Building Yeovil Pen Mill in EM.

Andrew Duncan

Member
Location
Reigate
Hi Andrew,

Your previous topic on the old forum is now archived at:

https://85a.uk/templot/archive/topics/topic_2547.php

I have added a link at the top of this topic. I'm sorry it took so long.

It's a long single page. Some of your other topics about your project are at:

https://85a.uk/templot/archive/topics/topic_3342.php
https://85a.uk/templot/archive/topics/topic_2326.php
https://85a.uk/templot/archive/topics/topic_2601.php

cheers,

Martin.
Hello Martin
Thank you for letting me know and for saving all that info. Very much appreciated.
Kind regards
Andrew
 
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C30F72BE-7EA7-4DAE-B542-85AB32834A04_Plan light weight main to tunnel1.jpg
@Andrew Duncan,
If it is allowed for me to think out loud about my thoughts:
I would suggest to put your 12mm mdf on top of your 4mm ply, instead in between.
It will be a lot stronger and more flowing going up or down.
Dont use any screws or small nails just some old fashion white carpenter glue.

Sinds i am busy with my thinking out loud thoughts:
Have you considered drywall sheets?
I think it will be very effective in sound reduction and as a bonus if you make it wet it will be very flexible for a track to follow if you want it go down or up.

As always following your progress with great interested.
 
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Andrew Duncan

Member
Location
Reigate
@Andrew Duncan,
If it is allowed for me to think out loud about my thoughts:
I would suggest to put your 12mm mdf on top of your 4mm ply, instead in between.
It will be a lot stronger and more flowing going up or down.
Dont use any screws or small nails just some old fashion white carpenter glue.

Sinds i am busy with my thinking out loud thoughts:
Have you considered drywall sheets?
I think it will be very effective in sound reduction and as a bonus if you make it wet it will be very flexible for a track to follow if you want it go down or up.

As always following your progress with great interested.
Hello Igor
Apologies for the late reply. Yes, you are most certainly are allowed to think out loud, and thank you for both your thoughts and interest.

You make an interesting point about the ply being stronger if placed underneath the trackbed (12mm MDF). However I'm trying to make these two sections as light as possible so to have the 4mm play pinned/clamped and glued to the edge seems like good use of the edge of the 12mm MDF to have a reasonable area for the glue to bond with the ply, otherwise, I'd need to add batten to the underside of the MDF which would add complication(to a very small extent) and more weight.

Drywall sheets I'm unfamiliar with. I'm not anticipating any problems with MDF which I find generally has sufficient flexibility. In fact I've used MDF throughout for all the baseboards so far, and have had to put bracing underneath every foot (300mm) or so for fear of it sagging/bending(too easily) which can be a bit of a pain. Ply might have been better but it doesn't damp sound as well.

Lastly yes I'll be screwing/clamping and gluing all the joints as you recommend. If the resulting structure is a bit "ringy" then I might try expanded foam sprayed into it to help deaden the sound?
Thanks again for your thoughts and interest in my project.

Kind regards
Andrew
 
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Last edited:
Some experience from mine line of work with those materials:

Expanded foam will dampen the sound a little bit or can even make it worse(due to contact noise).
If you would like to dampen the sound i would suggest rock wool.
Fill the empty spaces with it and the acoustic sound is gone, also the trembling of the sound is completely adsorbed.
This is not the case with any expanded foam (pu, pir, expanded ect).

Trains on your construction will make contact noise and will make air noise, both noises like all noises are trembling/resonating/vibration.
With expanded foam will only counter and not absorb contact noise.
Rock wool will counter both(air and contact), fibreglass wool is a bit cheaper and won't dampen so much as rock wool.

12mm mdf is pretty solid and will help reducing the noise.
What a lot people are placing cork sheets under there tracks, but personally i have no experience with that.
Expanded foam is perfect for modelling landscapes and hills, the foam is very easy to cut

1.png
2.png

3.png


Blue is your 12mm mdf
Red is your 4mm ply
Green is the insulation material
Yellow could be the foam or broken pir sheets.
Grey i have no clue ;)
The 2x1 soft wood and all the 4mm ply ribs are pretty ambitious, i suspect you are going to place fine mash or chicken screen on top of it?
And or cover it with old news papers soaked in wall paper glue, paint afterwards mixed with sawdust?

