glue or screw?

[SteamGene]

Obviously the only way to apply homosote to spline is to glue it.  But how about large sheets as in for a yard or industrial area?  Glue or screw.  My club seems committed to glue, but I'm not sure.
Gene

[Atlantic Central]

Gene,

Where I used large shhets of homosote for yards, etc., I did both, glued it with construction adheasive and attached it with 1-1/4" drywall screws. The screws simply eliminated any need to clamp or weight it down.

Sheldon

[SteamGene]

Thanks, Sheldon.  That makes sense.
Gene

[Jim Banner]

You might want to use screws.  Then if you have to replace it, you just have to unscrew them, rather than trying to break glue bonds.  A club I used to belong to decided to use Homosote under a yard.  Everything was fine until we applied ballast.  Then the Homosote swelled, twisted and warped.  This may have been related to the large area involved.  At least it never happened to the sub road bed under single and double tracks.

[SteamGene]

In this new age of co-operation, bi-partisan ship, and compromise, I glued and screwed one 2x8 and just screwed the rest.  I then noticed that the two sheets are not quite the same thickness.  I imagine I can take stiff construction paper to smooth out the 1/32-1/16th difference. 
In an effort to compensate for one of homosote's problems, I painted the exposed top of each sheet a Virginia clay brown. 
Gene

[lanny]

Gene,

On my layout, I built framework sections from 1 x 4s, used thin plywood (3/8 I think) to cover the open frame, and then glued and screwed Homasote on top. However, unlike Jim's club that had problems with the large yard area, I only used pre-cut 2 x 4 pieces, cutting them in strips, shapes, or using them 'whole' as needed.

I haven't experienced any problems with warpage. However, Jim has a very valid point about removing the homasote if it has been glued. That would be very difficult, perhaps impossible to do if you planned to reuse the Homasote.

One other thing I also found was that there 'normally' seemed to be slight variances in the thickness of the Homasote pieces. I did as you are doing ... shimming with well glued cardstock where needed to even up seams.

So far that has seemed to work well for me.

lanny nicolet

[Hunt]

Gene,
(Psst -- it is Homasote) 

Sealing the Homasote with in expensive latex flat paint makes it less susceptible to warping caused by moisture.

[Steve Magee]

There are alternatives to Homasote and all its water absorption problems, with many other benefits as well. I have been using a concrete joint expansion foam, locally sold as Abelflex but check with your local Home Depot for the US equivalent. It is black in colour, about 10 mm thick, sold in 20 metre rolls and in varying widths from 50 mm to 200 mm. I can curve the 50 mm and 75 mm widths down to 450 mm radius with no surface distortion.

I secure the foam to the sub roadbed (local particle board, or ply) with a white glue called Bondcrete, used in concrete repair - and yes it stays flexible. Just glue it down and align it, it stays in place but you can throw a weight of some sort on it if you are concerned. The track - Peco in my case - is glued to it with the same glue, and temp pinned through pre-drilled holes until the glue is dried (normally about 20 minutes). The pins are "on the draw" and easily pulled.

Some caveats - not suitable for handlaid track, and ideally prewire your track before gluing it in place, and keep your soldering iron away from it - ask me how I know - but these are far outweighed by the benefits - magnificent noise supression and it compensates for shrinkage in benchwork caused by air conditioning or just the fact that timber dries out in time. Even ballasted, the track is still flexible. And it's already at a good height for ballast profile - leastwise it is in On30 ...

Its worth a try.

Steve
Newcastle NSW Aust

[lanny]

Steve,

Hello to you from the middle of an Iowa blizzard ... hope you are enjoying truly beautiful weather in Australia.

You mentioned in you post to Gene ... "keep your soldering iron away from it - ask me how I know -"

Okay ... 'how do you know'?  :-)  <----------- sorry, that was a feeble attempt to be funny.

The material you used and the way you describe it does sound intriguing.

lanny nicolet

[gwfan]

I believe the stuff that Steve is referring to is sold as a foam filler to keep the bugs out of the joint between concrete and base frame of timber houses. You will find it in the building section of Lowes or HD in 20 foot rolls and 6" wide' (Last time I looked it was next to the concrete blocks.)

I would be very interested to know if anyone has used this. I've been debating between this product and the kitchen drawer liner also sold in both stores. Silent running is the goal.

[r.cprmier]

Gene;
Use contact cement.  Take a sheet of AC ply ext glue; and coat the FINISH side with contact cement.  Now, coat the fine texture side of the homasote likewise.   When dry, repreat process.  As an aside, you can also give the plywood a coat of shellac  as a sealer beforehand, but my preference is to use only cement.

When both pieces are dried, lay the plywood glue-side up, put down some slats, usually some 1/2X3X48 or so inches; provably about five, lay the sheet of homasote glueside down on that assembly, square the whole up to your satisfaction; and, without moving the assembly, slide the centre slat out, and you may now use two spring clamps to the centre section.  This holds it together where you want it.  Now, remove the rest of the slats, from centre outward.  I use a rubber roller on the floor and roll the whole thing together.  You can take the clamps out as the contact cement will have grabbed it in place by now.  This sounds like more work then it really is-but it works like gangbusters!  no warpage.  Cut your pieces as desired, and you are ready to go!

One thing I forgot to mention:  I use tortoise machines with velcro@ material as a fastener system; so I di coat the underside with a sealer; shellac, varnish, paint-whatever you have handy that will leave a smooth surface-not flat latex paint.  This provides a smooth relatively non-porous surface for the velcro@ to stick to.

Rich 

[Steve Magee]

Short note to gwfan - the stuff I use is joint expansion foam, not exclusion strip. It is designed to be inserted between concrete slab pours to handle any movement between the slabs.

Steve