Which thickness plywood to substitute for 1X4 and 1X3 pine?

[Capt. Grimek]

I tried a search but didn't find this: What thickness of plywood would
one substitute for 1X3 and 1X4" pine for L girder construction?
Would you use 3/4" ply for the equivalent thickness of a milled 1" board
or can you get by with less thickness?

Any general rule of thumb for how much more expensive it would be overall to use ply instead of pine for an 8'X16' space. (Most likely will be
3o" average around the room layout.)

Is the difficulty of screwing and cutting into ply worth using over pine if the house
is reasonably even humidity/temp. throughout the year?

Thanks.

[jamnest]

I use 3/4" plywood which I have the lumber yard rip into 3 1/2" wide strips to use for 1x4 lumber in constructing my benchwork. 

I ususaly leave written instructions for the lumber yard how to cut the plywood.  I use domino benchwork and to make things easier I had them cut a 2 x 4' section off of the plywood and had them cut the 4 x 6' section into 3 1/2 boards.  Since my modular sections are 6' long this made construction easier.  I told them to cut the scrap 2'x4' section into 1x4s.  They cut it into 4" wide boards which was too wide. 

Don't assume the guy in the lumber yard knows what a 1 x 4 board is.

[dstarr]

I tried a search but didn't find this: What thickness of plywood would
one substitute for 1X3 and 1X4" pine for L girder construction?
Would you use 3/4" ply for the equivalent thickness of a milled 1" board
or can you get by with less thickness?

Any general rule of thumb for how much more expensive it would be overall to use ply instead of pine for an 8'X16' space. (Most likely will be
3o" average around the room layout.)

Is the difficulty of screwing and cutting into ply worth using over pine if the house
is reasonably even humidity/temp. throughout the year?

Thanks.

I would not recommend using plywood to make L-girders.  The grain in each layer of plywood runs at 90 degrees to the grain in the adjacent layers.  When you rip plywood into strips (say 1*4 for an L-girder) you get a strrip with half the grain running the wrong way.  A strip of plywood has only half the strength of a same sized piece of dimension lumber (plain pine).   

   I wouldn't worry too much about shrinkage and swelling of ordinary pine indoors.  Most of the shrink/swell happens across the grain.  The length of a piece doesn't change much, and for L-girders it's the length that counts.  One trick is to bring the lumber home and store it in the train room for a few weeks before making bench work from it.  The lumber's moisture will adjust to the room humidity and the size will settle down.  Most lumber is kiln dried and comes out of the kiln very dry indeed.  It usually picks up a fair amount of moisture out of the air after it leaves the kiln.  Let it aclimatize to the humidity of your train room and it won't move much afterwards.

I assume you understand that dimension lumber never measures the full dimension?  A nominal 1 inch board always measures 3/4", and a nominal 2" board always measures 1 5/8 "?   

 

[BurbankAV]

3/4" ply would be a smart choice -- the cost savings of stepping down to 1/2" isn't worth it.  As far as cost relative to pine, unless you're working in oak-faced ply, you should end up saving some dough by using ply.  Figure on getting about 100 linear feet of material from a sheet of ply (12 strips, 8 feet each).  I did this with nice Arauco-faced ply at around $30 a sheet, and figure I paid somewhat less than for pine (would have been around $50.)  With pine, you'll also have to spend a good amount of time making sure you're getting good stock -- no absurd warp, twist, bow, checking, knotting, etc etc etc.

As far as working with the ply, any half-decent circular saw or skilsaw will turn a 4x8 into a pile of furring strips in just a few minutes.

I used box-frame construction, rather than L-girder, because my layout is pancake-flat, but one thing that I tried and I've been extremely happy with was the use of pocket-hole joinery.  This gives a nice clean look, with a super-strong joint, and no splitting at all.  Drilling the holes is an extra step, but then, so is drilling a pilot hole in any other type of contruction.

My blog is horribly outdated (I think I only did three or four posts) but you'll find one or two half-decent photos there, if you're interested.

Peter 

[markpierce]

I tried a search but didn't find this: What thickness of plywood would
one substitute for 1X3 and 1X4" pine for L girder construction?
Would you use 3/4" ply for the equivalent thickness of a milled 1" board
or can you get by with less thickness?

Any general rule of thumb for how much more expensive it would be overall to use ply instead of pine for an 8'X16' space. (Most likely will be
3o" average around the room layout.)

Is the difficulty of screwing and cutting into ply worth using over pine if the house
is reasonably even humidity/temp. throughout the year?

Thanks.

I would not recommend using plywood to make L-girders.  The grain in each layer of plywood runs at 90 degrees to the grain in the adjacent layers.  When you rip plywood into strips (say 1*4 for an L-girder) you get a strrip with half the grain running the wrong way.  A strip of plywood has only half the strength of a same sized piece of dimension lumber (plain pine).   

 

Huh?  I've always found plywood to be stronger and more stable than the same-sized solid wood.  Plywood wins "hands down" for benchwork.

