uPVC in layout construction?

[2ManySpams]

Afternoon all

 

Some may know that chez 2manyspams has had a fair amount of building work done recently. Now, the builder is clearing off site and I looked at the pile of leftover bits and bobs on the drive. This included a range of various uPVC sections - box, L, U, strip etc.

 

My mind has been wandering..... has anybody actually used UPVC for the structural frame of a layout, or lighting rig etc, rather than conventional timber / ply / MDF?

 

I've done a quick search and have found that folk have used it for backscenes, fascias and track protection but I can't see anything more adventurous.

 

Anyone else thought about this / actually used it?

[Stubby47]

I pass a Window retailer on the way home and he has a large Brute-style wheely-crate outside full of both uPVC and aluminium strip - just never managed to stop and ask if I could have some for free to experiment with.

 

Only thing with uPVC - it would need to be in a box section to give it some rigidity - I'm not sure even T or L section would not twist along it's length.

 

Stu

[2ManySpams]

Hi Stu

 

I think I'm curious more than anything to see if a material that's widely used in construction, small buildings, furniture and pipework can have any use in board construction.

 

I may have a poke around on our builder's scrap pile and have an experiment with some bits and a bottle of uPVC pipeweld that's in the shed.

 

My initial thoughts are that although it's lighter than steel section and timber, you'll probably need a bigger box section than convention materials to overcome the flexiblity of uPVC.

[Engineer_London]

In the picture, tucked beneath the tram is an experimental very short section of 3 1/2" gauge track, produced as a precursor to an outdoor test track.

3mm square section brass rail, cheaper unit cost than full profile rail, with brass rod locating pins silver-soldered into blind holes underneath the rail section. Rail assembly fitted into drilled holes in the uPVC base and retained by bending the pins or with simple clips. The UPVC board would have been conventionally supported on timber longitudes, mounted on posts.

 

The trial section shown was left outdoors for a year without adverse effects and checked for problems at temperature and weather extremes. Theoretical calculation suggested that the gauge would expand in warmer times, but not beyond workable tolerances for plain track.

[artizen]

I am using 3mm rigid PVC foamboard used in the sign industry for my layout construction. I am also using it for buildings. My test piece has survived the Australian summer so far in direct sun at temperatures up to 35 deg C and is now going through the winter. (Of course winter here is only down to around 6 deg C overnight and about 22 deg C during the day.) I expect it to have a life of around 5-10 years or about the life of the average layout really. Doesn't rot, warp or decay. Can be cut with a knife or sawn, drilled and glued with CA or PVA. So far, so good. Cheap too, the sign man throws it my way every time I ask for some!!!! His idea of scrap material is a sheet 1240mm x 620mm.

[2ManySpams]

Hi Ian - I think from your description that might be different to the stuff that builders over here use for guttering, downpipes and general building cladding. I can't see anyway that PVA would glue the stuff I'm thinking of! Do you have any photos of it in use on layout (board?) construction though?

 

All the best.

[Il Grifone]

My last layout* used uPVC box section as legs (double glazing window frames). Easy to cut and strong. I used 10 and 12mm threaded rod as stays. They're now supporting the boards for my new layout (Recycling )

* http://www.rmweb.co....2-dublo-layout/

 

EDIT The link should work now. Some of the supports can be seen in the photos.Please ignore the dodgy wiring. It was 'temporary'.

 

Rest assured, the 'Castle' now has a green tender and the 8F has cylinders and valve gear.

[34theletterbetweenB&D]

... both uPVC and aluminium strip ...

Both have worked well for me in creating my test layout from scrap materials, now coming up to 10 years old and structurally still as solid as ever. (This was all scrap from some appalling double glazing in a property I bought.) The u-PVC is roughly 25mm by 100mm box section with 5mm wall thickness, the ally extrusion 15mm by 50mm, 3mm wall broad U section. Both easily assembled with self tapping screws and more than up to the job for a 4mm layout. A single length of the ally supports a near three metre clear span, and it is perfectly stiff enough for the job, the u-PVC makes excellent legs (it was in shorter pieces than the ally). I will be using any such scrap I can obtain free for the permanent layout, ahead of that expensive organic stuff...

