I was following some replies on another thread about wood and its properties in regards to humidity and expansion. The posters (Scarpia and Dante) didn't want to hijack the post, but I find this subject very interesting and a potential problem for anyone building a wooden layout. I've been working in construction for 15yrs and have seen many of the problems associated with wood and the mixing of wood products. Some things can be minimized, some not. As far as expansion is concerned on dimentional lumber (2x4s,1x4s etc), problems can be minimized by simply sealing the endgrain with a good oil based paint. Another is putting a barrier between the endgrain and concrete, as a leg to a concrete floor. Easiest thing would be to put button feet under the leg (after sealing it). The right wood to use on concrete is treated wood, but it has many issues for this type work. (expands/ contracts length-wise horribly, corrosive chemical treatment requiring special fasteners) . I have built treated and cedar picket fences for a company for a long time and I have had an 8' 2x4 expand/contract 1/2". Thats excessive, but was brought on by moisture (rain) and drying (direct sunlight). Other issues with wood come from re-sawing, basically ripping a piece of wood into smaller strips. The forces in wood are pushing both directions the length of the board. When the forces are equal, the wood is stable and hopefully straight. When re-sawing, there may be an imbalance of those forces, and the wood starts "moving". One can see this while ripping on a tablesaw. The wood either opens up behind the blade or tries to pinch the blade, or my favorite , the corkscrew. Other problems can come up with uneven moisture, such as a heat source on one side , like strong sunlight, which can have the tendency to cup the board as that side shrinks. I just worked on a wood floor where the person had a woodburner in the basement below the wood and regularly cranked up the temp to warm up the first floor. The result was the wood floor (and 1x10 subfloor) shrinking on the bottomsides, heaving the centers upwards throughout the whole first floor and making one heck of a mess.
That was some of the bad and ugly, but as for the good- wood is cheap, easily cut, readily accepts fasteners, and available everywhere. With a little caution many of the bad things will never occur. One other thing I would recommend is NOT using hemfir over SPF (spruce pine fir). It will be stamped on the board which species it is. HF is very prone for moving around, but from what I understand is slightly stronger than SPF which is really not that important for our miniscule layouts, unless you're parking the car on it.
As for plywoods, OSB and particle board, someone please chime in.
Part of the problem with most dimensional lumber, even the stuff that's kiln-dried, is that its moisture content is too high. A lot of the wood at your local lumber yard was still a growing tree not that long ago. As it dries out, often not very evenly, it will bend and twist in weird ways: I've seen kiln-dried 2"x6"s that looked more like a Mobius strip than a piece of lumber.
Plywood is generally more stable, although entire sheets will "warp", especially the thinner ones. The main drawback to using plywood in place of lumber in benchwork is the somewhat limited screw-holding ability of the edges, although pilot holes will mitigate that.
I prefer kiln-dried pine (1"x2", 1"x3", and 1"x4") for benchwork, but it helps to use only Select or #1 grade - don't even look at strapping grade. I used regular SPF 2"x4" and 2"x6" (kiln dried) for the supporting structure, though, as I had lots left over after building the house. I also added a lot of under-layout shelving, using 3/8" sheathing plywood, for storage of non-train-related household stuff. After 20 years or so, there have be absolutely zero problems with expansion, contraction, warping, etc. The layout is in my unheated, but well-insulated basement.
As for OSB, MDF, particle board, and the like, they may have their places, but, in my opinion, not as part of a train layout. The off-gassing from OSB makes me ill, and most of the wood by-product materials are difficult to cut, don't hold screws or nails well, and don't stand up well to moisture, I did use 1/8" Masonite as facia for the layout, though, and also used it to form coved corners, too. Neither of these applications are of a structural nature.