Mark

[jrbernier]

  I have to agree with Mark - I used 3/4" plywood for my benchwork(I had the lumberyard cut it into '1x4' strips).   Much better for dimensional stability, no warping, and very clean.  I have a pair of 25' 'L' Girders I fabricated and they have been buried in the layout for 20 years now!

  The 'down' side is that you need to pre-drill all of your holes for wood screws.  Even 'drywall' screws have trouble 'biting' into the stuff.  The cost was cheaper than stock dimensional lumber when I did this in 1988, and is still less expensive now.

Jim

[ARTHILL]

two other little things:

1. It is almost impossible to screw into the edge of plywood, making L girder construction troublesome.

2. Do not conserve on money and buy wide pine boards to rip down to size. They will probably warp some much they won't work. Pick straight boards the right width, (that make take some doing.) If you can buy at an indoor lumber yard, they will stay a little straighter after you get them home.

[tomikawaTT]

If in doubt, use steel!

Specifically, steel studs.  They are totally standard in size, come with built-in screwing flanges, do not react to changes in humidity and are dead-easy to cut and join.

My benchwork (for a double garage filler with attached-table peninsulae 5x12 feet in extreme dimensions) is all fabricated from steel studs - nominal 2x4 heavy-gauge for C-act-like-L girders and nominal 2X3 for joists.  Risers are cut from either 2x3 or 2x4 material, some with flanges at different levels to support roadbed at two different heights on a single riser.  (Riser flanges are formed by bending the edges and/or main web of the stud 90 degrees after cutting into tabs.)  I have also made long bridges for hidden tangent track by laying it inside steel studs, rain-gutter style.  (The same technique is used for making detachable cassettes for swapping consists in hidden staging.)

Tools required?  Small square, tin snips, drill (and bits,) power screw driver and lots of clamps.  Cost?  Less than any decent grade of comparable wood here in the dessicated desert.  Weight - a fraction of the same structure in wood.

This may not be the best material and technique for everyone.  It works for me.

Chuck (modeling Central Japan in September, 1964)

[Capt. Grimek]

Thanks guys for all of the very detailed/concise answers. They are very helpful.
I hadn't thought about the grain running different directions in ply. Only thought about the glue laminations and dimensional stability as positives.
I am definitely going with L girder construction so if there are any additional tips regarding drilling/screwing into the edges of ply they'd be appreciated. It's good to know that using ply can be cheaper than dimensional lumber too. That seemed to vary based on where I shopped around.

I used pine 1x4s on my flooding cellar layout benchwork 18yrs. ago and it seemed to hold up fine (amazingly) and it's always damp down there and gets to freezing in the winter, so I'm not " too" paranoid about using pine upstairs but wanted to hear from both sides while I'm still in the track planning stages for some time to come.

I wondered about buying from outdoor lumber racks as opposed to Home Depot, etc. I'm asking now, because I'm thinking about starting that stockpile in the layout room now before the track planning
gets done. It should be in there for more than a couple weeks maybe a month before any cutting takes place. I do like the ease of working with the pine but if I moved to a warmer climate someday the ply might adapt (or not adapt) easier. All things to think about.

I'll want to construct my benchwork (around the walls-likely a folded dog bone) so that it can be moved
should I ever move so weight is a consideration to some degree. (I want to use a ply top and roadbed base rather than foam.)

Thank you for taking the time to help me out. I appreciate your taking the time.
Capt. G.

[markpierce]

Thanks guys for all of the very detailed/concise answers. They are very helpful.
I hadn't thought about the grain running different directions in ply. Only thought about the glue laminations and dimensional stability as positives.
I am definitely going with L girder construction so if there are any additional tips regarding drilling/screwing into the edges of ply they'd be appreciated.Capt. G.

In addition to screws, also use a good wood glue (carpenter's yellow glue?), particularly where there is a sheering force, but not where you might need to move a particular frame member.  So, you would probably want to use glue (as well as screws) when constructing the individual girders, but probably not use glue elsewhere.

Mark

[markpierce]

Oh, and use a good grade of plywood.  One without air pockets.

Mark

[ramoutandabout]

hve you thought about MDF i think its called. a compressed wood its great for benches too.  They use it in (dream plan build vol 8 ) step by step  building l-girder bench work.

 

ray

[BurbankAV]

I hadn't thought about the grain running different directions in ply. Only thought about the glue laminations and dimensional stability as positives.
I am definitely going with L girder construction so if there are any additional tips regarding drilling/screwing into the edges of ply they'd be appreciated.
Capt. G.

 

That's the advantage of pocket holes: your screwing out from the "edgegrain."  The joints are very strong -- Kreg Tool claims they're 35% stronger than mortise & tenon. 

(Sorry for the lousy quality -- I refer to it as an "iBlur")

But as you can see, you can create just about any type of joint with this system -- I'm even using it to attach my sub-roadbed!  [I realize that I sound like those guys whove just gone to DCC and rave about how they'll never go back.  But really -- I'll never go back!] 