I am looking forward to see some building and end result photo's.
With best regards Igor
 
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Wow that is nice stuff, regarding price wise compared with rock wool it is pretty expensive.
But you can put your track on top of it without deformation and achieve a big noise reduction.
Easy to model into a ballast bed shape.
Apparently the perfect solution does exist :cool:
 
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What about this product - here

Not self adhesive and only in one thickness but pretty good as sound insulation and has other uses apart from just doing your exercises on :) Not quite the same I agree but useful.

Rob
 
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I read this thread from the beginning on the new Companion. On 28 Dec 2020 Phil O wrote

""Going back just a bit, to those 247 Developments kits, the one marked as being a C15, is described as being a composite and they are normally in the E diagrams, even with a brake. The C diagrams are normally only 3rds. I would be interested to know which bit is correct. It would be great if these kits were to reappear."

I don't think he got a reply about the GWR C15 coaches. They they were built as 2nd/3rd gangwayed composites. When 2nd class was abolished on the GWR by 1910 they became third class only, so they were given a "C" number in the Diagram book pages.
John
 
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Phil O

Member
Location
Plymouth.
Thanks for the info John, I didn't know that the classification changed, when coaches were reclassified.
 
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Hayfield

Member
Location
Essex
Some experience from mine line of work with those materials:

Expanded foam will dampen the sound a little bit or can even make it worse(due to contact noise).
If you would like to dampen the sound i would suggest rock wool.
Fill the empty spaces with it and the acoustic sound is gone, also the trembling of the sound is completely adsorbed.
This is not the case with any expanded foam (pu, pir, expanded ect).

Trains on your construction will make contact noise and will make air noise, both noises like all noises are trembling/resonating/vibration.
With expanded foam will only counter and not absorb contact noise.
Rock wool will counter both(air and contact), fibreglass wool is a bit cheaper and won't dampen so much as rock wool.

12mm mdf is pretty solid and will help reducing the noise.
What a lot people are placing cork sheets under there tracks, but personally i have no experience with that.
Expanded foam is perfect for modelling landscapes and hills, the foam is very easy to cut

View attachment 1286View attachment 1287
View attachment 1288

Blue is your 12mm mdf
Red is your 4mm ply
Green is the insulation material
Yellow could be the foam or broken pir sheets.
Grey i have no clue ;)
The 2x1 soft wood and all the 4mm ply ribs are pretty ambitious, i suspect you are going to place fine mash or chicken screen on top of it?
And or cover it with old news papers soaked in wall paper glue, paint afterwards mixed with sawdust?

I am looking forward to see some building and end result photo's.
With best regards Igor

I have often thought that the way to defeat the noise train movements make on our modern baseboards, is down to the acoustics of the design we use. Yes filling what is basically a big drum with sound supressing material will have the biggest gain, yet this in itself will cause issues in gaining access to point motors and wiring.

In my opinion the diagram misses 2 important items. Firstly closed cell foam between the track and track bed. Secondly the glue we use to stick the foam to the track bed, track to foam and what keeps the ballast in place. In all 3 cases the glue must have some form of elasticity Latex (Copydex being a brand) glue I believe in one of the better solutions, modern composite glues like No Nails also work.

I use Latex as an impact glue to stick the foam to the base boards, coat both pieces with glue, let dry then put together (as you would with Evostick)
To stick the track to the foam I use latex neat (thin layer) with the track weighted down until try, then lay the ballast and dilute the latex 50/50 with water and use a dropper to apply the mix to the ballast. Or use a thicker mix of Latex and lay the ballast at the same time as the track (As you would with PVA), removing surplus ballast when dry

Don't use PVA as it locks everything solid making the sound supressing null and void. The idea is to supress all vibrations
 
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Using the self-adhesive version is so much easier, Track - Latex or PVA ? If you can stand the smell of Latex, then by all means, it is quieter than PVA but PVA sticks better in my opinion. In any event don't use pins, nails or screws.
 
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AndyB

Member
I know it's probably a bit late in the day but you could have considered this stuff
It is basically the same that C&L and Woodlands Scenics supply (if they still do) but cheaper plus you can get it with a self adhesive backing which really helps.

