Foam baseboard. Anyone used it?

[GridNorth]

I've decided to use 50mm extruded foam laid on top of 12mm plywood as my baseboard.  The plywood is laid on desks so there is is no opportunity to create a space for the wiring. Should I a) dig trenches in the surface of the foam and lay the bus and the wiring into that or b) dig the trenches on the underside to lay the bus and drill small holes for the wiring to power the track?  Does anyone have any direct experience of which would be better?

 

Al

[wasdavetheroad]

My layout has 150mm thick blue extruded polystyrene baseboards. When it was the base for a N scale layout I dug trenches for the wiring. Four years ago I decided to convert to OO scale and filled the trenches in. Now I have no wiring because I adopted radio control and battery power.

[jpendle]

I use layers of 25mm Extruded polystyrene for my base boards laid on top of a conventional baseboard frame. With a max baseboard size of 4' x 2' I find it has plenty of rigidity without the need for a ply base.

 

For your case I would suggest using 2 layers of 25mm foam, then you can dig the trenches in the upper layer put the wires in them and then put the foam cut outs back in to hide everything. Obviously you can do the same with one 50mm piece but it may be easier with 2 layers. If using point motors a 50mm piece will probably give you enough space to hide a solenoid type as well.

 

Regards,

 

John P

[GridNorth]

Thanks JohnP.  That's a damned good idea but I've just bought 3 x 1250 x 450 x 50mm boards which leads me nicely to my next question.  The foam can rest directly on two desks that I have pushed together.  I should also be able to secure it without resorting to nails or  glue simply by clamping it in place with end panels but what is the best way to wire the layout. Dig trenches in the top surface, dig trenches in the underside or raise the board by gluing a couple of pieces of 2 x 1 to create a space underneath.

 

Al

[jpendle]

I would raise the lot on some pieces of 2x1. Then the wiring can be hidden below the layout. It would also allow more depth if you plan on using larger point motors such as Cobalts or Tortoises.

 

Regards,

 

John P

[GridNorth]

After staring at it for 2 hours I've come to the same conclusion.  Thanks for your help.

 

Alan

[Ron Ron Ron]

A common way to build extruded foam base boards, is to frame the panels with lightweight thin ply panels.

These not only provide extra rigidity and preventing any sagging, but protect the edges of the foam from being damaged.

Much lighter and more rigid than mounting the foam on a board, which sort of defeats the object of using foam in the first place.

 

With such framing, you can now run all the main wiring along the front, or back of the layout, mounted on the ply panels, with short wire spurs and links running out from the edge onto the layout, to the track, point motors, lighting etc, etc.

It would remove the need to run most, if not all of the wiring from underneath the layout.

 

A variation on this method, for the sake of neatness, hiding the wiring and any electrical devices and protecting the wiring and electric fittings, is to create a cover or lid over the edge mounted wiring etc.

Alternatively, extend the end framing sections to protrude beyond the edge of the foam, by a few inches and use this to create a void along the front or rear edge of the board, with an optional hinged or removable cover or flap.

 

 

.

[TheQ]

Another vote for the wiring on the back,  or front,  I'd trench the top,  or to be more precise through the hill side at a fraction below track level. ( my boards generally are scenically  sloping upwards towards the back.) 

I've long since lost interest in working underneath boards while lying / crouching on the floor. 

[GridNorth]

My L shaped foam board will be against walls on three sides so I will be putting edging on the remaining sides.  The board will be sitting on top of L shaped 12mm plywood of the same dimensions so I'm hoping that the framing will hold it in place allowing me to lift it to get to the underside.  I will decide at the time whether to run the bus down the side or down the middle, it may depend upon the lengths of the wires from the bus to the tracks but either method should be feasible.  I've had enough thinking and agonising  over this so it will be a welcome relief to actually be able to get on with it. Unless of course someone comes on here and says "You don't want to do that because.......! 

