Using Insulation Board as the base

Discussion of model railway baseboard design and construction
NeilP
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Using Insulation Board as the base

Postby NeilP » Fri Nov 16, 2018 10:49 pm

Hi Guys,

I have decided to use Insulation board as my baseboard.

Do I need to use a particular type of spray paint which will adhere to this type of surface ?

Also, I was thinking of using a couple of shades of green for the base layer so I wandered you you can recommend any particular shades.

Any replies are gratefully received. This is my first attempt at building a model railway so a complete novice .

Many thanks

Neil

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Bufferstop
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Re: Using Insulation Board as the base

Postby Bufferstop » Fri Nov 16, 2018 11:52 pm

Hi Neil
I've used insulation board in the past, when there was little else available. First off lets make sure we are talking about the same stuff, about 12mm thick, compressed fibrous board, breaks easily if folded. Long term it requires a lot of support, or to be laid over a plywood base. It's almost impossible to totally seal it and it continues to absorb moisture over time. When it had been in place for twelve months or so it was sagging slightly between battens one foot apart, my cure was to insert from below a series of battens along the line of the track. It will accept thin track pins without trouble but won't hold screws which is a problem installing point motors. I now prefer either of two methods,
(i) 6mm ply for both surface and frame, the frame and cross bracing being between 80 to 100mm deep, cross pieces drilled through with 25mm holes for wiring.
(ii) Blocks of 50mm solid foam insulation (Kingspan or similar) faced around the edges with 4mm ply, with 12mm on the edges where boards are to be joined. (Not really suitable if you are using below board point motors) Wonderfully light if it's to be portable.

John W
aka Bufferstop
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NeilP
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Re: Using Insulation Board as the base

Postby NeilP » Sat Nov 17, 2018 10:30 am

Hi John

thanks for your quick reply,

I'm using the 25mm insulation board. I'm taking my inspiration from this video here https://www.youtube.com/watch?v=E_8WzxHrhlI

He is spraying directly onto the silver surface so my question is do I need to use any particular type of spray paint so it will key to the surface and dry correctly, or will anything do ?

I like this material as it is light and portable which sorts my needs, it's light and portable and cheap :-)

Big thanks for any help

Neil

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Bufferstop
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Re: Using Insulation Board as the base

Postby Bufferstop » Sat Nov 17, 2018 10:55 am

That's a thinner version of the rigid insulation I have used. It will need extra stiffening if you want to create much scenery, A few buildings will be ok, but for hills, mountains or cliffs it would be better bonded to a second sheet (which could have large areas cut away before bonding). No matter what the material, it's the depth that imparts the rigidity.
For painting the surface, if it's metallic foil a can of primer for metal surfaces, sprayed lightly should give something for other paints to key on to.
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NeilP
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Re: Using Insulation Board as the base

Postby NeilP » Sat Nov 17, 2018 11:18 am

Wow,

Great advice, thanks John.

I like the idea of doubling up the board if needed.

I think my scene should be quite light, no mountains etc, although I thinking of building a scale model of the Pyramid stage at the Glastonbury Festival, though that should quite light :-)

any tips on shade of green for grass course etc ?

thanks again,

Neil

Paul-H
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Re: Using Insulation Board as the base

Postby Paul-H » Sat Nov 17, 2018 12:22 pm

Don't forget the Celutex type of insulation cannot be cut with a hot wire/knife type cutter and if you try it gives of toxic fumes that will do damage to your eyes, don't ask how I know this but is bl@@dy painful


Paul

NeilP
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Re: Using Insulation Board as the base

Postby NeilP » Sat Nov 17, 2018 2:24 pm

I'll bear that in mind :-)

Neil

HarryR
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Re: Using Insulation Board as the base

Postby HarryR » Tue Nov 20, 2018 8:44 pm

NeilP wrote:Hi John

thanks for your quick reply,

I'm using the 25mm insulation board. I'm taking my inspiration from this video here https://www.youtube.com/watch?v=E_8WzxHrhlI

He is spraying directly onto the silver surface so my question is do I need to use any particular type of spray paint so it will key to the surface and dry correctly, or will anything do ?

I like this material as it is light and portable which sorts my needs, it's light and portable and cheap :-)

Big thanks for any help

Neil


I dont know if he mentions it that video, he does in another, that the silver backing should not be removed doing so affects the integrity of the product.

