Is a sub-road bed strictly necessary?

[Guest Jack Benson]

Bear with me.

 

The fact that the local(ish) DIY stores no longer stock cork tiles started all this, plus have serious doubts of the efficacy of both cork and the bond twixt cork and plywood baseboard top. It seems that cork has no real purpose and the bond tends to let go, which does drive the question ' why do I bother' ?
 

The current project is a micro of a couple of sidings at an army depot, just a few pieces of Peco flexi and turnouts , therefore no appreciable ballast shoulder, no elevation.

 

My baseboards are invariably decent ply, nice n'flat, why do I need cork or indeed any sub-road bed?

 

StaySafe

 

[Dagworth]

I have never bothered with it except on one part of Ravens where I used it to raise the level of the mainlines a fraction as they pass the reception yard to create a height difference. There it is purely for scenic reasons rather than for any perceived benefit of sound or running. 

Andi

[Guest Jack Benson]

28 minutes ago, Dagworth said:

I have never bothered with it except on one part of Ravens where I used it to raise the level of the mainlines a fraction as they pass the reception yard to create a height difference. There it is purely for scenic reasons rather than for any perceived benefit of sound or running. 

Andi

Andi,

 

Thanks, it saved a lot of mess and concern over the cork delaminating. 
 

StaySafe

[Lee-H]

2 hours ago, Jack Benson said:

Bear with me.

 

The fact that the local(ish) DIY stores no longer stock cork tiles started all this, plus have serious doubts of the efficacy of both cork and the bond twixt cork and plywood baseboard top. It seems that cork has no real purpose and the bond tends to let go, which does drive the question ' why do I bother' ?
 

The current project is a micro of a couple of sidings at an army depot, just a few pieces of Peco flexi and turnouts , therefore no appreciable ballast shoulder, no elevation.

 

My baseboards are invariably decent ply, nice n'flat, why do I need cork or indeed any sub-road bed?

 

StaySafe

 

I tried it on a layout many years ago but couldn’t see any benefit so I proceeded without it. The cork sheeting was useful for making road surfacing and crossings.

[Gordon A]

Putting down a layer of cork under the track helps in creating an illusion of the bed of ballast on which the track sits.

 

[fulton]

I use cork to give the ballast a shoulder, also if, like mine, the woodwork is not completely flat the cork layer gives another opportunity to correct things, never heard of it delaminating, unless you have used sealed floor tiles, I use PVA glue, when scrapping a twenty year old layout it was still well and truly stuck.

[brossard]

I have changed my thinking about cork completely.  Notwithstanding the lack of availability (someone at the club yesterday said that the cork trees in Portugal had been destroyed by fire).  Using PVA to glue the cork to the boards makes a direct path from the track to the board causing noisiness.  It is the 21st century and we should be thinking outside the box.

 

Anyway, my latest approach is to use Woodland Scenics closed foam underlay:

 

https://www.hattons.co.uk/34070/woodland_scenics_st1474_24_of_oo_ho_gauge_track_underlay_in_a_continuous_roll_5mm_x_1_75_x_24_/stockdetail

 

I glue it to the boards and the track to the underlay with Tacky Glue:

 

https://www.walmart.ca/en/ip/aleenes-original-tacky-glue-16-fl-oz-white/6000016940821

 

(I did ask Google for a UK reference, but it wasn't having it)

 

I get mine from the crafts section.

 

An advantage to Tacky Glue, is that if you make a mistake, taking the track up is pretty easy as it just peels away.  No need to soak (Tacky Glue is water soluble though).

 

I've had the track down and working on my 7mm layout now for just about a year and I'm very happy with it.  The method decouples the track from the boards so running is quiet.  My sector plate has cork underlay and the noise difference is quite marked.

 

John

 

[wasdavetheroad]

Apparently Tacky Glue = thick PVA

[brossard]

11 minutes ago, wasdavetheroad said:

Apparently Tacky Glue = thick PVA

 

Only it dries rubbery not rock hard.

 

John

[Nearholmer]

Answer to original question: no.

 

I’ve built multiple layouts, in several scales, without, and one with, and trains ran happily on all of them.

 

But, if you are modelling a bit of railway with deep ballast it can help to simulate the bulk of that.

 

I didn’t know that cork was now in short supply, because I was about to recommend the gasket supply company Charles Cantrell (advertisers in RM) as a source of truly top-notch stuff. Theirs is streets ahead of the very friable stuff often sold for railway modelling use, and jolly good value for money.

 

Personally, I have an abiding suspicion of any foamy/expanded plastics, because I’ve seen so many, in multiple applications, degrade exceedingly quickly.

 

Have you thought about good quality “two-wall and corrugations” packaging card? I’ve not tried it, but I’d wager that it would make a very durable roadbed, and it’s free!