Wayne
Well not having the expertise and experience that you have working with wood so take this with a grain of salt. My beef with using dimensional lumber is you'll spend half a day at one of the big box stores rummaging through the piles of wood to get a fair amount of lumber that is actually straight You'll have better luck if you go for the higher quality grade wood but now the cost goes up too. My remedy for this problem is plywood. I used to use 1x4 clear pine for bench work I have now changed my preference to 3/4 oak plywood. At $25/sheet you can rip (12) 3/4"x4"x8' lengths of bench work @ a cost of $2.08 per piece
A 1"x4"x8' piece of pine is $3.98 in Lowes. you do the math, no to mention that you will always have nice straight pieces of wood to work with which is really the selling point for me. Nothing worse then trying to work with twisted lumber and when installing risers etc. a little twist translates into problems. Yes the plywood may require one ore step of drilling a pilot hole for when you screw and glue the bench work together but no big deal. I built one section of bench work for the new yard using plywood and I am sold will never use anything else. Only problem is I'm running out of basement.
There's nothing wrong with using the plywood for benchwork as long as you know it's limitations. With 3/4 oak that cheap, I'm assuming it's 5ply. That means a thin oak sheet on the outer plies, and 3 filler plies. The drawbacks are poor screwholding, particularly when you hit a void and none through the ends, and delamination. Those problems can be overcome by using wood blocks, glued and screwed, at the joints if it becomes a problem. Since you're not going for a particular woodgrain/ species for visable appeal, you could also grab birch or poplar plywood if it's any cheaper, it's made the same way with the same fillers. 7ply or cabinet grade would be the best if it's in the budget.
Other than that, the best place to get dimentional lumber is at a lumber yard. They take better care of their lumber, have a much better selection, better service, people who have actually worked with wood before their employment, and can answer your questions no matter how silly you may think they are. Face it, it IS their main buisness, and mailboxes are a secondary thing gathering dust on the shelf. The box stores are all about those mailboxes and lights, with lumber being as important as the 40 different kinds of welcome mats and 20 different plungers.
Just bought a bunch of 1x4x6 at HD for around $2.00 each. Nice dry stuff and straight! If you get to know the people at the big box retailer you can get special treatment like a call when a new batch comes in. If you don't mind stocking the shelf they will sometimes let you got though the pallet, or get a manager involved!
Having a little knowledge of wood I'll chime in on OSB and particle board: OSB is not prone to the warping of plywood, nor is particle board. They are made of bits and pieces of wood and DO NOT have a grain pattern whichis what leads to warping. The grain dries unevenly and causes the warping, take away the grain and theres no warping. Many of the engineered joists that were mentioned in another thread use OSB for the webbing for that reason. One can easily build your own engineered joists for large open spans on benchwork but I wouldn't be inclined to rip either OSB or particle board into lengths and substitue it for dimensional lumber due to it's tendency to crack. I preferr OSB for table top or even cookie cutter benchwork because it is also resistant to expansion and contraction, again no grain. Note that OSB and Particle board do have their drawbacks: they are hard compared to plywood and it's more difficult to drive nails into, particulary small ones like track spikes. This hardness also means it's more difficult to get it to bend but unless you need really sharp transitions this shouldn't pose a problem. They do swell when they get wet and the adhesive that hold it together gets weak but by wet I don't mean humidity but actually wet/puddles, particleboard seems to be worse about this. Neither holds screws particulary well but neither does plywood.
As an aside, when shopping for nice wood it doesn't really matterif you go to a big box or an actual lumber yard. Either one will be, or should be, hesitant to let you rummage through the stacks. But, if you're nice and clean up your mess most will let you pick your boards. Also, for framing straight is more important than pretty so don't necessarily worry about bark on the edges or knotholes.
Question: has anyone tried the plastic boards? There sold as substitues for rough cut 1x cedar trim boards. Rather flexible but could be used to make L girders.
Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction
The composite stuff I've used for decks is not the best and I suspect the rest is about the same. It will not span any kind of distance without getting weak and bending under its own weight, and it's heavy. I've never tried screwing into it, but it is similar to MDF and I suspect it would be ok if drilled first and no torque put on the fastner. I don't think it would take nails well unless you heat the nails and melt them in.
