MDF or plywood which is best? - and other questions.

I've got the job of making the test tracks for my local (American interest) club and need some help. We've decided that in order to
accommodate at least 4 different scales (O, HO and N with 10.7mm gauge as well) we need to have boards which are 400mm wide and a 'standard' straight length of 120mm. Curved sections will be 8 in number based upon the outer section being O gauge with 45 inch radius (we've already tested long stock on curves which are 38 inches so the 45 should be more than adequate).
There will not be any need to add any ballast as the whole thing must be as light as possible so that it can be transported as easily as possible.
1. There has been some discussion about the best material MDF or plywood. We will probably use 4 or 6 mm thickness. Your opinions please.
2. Where can I get some O gauge flat bottom track? (Peco only seem to produce bullhead rail and the one member who has a large amount of O gauge claims that the sleeper spacing and rail profile are wrong). I'm quite happy to use setrack for the curves but would like to be able to get straight track that fits onto our 1200 mm standard board section length without cutting.
3. Where can I get some copper clad paxolin already cut to size suitable for making a joint 16.5 / 9 mm track in code 75 or similar. (this will probably be the last stage as we intend to use flexitrack for the 'single' HO and N scale tracks; the multigauge track is for additional usage on busy nights and also for testing HO stock on the smaller code 75 rail)
4. Where can I get some code 75 rail for No 3 above.
5. Anyone know if it is possible to buy a roller (or similar) gauge suitable for dual gauge 16.5 / 9 mm or will have to make it myself?
6. We will be using code 100 16.5 mm track for our HO test track, probably PECO unless anyone knows better product. (We decided not to use code 83 as it comes off the sleepers too easily)
7. Any suggestions for location dowels or other systems that will be easy to put together for accurate rail lining up, and take years of weekly setting up and taking down.
8. I'll probably use flat brass or NS metal screwed to the baseboard edges with the rails soldered to them to ensure rail alignment. Anyone know where I can but some flat brass on the cheap - preferably in strips so that I don't have to mill it down to size. Any one got any other ideas for lining rails up.
9. Should we use cork underlay which is normally used to provide depth and ballasting and for sound deadening purposes.
Anyone with any suggestions which I need to consider before final decisions are taken prior to construction.
TIA
Mike
--
Mike Hughes
A Taxi driver licensed for London and Brighton
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On Fri, 10 Nov 2006 10:49:35 +0000, Mike Hughes
Mike,

In 6mm thickness, you might find MDF the better bet since it will probably be a lot flatter than your average bit of 6mm ply. I've been using a fair bit of 6mm ply over the past year or so and the stuff was warped in the pile in the supplier's store.
MDF usually gets a bad press since you have to treat it with a bit of care when cutting and sanding since the dust is not too healthy. It is also a bit heavier than ply, but in 6mm thickness I don't think the difference in weight will be that much. It is also supposed to be susceptible to water and damp, although I did use it on a layout some years ago and the boards sat in my unheated garage for several years and showed no signs of any problems. But it is normally recommended that you seal the surface with varnish or size to avoid problems with direct application of liquid. It will require the same amount of bracing as 6mm ply.

Beg, borrow, steal or buy some 7mm PCB point sleepering - comes in 300mm lengths, 7mm wide and should do the job nicely. Cutting modern PCB is not too easy since the fibre glass centre plays merry hell with the cutting tools. I do it with a cropping tool but I wouldn't buy a 150 tool to just cut a strip of PCB :-)

Look around for pattern maker's dowels. Quite a few people supply them for use in location baseboard joints.

Also look at using brass c/sink woodscrews at the edges with the rails soldered to the heads. But if you want metal strip, you can get a range of sizes at a K&S metal centre at a good model shop. Or try mail order with Eileen's Emporium.

Cork is the usual recommendation, but you might also want to look at foam underlay like the stuff sold by C&L. It probably has a better sound deadening effect than cork, and the resilience could give better running.

Jim.
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"Jim Guthrie" <

6mm? 6mm? That's only good for gussets. :-)
3/4 plywood, nothing else is a good.
1 x 4s and 1 x 3s to built 'L' girders with all track supported on risers screwed to 1 x 3 stringers.
-- Cheers
Roger T.
Home of the Great Eastern Railway http://www.highspeedplus.com/~rogertra /
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On Fri, 10 Nov 2006 09:11:41 -0800, "Roger T."
Roger,

This is the North American "just in case there's an earthquake" school of baseboard building. :-)
As Nigel has mentioned in his message, 4mm and 6mm ply structures can be incredibly strong and might exhibit less deflection that your setup, and weigh a lot less.
Jim.
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"Jim Guthrie" <

It certianly is.

