Tag: Latex

Laying Track to Foam

I chose to use foam as the baseboard of my layout. I started experimenting with this in 2008 (Photo). This actual track on the test rig was only pinned in place as it was never permanent.

  • Foam base is great to lay my Peco code 75 HO flextrack. I can easily pin it in place using ordinary dressmaking pins. But you can’t nail it down.
  • Instead, I use an adhesive, LATEX CEMENT and I buy it from carpet suppliers or carpet layers. I take a 1 or 2 litre plastic container and get it filled for say $10 or so.
  • It needs to be thinned with water to a consistency of milk. I originally thought it would need to be thicker, but the thinner it is the better it penetrated under sleepers etc.
  • What happens if you change your mind and want to move something? It is actually reasonably easy just by dissolving the dried latex – see the last photo.
For the track base I use a product from DCCconcepts (in Western Australia) called Trackbed OO/HO Scale 3mm
The company describes the product as:
“A box of 100 feet (31metres) of high quality, OO/HO Scale trackbed (3mm thick / scale 9~10” approx high).
Made from very long life EVA, closed cell foam trackbed with precut ballast shoulders and a pre-scored track centreline underneath to allow it to be easily split for laying along track centre-lines if wanted.
Based on tests and feedback each piece is 605mm / 2 feet long for easy handling. Cuts perfectly with a snap off knife.”
STEP 1 – track pieces were pinned into position according to the layout sketches. The layout plan was derived in a slightly odd way. Firstly I laid out old code 100 track, some points, paper copies of points until things were as I wanted them to be. I then took a whole series of overlapping “aerial photos” as shown above and below.
And subsequently “stitched” all the photos together on a PC so that I had a somewhat bizarre mosaic diagram of the layout:

STEP 2 – the Code 75 Peco flextrack was adjusted into position with dressmakers pins (easy in foam)
Curves were laid out with Masonite (hardboard) templates. In this case 1m radius.
Note the use of plywood alignment pieces to keep the track joins in line.
STEP 3 – once I was convinced I had the track in the right place, guidelines  were needed to allow the underlay to be glued in the correct position.
To do this I made a little mobile jig from an old loco pony truck with a ply guide screwed up from the bottom so it just cleared the rails.
  • This foam roadbed is lightly cut down the centre to make it easier to lay curves.
  • The other advantage of gluing the track to foam is that it provides an improved noise barrier.
  • That is lessened of course when the track is ballasted but I am experimenting with very dilute latex as a ballast adhesive.
STEP 4 – I ran this mobile jig along the pinned track to get a guideline for the edges of the underlay.
STEP 5 – I took no photos of this process, but the diluted latex cement was brushed along between the guidelines onto the foam (none was brushed onto the bottom of the underlay). The underlay was butted up to the end of the previous piece with a little cement brushed onto the end. No weights or clamps were necessary although some pins were used around curves.
The photo above shows the container of diluted latex glued to a block of wood to help prevent spills. The photo actually shows a point being glued to the underlay and weights ARE needed for this process.
STEP 6 – The track is held in position by long dressmaking “T” Pins.
This aligns the track but allows it to be lifted to coat the underlay lightly with latex cement.
STEP 7 – for long runs, I held the track up with paddle pop sticks which allowed me to brush on the cement.
I used a chisel shaped brush about 10mm wide and applied it sparingly down both sides.
As above but a little more latex cement was needed under the PCB sleepers which were later cut across the join. A better solution would have been to use a more powerful adhesive under the PCB sleepers eg. Liquid Nails, as this track needs to be cut and remain strongly fixed.
STEP 8 – Once the glue is in place, remove the paddle pop sticks and place weights on the track until the glue sets.
The long brown strip is paxolin – about 3mm thick and cut to fit precisely between the rails. It serves to align long straight section and can be left in place until the glue sets. It can be made from any similar rigid maerial.
I have many of these 2mm (0.080″) plywood pieces cut to be a neat fit inside the tracks.
They guarantee alignment of track especially with crossovers.
Small pieces are great for keeping curves aligned where flex track joins. In this photo Carr’s Flux has been used to get a good soldered join between rail and sleeper (tie).
Using a long straight edge on the edge of the rail and the paxolin stip between the rails to align trackwork past the future station site.

WHEN THERE IS A DISASTER:

If everything goes pear shaped, then Latex bonded track or points can be lifted. Realising an extra crossover was needed, I had to lift a section of track. Brush some water onto that section and leave it for an hour or so and a thin spatula can be worked under the sleepers to free the track/point. The old latex can be removed with a wet sponge.

Yes, yes … I know if I am flooded out, the trackwork may be in trouble. But the bloke in the house across the road will really be in strife. The peak of his roof is lower than my floor!