Optimum baseboard thickness using Ply.

[chaz]

Six inches would guarantee no warping though, LOL.

 

Except in the owner's back.

[trisonic]

Be careful to calculate properly! If the outside measurements are 4’ by 2’ then for the bracing it’ll be shorter by the combined thickness of the wood of the longerons (sic).

 

I like Chaz’s idea - I personally believe most baseboards are over built and could double as dance floors....just my opinion, so don’t attack me.

 

Best, Pete.

[woodenhead]

Davknigh's is also good and more straightforward for me, as my layout is N gauge and it won't be moving about I can probably get away with the more simple structure.

[John_Miles]

Bracing is needed to stiffen up baseboards, unless you used very thick play. This is especially true for open topped baseboards. If you don't get the bracing right, then you will find you can get hold of one end and induce quite a large twist in the baseboard. This can be very damaging for scenery and buildings later one, especially for an exhibition layout which gets bashed around in vans traveling up and down motorways. In effect your baseboard is a beam, more accurately a truss, and hence needs bracing in both directions.

[jcm@gwr]

Just to throw a spanner in the works,

I've built an exhibition layout, from cardboard!

 

Mixture of reasons, initially inspired by the '£100 Layout' thread,

then someone said 'it's not possible', so I just had to!

 

The layout is 78" x 16" (x 11" high), length was determined by

need (0 Inglenook) & the longest pieces of 'U' section, width and

height by the dimensions of an A2 sheet of card (32" x 22").

 

It was glued together with PVA, then coated with Shellac, followed

by a coat of matt floor seal. It is strong, strong enough for what I

wanted, and it's light as well. 

 

It's now done 5 local exhibitions, with no visible signs of fatigue.

As I'm not good at posting photos, here is a link to some pics

my friend took and posted on another forum for me:-

 

http://mrlforum.co.uk/forums/index.php?/topic/2465-inglenooks-and-timesavers/&page=2

 

Obviously every layout has different needs and stresses,

so not every choice will suit everyone, but you will find

what does work for you in your situation.

 

Cheers, Jeff

[34theletterbetweenB&D]

... I personally believe most baseboards are over built and could double as dance floors...

 

What this comes down to is some engineering understanding, just one of the reasons I like this hobby so well; it encourages the development of a wide range of skill and insights. J.E. Gordon's two fine books 'The new science of strong materials' and 'Structures, or why things don't fall down' changed my thinking forever in the 1970s; and I commend them to all who intend to construct a baseboard - or anything else - with an intent of selecting and using materials for the lowest cost path to a fully satisfactory end result.

 

Just a hint: a well designed railway freight vehicle easily carries a load twice its tare weight or more. So if the worst case of imposed load on a 4mm layout - let's say it is an ambitious four track job, with full length trains - is maybe 4kg per metre, what might be your target for the build weight of the trussed beam that carries that load?

[peterfgf]

Superb books - they provide an excellent understanding of engineering materials.  Well worth reading if you can get them.

[Mike Storey]

Does the book discuss subsequent atmospheric or unintended stresses on the materials or type of construction used? The initial calculation of train and scenery weights on a surface area, and corresponding solution, is simple, but as so often found in our hobby, inadequate.

[34theletterbetweenB&D]

I would say it is rather good on considering the whole life of the structure, and designing for the complete set of properties required in that planned lifetime. It doesn't cover model railway support structures at all, as a generalist overview style of book. That's where the experience and brainwork has to be applied using the principles that are so well explained.

 

The real point is that there is no 'one size fits all' prescription: what may be done by an individual for a 'stays at home' layout, will not necessarily be appropriate for a club layout that is going to travel hither and yon for exhibition.

[chaz]

I would say it is rather good on considering the whole life of the structure, and designing for the complete set of properties required in that planned lifetime. It doesn't cover model railway support structures at all, as a generalist overview style of book. That's where the experience and brainwork has to be applied using the principles that are so well explained.

 

The real point is that there is no 'one size fits all' prescription: what may be done by an individual for a 'stays at home' layout, will not necessarily be appropriate for a club layout that is going to travel hither and yon for exhibition.

 

And there are numerous ways of skinning this particular cat! I would certainly prefer a baseboard made with cardboard to one that had a pine frame.

[Welly]

Just to throw a spanner in the works,

I've built an exhibition layout, from cardboard!

 

....

 

The layout is 78" x 16" (x 11" high), length was determined by

need (0 Inglenook) & the longest pieces of 'U' section, width and

height by the dimensions of an A2 sheet of card (32" x 22").

That's interesting - how thick is the cardboard?

[MPR]

J.E. Gordon's two fine books 'The new science of strong materials' and 'Structures, or why things don't fall down' changed my thinking forever in the 1970s; and I commend them to all who intend to construct a baseboard - or anything else - with an intent of selecting and using materials for the lowest cost path to a fully satisfactory end

Entirely appropriately, the former is subtitled "or why you don't fall through the floor." I also thoroughly recommend these books - they were required reading as a first year engineering undergraduate. The key to making baseboard structures adequately stiff is to think beyond rectangular box structures. Weight for weight adding diagonal bracing will massively improve the stiffness of the structure. If you don't believe this, mock it up with card first. Buckminster Fuller and Barnes Wallis got here first!

[RBAGE]

What about an open framed layout with a ply trackbed running on risers? What is the recommended ply thickness and riser spacing for a 4mm scale layout?

