Baseboards

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Too much plywood

Yes indeed, extruded and expanded polystyrene are very different beasts.

As Q says, ceiling tiles and the "white foam" products are expanded whereas Styrofoam (sometimes referred to as "blue foam" although it also comes in pink) and celotex are extruded.  The white foam is normally far less dense than the extruded and therefore, not really suitable for load-bearing baseboards without plenty of support.  It's also very messy stuff because of the "prills" that become statically charged and stick to everything.  White foam is, on the other hand, much cheaper than extruded foams.

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Polystyrene ceiling tiles, I use myself for small layers of scenery, the Available Extruded types are generally fairly thick, and turning either sort into piles of dust or bubbles is an expensive waste. 

:)Your choice of method of baseboard construction is always your own choice, we all have our own favourite method.:)

:)Rule 1 it's my railway I'll do what I want, (with permission from SWMBO:???:).


Over the years looking at the discussions on baseboard construction I have seen several decend into confusion between:

Expanded foam polystyrene which turns into bubbles, and is a fire hazard but not really on a model railway encased by plaster.

Extruded foam Polystyrene which turns into dust and is difficult to set fire to.

Celotex, which isn't actually polystyrene  but polyisocyanurate (PIR) and depends on a tin foil covering for full stability.

Foamboard,  which is normally two layers of cardboard (shiny or matt) with foam glued between and has been used successfully for very lightweight boards.  You can also get it foam glued between two layers of plastic.

Then there is another type I can't remember the name of that is foamed plastic but with a smooth surface.

:) Enjoy your building  of your railway:)

Now I've finally started a model railway…I've inherited another…
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Hi Kevin,

Q brings up a couple of interesting points that if you don't mind I'd like to address.

Asking advice often results in diametrically opposite answers, governed of course by rules 1 and 2. That said, there are some fundamentals when it comes to baseboards, their design and what materials are used. It really is one of those areas where you makes yer choice and pays yer money.

Good 'ol wood (from balsa through various types of ply and composites such as MDF to oak) has intrinsic strength, longevity and doesn't require sophisticated (read expensive) tools unless you decide to get fancy with tenons, dovetails and the like. And even they can be done with basic tools. We've been messing about with wood for thousands of years, done right it will outlive us by at least a factor of 5. Buying cheapo will however get you cheapo. Not enough seasoning and the results can be interesting. I don't know whether you can get it in the UK, but Radiata pine (from New Zealand) is the best softwood I've found in quite a few years. Plantation grown and sustainable, kiln dried, straight grain, minimal knots, minimal shrinkage, 10/10.

HD foam is a relatively new material, and it's light. However, it's meant to be covered (in a wall or on the floor), is not intended to carry any structural loads, needs additional work when using switch motors (some sort of frame and air space) and unlike white open cell foam is not flammable (it contains a flame retardant called hexabromocyclododecane - HBCD), but it generates lots of oily black smoke. Some of the issues with this material are that it easily dents, regular CA glue goes through it like a hot knife through butter, most aerosol paints likewise, and water based adhesives don't readily stick to it (same for plaster cloth unless it's fresh and gets too hot to touch, in which case it welds to the surface). High quality emulsion paints low in VOCs adhere poorly, cheap ones with lots of VOCs stick well. Whether we should be using high VOC paint is another issue. At least they're cheap. I use HD foam for hills, embankments, etc., it's easy to shape, and cuts easily with a hot wire. Don't use any knives from the kitchen, it will blunt them on the first cut. And wear gloves when handling and a mask when sanding, like the building professionals.

My personal preference is Baltic birch ply, by definition an engineered wood product, which is used for the frame, cross braces and top. Works fine with flat top, open frame, or anything in-between. No solid wood except for the feet and corner braces. Over the past 12 years or so I've built 25+ modules of various sizes (6 x 2 to 4 x 1 feet, straights, angles) with this material. Before I finalized this approach I tried wood frames/ply tops, wood frames HD closed cell tops (pink or blue HD foam), hollow wood doors (too much like sounding boards, OK if you like noise), balsa (Gene's idea), MDF, foam board, HD corrugated cardboard…

There are very good arguments for not using dissimilar materials in making a module, or carefully planning what is used where. Wood shrinks and expands differently to HD foam for example. Which means leaving some space for this when using an HD foam top and a wood frame. Which means an elastic filler is required that is compatible with both wood and HD foam.

