marker pen then just made two passes to cut out the chunk of metal. I did use the disc to cut the slot by running the blade along the top of the chassis halves at an angle.

      I did not modify the bronze pickups. Just left them in place so they conduct power from the trucks to the frame halves and then attached power pickups directly to the frame halves as described in the article. On my models the plastic cage around the motor is so open there was no problem soldering the orange and gray wires to the metal tabs I left on the brush caps.

      Streamlined backshop makes the curved enclosures, see my previous post on here for more on those. They fit nicely in a cab roof but on this model you will need to remove the top of the plastic window insert creating 4 separate window inserts. I used Plastruct Bondene liquid cement to glue them in.

      These models weigh so much to begin with, the small amount I removed had no noticeable effects on pulling power. Sounds like you have one of your own to do–have fun with the project–Larry

  • Thanks Larry, I am pleased to see my list copies yours!