New layout planned using Mianne Benchwork

I used the 1/2" 5x5 birch multi-ply for mine, it worked out very well with the Mianne benchwork.  I don't know where you're located, but Russell Plywood in Reading PA has the 5x5 sheets in stock.  I believe I paid $25/ea for them, but I didn't have to ship them.

Thanks,  I’ll contact them and order two sheets.  Thanks

Wayne,

I have a 5x9 postwar style layout using Mianne. I contacted Tim and he gave me the dimensions for cutting two 4x8s into three usable sections. They fit perfectly. Yes, I had leftover plywood but actually used some of it for various things.

Maybe not the best solution for you but thought I'd mention it.

I have an around the room layout with Mianne benchwork (it is 30” deep on all sides). I used 4x8 sheets of 1/2” veneer plywood that I picked up in Home Depot. I spent some time figuring the best way to cut the sheets with minimal waste, and they were able to cut them for me to the size I needed. They didn’t even charge for the additional cuts.

You could get two 4x8 sheets, and have them cut to give you two 4x5 pieces. Then have the two remaining 3x4 pieces ripped to 2.5x2.

Keep in mind that a 5X10 layout with the Mianne benchwork actually is slightly more than 5' across, so you really are better off buying three 4 x 8 sheets and cutting them up.  The 5' is measured from center to center of the legs.  I ended up with finger joints between sheets to span the I-beams and not try to hold the material on that narrow beam.

As John states, the measurements are to the center of the legs - this is also the center of the I-beams running between the legs. I choose to use the stated measurements (in my case, that was 30” between the centers of the legs/I-beams). I used 1/2” homosote on top of the plywood, so the resulting edge sandwich of plywood and homosote was a tad bit unsightly, so I used the addition space on the legs/I-beams to add some edge banding to coverup the edges (I assume you could also do this if you ran the plywood to the outer edge of the legs).

I ran the plywood well past the benchwork, that solved the problem of the unsightly gaps.

This is with the fascia installed.

I absolutely love mine easy to work with and no trouble with assembly. Great product.

Size is 10 feet wide by 5 feet deep.  Does that make a difference.

Well, the actual size to the the outside of the legs on the 5' side will actually be 61.75", see what I'm getting at?  On the 10 foot side, it'll be 121.75" to the outer edge of the legs.  The Mianne measurements for the size is to the center of the I-beam, not to the edge of the leg.  So, the 5x5 birch isn't going to make to the edge, if you put any kind of fascia on, you'll have to fill the gap all around the edges.  I ended up cutting a lot of plywood to make things work.  Here's what I mean.

Here's an example of the finger joints to join sheets with no support exactly at the seams.  When you get done, this is as strong as the rest of the sheet, you end up with what is, for all intents and purposes, a single huge sheet of plywood.  The fingers are glued, screwed, and clamped.  When they're done, they're very strong and line perfectly, it's like there's no seam there.

Well,  it sounds to me that if I get two 4x8 sheets I will be better off.  Will this allow me to have an overhang.  Should I assemble the benchwork and then figure out what cuts I need to make.

I'd certainly assemble the benchwork first before cutting the wood.  In order not to have any unsupported seams, you'd really need three 4 x 8 sheets.  Of course, if you use the finger joint method I illustrated, you can just piece the last part together using two 4 x 8 sheets. 

Running the wood to the outer edge of the legs allows you to easily add a fascia.  If you want the wood to overlap past the leg line, then you might consider the construction method used for my layout. New Train Room Finally Getting A Layout!

Blocks of wood were cut to butt against the I-beam and extend flush to the edge of the plywood.  They were then glued with Loctite PL3 Construction Adhesive, stapled and clamped.  When the adhesive cured, the fascia was attached to these and came up to cover both the plywood and the Homasote topper.

Looking at the illustration in Mianne of the Model ST-5x10TSR it appears that the center portion consists of a 4 foot section and the outside portions are 3 feet wide.  I think when I am ready to order I’ll ask Tim what to cut to plywood to so that I eliminate any seams.

If you want it to go edge to edge to the outside of the legs, it'll take three 4x8 sheets to only have the seams over the I-beams.  Truthfully, that's too much work to make happen, the I-beams are only about 5/8" wide!  How much support do you really have with 1/4" of plywood on that narrow beam?  I'm a lot more confident of the strength having the joints.