Just keep it away from UV light. I had some on my boat and it didn't take long to crumble into dust :(
 
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I don't know, I purchased some plastic boxes - just the right size for the RCTS's GWR locos series and similar - left one of them next to an upstairs window, and a couple of years or so later when I picked it up, it literally fell to pieces. Three more in a bookcase in the depths of my study where direct sunlight does not reach are OK several years later still.
 
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Matt M.

Member
Location
Australia
Without going into the joys of intricate chemistry (molecules) and physics (bonding), plastics have
a shelf life like most things.

They are very prone to failure due to heat and also UV unless stabilised. The exterior plastics on your
car are usually UV stabilised.
UV absorption in plastics causes photon excitement. This is what happens in your solar panel as well.
In plastic as in your body this creates unstable atoms with unmatched electrons called 'Free Radicals'.
These can bond with other molecules causing large chain chemical reactions which are known as
oxidisation.

Yep, your plastic is rusting.

And like with all rust the structural integrity of your moulded object becomes compromised.

You use different UV stabilisers depending on the type of plastic you are trying to protect.
And the plastic type depends on the end application.
Things like 2,2,6,6-tetramethyl piperidine in various derivatives are good at slowing down
photo degradation of polymers. As is Benzotriazolas which is used in high temperature
plastics like acrylics and polycarbonates.
But nothing totally stops it from happening. Just slows it down.

Direct sunlight and unprotected plastics are a no-no.

Heat is another problem. Thermal degradation.

Sort of like glues the resins that hold plastics together are set at a heat point that gives maximum
bonding strength for a given period, the life of a component. (There are other considerations such as
pressure and flow rates during manufacture and fillers and other stuff added like flame retardants).

There are sintered plastics which are bonded by heat and pressure but not liquified during the process.
You may have met the failure point of those plastics if you had a set of orange coloured drawing rulers
and set squares from the 1970's that turned into a liquid in your desk draw.

There are classes of plastics called thermosetting plastics which are heat resistant and once set cannot be
softened and re-moulded. They will burn however, as all things do given enough heat.

However, continuous heat cycles cause the bonding of the resins to lose elasticity and they become brittle.
If you have pulled the interior trim out of a car made 20 years ago and not broken some of the large
thin mouldings like hatch panels then you have been very lucky.

You also get thermal expansion not just of the plastic but what ever it is attached to. This can cause stress
fracturing.

Most plastic is rated at a 50% loss of original mechanical properties at 100,000 hours (about 10 to 11 years)
of continuous exposure at whatever the particular plastic's maximum operational heat range is.
And engineers are getting very good at working this out. The car industry is fantastic at making
plastic components that last as long as the length of time the majority of first owners of the car
keep the product (otherwise known as warranty period). The failure of engine cooling equipment
at the 100,000 km mark is notable. Water pipes, thermostat housings and overflow bottles are
an almost fast-moving item in spare parts.

Plastics are also vulnerable to other environmental contamination such as bacteria, mould, acidic and
high alkaline atmospheres, and other chemical pollutants.

But in a temperature stable environment, out of direct sunlight the correct plastic should last a reasonable
amount of time.

As to types of foam...

Expanded or extruded polystyrene is a very carcinogenic and a possible neurotoxin.
If you are going to use it hot wire cutting is the best method to trim to size but do it in a well ventilated area
with adequate personal protection. I spent years in the sign industry with this stuff and it is not a joke.
The extruded sheeting for building insulation has the added joy of flame retardants which are developing
a very poor reputation for personal health and environmental damage.

Expanded polyethelyene is better and is resistant to a lot of things. Very stable, doesn't powder when cut,
electrically inert but can hold/absorb water so you may wish to use at water resistant version.
The water resistant versions are the same but do come with added chemicals for cross linking purposes.

For sound deadening under or over a ply substrate you could also look at bitumen or high quality butyl rubber
vibration damping sheets used in the car industry.

Sorry for high-jacking your thread Andrew.

Regards, Matt M.
 
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message ref: 1726

Andrew Duncan

Member
Location
Reigate
Without going into the joys of intricate chemistry (molecules) and physics (bonding), plastics have
a shelf life like most things.

They are very prone to failure due to heat and also UV unless stabilised. The exterior plastics on your
car are usually UV stabilised.
UV absorption in plastics causes photon excitement. This is what happens in your solar panel as well.
In plastic as in your body this creates unstable atoms with unmatched electrons called 'Free Radicals'.
These can bond with other molecules causing large chain chemical reactions which are known as
oxidisation.