Peter 

[dstarr]

 Up here in the northwoods we have two Borgs (Home Depot and Lowes)  and one real lumberyard.  The Borgs are price driven and so the lumber they have tends to be pretty low grade, lots of knots, twisty, and ugly looking.  The real lumbryard has much better lumber, prices as good as or better than the Borgs, and they deliver.  The 4*8 sheet goods will NOT fit inside my car, and since Detroit left off rain gutters, roof racks are kinda precarious.  And expensive.  A Thule ski rack goes for several hundred dollars. 

  I'm half way thru an around the walls layout.  It's very thin in places (6" wide).  The idea being to get dual use out of the downstairs guest room, trains and guests.  My bench work is 1/2" plywood with a frame of 1*4's around the edges.  I dado the 1*4's to accept the plywood, and the rest of the joinery is plain butt joints. The plywood center stiffens the 1 * 4 outside frame and the resulting unit is strong, stiff and light.  Most of the strength comes from carpenters glue in the dado joints. 

  The entire layout is supported by wall brackets screwed to the studs.  No legs.  It it good and stiff, also good and level.  I got a Zircon electronic stud finder at Walmart and was able to hit every stud, first time.  I'm nearly ready to start doing roadbed.  I will try making my own from white pine with a bandsaw.  The pine will take track nails and spikes if I get the time to do some hand laying.  If that doesn't work out, I will back off to cork and put the flex track down with latex caulk.

 

 

 

[pkeppers]

two other little things:

1. It is almost impossible to screw into the edge of plywood, making L girder construction troublesome.

 

 

I dont agree with this.  I have a large layout built entirely with 3/4 plywood ripped into 3 1/2 inch strips (3" for the upper deck).  As in LOTS of benchwork, and it is all joined by drywall screws, not corner blocks, biskets or glue.  Drilling holes IS necessary but you will often split pine if you dont drill holes too.  Getting the size of the drill hole right is more important too.  Too small and it splits, too big and you dont get a good bite.

 

However, done right it works great.

[dmitzel]

This is a really timely thread for me, guys. I've had some 3/4" Birch ply 1x4's sitting in my layout room for a couple of years now - just haven't had the free time to get going on the "Big One." HD had a special on 3/4" Birch 4x8's back then - I bought seven sheets - and ripped five of them into 1x4's (well, 3/4"x3.5"x8' actually) with the help of an old MRR buddy.

I've been meaning to get started with a shelf around two of my basement walls (20'x12.5') but needed an idea how to best assemble the eight-foot ply 1x4's into box frames that can hang off the drywall, anchored to the studs underneath. This thread has more ply-benchwork ideas than the Kambach benchwork book I have in my library.

Now, to just get the motivation needed...

[jackn2mpu]

 Up here in the northwoods we have two Borgs (Home Depot and Lowes)  and one real lumberyard.  The Borgs are price driven and so the lumber they have tends to be pretty low grade, lots of knots, twisty, and ugly looking.  The real lumbryard has much better lumber, prices as good as or better than the Borgs, and they deliver.  The 4*8 sheet goods will NOT fit inside my car, and since Detroit left off rain gutters, roof racks are kinda precarious.  And expensive.  A Thule ski rack goes for several hundred dollars. 

  I'm half way thru an around the walls layout.  It's very thin in places (6" wide).  The idea being to get dual use out of the downstairs guest room, trains and guests.  My bench work is 1/2" plywood with a frame of 1*4's around the edges.  I dado the 1*4's to accept the plywood, and the rest of the joinery is plain butt joints. The plywood center stiffens the 1 * 4 outside frame and the resulting unit is strong, stiff and light.  Most of the strength comes from carpenters glue in the dado joints. 

  The entire layout is supported by wall brackets screwed to the studs.  No legs.  It it good and stiff, also good and level.  I got a Zircon electronic stud finder at Walmart and was able to hit every stud, first time.  I'm nearly ready to start doing roadbed.  I will try making my own from white pine with a bandsaw.  The pine will take track nails and spikes if I get the time to do some hand laying.  If that doesn't work out, I will back off to cork and put the flex track down with latex caulk.

 

 

 

David:
I too was severely disappointed with the 'quality' of wood available at Home Desperate and ended up going to a regular lumber yard that deals with both professional construction people and Joe Public. Paid a little more, but worth. And as you, a 4x8 wouldn't fit in either my car or my wife's. So I had the yard cut down the 4x8 to the sizes I needed (a 2x4 foot section off the length, and then split the remaining 4x6 foot section down the long side to a pair of 2x6 footers). Those I was able to fit into my car through the trunk and folding down the rear seats. Even if you can't fold down the seats, you can always use bungee cords to hold the trunk lid down and let the wood overhang the rear of the car.
For putting things together, I used the 2-drill method. Have a countersink/bore bit in an electric drill and a screwdriver bit in a cordless drill. Even with cutting the pine used for the frame, I was able to assemble and skin a 2x6 foot section in 30 minutes.