The pipes at 1:87 scale

DN 1000 (rated diameter) pipe

According to the above-mentioned PAM Classic document, an excerpt of which is given above, the external diameter ø DE of the pipes DN 1000 is 1048 mm, i.e. 12 mm to scale; their collar diameter (dimension ø B) is 1191 mm, i.e. 13.7 mm to scale. Now the Evergreen tubes stop at 12.7 mm! So, let’s try a smaller size…

DN 900 (rated diameter) pipe

The outer diameter of the DN 900 pipes is 945 mm, or 10.9 mm to scale; their collar diameter is 1082 mm, i.e. 12.4 mm. An Evergreen ø 12.7 tube for the collar, and another ø 11.1 for the body, seem quite suitable. So, okay for DN 900 pipes! Their total length (Lu + P) is about 7150 mm, or 82 mm to scale.

Making the pipes

We’ll try to make something that really looks like the original. And, with this method, the pipes will be able to be really fitted together; for example, a small diorama showing the laying of pipes in a ditch, with a hydraulic shovel for digging, a semi-trailer for the pipe supply and a crane — or also a hydraulic excavator, as in the picture — for their handling…

Pipe laying in city of Montpellier.

Dimensions of a DN 900 pipe at 1:87 scale

In red, real dimensions reduced to 1:87.

Making the body

The body is cut into a . Thus, four pipes can be obtained from a single tube. The best is to cut them a little too long, then adjust the length to 80 mm in a drill mandrel (not too tight), at very slow speed, because this polystyrene softens very easily. At the same time, slightly chamfer the two ends with a cutter or a scalpel, using the back of the blade and not the cutting edge, which would attack the plastic too much.

Making the collar

Given the narrowness of the collar, this part is to be machined directly onto the by first making an external chamfer of about 30° on almost the entire thickness of the tube mounted in the drill mandrel already used. The collar is then cut out to about 4 to 5 mm in width.

After making a mark 1 mm from the mouth of the pipe, slide the collar on until the mark and then stick it from the inside with liquid glue for polystyrene model, like Kibri’s.

Once the glue dries, still in the drill mandrel, trim the collar length to obtain the pipe’s total length of 82 mm.

Of course, you’ve better doing this production in series.

Painting and decoration

For the outside, I used a mix of Humbrol mate colours: 90% black no.33 and 10% aluminium no.56. When the paint is dry, I make it shine a little with a paper towel.

To colour the inside of the collar, I paint it with a black felt pen. As for the inside of the pipe, which is actually covered with a greyish special cement, it is left white.

View of real pipes.

The ideal would be to have decals of the Pont-à-Mousson logo, or a stencil to paint this logo on the pipes.

Ref. Evergreen 234:
Sachet of two tubes diameter 11.1
€4.00 - price 2014
At train-modelisme.com

Ref. Evergreen 236:
Sachet of two tubes diameter 12.7
€4.00 — price 2014
At train-modelisme.com