OSB kind of has a grain. Orientated Strand Board has the large chips directed the length of the sheet, which gives it the Orientated part and more strength along that axis. On the back of the sheet, there are stamps that indicate the rated spans and an arrow to indicate the "grain" of the sheet. Supports should be perpendicular to the arrows or the board will deflect easier. They still expand and contract with humidity but is still fairly stable. When measuring a sheet, you will notice it's a little under 48"x96", and thats because it's normally used on roofs and walls and the expansion gap is deducted from the size, so there should be an 1/8" gap all around the sheet when installed. When this isn't followed you see bubble-puckers on the roof instead of a nice flat roof. I would recommend the same gap if using for the layout if you have humidity swings.
I have used OSB as table tops on many things. It doesn't hold nails or screws worth a hoot but takes glues and caulks well, so it could be a good base under a foam scenery. The resins used to glue it together do have a unique smell for awhile, but will go away in time. One could paint the entire sheet and eliminate that and expansion/contraction at the same time by using a good sealing coat of oil-based paints.
i am starting a second layout and am using 3/4" birch plywood for everything. As I am using open grid construction i am making 1x4x 4 foot long strips from a 4X8 sheet to use instead of pine or birch 1x4's. I have an air nailer and I glue the pieces together and nail them which holds everything while the glue dries.. This makes for very strong benchwork. I also use a couple pieces glued in an "L" shape for the legs..
I am using the plywood on the top also . it will hold nails for the track forever.
Anybody still using Douglas Fir?
Conemaugh Road & Traction circa 1956
I believe it's covered under the standard dimentional lumber SPF, Spruce-Pine-and Fir. Guess it all depends on what gets in front of that chainsaw. I do recall putting in some douglas fir beams as well that were specified to be that particular species.
Many folks condemn the box store lumber out of hand. After almost two years in my train room I'm finding (so far!) that the wood is plenty dry and stable so picking through the piles for straight pieces at the store and stacking and dryingthe wood properly will stand most folks in perfectly good stead.
Rushing home with any wood and building with it is a crap shoot. I have little layout experience but a lot of boat and musical instrument work experience with woods. Buy your wood if you can afford to, well in advance of anything else you buy to start a layout.
We've had anywhere from 39% humidity in the room to 80%+ and the track hasn't kinked even though I haven't closed up my power district gaps yet. Thoroughly drying in the room seems to have been the ticket.
I'm "old school" cookie cutter construction. Don't like foam sheets. I'm too clumsy and WILL someday lean on the layout in the wrong area at the wrong time and I don't like the off gassing of plastics in a confined space with no windows.
I also feel that foam can be louder than plywood when running trains. I've done some db meter testing and in cases where the volume is similar, the frequency ranges are vastly different. The higher resonance pitch of the foam irritates some more than the lower rumble of plywood, finding it more manageable. I don't see the light weight advantages if one isn't building a portable layout or dioramas, etc.
I've had several friends who've used the OSB and other similar products and eventually came to grief with severe warpage or moisture containment, etc. They used to off gas formaldehyde but not sure what's used now. Just 'cause you're not smelling anything doesn't mean it's not harmful to you or yours. But then I"m chemically sensitive and avoid all solvents these days. (Worked as welder and paint crew at a shipyard). It's acrylic paints, plywood and carpenter's glue for me.
Raised on the Erie Lackawanna Mainline- Supt. of the Black River Transfer & Terminal R.R.
I have just completed the construction of my benchwork for a large N scale layout in my basement. For the framing I used pine 1 x 4's which I could rip on my tablesaw into 1 x 3's or 1 x 2's as required. The 1 x 4 lumber was purchased at Home Depots in Hagerstown, MD and Charles Town, WV. It was Black Label Clear Pine which they started carrying about 1-2 years ago and is imported from New Zealand. It is clear of knots and is usually pretty straight although you do have to go through the piles to pick out the really good pieces. It's not cheap, but it's far better than anything else they carry.
My local Lowes in Martinsburg, WV carries 1/2" (15/32) Arauco Brand A/C grade plywood that has 5-plies and is usually pretty flat. It sells for $25-26 for a 4 x 8 sheet. I always go down 2 or 3 sheets from the top of the pile to get the flatter sheets. The outer veneer layers are as thick as the interior plies. They also sell this brand of plywood in 3/4" thickness.
