Benchwork - 1x3 or 1x4?

[ksteppe]

I was wondering why some modelers were using 1/2" or 5/8" plywood with the 2" foam.  It seemed like overkill to me.

I'm new and just starting out .. but from a design point, if you are going to use high density foam board, 1/4"  plywood would be more than enough to support the foam and anything you can put on top of it.  My construction plans are for 1x4 sides with steel angle brackets in the corners, 2x2 legs, cross members 24" on center, 1/4" plywood, 2" foam on top.

Just my thoughts.

Kent

[rrebell]

1x4 and just 2"foam, any more is overkill, use the 1x4 as you need to hide things and a 1x3 will not hide a switch machine of many types!

[fwright]

JamesG

The book you mention - on Amazon it is listed for a price exceeding $200??!! Wow, it must be an outstanding book.

I think somebody is being really ridiculous.  Some hobby shops probably still have it in stock (my copy says $14.95).  Kalmbach might even still have it.  The book is How to Build Model Railroad Benchwork by Linn Westcott.  ISBN 0-89024-289-5.  There was both an original Edition and a Second Edition published.  Both have the table I mentioned.  The Second Edition has a little less detail on L-girder construction and a little more (sometimes very little) on foam and modular benchwork.

Regardless, you have some interesting points. I am planning on building a permanent structure and don't really understand a need for the L-girders versus open grid.

Perhaps a trip to the library is in order and I will read Westcott's book.

Open grid and L-girder are really very similar approaches to benchwork.  True L-girder puts the joists on top of the girders instead of between the girders.  Advantages of L-girder are:

• easy to vary length of joists to form curved aisles or layout edges.
• easy to move a joist a few inches to place a switch machine or scenic feature.
• don't have to cut joist lengths precisely for a solid joint with the girder
• easier to locate legs away from layout edge.

Disadvantages are

• thicker layout.  This tends to be important on multi-deck and shelf layouts.
• Personal experience is that L-girder is easier to "rack" when transporting or moving
• slightly higher lumber, screw, and glue costs for the flanges

I tend to use a combination, using L-girders, but placing the joists in between the girders on my 4x layouts.  This gives me thinner benchwork at the cost of some flexibility in layout design.  An example can be seen in this photo.

As I said in the earlier post, the L-girders provide better resistance to warping than straight 1x lumber. 

As for supporting subroadbed, the combination of risers and cleats is the same regardless of whether you used L-girder or open grid.

Fred W

 

[JamesG]

Fred W,

Thanks for your guidance and advice.

The book you mention - on Amazon it is listed for a price exceeding $200??!! Wow, it must be an outstanding book.

Regardless, you have some interesting points. I am planning on building a permanent structure and don't really understand a need for the L-girders versus open grid.

Perhaps a trip to the library is in order and I will read Westcott's book.

[fwright]

JamesG

I am about to start building my benchwork and my research has shown that we often over-build our bench. My 'empire' is HO.

I am going to use Fir as the frame with a 1/2" Birch plywood - all covered with 2" of foam. My layout goes around the room and will be 2' wide and have runs of 10 and 12 feet. I plan on using cross pieces every 16" inches.

So my question to those who may know: Could I use 1x3 Fir? It is almost half the cost of 1x4.

.. James

Frankly, I've never seen any real research or analysis other than the tables contained in Westcott's How to Build Model Railroad Benchwork (highly recommended).  His tables contain the maximum span for a given deflection of various dimensions of lumber.  The rest is all anecdotal evidence - "this worked for me in this particular configuration, so it must be good everywhere".  So I use Westcott's tables.  Now his tables assume large loads (250lb person on top).  For a clumsy person like me that occasionally leans (either on purpose or accidentally) on his benchwork, that's a reasonable level of overkill.

Separating out the subroadbed (plywood and foam) from the supporting structure keeps the issues manageable.  You don't need both 1/2" plywood and 2" foam - either one by itself is good enough for subroadbed on 16" support spacing.  Or go to a combination of glued 1/4" plywood and 1" foam sandwich.