[Matt C]

You dont want to do that because  !       Na go for it 

[Andy Hayter]

I did as you are suggesting Gridnorth, although I am using conventional DC rather than DCC - so my need to be able to access wiring is probably more acute than yours, given that at some stage something will go wrong.

[Stentor]

I seem to remember that there was an issue with running wiring through foam boards which put me off using them despite the obvious weight advantages.

There was interaction between the wire and the foam dissolving the sleeve?

 

Am I misremembering or is this an issue?

 

Any advice appreciated.

 

//Simon

[Andy Hayter]

There is a potential problem that the additives in the PVC sleeve which makes the wire flexible can migrate into the foam.  This could make the PVC wire sleeve become rigid and brittle.  But we aren't going to be moving the wire or bending the 4/5/6/15cm of wire embedded in the foam.  The most vulnerable bit might be the 1-2mm exposed just below the foam where additive migration might still occur.

 

After having wired up 3 years ago I have seen no signs of any problems.

[Ron Ron Ron]

4 hours ago, Andy Hayter said:

..... I am using conventional DC rather than DCC .........

 

Just for clarity Andy; would that be conventional DC as opposed to unconventional DC, whatever that is? 

Could you explain the difference?

 

On the other hand, are you in fact suggesting that DCC is somehow unconventional?

 

Regards

Puzzled, of Little Snoring.

 

[jpendle]

So, with the caveat that this may not work for you.

 

My baseboards are set at around 3'6" high. This means that as long as I make my wires long enough, I can sit on a chair and do all the wiring I need to under the layout.

 

For point motors, I solder the wires on my work bench first, then cut out a rectangle in the foam, glue the point motor to the bottom and then glue the foam back in place.

 

I use Wago Lever nuts to make all the connections under the baseboard, no soldering involved.

 

Regards,

 

John P

[Ron Ron Ron]

On 03/11/2019 at 11:58, Stentor said:

I seem to remember that there was an issue with running wiring through foam boards which put me off using them despite the obvious weight advantages.

There was interaction between the wire and the foam dissolving the sleeve?

 

Am I misremembering or is this an issue?

 

Any advice appreciated.

 

On 03/11/2019 at 12:03, Andy Hayter said:

There is a potential problem that the additives in the PVC sleeve which makes the wire flexible can migrate into the foam.  This could make the PVC wire sleeve become rigid and brittle.  But we aren't going to be moving the wire or bending the 4/5/6/15cm of wire embedded in the foam.  The most vulnerable bit might be the 1-2mm exposed just below the foam where additive migration might still occur.

 

After having wired up 3 years ago I have seen no signs of any problems.

 

From what I can glean, the risk of chemical interaction between foam and wire sheathing depends on the type of foam and the type of wire sheathing.

Newer electrical cable designed for house wiring is supposed to me more resistant to these effects. Older stock isn't.

 

If running electrical wires and cables in and under a foam baseboard, or which makes contact with any foam used on the layout, including foam scenic structures,  I personally would consider it prudent to provide some form of insulating medium between the relevant surfaces.

 

One method, would be to enclose any wires that will be in contact with the foam, in cotton/textile cable sleeves..

The relevant section of wire or wires are simply threaded through these cotton tubes, before laying

This stuff is readily available and is quite cheap.

Several metres can be bought online, for just a few £££'s.

It's available in various internal diameter sizes (e.g. 4, 6, 8, 10, 16mm) and colours.

 

I have yet to investigate if coating the foam surface, in the vicinity of cable runs, with paint or PVA, would work equally as well.

It would have to be a coating that doesn't react with the foam.

 

Any other ideas?

 

 

Ron

 

 

[Andy Hayter]

To be honest I really do not think we as modellers have a problem with our 12-14V DC 1amp current*.  Even with 5amp DCC currents I do not see a major problem.  It is when you have wiring in the roof from your photovoltaic cells running through such insulation that the problems can lead to unfortunate consequences.

 

* In my case I always have a single wire going through a hole.  If the insulation were to degrade and fall off then the foam itself is an equally good insulator and there is no possibility of the wire touching another and causing a short because it is sat alone in its hole.