In the MR Special Issue How To Build Realistic Reliable Track (published in 2009) there was an article entitled “Quiet roadbed, better train sound” by Bob Kingsnorth. He did some wonderful experiment and concluded that “camper tape” under cork was the most effective sound attenuator. Has anyone done additional experimenting? And, last but not least, what is “camper tape?” Where can I get it? What form does it come in? How much does it cost?
Thank you,
The GN Goat Kid
It’s usually closed-cell nitrile ‘foam’ tape with adhesive both sides. Also known as ‘topper tape’, it’s the stuff used to attach caps or the sides of slide-in campers to pickup truck beds.
Wide range of sources online.
What widths does camper tape come in?
GN Goat Kid
You will also get a quieter track by using semi-flexible glues / adhesives rather than traditional rigid adhesives, like white glue …
If you are going to use closed cell foam tape, why ot go all-out and use 3M VHB tape? It would certainly hold a camper-top on!
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It is not hard to get, but you better never want to take it apart again.
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-Kevin
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i read that the major cause of noise is nails between the track and wood benchwork.
I assembled my layout [15 feet by 16 feet] by gluing the track to foam [no underlay] glued to 3/8 plywood [Dap caulking] … I also set the ballast [and ground foam] with a mix of Dap caulking, water, and alcohol …
No rigid adhesives, no nails anywhere , it’s actually rather quiet … 
I use a floor underlayment called easy mat. And it is 3/16 thick, same as cork. Has a peel and stick bAcking. And kills noise. Which is what it is designed to do. I handlay my track and it holds nails very well. Per strip it is cheaper than per strip of cork. Even quiets down pink foam.
You bring up a very good point. I have been trying to find a flexible adhesive that will allow me to reposition the track in the future. Do you have any recommendations?
I had the intention of using topper tap on my current build. I abandoned it. It was too sticky, too hard to shape curves without folding and distortions. It’s not intended for the purpose to which we want to put it. It is meant to be laid straight, not curved.
I don’t have a lofty experience to call on in the hobby, but what I have has taught me that cork is a truly excellent silencer. So is foam. The trouble isn’t those two, even if used in combination for Tim the Tool Man’s ‘more power’. The trouble is that, when we go to ballast, we impose a rigid shell over our silencing foam/cork and creat a sound box that is (enter figure relating to length of ballasted tracks on your layout) long.
If your goal is to have silent, barely clickety-click, running on your layout, you would need to first lay a thin cork sub-roadbed. It should be wide enough to accommodate all your ballast, including double or triple mains wide. Atop that you place your preferred roadbed, even plywood if you wish. Apply tracks, ballast, and you’ll have fairly quiet running. But, if you use an adhesive, and then a topper or usual roadbed, which now has two densities of cancelling sound properties (dual density works best, which I can explain later if you wish), you’ll undo it all with that hard shell of ballast over it that makes contact with the platform on which the roadbed rests.
DAP Alex Plus with silicone. The stuff that dries ‘clear’. It works far better than any of the ‘coloured’ ones, trust me. The stuff that is labeled clear is actually white squeezed out of the tube, but it will dry clear, if very slightly yellow. Most importantly, it is flexible and easily sliced through with an old butcher knife.
The trick, as always, whether using it to fix foam/cork into place, or the tracks they support, is to keep the amount to a minimum. You lay a single thin-ish bead, along the length of roadbed, then smear it thin like paint. That’s all you need.
You can’t really bend it laterally whether it bends or not and preserve the point of using it. You need to cut wedges or notches toward the inside radius, as in bending moldings, or cut and miter-bevel a series of straight pieces and abut them.
Remember this is subgrade, and doesn’t have to be smooth or continuous the way the cork roadbed overlay is. Doesn’t really have to be full side-to-side under the whole width of the bottom of the cork ‘ballast prism’ either, and could easily be tiled or pieced together under the paper track-layout templates. Its purpose is only to attenuate any acoustic energy that makes it past the cork.
An additional question is how transition spiraling and superelevation was handled in this design: do you superelevate the camper tape layer, or just shim the cork on top? I think the latter would be easier and better long-term.
Yes, you’d need an acoustic break between hard ballast and hard scenery. We should take up what methods work and what methods don’t. Is there a reason something like clear silicone in a shaped bead with ballast sprinkled on and then Dullcoted wouldn’t work well enough for this purpose?
I evidently read the same article at some point. I used the camper tape (purchased from Rural King in their automotive/trailer department) as a subroadbed and then laid cork roadbed on top of that. Did not really have problems with curves. I have a minimum radius of 30" on my layout. Plus you can cut the tape and apply in short lengths to avoid any kinking on curves. Super quiet.
wdcrvr
Still building layouts the old way…
3/4" plywood over 1x4 framing, or on suitable risers, homasote or Homabed/Cascade roadbed.
Generally nail the roadbed down with brad nailer.
Glue the track with adhesive caulk, real adhesive caulk, not Alex plus, generally prefer clear PolySeamSeal.
Ballast with via several methods…
Superelevation between roadbed and ties…
Trackage has always been solid and quiet. As someone who builds HiFi speakers, I think the real secret to quiet track is solid, none resonant benchwork.
Sheldon
All of the HO scale layouts that I have built have been framed with 2x4 pine lumber and a 1/2" cabinet grade plywood layout surface. I nail my track down into the plywood surface.
While unballasted track laid directly on the plywood surface has been relatively quiet, there is even less noise when the track is laid on foam or cork roadbed. Add ballast to the track laid on roadbed, and the noise level increases. Glue down the ballast on track laid on roadbed, and the noise level increases more. At least those are my unscientific observations.
Rich
Just my theory, cork and foam are too soft, they allow vibration. They dampen it until you ballast, then the ballast/glue becomes a speaker cone.
More rigid base means less virbration transmitted in the first place.
That’s how we build speakers systems without virbrations we don’t want…heavier, more solid, not soft and spongy…
Sheldon
Well, as I say, those are my unscientific observations.
My theory is that the weight of a loco is so insignificant that the noise factor is hardly noticeable.
Rich
I
Agreed, and that’s where I lost interest. I don’t enjoy much about building layouts, believe it or not; they are a means to an end. When they become too close to a chore, I back off or look for shortcuts. My third layout had a cork-rubber sub flooring underlayment cut in strips, with all them little wedge-shaped gaps cut out of them so that I could lay it around curves. Won’t do that again any time soon.
That was my expectation, and it worked rather well. In fact, I had 5/8" plywood cut into sub-roadbed, and intended to have that ‘dual density’ factor imposed by the cork/rubber which became the roadbed. The plywood was surprisingly quiet already. Once it was all ballasted, I found it to be quite quiet.
Thanks, and much appreciated.
There’s a product out for Christmas that boasts you can apply it to a wide range of items and surfaces to turn them into Bluetooth speakers. Toy dump trucks, coffee tables, windowpanes … “it’s a speaker!” (Carefully ensuring on the package there’s no note about plus or minus 3db 50-15000Hz or whatever [;)]
I promptly thought about something we did in college with a dorm neighbor prone to blasting loud music from time to time. There was apparently a product called a ‘wall driver’ that would convert an area of sheetrock wall into a kind of flat-plate speaker ‘cone’ – we decided that a reasonably large voice-coil linked to a stud or nail could, as my roommate picturesquely put it, ‘turn the whole wall into a large defective woofer’. For the purpose necessary, it performed almost astoundingly well. But it soured me on any future tolerance of amplified running noise in model railroading via a similar effect…