All of the new lumber that I purchased for the benchwork was allowed to acclimate in the train room for at least several weeks. The train room is climate controlled so the temperature is 68-70 F year around and the relative humidity varies from 20-30% during the winter months to 50% during the summer months when I control the relative humidity with a dehumdifier.
The lumber yards in my area, at least the ones that are still in business, cater to the construction trades and most of their plywood and lumber is crap. The only lumber yard in my general area that I have found to have good quality 1 x pine lumber is N. Z. Cramers in Woodsboro, MD, for those who live in the area. I bought most of the 1 x lumber for my last layout from them. That was about 15 years ago, but at that time their # 2 pine was better than the "Select" pine that was available at the big box stores or at other local lumber companies. I was in their area a year or two ago and I stopped in to check to see if they still had the same quality of 1 x lumber. It looked like they still carried good lumber. I was thinking about going back there to load up on 1 x 4's until I found the Black Label pine at the Home Depots which saved me a 3-hour roundtrip.
Bob
"With 3/4 oak that cheap, I'm assuming it's 5ply. That means a thin oak sheet on the outer plies, and 3 filler plies. The drawbacks are poor screwholding, particularly when you hit a void and none through the ends, and delamination. Those problems can be overcome by using wood blocks, glued and screwed, at the joints if it becomes a problem. Since you're not going for a particular woodgrain/ species for visable appeal, you could also grab birch or poplar plywood if it's any cheaper, it's made the same way with the same fillers. 7ply or cabinet grade would be the best if it's in the budget"
Totally understand never even considered the # of ply's as being a factor but it makes sense. I would have thought that oak would have been the more expensive choice but at my Lowes Birch was a bit more money and I don't believe they even stocked poplar. I understand about the voids but I'm not overly concerned as I glue and screw everything. I might be overkill but I clamp each section until the glue is dry. Even though I've been pretty luck so far about hitting the grain knock on wood, (no pun intended I still clamp everything mainly just because I have all the clamps. If I may ask a question with running the risk of hijacking the thread, is there any wood glue thats better then the next? I use Elmers yellow carpenters glue and so far have never had an issue with it on any project model railroading or not. One of the clerks was showing me this stuff called "Gorilla Glue" He claimed it the best stuff there is and was explaining you need to wet the wood first before gluing it. Now I know it's his job to try and sell stuff so I can't fault him for that but is there "the best glue" one should use?
Just a couple of bits of info:
Coastal Douglas Fir and Southern Yellow Pine are by far the strongest of the softwoods, but their extra strength is likely not required for the typical short spans of model rr benchwork.
I posed the question regarding use of PVC trim boards for benchwork some time ago but received no response. I have used some 1x2 stock in a weight-bearing application that depends on its screw-holding power and found it satisfactory so far (almost 1 year). It is very easy to work.
Dante
I recently jumped on the ripping plywood into 1x4 bandwagon.
The local HD store has a "special purchase" of "semi-cabinet grade" birch on one side 3/4 for $29.
It is $5 cheaper than the 1/2" of the same style.
I bought it to make some shelves, and then decided to go back for more to do benchwork for my new second level. I have built one "table" so far and it's nice to have no warps and everything exactly the same dimensions. The hardest part is the actual ripping. I have the store cut it in half, and then use a long piece of aluminum channel clamped to the board as a giude for my circular saw. I'm getting ready to make a jig to compensate for the offset of the saw foot, so i don't have to measure every time.
BTW, I have found HD generally has cleaner straighter 1x4 selection than the other place. Of course the oter place is 2 miles and HD is 7 miles.
I also use a counter sink bit which pre-drills at the same time. I used to think this was unnecessary, but changed my mind about a year ago. It makes working with the plywood much easier.
I made a couple of tables for my wife's art projects entirely out of plywood (so the legs are an L shape) following an article that appeared in MR by Jim Hediger for one of the Model Railroader annual project layouts. They appear to be still quite sturdy after several years, with the proviso that they are never moved. But for my own layout, which uses David Barrow style 2'x4' dominos, I used dimensional lumber, some of it bought at an ultra bargain price. I found it pays to take a 6' or 8' piece and really decide how to exact the 4' sides or 2' ends. Some pieces were suited only to the 2' lengths due to knots and bends.