The only real way to get some sense of what works best is to actually  try it. It's one of things where a bit of investment in materials and  time and a few small modules (2 x 1 feet) pays dividends down the road. As Q said, it's YMR.

Have a look the photo's below for a 4' by 1' module built from Baltic birch ply (12 mm frame, 9 mm top). It weighs 11 lb. Glue and hard-wood dowels for the frame, screws are not necessary, although the top currently has SS screws. I'll replace those with dowels. This would take 2 OO gauge tracks and require minimal scenic work. I'm using this one as a bridge between two 4 x 2 foot modules with 3 tracks on 2" centers.

Nigel









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Birch plywood in a 9 ply configuration would make your eyes water pricewise in Europe Nigel ……………… :shock: :shock:

However, an excellent looking baseboard.  :thumbs

In passing, white foam - "expanded" polystyrene - is often manufactured with a "fire retardent additive" incorporated in the expanding process.  It will burn but, as soon as one removes the flame source, it goes out.  A necessary step to meet building regulations.  It can also be manufactured as a very dense foam rather than the typical "soft" foam.  Surprisingly, there are millions of cubic metres of the stuff built into concrete bridges over motorways etc. in the form of dense cylinders.  It reduces the bridge weight by "using up" volume without effecting the structural strength, which comes from the pre-cast concrete beams.  Without them, the bridge would collapse under it's own weight.

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[user=6]Petermac[/user] wrote:
Birch plywood in a 9 ply configuration would make your eyes water pricewise in Europe Nigel ……………… :shock: :shock:

However, an excellent looking baseboard.  :thumbs

In passing, white foam - "expanded" polystyrene - is often manufactured with a "fire retardent additive" incorporated in the expanding process.  It will burn but, as soon as one removes the flame source, it goes out.  A necessary step to meet building regulations.  It can also be manufactured as a very dense foam rather than the typical "soft" foam.  Surprisingly, there are millions of cubic metres of the stuff built into concrete bridges over motorways etc. in the form of dense cylinders.  It reduces the bridge weight by "using up" volume without effecting the structural strength, which comes from the pre-cast concrete beams.  Without them, the bridge would collapse under it's own weight.
Oh it does here, I weep every time I buy it. It's usually B/BB, so that ups the price. It's difficult to find BB/CP grade here. I used to be able to that one in Canada. The core is apparently made in Russia or Finland, the outer birch layers are applied in the US. Specifications are for sustainable growth, and formaldehyde-free glue.  It does become reasonably cost effective if it is used for the frame as well as the top though. One 2 x 4 foot module comes to around $30 US calculated on square footage used (and the thicknesses), and I normally have enough left over from the two  5 x 5 foot pieces used to make two 2 x 4 foot modules to make an additional one-foot wide module. To make sure it's cut properly I normally take the 5 x 5 pieces to the woodwork shop at my local Community Center, and spend an afternoon cutting and gluing. Gets a lot cheaper if I use the 6mm thick one for the sides and the top. That Radiata pine looks tempting for the frame, I will probably give that a try.

For those of use space-challenged, T-track modules in N-scale  are an interesting approach. The module size lengthwise is in multiples of 308 mm (12.126"). Depth is only 13". A  928 mm (36.535") module kit is $35.00. Baltic birch ply as well, cut and ready to glue. The lengths are funny because it uses Kato T-track. I'm seriously looking at moving from HO to N at home (and RTR). 12 x 2 feet comes down to just over 6 x 1 (5 x 1 if I do it myself). Add on a fiddle yard and the total cost is less than $100.