[2ManySpams]

34B-D

 

A few questions:

 

Where is you test layout stored - inside the house / outside in a shed? Have you had any issues with warping or thermal expansion of the uPVC / Ally combination? Did you top it out with ply or use something else? Do you have any photos of the construction?

 

Many thanks

[34theletterbetweenB&D]

It's in an unheated single skin brick outbuilding and the inside temperature reflects the outside; I was making lovely DIY 'steam' effects during the cold snap at the end of 2010. That said it doesn't get so hot in summer now since I have largely insulated it. and begun the lining out one end. (Hopefully reaching the end of this tunnel this year and can then embark on building the 'proper' layout, in what will be a 'civilised' room)

 

What's on top to form the track base? Anything else I had suitable in the way of scrap from the new house. Lots of melamine faced chipboard, some veneered chipboard and painted chip board (the 'fitted' furniture was of the highest possible quality) attached to the framing by self tappers.

 

The whole ensemble is of an elegance that would have Heath Robinson cheering: you will have to imagine it as I don't have a digi camera.

 

Never a trouble with expansion or contraction that I can discern, and I am a fanatic for reliable running. It's as smooth as the day it was built hurled together, save for 'the hump' where a water leak has swollen some of the chipboard.

[Allegheny1600]

Hi Chris,

A few years ago, I experimented with using uPVC section (of the electrical trunking type, with removeable cover) and obtained some of approximately 2" x 1" in section. My aim was to try and replicate a typical 4' x 2' baseboard in plastic, rather than timber and ply. Having cut them into baseboard sized pieces of 4' long, I discovered they were very 'bendy' indeed! To counter this, I reasoned that if the interior of each section was filled with material - it should become stiffer (with the cover glued in place!).

I then obtained some foam filler, dispensed from a decent sized can of the stuff.

Unfortunately, these experiments were carried out (outside, of course!) in midwinter, the spray foam did not spray very well, I could not get it to reach the centre of the 4 foot length and it would not 'foam' very well, either!

Evidently, I should have experimented in summer but I didn't want to wait six months or so for warmer weather!

The expense of this experiment and the realisation that for a very small (if any) saving in weight over timber and/or ply construction, there was a substantial increase in cost - made me lose all interest in the idea!

.

IF you can obtain rigid (approx) 2" x 1" section that doesn't need stiffening, it would be interesting to see your results, please!

However, I would suspect that to gain sufficient stiffness, you would require somewhat larger profile - which could give problems with regard to point motor siting, etc. Plus, would it actually be any lighter than the modern equivalent of 2" x 1" timber?

HTH,

John E.

[Re6/6]

Chris, by all means experiment, but I would be cautious about this material.

 

Although different, on Matford we used plastic/composite stuff which was so-called laminate flooring which was manufactured wholly out of a plastic and we wrongly thought that it would stable, being man made. How wrong we were! After a couple of years it gradually took on a banana shape along it's length which was totally unexpected! The whole 'undercarriage' will be replaced with traditional marine ply which can be trusted better.

 

As I said it isn't quite the same stuff, but we would have expected better from a manufactured material.

[2ManySpams]

that's the only thing that worries me about uPVC is the long term stability under load. It is by nature a 'plastic' and therefore prone to creep over time, particularly under a bending load. I would have thought that end loading, ie along the axis of the material, such as in legs would be no problem.

[Re6/6]

IMHO for what its worth polyfoam insulation board is the only way to go for from now on. We'll be using it on the Balcombe > viaduct > Lewes project (except for the viaduct itself) and the other projects that we're working on. As you will see on the blog they have been made for some time and stored in a damp garage and hasen't moved a millimetre.