Filcris behaviour in the current heatwave

[Ralphmp]

Previous posts on using Filcris as track support have mentioned that the material expands/contracts during hot/cold weather. Just curious if anyone using Filcris has encountered any issues with the consistently high temps we’re experiencing at the moment.

Thanks.

 

[stockers]

Not Filcris - but plastic decking. The track on the plastic decking was fine as the rails and plastic seemed to both move sufficiently to keep everything more or less in alignment. However the plastic decking (about 16 meters of it in a straight line) was twisting the track on an adjacent piece of timber decking because the wood was not moving as much - this pushed all the pressure (base material and track) on to the curve at the end of the long straight.
The base of the curve is supported on short posts only set a few inches in to the soil and I have now unscrewed the full curve - this seems to allow sufficient movement to both base and rail and all seems well. I did add a few more screws to the straight section whilst at it as well.

 

[stockers]

The plastic decking I used contains a lot of wood products! - sawdust I assume. This is claimed to reduce the expansion issues. The instructions still suggest leaving up to 15mm expansion joints.

 

[PhilP]

Perceived wisdom is now to use 'planks' of Filcris across the track-bed, leaving a small gap between each board..

 

[Ralphmp]

Thanks guys - appreciate the swift response..

Alan - I seem to recall you mentioning the composite material you're using in a post a while back but I can't find it. Could you re-enlighten me on what the stuff is and where it comes from please? Thanks again.

 

[stockers]

Thanks guys - appreciate the swift response..

Alan - I seem to recall you mentioning the composite material you're using in a post a while back but I can't find it. Could you re-enlighten me on what the stuff is and where it comes from please? Thanks again.

Our Products | WPC Decking but watch the delivery cost!

 

[Ralphmp]

Thanks

 

[JimmyB]

The base of the curve is supported on short posts only set a few inches in to the soil and I have now unscrewed the full curve - this seems to allow sufficient movement to both base and rail and all seems well. I did add a few more screws to the straight section whilst at it as well.

View attachment 240330

If the screws are in slots they hold "whatever" in place but allow movement, this is what cabinet makers do with large wooden panels, especially where grains run in opposite directions.

 

[Greg Elmassian]

So, I looked it up and filcris is HDPE, high density polyethelene.... a number of people here in the US have used it as "ladder track"... usually 2 parallel strips on edge to support the track, and usually then backfilled with earth.

A friend who lives close by here in San Diego, is 15 miles inland of the coast, thus he experiences 20 degrees (F) higher in summer than my coastal location.

The relevance is that before he backfilled the earth around his ladder track, it was very clearly obvious that the HDPE ladder support expanded much more than the plastic track and brass rails. So it seems that not only plastic expands more than the rail, but HDPE even more than the typical G scale plastic ties. (Also most tie strips have gaps between the ties every so often to allow for expansion).

In this case, the HDPE used was also a dark brown, which I'm sure did not help the situation.

Greg

 

[stockers]

The problem is Jimmy, the track moves lengthways and this cause sideways distortion. Which way do you put the slots. Also, I agree a cabinet will move but outside - with damp and natural movement in the wood, over several metres - not so sure. Also, building wooden buildings is my job.

 

[Greg Elmassian]

Wood expands about 10 times less than aluminum with heat.

Plastic expands about 10 times more than aluminum.

So, if you compare plastic to wood's expansion, it can be 100 times more.

See this interesting table of expansion (count the zeros): Thermal Expansion: Table of Coefficient of Thermal Expansion of Building Materials - linear expansion of glass, metal, wood, masonry & plastic in response to temperature changes

 

[Rhinochugger]

I don't think I have any problems with filcris - mine is in a ladder construction with the track laid directly on top.

However, it is laid in a gentle 's' curve, with a sharp curve (8ft dia) at one end.

Haven't noticed any undue problems - the length of filcris ladder is about 30 foot (I think)

 

[stockers]

I think the curves absorb most of the problems Ian. With our relatively small layouts, it is not as major a problem as in the big world!

 

[dunnyrail]

I have built a friends line using Filcris Decking Planks and cuts 2x1 for bottom suports to make U shaped Boxes, was originally at ground level hence the Plastic. Problem was with 0 Gauge that the Filcris Contraction quite a bit at night in the cooler-air causeing all sorts of track issues. In the end I made expansion joints that allowed the track to float and expand/contract pretty much the full length of the fishplates. Plastic Squares are nailed into the Centre of the sleepers every 2 or 4 yards to allow a little movement in all directions. Works well enough to a point but the extreme heat now is causing more of the expanding tube soledered joints to fail. Will be relaying at some stage with eco board that has lots of holes in it with possibly less expansion issues. Well according to his mate that has recommended the change. This guy has used the eco with no problems and all his fishplates are soldered up solid, remember we are talking 0 fine scale. Had we have been laying the my mates line originally at 3ft which it now is I would have used Decking Board covered with Roofing Felt. Nay a problem with this stuff.

 

[Greg Elmassian]

A perforated board will expand and contract the same amount... keeping it out of direct sun is probably the most important.

Greg