Nigel
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Hi Nigel.   Thank you for your reply. An excellent demonstration in how baseboards should be "Built", but with my most recent portable "Creation" ?? It is exactly the opposite. By necessity , for public transport ,  as I don't drive, it isn't as if I'm going to an exhibition, but as a proving ground for my own benefit . Whereas you have gone for total strength etc , my baseboard is 6 mm ply with a lightweight 3mm underframe? which fits into a "toolbox" like case.But even though it will stay put, I can practice wiring, ballasting, and in the meantime I hope keep the dust off the track. all the best. Kevin

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Kevin
Weight was not an issue for us but I also wanted to be able to move the boards should the need ever arise.
We used 4"x1" maple to construct a frame and then used plywood on top. By using shelving units at each end as the "legs" we gain storage underneath, nothing bolted to the wall and a structure strong enough to be moved without damage or warping.
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Hi Andrew. Thank you for your reply. Earlier in this thread I mentioned 3" x 1" timber being too heavy? Does that mean that 4" x 1" Maple is light, or do I need to get down to the "gym"?. When you mention shelving, for me that would only be another place for rubbish? (One of Murphy's Laws?) I started with "Really Useful Boxes" then I used an odd bit of ply and a set of castors to make a dolly.   all the best. Kevin

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Hi Kevin,

Maple is dense and heavy. The lightest (least dense) is balsa, but not really practical as it can dent easily. Your 6mm/3mm ply is about as light as you will get, unless you go for foam board or cardboard. I'm not joking about the last one, heavy duty corrugated when glued up properly is very robust.

Softwood tends to be light - Radiata pine averages around 430 kg/m3, compare with maple which is around 700 kg/m3. Good for legs, not for tops or framing. Birch core ply is dense, around 700 kg/m3. Stronger than regular ply, so you can use half the thickness.

If you use 3" x 1" framing, (which is nominal, it's more like 2.75" x 0.75") white or Radiata pine will be much lighter and cheaper than maple (which is also more difficult to work with). I use 4" sides (frame+top), which reduces the bracing requirements (the smaller the height of the frame the more bracing is required, 12" centers compared with 16" centers). If you can find it poplar-core ply is the least dense. Weight (density) is important if when you have to lug them around.

Compare above to Dow Styrofoam (the blue stuff) - 40 kg/m3. One thing many do not realize is that HD construction foam has a higher density skin (which is why it's smooth), which is important for strength. Even that will only take 1.8 kg/cm2 (25 psi, basically pointed finger pressure). Damage that too much and all bets are off re rigidity. 

Nigel

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Hi Nigel.  Thank you for your reply , I will have to figure out how to put some photos on line, and then everyone will know what I have built so far ( but a certain amount of embarrassment maybe getting in the way??). all the best. Kevin

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Hi Kevin,

If you have a look at the photo's I posted you'll see that I'm about 1/32" out on the corner, and those dowels really should be sanded down. One recent effort resulted in a moments inattention while pushing a board though the table saw, end result being the blade bit into the edge and left me with a section about 8" long that was at it's maximum 1/8" from the edge of the frame. Having "scrooge" genes, and a waste not, want not approach, a rescue was called for. Masking tape to form a dam, 2-part epoxy slightly proud, let set, peel paper off, sand down (with a mask on), job done! The spirit is always willing, the end result not always what we wanted.

It's difficult to be exact when working with wood. I aim for 1/64" (the professional woodworker at the center thinks I'm somewhat optimistic), unfortunately we're at the mercy of less than true blades (and eyes), humidity and temperature. A worn tape with a wobbly bit at the end doesn't help either. What does help is a dividing tape or 30" ruler, full scale on one edge, half on the other.  

Nigel

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Hi Nigel.   Inattention indeed? A moments inattention can lose you a finger, or more. During WW 2 my mother worked in a factory, on a shaping machine, while she was making adjustments the person next to her had a"moments inattention " and mum ended up in hospital minus one and half fingers on her left hand. Later mum returned to hospital to have her fingers made equal. I thought you were living in a small apartment ? Where does the table saw live in a shed? And that baseboard, did you say that was to bridge two other baseboards?all the best. Kevin

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Hi Kevin,

Hands always 12" behind the blade, wood pusher stick, feather board (this is a commercial table, no safety guard on the blade). I do know how to use a table saw. The inattention was due to somebody behind me using the band saw and almost going through a finger instead of the chunk of walnut when he hit an undetected brass nail (the block had been previously checked with the magnet for steel nails). Lots of noise (loud enough to go through the ear muffs), claret, drama and confusion.  And I was halfway through the cut. One of those "oops" moments.