At 7500ft+ in Colorado, wood tends to take on incredible curves as it dries in the thin air.  Using L-girders pits the grain in each piece against each other, which tends to prevent these curves.  So I use L-girders of 1x2 for the joists just to prevent the movement with time.  In more normal climes, this is probably not necessary. 

my thoughts, your choices

Fred W

[hon30critter]

James

I would listen to cacole and Sheldon. It is not so much the price as the quality and stability of the wood. If the 1x3s are half the price of the 1x4s there is a message there. The 1x3s are clearly inferior quality. Given the cost of the model railway that you will put on the top of the framework why risk problems with crappy lumber?

Dave

[ATLANTIC CENTRAL]

JamesG

I am about to start building my benchwork and my research has shown that we often over-build our bench. My 'empire' is HO.

I am going to use Fir as the frame with a 1/2" Birch plywood - all covered with 2" of foam. My layout goes around the room and will be 2' wide and have runs of 10 and 12 feet. I plan on using cross pieces every 16" inches.

So my question to those who may know: Could I use 1x3 Fir? It is almost half the cost of 1x4.

.. James

Well, as a residential designer, experianced old house carpenter, and 40 year model railroader, I'm going to go against the crowd here.

I'm starting a new layout right now, one I am building in modules to allow it to be moved later.

My choice - 1 x 6 poplar with 1/2 furniture grade birch plywood. Poplar is harder, yet soft enough to be easy to work with. It's cost is reasonable, it is plentiful. IT STAYS STRAIGHT. Any exposed areas you later choose to paint will take paint nicely.

It has become the wood of choice for custom milled interior trim for all these reasons and more.

My reason for 1 x 6 is that I plan to make some modules as big as 4' x 6' or 8' and I want to limit flexing as much as is practical. And yes, I've never built a layout that I was afraid to climb on.

Sheldon

[BATMAN]

I think sometimes our lack of engineering skills really shines through when it comes to benchwork construction. We MRRs ( myself included ) build our benchwork like we are building a house.

Everyone following this thread should go and take a good hard look at their layout and try and guess how much weight per square foot we are looking at. I dare say it would measure in ounces rather than pounds per square foot.

Below is a pic of mine. 1' x 4' grid with 2" of foam on top. In the past I have put down a 3 SQ. FT. piece of plywood on top of the foam and all 180LBS of me has climbed on top of that to do some work. There was no evidence I was ever there after I had climbed off.

So why do we need plywood under the foam? Unless you have money to burn you don't. I have said it before that working through foam is easy and working through plywood is easy, but working through both can be a real pain, depending on what one is trying to do. If you want to mount a switch machine or something else underneath, just glue a small square of 1/4" ply to the underside. Covering a whole layout with plywood to accommodate 4 square inches required to mount something is not logical.

1" x 3"s should be fine, but you may find 1" x 4"s cheaper as they are more common in some areas. Plywood is unnecessary unless you have a specific reason to use it. Good luck.

 

                                                                   Brent

 

[selector]

cacole

...

Some recommendations here in the past have been to let the wood cure in the room you're going to build your layout in for at least one month, but even that is not going to prevent it from warping. 

..

 

Chuck, I agree that it won't prevent the wood from warping, but by letting it do that before you cut it and make it non-returnable, you can soon enough detect which of the various lengths should be returned before they become kindling....expensive kindling.  So, I am one of those advocates who strongly suggests that nice lengths of milled lumber, no matter of what description, should be left in their eventual environment for about a full week prior to using them.  That way, the bad eggs can be gathered up when they show signs of turning into pretzels and returned for better ones.

Crandell

[cacole]

The size of the lumber might not be as much of a question as the quality.  Cheaper lumber is not kiln dried and is very likely to warp after you get your benchwork together.

Home Depot and other stores around here have lumber that is so green you can feel the sap in it, and it begins to warp and twist before they can sell it.  It must have been cut no more than two or three weeks ago and immediately shipped without any time to cure.

Some recommendations here in the past have been to let the wood cure in the room you're going to build your layout in for at least one month, but even that is not going to prevent it from warping.  Douglas fir is the worst of all for warping as it dries out, and tends to twist due to the way the grain runs through it.