He has quite few builds on Youtube using that material, all are worth watching "Calverton" being my fav

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Bufferstop
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Re: Using Insulation Board as the base

Postby Bufferstop » Tue Nov 20, 2018 11:01 pm

Rigidity of the track bed is what you are aiming for I'm assuming this is 00, Settrack is the strongest (the plastic base is stronger and the rail fixings are a hard plastic. Code 100 Streamline is a bit more likely to pop a rail out if the board flexes too far. For code 75 it's best if you can't detect any flexing, as the rail fixings are necessarily thinner.
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gppsoftware
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Re: Using Insulation Board as the base

Postby gppsoftware » Mon Feb 10, 2020 2:57 am

Simple reply to the use of [fibre] insulation board or 'cannite' as its known in some countries: don't use it for structural or track bed purposes.

I used it years ago for track beds and ruined a layout with it. It absorbs moisture and warps just like that other awful stuff that a certain track manufacturer has been pushing for years: Sundeala.

Both warp at rates Captain Kirk would be proud of.

You only build layout boards once. Do it properly first time otherwise you'll be cursing forever more.

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RAF96
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Re: Using Insulation Board as the base

Postby RAF96 » Wed Feb 12, 2020 9:55 am

I had a layout with chipboard tops covered in wIckes laminate flooring underlay tiles glued down with contact adhesive. These 18” square tiles are a soft hardboard material, one side textured like normal hardboard and the top side rougher. I thought great it is easy to put track pins in and will insulate sound like cork.
It did until I ballasted it and then it warped all over the place.
Fortunately I moved house not long after and that unfinished layout went in the skip.
Present permanent layout is ‘sturdy’ with 18mm ply frames 150mm deep and 9mm tops. Strong enough to stand on. No cork or other insulation.
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Bufferstop
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Re: Using Insulation Board as the base

Postby Bufferstop » Wed Feb 12, 2020 12:48 pm

The terminology has changed over the years, up to the end of the last century I think most people using the term "insulation board" meant half inch thick compressed wood fibre board, which the last time I saw it being used, was to build up a flat roof to give it some fall once covered with bitumastic felt. I presume closed cell rigid insulation or expanded polystyrene cannot be used due to a blowtorch being used to apply tar as a sealant. The old fibre board was a poor base as it could not support over a span of one foot without rigid support and it wouldn't take screws at all.
Modern closed cell rigid insulation can form a very light self supporting baseboard, the possible span depending on the thickness used. It has two disadvantages, it can't support an operator leaning on the board, and it's too thick to mount point motors beneath the board. A thin deep plywood profile board and a mid length support will allow for an operator leaning on the edge of a span. Servo style (I'm including Tortoise) point motors connect by a linkage can be mounted above or below the board. Peco style "clip to the point" motors can be used where a single point or crossover is required by cutting a well below the point to accommodate the motor. Their use at complex junctions is a problem as so many in one place will weaken the structure.
Growing old, can't avoid it. Growing up, forget it!
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Bufferstop
Posts: 12434
Joined: Thu Mar 11, 2010 12:06 pm
Location: Bottom end of N. Warks line

Re: Using Insulation Board as the base

Postby Bufferstop » Wed Feb 12, 2020 12:49 pm

The terminology has changed over the years, up to the end of the last century I think most people using the term "insulation board" meant half inch thick compressed wood fibre board, which the last time I saw it being used, was to build up a flat roof to give it some fall once covered with bitumastic felt. I presume closed cell rigid insulation or expanded polystyrene cannot be used due to a blowtorch being used to apply tar as a sealant. The old fibre board was a poor base as it could not support over a span of one foot without rigid support and it wouldn't take screws at all.
Modern closed cell rigid insulation can form a very light self supporting baseboard, the possible span depending on the thickness used. It has two disadvantages, it can't support an operator leaning on the board, and it's too thick to mount point motors beneath the board. A thin deep plywood profile board and a mid length support will allow for an operator leaning on the edge of a span. Servo style (I'm including Tortoise) point motors connect by a linkage can be mounted above or below the board. Peco style "clip to the point" motors can be used where a single point or crossover is required by cutting a well below the point to accommodate the motor. Their use at complex junctions is a problem as so many in one place will weaken the structure.
Growing old, can't avoid it. Growing up, forget it!
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MickleoverTestTrack
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Re: Using Insulation Board as the base

Postby MickleoverTestTrack » Sun Feb 16, 2020 7:24 am

As they found out a couple of years ago, it ain't non-flammable either!

I tried 25mm an 50mm Celotex, but I'm wary of what harm it might cause being cut. The lightweight dust seems to hang in the air for ages after being cut, I guess that is why calvertfilm does all the work outdoors.


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