One other thing, Mianne has you attaching the top only at the legs, but that lets the whole piece of plywood rattle against the I-beams.  Mine are secured to the I-beams throughout the layout.

@gunrunnerjohn posted:

I used the 1/2" 5x5 birch multi-ply for mine, it worked out very well with the Mianne benchwork.  I don't know where you're located, but Russell Plywood in Reading PA has the 5x5 sheets in stock.  I believe I paid $25/ea for them, but I didn't have to ship them.

What did you use for facia on your layout it looks great

@gunrunnerjohn posted:

I ran the plywood well past the benchwork, that solved the problem of the unsightly gaps.

This is with the fascia installed.

Rally like your facia. What did you use?

@WaynePa posted:

Looking at the illustration in Mianne of the Model ST-5x10TSR it appears that the center portion consists of a 4 foot section and the outside portions are 3 feet wide.  I think when I am ready to order I’ll ask Tim what to cut to plywood to so that I eliminate any seams.

I definitely suggest talking to Tim. He sells this stuff, knows it inside and out, and is very helpful. I had a few calls/emails with him after my bench work arrived but before I purchased plywood and moved forward with construction.

@Prewarrkt posted:

Rally like your facia. What did you use?

You can see all the details here: New Train Room Finally Getting A Layout!

The fascia is two layers, the first layer was up to the top of the plywood and is 3/8 3-ply Lauan Mahogany which is very flexible and easily bends around the curves.  The second layer is 1/8" birch ply, also easily bent, it went on after the Homasote was installed and trimmed to match the curves of the plywood.

I was doing a search and found poplar plywood at Lowes.  A 5mm 4x8 sheet sells for $14.98.  Would this be a good substitute for birch plywood which is much more expensive.

@WaynePa posted:

I was doing a search and found poplar plywood at Lowes.  A 5mm 4x8 sheet sells for $14.98.  Would this be a good substitute for birch plywood which is much more expensive.

I would think that 5mm is a bit too thin - you’re talking about a less than a quarter of an inch. I’d stick with half inch. 

One other comment... when it comes to the placement of the seams, John’s finger joint work is incredibly elegant, but I think for a 5x10, there is a much simpler, if less elegant solution - you could cut a length of the excess plywood and use it as a cleat. Screw it on the the underside of the plywood bridging the seam with screws on either side of the seam.

FWIW, Paul, we did that type of joint as well.  The fingers were so very elegant, it was cool to see them used.

As for the 5mm plywood for the base, no way!  The 1/2" birch multi-ply is very rigid, it has 11 plies which will really resist warping over the years.  I can imagine 5mm (0.2") stock could easily develop a washboard look after a spell.

You're spending thousands of dollars on track, scenery, and trains, why try to save $40-50 on the foundation?  IMO, a bad place to economize!

Point well taken

What is the width of the girders.  Could two sections of plywood be attached securely.  I have room for a 5x12.  Would that be easier to put a top on.

The top of the I-Beam is 5/8" wide.  That only gives you a little more than 1/4" overlap for a standard width plywood panel if the span is four feet.  That was the reasoning for not trying to cut on the I-Beam lines and just go with joinery in the open spaces.  Personally, I think it worked out great and made the whole assembly much more solid, and I'd do it that way again if I had it to do over.

I thought there were some fasteners that you could use to join two pieces of plywood together.

You can use biscuits to join plywood, we did that in one place on my layout, just to solve a fit issue.  Here's a page describing Biscuit Joining Basics that will give you an idea of the process.  Note in order for this to work, you have to have a biscuit cutting tool and know how to use it.  However, there are limitations to this type of joint.  A short quote from the previous link I provided.

Biscuits don’t fare well when matched against other joints in wood-joint torture tests. Because biscuits are relatively short, it doesn’t take a rocket scientist to realize that this joint isn’t as strong as traditional mortise-and-tenon or half-lap joints. 

I still think trying to hit the tiny I-beams with the edges isn't a great idea.  The joinery we used for mating the plywood in the open will provide far stronger joints.

Lap joints are superior however when you have to join something on the fly or you need a quickie in a minor stress situation, biscuits are fine.   Additionally, the adhesive utilized will effect the joint integrity.

We have used lap joints on boat ribs and keels however my biggest concern in RRing is a lumbering obese model railroader (me) trying to re-rail a car.