The point is that such small errors are easily corrected. Even an under-size or less than straight cut can be adjusted with an appropriately sized strip of wood glued in place and sanded down. Painted up only you know.

My recipe for dealing with small errors, dents, screw/dowel holes started in the wrong place? (It happens, even when you measure thrice, just because it's exactly 6" matters little when it was supposed to be 4"). 5 minute epoxy mixed with fine sawdust (3 parts of epoxy, 1 part sawdust, made using #400 sandpaper, eyeball measurements). Much more durable than regular wood filler, and it fills deep holes in one go. Doesn't stick to masking tape, so edge issues can be dealt with. Sands down smooth and matte as well.

Nigel

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Hi Nigel.  The third party "Elememt"strikes again, I don't know how your "Community"? Deals with safety, Here in the U.K. HSE Law is really over the top. It could be a good thing that you have going over there, as long as every works together and cleans house,  ot leaving it for someone else.   Kevin

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Hi Kevin

That's why we have a professional woodworker on hand. One of those cases where "follow the instructions" comes in useful.

We have pretty much the same safety laws here (OSHA).
 
Nigel

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Hi Nigel.   And a " First Aider"? I hope. When I purchase timber, if I'm feeling lazy? I have to pay to have someone at the timber yard to put it on the saw bench.   all the best. Kevin

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Hi Kevin,

Getting the boards cut to size at the yard certainly cuts down on time and effort. Sweat and tears we can all take, it's the bloody bit that's worrying.

My experience with several lumber yards over the years has been that really explicit instructions are required, and I always ask - is your setup accurate? "Straightening cut, then 4' exact, then 2' exact, then 3.75" exact (or the difference between the thickness of the ply and 4"), make sure you level the base on the last cuts, etc". I cut the ends to length when I get home (or at the shop). It helps if you can give the operator a cutting diagram, free-hand is fine. As I said, I must give Radiata pine a try for the frame. Nice wood to work with and it glues-up well. Lot cheaper than a second sheet of ply as well.

Mind you, if I'm paying $35+ for a sheet of 5' x 5' ply I want the cuts thrown in for free. Most yards around here are happy to oblige, especially when you tell them what it's for and that it must be 2 x 4 feet (or whatever).

Nigel

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Hi Nigel.   I never gave "Squaring Up" or any "Straightening Cut" instructions a thought, until you mentioned them.I usually go to the counter tell them my requirements, they tell me the cost and sketch my instructions on a sheet of paper, which I take to the screen(Vertical Blind) and wait on the safe side(HSE design) hand over my diagram and collect the sawn timber. If I am lucky? and it isn't a big job or they are not too busy they don't charge for cutting.
In the case of 4' x 2', I may look for an off cut, and for the sides, as in your photo I would usually get it cut from the same piece of ply, again with the my instructions written on a sheet of paper.    Kevin

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Hi Kevin,

It's a good policy to always have a squaring cut done (at the store or at home). That gives you a true 90° on 2 sides, that's the datum point for all cuts that follow. If you're lucky the sheet is square, my experience is that 2 sides are parallel 2 are not, often by as much as 1/4"/6mm. Just an 1/8"/3mm out will generate headaches, grief and more work down the road when you come to attach the top to the frame.

I was looking at some  2 x 4 feet pieces of ply in the hardware store recently. Birch finished was 241/8" to 241/4", 48" to 481/4", not one square edge among 25 pieces. Plan vanilla  ply was 237/8" and 477/8" and nothing square. I promptly went to the lumber shop that stocks Baltic birch and had it cut properly. 

Nigel

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Hi Nigel.   I appreciate what you say about "Squaring" , but I just took it for granted, that it would be square.all the best. Kevin

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