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How Would a Dentist Fill The Gaps Between Tracks?

Online Train Club member Joshua is not a Dentist but asks:

“I know when I go to the dentist he tells be to floss between the gaps in my teeth. He doesn’t seem to want to close the gaps, whereas on my railroad that’s precisely what I want to do. I want to leave tiny gaps 1/32th between track to allow for movement, but I have 4 gaps closer to 1/16th. How can I fill these or should I make an appointment with my Dentist? Ha! Ha!”

13 Responses to How Would a Dentist Fill The Gaps Between Tracks?

  • Robt.says:

    use a rail joiner with a small piece of track in it,
    that should fill any space.

  • Kevin Chingsays:

    Hi Joshua
    I would not fill the gaps in the tracks as with hot and cold temperatures the track will want to move with heat transfer if the trains do not derail then its ok if the gaps are more than 1/16th inch then cut out about an inch to an inch and a half and replace with a new piece of track and a couple of rail joiners and solder one connection or both depending on heat movement. I hope this helps happy modelling.

  • Meltonsays:

    Do just like the rail road crew do & use Thermite Welding. It will fill the gap and make a permanent bond. There are You Tube videos on exactly how to do it. Just go there and type in Thermite Welding Rail Road in the search box. It should be much easier to do on the small scale rail track than on the full size, but you will get the idea.

    • Robert Cartersays:

      Don’t do this. Thermite is highly dangerous and reaches temperatures in excess of 1600 Celsius. You’ll wreck the layout and possibly your home.

      • David Stokessays:

        Robert, I think there is a joke lurking there. The point being made is to join your rails and don’t have gaps. Personally I find gapping track, especially at turnouts, is essential. for electrical reasons, but I fill that gap with a sliver of styrene to stop rail creep from closing it up and causing a short..

    • Bob Sandonesays:

      This is not real road crew work. Read the response below. As a welding inspector, I can attest to this.

  • David Broadsays:

    Take out the piece of track which is too short and put a longer bit in. Your gaps should change with temperature, you need a gap on a very hot day We have to use extra rail joiners and short rails to let the track on our lift section by the window expand and contract enough in the sunlight. I only lay track on the outside railway on very hot days. Its quite amazing how much a rail will distort sideways when it expands to be just 1mm too long on a hot day.

  • philsays:

    I like to leave gaps between rail ends to allow for expansion. 1/32-1/64 is ok. I have found over the years that code 100 expands the least, code 70 the most.

  • david zucalsays:

    If you have a heating and cooling system in you train room that is attached to a wall thermostat, and also a dehumidifier for a steady humidity level, expansion and contraction problems go away. The best and easiest way to fill track gaps is with a squeeze tube of Bare Conductive electric paint (www.bareconductive.com) made in the UK. It’s black in color and is very thick like epoxy. It can also be used to cold solder. Just apply a drop, shape with a tooth pick, and let it dry over night. The next day file or sand it to the shape of the rails. Purchase the smallest tube available because it can harden within 6 months of opening if you don’t store the tube in a small air tight zip lock bag. I’ve been using it on an O gauge layout running 18 volts and up to 10 amps without conductive issues or rocking rolling stock.

  • Gary Manganiellosays:

    When laying the track…put a business card between the two track rails you are joining. This will leave room for expansion and still be close enough for a smooth operation. Pull the card out when tracks are securely laid.

  • Craig Inghamsays:

    Gaps at rail joints serve multiple purposes. One is to form electrical contact or to seperate electrical sections. Also, don’t ignore rail expansion and contraction caused by temperature and humidity changes. You will be using rail joiners or insulators. Where you want to continue power from rail to rail, use wire drops from each rail – don’t rely on the rail joiner. An insulating joiner will serve the isolation purpose. If you cut the rail to isolate a section, and can not slip an insulated joiner in place, make the cut wide enough to slip a piece of plastic or other insulating material in the gap. Glue it in place and trim any exposed matrial on the inside and outside of the rail. Works well and is inexpensve. I love ‘cheap.’

  • Morgan Bilbo, PRR fansays:

    Very interesting. I too, have that problem. Never hears of an electrically conductive glue or adhesive. Solder is the only thing I knew. And soldering rails is OK as long as you do allow gaps every here and there. When a gap is too large, it’s a pain in the you know where to have to remove that section and replace with a “itsy bitsy longer section/rail. And sometimes it’s only one rail that has the “too large” a gap. So where in the U.S. can I purchase this “Bare Conductive Electrical Paint” or equivalent?


    I have a very good modeler friend with an extensive layout. He showed me first hand how it inserts bits of styrene sheet between his tracks to isolate them like in a block. After they are inserted and fastened in with styrene glue, he then takes a wire wheel on his rotary tool and runs the wheel against the side of the rails and styrene. The sturene is burnished off leaving a nice clean profile with the rail in the gap. Very hard to see and works well.

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