Seaming thin plywood over a narrow beam enhances the total break or lack of linear integrity.   No over lapping plys. 

I once was called out on a platform job where a well meaning handy man fabricated a dozen 4 x 8 platforms and then screwed them together.  There was a peak at  almost every 4 foot seam.  A level rocked over most of the end seams.

And the expert speaks, I'd listen to him.

Thanks John, however,  I'm not really an expert.  I just play one on the forum.

You do an excellent expert imitation Tom, totally fooled me.

John,

You mentioned that the plywood is only attached at the legs and that the I beams will rattle.  Well I looked at the illustration of the ST-5x10TSR which is the layout I plan to build.

It has a total of twelve legs. Four in the front and back and four in the middle.  So, if the plywood fastener hardware is installed on the legs in the center the plywood would be secured in the front, middle and back of the sheet. By my count there would be twenty four screws holding the sheets in place.

That is unless the printout is not what is supplied by Mianne.

Tim also offers some additional fasteners which can be used in between the legs. I have 16 extras which I won’t be using (see pic below). The long end rests under the lip of an I-beam, the short end rests on the underside of the plywood. When you screw up through the hole, it snugs the plywood to the i-beam. If you can use them, shoot a note to my e-mail (in my profile).

@Apples55 posted:

Tim also offers some additional fasteners which can be used in between the legs. I have 16 extras which I won’t be using (see pic below). The long end rests under the lip of an I-beam, the short end rests on the underside of the plywood. When you screw up through the hole, it snugs the plywood to the i-beam. If you can use them, shoot a note to my e-mail (in my profile).

Hi Paul,

reply sent issue with mail.  See my profile and respond.  Thanks

@WaynePa posted:

Hi Paul,

reply sent issue with mail.  See my profile and respond.  Thanks

Sent an email... let me know if you received it.

Hi Paul,

Got your e-mail.  I just logged onto the forum.

Another way to fasten the decking for a permanent layout.  

Position and clamp in place your decking where it is to be located.  Drill two 1/4" holes at a distance in each sheet each over the top of two legs for a temporary  indexing 1/4" dowel.

From underneath the platform pencil lines on each side of each support beam and top edge of each leg. 

Then turn each decking piece over and drill a small (3/32" +/-) hole at the end of each beam centered between the lines.

Replace all the decking over the frame work with the dowels in place.

Locating on the 3/32" holes draw a line  which will be the beam center line, or snap a chalk line.

One by one lift each piece of plywood.  Run a 1/8" to 1/4" bead of silicone on the top of each frame member.

With a gentle clamping force draw the plywood onto the bead and shoot a 18 ga brad gun all along each line every 6 inches.

This will help to eliminate  oil can condition and attenuate sound.

Thot: consider to never use pine decking, three ply plywood, or CDX plywood.

1/2" X 5' X 5' multilevel Birch plywood is a light weight extremely rigid decking of high integrity.  The 60" sizing is complimentary to it's frequent cabinetry use.  Usually never available in big box stores.  Better lumber yards carry or can order it.

If weight is not a problem then my choice is 3/4" X 4' X 8' Advantech,  the new go to in underlay flooring.

@WaynePa posted:

I was doing a search and found poplar plywood at Lowes.  A 5mm 4x8 sheet sells for $14.98.  Would this be a good substitute for birch plywood which is much more expensive.

I used this stuff ("¼ inch underlayment) as decking and it is OK as long as there is a joist about every 12 inches. I went the heavy-framing, light-decking route but if doing it over I would go with Tom and GRJ's ½" Birch plywood on much simpler lighter benchwork. This because my Pike is an around-the-walls "shelf" layout with two corners brought way out into the room such that there needed to be some crazy benchwork for support of the thin decking. ½" Birch would span much better and nor require a bunch of angle joists.

Tom recommended the Advantech to me, but the weight of a 4x8 panel threw me off, that 3/4" 4x8 weighs 78 pounds.  The 5x5 1/2" birch multi-ply weighs 38 pounds.  I figured the birch would be easier to work with, I can actually flop those around pretty easily.  The birch panels were actually fairly reasonably priced, they were less than $24/ea.  The difference in the price of quality wood and cheap plywood for the whole layout was around $150, seemed like a no-brainer for me!  The 5x5 panels were also much easier to handle and cut to size.