[brossard]

2 minutes ago, Nearholmer said:

 

Personally, I have an abiding suspicion of any foamy/expanded plastics, because I’ve seen so many, in multiple applications, degrade exceedingly quickly.

 

Have you thought about good quality “two-wall and corrugations” packaging card? I’ve not tried it, but I’d wager that it would make a very durable roadbed, and it’s free!

 

So, have you seen or experienced any layouts with the WS foam underlay?  Define "exceedingly quickly".  I am aware that the Peco open cell foam underlay has a rep. for deteriorating "quickly" (although I don't know what that means, weeks, months, years?)

 

Surely any paper product used for underlay will deteriorate quickly because it will be exposed to water at the ballast stage.

 

John

 

[Nearholmer]

I’m talking five to ten years to begin to see breakdown of expanded plastics or plastic foams, shorter if they are subject to punishing mechanical loads (things like furnishing foams).
 

Good card will withstand a dousing with PVA solution, and once that dries it ought to be good for a decades. Cardboard boxes do decay, but in a dry environment they take a blooming long time about it.

 

It might not be a very scientific way of getting a feel for the difference, but it you buy an old model loco, say from the 1980s, the cardboard box will still be happy (scuffed and worn maybe but, if it’s been kept dry, not decomposing), whereas the expanded polystyrene ‘cradle’ will often display embrittlement, discolouration, and, in bad cases, leeching-out of constituents.

 

As I said, I have an abiding suspicion of plastics, and that is partly because they haven’t had time to rack-up a positive track-record over many decades.

 

 

Edited November 1, 2021 by Nearholmer

[Andymsa]

18 hours ago, brossard said:

I have changed my thinking about cork completely.  Notwithstanding the lack of availability

 

not sure where you buy your cork from but I seen plenty around in various shops

 

[SamThomas]

16 hours ago, brossard said:

 

Only it dries rubbery not rock hard.

 

John

So, it's more like Copydex then

[RobinofLoxley]

I am using a thin plastic membrane whose main use is in building applications so I'm not expecting breakdown.

It's about 2mm thick and compressible but has a closed cell. Open cell foams break down partly due to the structure and partly the surface area which is massive leading to mechanical and chemical degredation.

 

It's correct that a small layer under the track to raise it slightly improves the appearance but cork does nothing for noise suppression. 

 

It's unclear if cork is a sustainable product but if not we shouldn't use it. The future is in bioplastics.

[ColinK]

Another vote for Cantrell’s cork.  I’ve used their cork chippings for ballasting my G scale layout. 
 

My current 00 exhibition layout uses Peco foam underlay and it’s been down for 10 years without any problems, it is lightly weathered using paint and blended into the scenery.  Nobody has noticed/commented on it. The reason I chose the Peco underlay is so I can remove the trackpins and resuse the track on my next layout.

[Philou]

I've used flooring underlay - the green stuff that I think is wood-fibre based. It's not kind to cutter blades but it's about right at 3mm to raise the track sufficiently to make the 'cess', a feature that is very often overlooked when modelling the track bed. In @Jack Benson 's case where a yard, or sidings, are modelled, then there would be no need.

 

It's my understanding that it's when ballast is being glued with PVA (or any other glue) it's absorbed into the sub-base and forms a solid mass hence transferring the sound direct to the baseboards. The answer probably is preformed foam simply weathered and NO glue a la @ColinK. It comes down to just how much realism is desired against sound reduction.

 

I did find that after 10 years in stock, my foam underlay (not Peco) crumbled to dust.

 

Cheers,

 

Philip

[pheaton]

1 hour ago, SamThomas said:

So, it's more like Copydex then

yeah but without the stench... copydex however doesn't age well with exposure to sunlight it will discolour quite heavily whereas pva is very stable

[SamThomas]

43 minutes ago, pheaton said:

yeah but without the stench... copydex however doesn't age well with exposure to sunlight it will discolour quite heavily whereas pva is very stable

Agreed - it does have a bit of an "unneutered tomcat" sort of smell. Was not aware of the issue with UV light.

[PMP]

19 hours ago, brossard said:

 

So, have you seen or experienced any layouts with the WS foam underlay?  Define "exceedingly quickly".  I am aware that the Peco open cell foam underlay has a rep. for deteriorating "quickly" (although I don't know what that means, weeks, months, years?)

 

Surely any paper product used for underlay will deteriorate quickly because it will be exposed to water at the ballast stage.

 

John

 

Like you I’ve used the Woodland Scenics underlay with no problem at all on two layouts. No issues with degradation of any kind. I superglue the track to the foam bed.