 

Bob 

[Mick Bonwick]

I'm using 9mm birch ply for the trackbed, and risers will be approximately 600mm apart, depending on frame positions. This is not yet a proven success - it is still in the construction phase! If there's anybody out there who thinks this is destined for failure, I'd appreciate a response soon.    

[Joseph_Pestell]

Perhaps the best baseboards that I have ever seen were made from aluminium (a club in the South London area but I can't remember which). They were lucky enough to get a free supply of offcuts from BR.

 

But since we are talking ply, my own past experience is for 6mm framework and 9mm trackbase. Unless the framework is very deep (150mm plus) which is heavy and expensive, it still needs diagonal cross-bracing to stop twisting.

 

But comments above are absolutely right. There is no single "right" answer. It depends on the layout dimensions and the stresses that are going to be put on it.

[chaz]

I'm using 9mm birch ply for the trackbed, and risers will be approximately 600mm apart, depending on frame positions. This is not yet a proven success - it is still in the construction phase! If there's anybody out there who thinks this is destined for failure, I'd appreciate a response soon.    

 

I think I would put in more risers closer together.

 

 

Trackbed on the board shown is 6mm and the risers are 200mm apart. I wouldn't say your plan is bound to fail - it depends on many factors but with your thicker roadbed I would advise a riser every 300mm.

 

Hope that's helpful.

 

Chaz

[Mick Bonwick]

Yes, Chaz, that's very helpful. Thanks very much, 'twill be borne in mind.

[newbryford]

Does the book discuss subsequent atmospheric or unintended stresses on the materials or type of construction used? The initial calculation of train and scenery weights on a surface area, and corresponding solution, is simple, but as so often found in our hobby, inadequate.

 

Does the book also allow for lazy a£$e operators leaning heavily upon slouching across the backscene?

 

Cheers,

Mick

[jcm@gwr]

Welly,

 

The 'U' (& 'L') sections are approx. 4mm thick

and the sheets were 2mm (which I then overlapped

to increase the strength, so ended up 4mm thick).

 

The sections were protective 'edges' from packing

on various white goods, w/tops, etc.

The sheets were purchased from Hobbycraft, but

are probably available from artists suppliers, etc.

 

Jeff

[RBAGE]

I've been looking at various US outline layouts on Youtube. With their extensive and multi layer construction, many seem to go for something considerably thicker. In the region of 18 mm to 25 mm ply ( have a look at Fishplate Films - Gregg and his alter ego "Lord Stan Dardgauge" - good for a laugh).

 

Is this over the top? 

 

It's one thing to have flat and fully framed and cross braced boards at 6 mm or 9 mm thick but I would have thought that something more substantial would be needed for something which is only supported on risers running in only one direction.

 

I don't want to break the bank buying hefty great lumps of expensive ply or break the shed floor with the weight for that matter.

 

Is the US approach just over engineering?

 

Bob 

[Joseph_Pestell]

I've been looking at various US outline layouts on Youtube. With their extensive and multi layer construction, many seem to go for something considerably thicker. In the region of 18 mm to 25 mm ply ( have a look at Fishplate Films - Gregg and his alter ego "Lord Stan Dardgauge" - good for a laugh).

 

Is this over the top? 

 

It's one thing to have flat and fully framed and cross braced boards at 6 mm or 9 mm thick but I would have thought that something more substantial would be needed for something which is only supported on risers running in only one direction.

 

I don't want to break the bank buying hefty great lumps of expensive ply or break the shed floor with the weight for that matter.

 

Is the US approach just over engineering?

 

Bob 

 

Completely over the top for most circumstances. But I can see some justification for it on a multi-level layout if it allows you fewer supporting risers.

 

Or it might be that they got a free supply of it. I was once involved with a club where we used a large quantity of thick ply that had been recovered from sauna cabins.

[BG John]

Old wardrobe found in a shed when I bought my house. Free 16mm ply trumps bought 4/6/9mm or whatever, despite the weight

[RBAGE]

On one US site, I've seen that they use what is called Homosote. It looks like fibre board and comes in 1/2 inch thick sheets at 8' x 4' which they have had cut into 2" strips.

 

They then laminate and stagger the strips (3 strips for each track) so that the track base is 1.5 inches wide and 2 inches deep.

 

This makes the track base flexible in the horizontal plane to achieve the track formation but fixed when the 3 layers are screwed together. The assembly is very rigid vertically so no risk of severe undulation.

 

Once you've started the laminated and staggered roadbed, you just keep on adding to its length, keeping the joints staggered. It looks very impressive.

 

Has anyone seen this?

Does anyone know if you can buy Homosote or equivalent in this country?

If there is a UK outlet, will they cut into 2" strips?

 

Might be worth a go apart from the obvious problems of getting the point motor actuation wire to operate through 2 inched of fibre board.

 

Bob

[57xx]

The key to making baseboard structures adequately stiff is to think beyond rectangular box structures. Weight for weight adding diagonal bracing will massively improve the stiffness of the structure. 

 

This is the first time I've seen someone else with the same thinking! Just look at any properly engineered structure and you'll see lots of triangles. I realised where I'd gone wrong after making my last set of boards and there was still some torsional twist even with 6" deep sides. I'd just blindly followed what has gone before, monkey see, monkey do. All future boards will be with diagonal bracing and  I'll get round to retrofitting it to the current boards.