Yep, your plastic is rusting.

And like with all rust the structural integrity of your moulded object becomes compromised.

You use different UV stabilisers depending on the type of plastic you are trying to protect.
And the plastic type depends on the end application.
Things like 2,2,6,6-tetramethyl piperidine in various derivatives are good at slowing down
photo degradation of polymers. As is Benzotriazolas which is used in high temperature
plastics like acrylics and polycarbonates.
But nothing totally stops it from happening. Just slows it down.

Direct sunlight and unprotected plastics are a no-no.

Heat is another problem. Thermal degradation.

Sort of like glues the resins that hold plastics together are set at a heat point that gives maximum
bonding strength for a given period, the life of a component. (There are other considerations such as
pressure and flow rates during manufacture and fillers and other stuff added like flame retardants).

There are sintered plastics which are bonded by heat and pressure but not liquified during the process.
You may have met the failure point of those plastics if you had a set of orange coloured drawing rulers
and set squares from the 1970's that turned into a liquid in your desk draw.

There are classes of plastics called thermosetting plastics which are heat resistant and once set cannot be
softened and re-moulded. They will burn however, as all things do given enough heat.

However, continuous heat cycles cause the bonding of the resins to lose elasticity and they become brittle.
If you have pulled the interior trim out of a car made 20 years ago and not broken some of the large
thin mouldings like hatch panels then you have been very lucky.

You also get thermal expansion not just of the plastic but what ever it is attached to. This can cause stress
fracturing.

Most plastic is rated at a 50% loss of original mechanical properties at 100,000 hours (about 10 to 11 years)
of continuous exposure at whatever the particular plastic's maximum operational heat range is.
And engineers are getting very good at working this out. The car industry is fantastic at making
plastic components that last as long as the length of time the majority of first owners of the car
keep the product (otherwise known as warranty period). The failure of engine cooling equipment
at the 100,000 km mark is notable. Water pipes, thermostat housings and overflow bottles are
an almost fast-moving item in spare parts.

Plastics are also vulnerable to other environmental contamination such as bacteria, mould, acidic and
high alkaline atmospheres, and other chemical pollutants.

But in a temperature stable environment, out of direct sunlight the correct plastic should last a reasonable
amount of time.

As to types of foam...

Expanded or extruded polystyrene is a very carcinogenic and a possible neurotoxin.
If you are going to use it hot wire cutting is the best method to trim to size but do it in a well ventilated area
with adequate personal protection. I spent years in the sign industry with this stuff and it is not a joke.
The extruded sheeting for building insulation has the added joy of flame retardants which are developing
a very poor reputation for personal health and environmental damage.

Expanded polyethelyene is better and is resistant to a lot of things. Very stable, doesn't powder when cut,
electrically inert but can hold/absorb water so you may wish to use at water resistant version.
The water resistant versions are the same but do come with added chemicals for cross linking purposes.

For sound deadening under or over a ply substrate you could also look at bitumen or high quality butyl rubber
vibration damping sheets used in the car industry.

Sorry for high-jacking your thread Andrew.

Regards, Matt M.
Hello Matt
A masterclass in plastics and what we can expect from them over extended periods of time is really interesting, so thanks for this Matt, no apology necessary!
Kind regards
Andrew
 
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Andrew Duncan

Member
Location
Reigate
Hello Everyone
I've been preoccupied with a lot of "stuff" of late and come back to see a mass of replies and conversations going on, so apologies for not replying to any of you and in particular Igor, to you for starting this interesting conversation. So briefly thank you for opening my eyes to the downsides of using expanding foam to deaden the sound.

I didn't know, incidentally that there was a difference between Rockwool and glass fibre insulation. Does anyone know where to get rock wool, as opposed to glass fibre?

One other last thought. The reason I didn't use the closed-cell foam type of underlay for the station area is that my experience of using it on Yeovil mk1 was that when building point work, it sometimes allowed distortion of the rail in the vertical plane. This was then quite difficult to correct afterwards.

Kind regards
Andrew
 
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Matt M.

Member
Location
Australia
HI Andrew,

Thank you for the kind words, but really just a footnote to an introduction of plastics.
I have a rough grasp of some of the issues from practical experience plus research
for practical use.

Regards, Matt M.
 
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