I also used Peco foam underlay and didn’t experience any degradation over ten years. I had used acrylic car spray on it which may have given it something ’extra’. 

[sjp23480]

2 hours ago, Philou said:

I've used flooring underlay - the green stuff that I think is wood-fibre based. It's not kind to cutter blades but it's about right at 3mm to raise the track sufficiently to make the 'cess', a feature that is very often overlooked when modelling the track bed. In @Jack Benson 's case where a yard, or sidings, are modelled, then there would be no need.

 

It's my understanding that it's when ballast is being glued with PVA (or any other glue) it's absorbed into the sub-base and forms a solid mass hence transferring the sound direct to the baseboards. The answer probably is preformed foam simply weathered and NO glue a la @ColinK. It comes down to just how much realism is desired against sound reduction.

 

I did find that after 10 years in stock, my foam underlay (not Peco) crumbled to dust.

 

Cheers,

 

Philip

Another vote for flooring underlay from me, but I use a closed foam example which comes in 4'x2' sheets - or the metric equivalent. 

 

I used to get it in Wickes, but they don't appear to stock it now.  It looks very similar to this stuff from Amazon: https://www.amazon.co.uk/XPS-Underlay-Insulation-Laminate-Fibreboard/dp/B098LRLQZW/ref=asc_df_B098LRLQZW/?tag=googshopuk-21&linkCode=df0&hvadid=535908606674&hvpos=&hvnetw=g&hvrand=10767304736419707524&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006483&hvtargid=pla-1396045330734&psc=1

 

Its very cheap - £7.50 for 5sqm, seems durable (although I haven't used it long enough to verify), is noise dampening and is easy to lay - I just laid the sheets on the boards, lay the track and then cut around the underlay to remove the excess.  

 

I think I read that @Tony Wright used similar something similar on Little Bytham, but I could be mistaken.

 

Steve

[doilum]

On 02/11/2021 at 08:09, Andymsa said:

not sure where you buy your cork from but I seen plenty around in various shops

 

Freely available at low cost on Amazon etc. Old school contact adhesive makes for a permanent fix. 

[Roy Langridge]

20 hours ago, doilum said:

Freely available at low cost on Amazon etc. Old school contact adhesive makes for a permanent fix. 

 

My go to for cork has always been Fred Aldous: https://www.fredaldous.co.uk/

 

Good price and excellent service (no connection other than as a happy customer).

Roy

[Chris Turnbull]

No underlay here.  Looks OK to me.

 

 

Chris Turnbull

[Jol Wilkinson]

On 01/11/2021 at 14:01, brossard said:

I have changed my thinking about cork completely.  Notwithstanding the lack of availability (someone at the club yesterday said that the cork trees in Portugal had been destroyed by fire).  Using PVA to glue the cork to the boards makes a direct path from the track to the board causing noisiness.  It is the 21st century and we should be thinking outside the box.

 

Anyway, my latest approach is to use Woodland Scenics closed foam underlay:

 

https://www.hattons.co.uk/34070/woodland_scenics_st1474_24_of_oo_ho_gauge_track_underlay_in_a_continuous_roll_5mm_x_1_75_x_24_/stockdetail

 

I glue it to the boards and the track to the underlay with Tacky Glue:

 

https://www.walmart.ca/en/ip/aleenes-original-tacky-glue-16-fl-oz-white/6000016940821

 

(I did ask Google for a UK reference, but it wasn't having it)

 

I get mine from the crafts section.

 

An advantage to Tacky Glue, is that if you make a mistake, taking the track up is pretty easy as it just peels away.  No need to soak (Tacky Glue is water soluble though).

 

I've had the track down and working on my 7mm layout now for just about a year and I'm very happy with it.  The method decouples the track from the boards so running is quiet.  My sector plate has cork underlay and the noise difference is quite marked.

 

John

 

 

I get EFP30 closed  cell foam from efoam,  cheaper than other suppliers I have found.

 

https://www.efoam.co.uk/closed-cell-polyethylene-foam.php

 

I have used F Balls F3 carpet adhesive, for both fixing the foam and the ply sleeper track to the foam. This is not unlike Copydex but the smallest quantity is 2.5L. It remains slightly flexible and therefore may transmit less noise to the baseboards than PVA.

 

The original London Road P4 LNWR layout, built in the mid 1980s,  used 3mm closed cell foam with PVA and hasn't suffered from any issues. The extension to London Road built in 2010/201has  EFP30 as above with Balls F3 and has also suffered no problems, despite mainly being stored in a ventilated shed at ambient and subject to  temperatures and transport to exhibitions with the varying temperatures found there. I would therefore have no hesitation in using or recommending that approach.

 

 

Edited November 4, 2021 by Jol Wilkinson
Spelling/typos