Use of Shuttering Plywood for track bed

D

davecar

Registered
Hi All,

I am in the process of making a new loop on my track which involves very gentle curves created with Peko flexi track. The track is raised by about 8/9 inches on p[illars and I am using external plywood cut to shape with a jigsaw. I am then giving it two coats of preservative and then covering the board with green roofing felt, so it should be well protected. I did think about using decking cut into small strips to create the curve but don't think this will work. I bought my first piece of 18mm external plywood from B and Q the other day and I thought it was very expensive. In sourcing another supplier I have come across shuttering plywood. Apparently this plywood is used on building sites to make concrete molds. The veneer is not attractive ( I am covering it with roofing felt anyway) and it is suppose to be resistant to weathering, warping and rotting!

Has anyone any expereince of using this or any other alternative?

Kind regards,

Dave
 
18mm wbp ply from travis perkins is about 18 quid plus vat for a 8 x 4 sheet
 
I believe shuttering ply is only used to make the moulds then skipped, so not sure how robust or weather proof it is over time. Probably quite cheap then?

As Sparky suggests WDP ply is the stuff to use....
 
I've used OSB (oriented strand board) for some of mine. It seems good enough at 12mm thick, been there three years now with no sign of deterioration, unlike other wood stuff around the railway.
 
Shuttering ply, CDX or Millcert, is used for many things. It has quite a long life if treated with wood preserver and doesn't delaminate like WBP (so called exterior ply). I have a pair of garage doors made from CDX and they are over nine years old.

When covering any board or ply, make sure it is covered and that the edge of the felt prevents water running under the board ply.

Also, any ply or board needs a reasonable support to prevent sag.
 
I think exterior ply is like so many of these products - extremely variable depending on source but there is no way of knowing what you have got until it has been down for a while. Years ago I made some outdoor furniture incorporating exterior ply and it has lasted nearly 20yrs. 3yrs ago I bought what appeared to be the same stuff from the same shop, it didn't last a year before it twisted out of shape.
Even marine ply can be suspect.
You pays yer money and you takes yer chance I suppose.
 
bobg said:
I've used OSB (oriented strand board) for some of mine. It seems good enough at 12mm thick, been there three years now with no sign of deterioration, unlike other wood stuff around the railway.
Click to expand...

Use OSB2 outside but it's still wise to preserve it as well.
 
There is still a limited offshore oil related industry in Great Yarmouth. Consequently certain items 'find' their way onto local car boots. I've been buying sheets of used exterior grade construction sheathing of US origin. It's cut into 42 inch squares for use on pallets (usually stacked drums containing drilling fluids). Thickness is 0.45 inches (roughly equivalent to 12mm). Convenient size and at £2 a go it's a snip. I give it two coats of fence preservative and then cover with sanded roofing felt using the tar type adhesive for joints to maintain a waterproof seal. There are some pics - see [style="color: #0000ff;"]HVR reborn in the photo section.
Mike.
 
WBP or exterior grade ply relates more to the glues than the wood (Water Boil Proof).

Shuttering ply is WBP, but the quality of the face ply is poorer, and will often have gaps 'pieced' in.

Both will eventually delaminate and fall apart when exposed to our Great British weather. Preservative and felt covering will provide signifcant additional longevity.

On the other hand Marine Ply, the cost of which will undoubtedly make you wince if you thought WBP was dear, will give added durability.

The best protection to plywood is a sealant or paint that prevents the water from entering the grain of the wood.
 
Rhinochugger said:
WBP or exterior grade ply relates more to the glues than the wood (Water Boil Proof).

Shuttering ply is WBP, but the quality of the face ply is poorer, and will often have gaps 'pieced' in.

Both will eventually delaminate and fall apart when exposed to our Great British weather. Preservative and felt covering will provide signifcant additional longevity.

On the other hand Marine Ply, the cost of which will undoubtedly make you wince if you thought WBP was dear, will give added durability.

The best protection to plywood is a sealant or paint that prevents the water from entering the grain of the wood.
Click to expand...


England must be importing better quality than it used to!

Over here, quality is not considered of any importance(by the vendors). There is a warning that the sheet must be treated and sealed - as exterior ply it is absolute rubbish! Whilst the shuttering ply doors have been OK for 9 years, the hardwood ply is disintegrating after only for years. The micro thin exterior laminations split letting water into the interior laminations which then travels along the huge voids causing further damage. It isn't even fit to use inside!
 
As a user of timber in my profession - I tend to agree with Rhino.
WBP in shuttering ply can give a lasting result. Also - as Mick suggests, the laminates make a huge difference in the long term survival.
The problem is, ply is not usually made to defined standards. There are standards for marine ply but one does not have to comply with them to call it 'marine ply'. I think its BS1050 or something like that - but my memory is carp.
 
stockers said:
The problem is, ply is not usually made to defined standards. There are standards for marine ply but one does not have to comply with them to call it 'marine ply'. I think its BS1050 or something like that - but my memory is carp.
Click to expand...

:rolf::rolf: I don't know the BS number but your right about "defined standards"! To work to a standard doesn't always mean best practise - consistently doing it the same way every time is the main aim (good, bad or indifferent!).

I've so many bees in my bonnet I could start an Apiary :rolf::rolf::rolf::rolf:
 
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