If you've been following along on the progress of our toy train layout project, you saw on the previous page where we assembled the supporting framework (also known as "benchwork) using a Mianne benchwork kit.  That kit gave us a solid supporting framework for the layout while minimizing how much sawing and sanding we had to do in the train room which also contains my blues bar, Bluejeans Place !  

Now we move on to the next step, namely cutting plywood and Homasote for the layout's top platform.  The plywood provides a nearly level, strong underlayment for the layout and will eventually be attached to the benchwork.  The Homasote, a noise-insulating material made out of cardboard, will be cut from its 4' X 8' sheets and glued directly to the plywood using a construction adhesive. 

A major problem with screwing the Homasote to the plywood is the screws will act as noise conductors. By gluing rather than screwing the Homasote to the plywood, we'll eliminate that problem and keep the layout a lot quieter than the noise usually  generated by O-gauge trains as they roll down the track.   The train track, rail ballast, structures and scenery will be installed on top of the Homasote.

(Quick funny story:  When I was looking for layout materials, I called Piqua Lumber in Piqua, Ohio and innocently asked, "Do you carry Homasote?"  The gentleman answering the phone said, "Sure, what are you building, a train layout or a home music studio?"  It turns out those are the two primary reasons people come to Piqua Lumber for Homasote!)

But I digress.  So, on a very chilly night (45 degree F inside the garage) in early February, inside an hour, Sylvia and I cut the four pieces of 3/4" plywood for the layout's top platform.  Using a circular saw, we cut three down from 4' X 8' to 4' X 6' and the fourth one down to 38" by 6'.

Following that, as you can see here, Sylvia and I painted the plywood on all sides (front, back and each of the four side edges) with some medium dark tan commercial latex paint to seal the wood. 

Why did we paint the wood and, later, the Homasote?  Simple--while our basement where the layout will be located is dry, my local lumber yard and hobby shop friends pointed out to me that any wood or Homasote hanging in the air--as it will be mounted to the benchwork--can absorb natural humidity out of the air, especially the large planar surfaces of the front and back plywood sides.  On a secondary note, by using plywood sanded on one side and painted on both, drilling holes would be somewhat easier since the sanding and painting will help to prevent the drill bit from splintering when breaking through the wood's surface.

Once the cut and painted plywood dried, it was time to mount it to the benchwork. 

We used a combination of the Mianne Benchwork attachment plastic hardware and some small angle irons to make sure the plywood was "tied down tight" for the long term. 

Here's an interesting picture taken of the underside of the layout as we were moving the plywood into place on top for attachment to the benchwork.

We found a ten dollar jointed ratchet wrench from Sears with an extension and a # 2 Phillips screwdriver socket worked great for putting in the various screws.  A power drill helps here at times, but this wrench was the real workhorse for this task.  The socket extension helped prevent some skinned knuckles!

A few minutes later, we attached the second of the plywood sheets to the layout benchwork. 

When we checked these sheets with a level, we found the "bubble" was between the two black lines meaning it was "level".  We had leveled the Mianne benchwork after assembly with only two of the legs needing their adjusters moved up or down.  The few bucks extra for 3/4" rather than 1/2" plywood paid off in spades here when we found no sag and perfect levelness after installation of the plywood.

Part way through the attachment of the plywood, my daughter Christine's dog, Felony, a boxer mix of some sort, decided she needed to inspect my handiwork at attaching plywood to benchwork!  (Where did her dog's name come from?  The dog was an abused animal before Christine rescued her so her name is for "Animal Abuse - A Felony of the Fifth Degree".  But we digress (again)...)  I'm glad Felony's inspection of my work went so well--I wasn't going anywhere fast with 80 pounds of dog standing over me! 

Of course, Lexie, Christine's other dog, wasn't about to let me finish a task without her checking on my work, either!  (I got two barks when I finished screwing in the L-angle.  I guess Lexie thought I did that task right!

With the plywood cut and installed, it was time to plan out where the Homasote sheets would be installed using an idea Jeff Gates, my brother-in-law, passed to me.  Jeff suggested we install the plywood from the layout's front left to right with three 4'X6' sheets, then the smaller 38" X 6' sheet; then install the cut Homasote in the opposite direction so the Homasote would overlay the breaks between the plywood sheets.  My friend Jeff Seymour, an engineer by trade, agreed with this thinking as it would increase the layout platform's strength. 

Back out in the garage, we remeasured and cut the Homasote to size.  Sylvia had the technical jobs -- measuring and cutting; I had the "go-fer" job -- you know -- hold this, get that, plug in the saw, and so forth!     

If you've never cut Homasote 4' x 8' sheets before, notice how we clamped it in place before cutting it.  This noise-insulating material, made from recycled paper, has virtually no lateral strength.  If you don't clamp it in place, it will flop around on the sawhorses as you make your cuts--even if the "go-fer" is holding the loose end where you're cutting!  Measure again AFTER putting it in place to make sure you've corrected any sagging of the Homasote between the sawhorses.  Don't be surprised if extra sawhorses or support is needed--the Homasote flexes very easily when suspended.  Put your mask and goggles on too--the Homasote dust is very fine -- thin like lint, but with the weight and color of greyish talcum powder.  I don't care where you stand, you're going to get a Homasote dust bath by the time you finish cutting four sheets of this material.

To compensate for any minor differences caused by cutting the plywood, we decided to remeasure for the final sheet of Homasote's location.  It was a good thing we did as Sylvia found a difference of 3/4" in width due to the rough edges of other three sheets and the "air crack" between them from the very slightly uneven side edge cuts at the factory.

With the last of the Homasote cut to size, we "dry-fitted" the pieces to the plywood for a couple of days so they could acclimate to the near constant 55 or so degree basement temperature.  This allowed the material to lose any bows or flexes and lay flat.  On the third day, we pulled the Homasote off, laid out Locktite construction glue in a 1/4" bead and glued the pieces into place.  As soon we made the final placement adjustments of each piece, we clamped and weighed the Homasote pieces down to dry in place for three days. 

 While we had a couple of corners that needed an extra shot of glue on Day 2 to stay cemented in place, overall, the gluing worked fine on the first attempt.

On Day 3, we took the weight off the Homasote and removed the clamps. 

As you can see from this final picture before we unclamped the last piece, the surface is perfectly flat and "on the bubble" !

From here, it's a short bit of work to patch the spaces between the Homasote sheets so we have a smooth end-to-end layout surface. 

Click here to see how we dry-fitted the track to the layout.