[JamesG]

Thanks for all the input. This is exactly the type of guidance I was looking for and the advice I need to get my head wrapped around this project.

 

[DigitalGriffin]

WAY OVERKILL.  1 x 3 is MORE than enough for 2' span.

[tomikawaTT]

Quick and dirty rule of thumb:

• If the supports are less than 2 feet apart, use 1x2.
• If the supports are less than three feet apart, use 1x3.
• If the supports are more than 3 feet apart, use 1x4.
• If the supports are more than 6 feet apart, use something heavier (stiffer) like engineered shapes.

My own benchwork is steel, along three walls of a double garage with two wrap-back peninsulas, but I apply the same basic rules.  My 'C act like L' girders are heavyweight 2x4 equivalent, but all of my joists except those adjacent to legs are 2x3 equivalent.  Maximum joist spen between girders is 3 feet.

For my shelves, which have a maximum unsupported span of 2 feet, I lay the 2x3 steel wide side down, which gives me two vertical sides to screw risers to.

Chuck (Modeling central Japan in September, 1964)

[dstarr]

1*3 ought to be plenty strong enough, especially every 16 inches.   My around the walls layout uses 2 inch foam on top of 3/8 inch plywood.  I have 1*4's on all sides of the plywood to stiffen it. 

My layout  is entirely supported by wall brackets.  For the 6 inch and 12 inch sections of the layout I bought brackets at Lowes, for the 24 inch sections I made up brackets out of 2*4 with plywood gussets.   The brackets were installed on every stud, which is 16 inches on one wall and 24 inches on other walls. 

It's strong enough.  I don't climb on my layout, mostly because I don't have to, partly because it would crush the foam,  and partly I fear the brackets might pull out of the studs.  

[BIG JERR]

yes : with 2" foam & i/2" ply double yes,and you could increase your spacing centers (16 " to 20 or more). the two inch pink is very stable in fact you mite consider loosing the ply... your main problems will be from poor graded 1x 3 s or what big ticket stores call economy grade ,they can do some wild warping so be careful choosing and avoid knotty pieces.

another option is consider ripping ply sheets to 1x3 ect ,they will stay petty striate but you must drill a pilot hole if your screwing your frames together. a MUST is use glue at all joints and perfectly SQUARE end cuts (chop saw)regardless of the material.... Jerry

[ctclibby]

Hi

Are you planning on standing on your layout?  Just kidding...  I used 1x2 for the edges, same for the 16 inch center ...um... joists.  With proper support underneath, you could probably stand on that; although at my 240lbs, a 'sky hook' might be a thing to have....

Why 2 inch foam?  1 inch is half the cost and is easier to break.  If you are planning on going below roadbed level, why not create a canyon by lowering the surface to what you need for that 6 or ? inches.  Don't get me wrong, 2 inch high trestles are great. 8 inch high trestles are even better?

I suspect that 1x4 is used because it is common at almost all lumber outlets.  I can NOT buy 1x3 where I live and would have to travel 90 miles to get them, hence the 1x2 design.

ctclibby

[DrgnTrappr]

I just started building the bench work for a moduler layout and I am using 1X3,s with plywood and 2" foam. After posting a couple of questions here I am putting in my cross braces at 24" on center, I was told that this would be plenty of support.

I am sure that others with more experience than me will reply, but I hope this helps.

Ron

[Curt Webb]

I just completed my bench work. I used 1x4's under 1/2 inch plywood. My layout is a stand alone and not supported by a wall. I built a 13x8 ft total area (rectangle shape) in 4 moduules that will be bolted together. Because of the space I have available I had to build 2 access points in the bench work so I wanted to use the larger lumber to support this.

[JamesG]

I am about to start building my benchwork and my research has shown that we often over-build our bench. My 'empire' is HO.

I am going to use Fir as the frame with a 1/2" Birch plywood - all covered with 2" of foam. My layout goes around the room and will be 2' wide and have runs of 10 and 12 feet. I plan on using cross pieces every 16" inches.

So my question to those who may know: Could I use 1x3 Fir? It is almost half the cost of 1x4.

.. James