Having built both UK and North America model railways, using the construction methods of both, give me the North America earthquake proof system anytime. It's stronger, easier to build, and far superior to the flat "baseboard" approach of UK model railways as scenery is easily built below and above track level.
I can lean on my benchwork to build scenery in the far corners without fear, sit or stand on it if I had to (I have sat on it to build scenery towards the backdrop and to paint the back drop) but of course, it's not recommended. :-)
Mind you, my railway while transportable, is not portable by any means. It was built to break down into six foot or smaller sections in case of a move but in doing so, the backdrop would need to be completely removed as well as built in shelves etc., underneath the layout. Scenery, track etc., was build right across the breakaway points and moving the layout would involve cutting through scenery and track at the breakaways.
-- Cheers
Roger T.
Home of the Great Eastern Railway http://www.highspeedplus.com/~rogertra /
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Roger T. wrote:

I did not mention flat. Using 4mm ply throughout won't work for a traditional "pasting table flat top layout". I think my suggestion may be "American style, but with sensible regard to weight of materials".
As to "why use 4mm ply" ?
1) Ability to lift it and carry it between places. A well made lightweight board will be an easy one-man lift. Something made of 3/4in plywood will need a weightlifter or fork-lift to move it. Particularly if packed into a case to protect the track, electrics and (though not in this case) scenery.
2) Cost. Why spend unnecessary money on 18mm ply when 4mm/6mm will do ?

You can do this with 4mm ply. You can build a full sized working aircraft out of it if you use it properly.

About as portable as a house !
A friend of mine runs a very high-end custom packing case company, and also has a superb exhibition layout. He'd not build cases or layouts from anything thicker than 8mm, most is 4mm or 6mm.
If you want the ultimate in lightweight, then build it from foamboard, with a little aluminium angle to protect corners. However, that won't withstand a person sitting on it, or big impacts. But it will stand exhibition use.
- Nigel
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Webmaster at http://www.2mm.org.uk/
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On 10/11/2006 17:11, Roger T. said,

This is a model railway we're talking about, not full size :-)
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Paul Boyd
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Mike Hughes said the following on 10/11/2006 10:49:

To add to Jim's advice, I would say that especially if you do go for ply, you should try to buy it from a timber merchants rather than a DIY store. Not only will it be cheaper, it should also be better quality, and flatter. This will be because it's stored flat, and not on edge! Some DIY store "ply" consists of two layers of veneer with a sawdust filler between. Not good.
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Paul Boyd
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Mike Hughes wrote:

Ply. But only if its the proper stuff - lots of thin layers of birch, alternating black and white. The stuff 99% of DIY sheds sell is garbage; is a thin surface and all sorts of rubbish, gaps, and filler.
If on a budget, or unable to find a decent source, MDF is probably better.
4mm ply should be fine *if* properly braced and *if* the structure is well designed. You may need some 6mm in some areas, or alternatively 4mm doubled up to 8mm. Ply sheet, appropriately triangulated, with holes cut in it can be incredibly strong.
- Nigel
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Webmaster at http://www.2mm.org.uk/
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You can get joint 16.5/9mm flextrack, which should save you having to build it by hand. See http://tinyurl.com/yl43h2 The first item on this page is the joint HO/HOe flextrack (HOe is HO scale on 9mm track). It is quite pricy, at 5.60 for 680 mm., but in my opinion it is better than making the track by hand.
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Jane
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Wish I'd known about that when I moved the layout in to the garage.
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All the best,

Chris Wilson
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Peco O gauge track sort of looks like bullhead but is actually flat bottom - it uses the same connectors as the "OO/HO" track. Sleeper spacing is to British standards, but does that matter too much on a test track?
--
John Bishop

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Mike.
I go with much of what Jim has said.
We built new Club boards in 6mm 'Birch Faced Ply'.
This is the best stuff. It costs but it is well worth it iif you want it to last.
However, two boards had a built in warp in the tops and no matter how much bracing was applied, it couldn't be rectified. We also found the board end too week in 6mm to bolt together.
So we settled on 6mm MDF tops, sealed both side and edges as soon as the boards were built, 6mm ply sides with 9mm ply ends.
Best of luck.
DaS
Mike Hughes wrote:

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So we settled on 6mm MDF tops, sealed both side and edges as soon as the boards were built, 6mm ply sides with 9mm ply ends.
David, How do you mean by "sealed" ? What with ?
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Andy Sollis
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Matt varnish, but not water based.
Dave
Andy Sollis wrote:

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Matt varnish, but not water based.
Dave
Cheers Dave.
Andy
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