cork track underlay

I think you might mean foam board - a stiff whitish foam sandwiched between thin card. I tried using this material as the underlay for a layout a few years ago and wouldn't recommend it for the following reasons

a) It does not do anything to reduce the noise of the locos and stock

- if anything, its card surface acts as an effective diaphragm and increases the noise.

b) The thicknesses appear to be nominal and you can get variations between batches so that you have to resort to packing to ensure that joints are level.

You would be better sticking with cork, or you could look at using foam sheet. C&L sell 5mm foam sheet,

and a cheaper source can be foam rubber ground sheets sourced from camping shops.

If you use foam underlay, to get the best results, don't pin your track down hard, but use the pins just to locate the track and make sure that there is clearance between the pins and the holes in the sleepers so that the track can move up and down. This gives good sound insulation properties, but also gives a form of suspension which can improve running - just as in the real thing.

Also, if you have to use glue with the foam, use a carpet glue. This glue does not set hard, but remains flexible when set - unlike your average white PVA glue which goes rock hard and can negate any advantages when using foam. For ballasting, use dilute Copydex or Artistes Matte Medium to hold the ballast in place since these adhesives stay flexible when set.

Jim.

make

Assuming that one is modelling track that's in desperate need of packing and tamping!

Not if you use a firm foam like the foam supplied by C&L. The movement will probably be imperceptible under all but the heaviest loads, but it is there none the less, and provides an element of resiliency, as well as sound decoupling

And full scale ballasted track does have some resiliency, even when newly ballasted and tampled.

Jim.

In message , " snipped-for-privacy@hotmail.com" writes

I use roofing felt.

Hi Jim,

Or a lot?

regards,

Martin.

---------- email: snipped-for-privacy@templot.com web:

I've been experimenting with some 2.5mm Polyethylene foam sheet material. I'm sure its also sold in many DIY shop for use as underlay for laminate flooring, any packaging company should be able to supply some.

Malcolm

suspension

when

Very little movement indeed, in 4mm scale one is talking about circa;

0.333333333333333333333333333333333mm > 1.33333333333333333333333333333333...

Even on all-welded track under a heavy fast freight...

I think I've seen that one when it was mentioned on one of the Yahoo Groups (Templot?) I'm on dialup here, so I won't download it again, but I don't think you could call it well ballasted and tamped :-)

Jim.

Thanks all for the tips

Hi Jim,

Well no. I edited that part out of your quote. :-)

What I can't make up my mind about, is whether this is extraordinarily badly maintained track, and an accident waiting to happen when those remaining fish-bolts break.

Or just par for the course for North American spiked track on secondary lines. Some comments on US groups indicate the latter, and that "I ought to get out more." :-) If I do, I won't be getting that close to that rail joint!

Martin.

I have had success with a kind of wood pulp felt used as expansion insertion between concrete blocks from a local builders suppliers. Its about half an inch thick and comes in various widths from a couple of inches to about a foot wide. I used some for my god sons layout (housed in a shed) about - err - a few years ago now and its still fine. As an experiment I left some outside with a bit of track fastened to it for a couple of years and it was also fine. I liked it as I could use a hacksaw blade or similar to score a slot to hide the wire-in-tube point control in the surface (it was sitting on melamine coated board shelving in a cramped space, so all the wiring and point control was set into the surface, with a quater inch jack to connect the power).

I would use it again.

You can get book-binding PVA which stays rubbery, helps keep the noise down - Diluted copydex is something I plan to try - Havent had a chance yet.

Mike

You might look at foam concrete expansion strips. 20 metre rolls, about 10 mm thickness and available in widths up to 200 mm. Track (Peco in my case) is glued to the foam after the foam is glued to the (chipboard) base.

Steve Magee Newcastle NSW Aust

"Jim Guthrie" wrote

Not having been near C&L's stall lately, how does this material compare to mousemat foam? Dead mousemats are readily gettable for nowt, and look like they might do the business if angle-sliced to give a ballast shoulder and coated with the ballasting material using, say, Copydex (PVA might migrate into the foam and dope it solid once set, thus losing the bounce).

Tony Clarke (with a boxful of rescued tatty mousemats)

In message , " snipped-for-privacy@hotmail.com" writes

I am using a 8mm foam camping mat which gives a perfectly flat surface. Ballast is beach sand (this is in N) fixed with diluted "Marvin Medium" which seems to retain the resilience in the foam. I am ballasting at the moment but initial impressions are good, particularly the noise transmission (or rather the lack of it).

8mm = ~4ft in N! Are you using it for the whole baseboard or just track underlay?

In message , MartinS writes

Actually 8mm= 50" as it is 1:160 !

I have covered the whole baseboard (all 4 square feet of it) with the mat. As I am not modelling a main line I don't need a pronounced shoulder to the ballast and it is quite easy to create a small shoulder with the ballast itself, at least with the thick sleepers on Peco track. I'm not sure what I would do with the thinner PCB sleepers used for 2mm.

What do you want it for?

a) ballast former; b) sound deadener; c) both a and b.

For a: any easily shaped material of the right thickness will do, so long as it doesn't warp when you fix the ballast in place with thinned glues or when you paint the track. Cork is the traditional material, but good quality foam-core, craft foam, etc also work. Very strong recommendation: do not go cheap with any track or layout materials. You will regret it.

For b: a sound-absorbing underlay alone is not enough. Sound is tricky to control. There are basically three methods, which should be combined.

1) Reduce resonance in the layout by decoupling the sound source from the resonator - cork underlay and glues that remain pliable will do this. That means no pins (except for temporary fixing), and acrylic or latex glues. (Most PVA glues set rock hard.) Use rigid fastenings between track and roadbed only where absolutely necessary, eg, at joints with (re-)movable baseboard sections.

2) Increase the mass of the roadbed so that it absorbs the sound energy without resonating. In the 1960s, a club in the USA built its roadbed out of plaster cast in place in troughs 3" deep shaped to follow the track plan, in order to avoid the expansion and contraction of wood roadbed caused by humidity changes. The top of the roadbed was shaped to ballast contour while wet. A side effect was almost total damping of motor noise etc. Using 3/4" or thicker plywood for the subroadbed (track board) will have much the same effect, especially if combined with method 1.

3) reduce echoes etc in the layout room. Install carpeting or rubber matting, sound absorbing ceiling tile, curtains below the layout, etc.

The aim is to reduce ambient and resonant noise to the point where you can hear the wheel clicks and the little loudspeakers ion the engines.

HTH