My own experience is that the very worst quality wood are the 2x2s that I use for legs. And the worst of the worst are the ones I bought at Lowes; I have had better luck at Menards which is strongly present here in the midwest.
Some of those 2x2s are better suited to be used as templates for easement curves! Ripped 2x4s are marginally better for 2x2 legs. I use trusses and gusset plates for the legs for added stability, at least until the freestanding domino is bolted into place (before then I move them around like big chess pieces, which is one of the advantages of the domino approach, although many dislike it due to its overbuilt appearance and lavish use of lumber and screws).
When I started building the dominos I really loaded up on lumber and built dominos as needed. I will say that it is a decided advantage to have plywood and lumber go through a year or two of full seasonal changes properly stored in your basement before using it. That seems to minimize further warping. But not everybody procrastinates like I do ....
Dave Nelson
I agree. I have never been able to find straight 2 x 2's at any big box or lumber yard in recent times. Whenever I've needed 2 x 2's, I've ripped straight and dried/seasoned 2 x 4's (another disappearing item) into 2 x 2's on my table saw. I think Dave has hit the critical point about dimensional lumber, you should acclimate it/season it in the area in which it will ultimately be used. If you have time to do this, you will avoid much, if not all, problems with warping of the lumber. When I dry my lumber I stack it on 2 x 4 sticks to keep it off the floor and each layer is separated by additional 1 x sticks to allow for air circulation between the pieces of lumber. Do not stack lumber directly on the floor, especially if it is unpainted or uncovered concrete. The lumber will absorb moisture from the concrete surface. After I've stacked the lumber, I place some weights on top of the pile to help keep the lumber flat.
There are two issues I see with using plywood as lumber. Both have to do with the binder used to hold all the plies together. I have seen plywood (3,5 and 7ply) with thin, missing, inadequate binders applied in construction and the layers will delaminate. Ripping the sheet into small strips does not help that situation and when you take into account that in a L-leg, you are forcing a screw between the plies, essentially putting pressure to seperate that joint. This will be hidden by the opposing piece but will be evident by a bit of a hump around the screw area on the face of the affected piece. The visable piece (the one the screw goes through) will be fine, as the screw is putting compressing forces on the plies.
The next issue is about the strength of the binders between the plies. When making the L-girder, you are gluing an edge to a face. Now understand I'm talking about overall strength, but the edge joint has glue spread across all layers on a butt-joint. Not particularly the strongest joint but all layers are covered and there are things that can be done to strengthen this. The piece that has glue applied to the face is depending on the strength of the binders to keep from being pulled off. The screws can definately help with this as long as the holes are drilled to keep from peeling the plies apart.
As for glues, wood glue is what I would use for any butt-type joints and lap-joints. Gorilla Glue is what I would prefer when putting wood in a daedoed joint. Gorilla glue expands to force itself into the wood and is very strong, provided the joint IS TIGHT. It will act like the expanding foam in a can, and if the parts are not properly clamped and held, will do things you don't want to happen. The foam that expands out of the joint has no real strength to it. I built some I-joists for my layout using luan and 1x2's. The 1x's were economy grade, so they were not the prettiest things out there. I used 1 blade from my daedo set (1/4") and ripped a channel 3/8" down the 1xs and then put some gorilla glue in the slot and put the luan in. It was a snug joint and I then put it in my "clamp". That was a sheet of osb with a stud screwed the length of it, then the I-joists were placed side by side and then followed by a 2x4 (not screwed) and a second 2x4 screwed. I used plain old cedar shims and placed between the 2x4's to squeeze and straighten the joists and left it for the night. The next day I pulled them out and was able to put them together. An 8' piece only weighed a couple lbs but was strong and straight, and will remain that way.
I've gotten all my wood from the big box store, no problem. I spend more, because I buy the precut pieces (I have no room for a table saw nor do I have a vehicle that can carry more than a 6' long piece of wood). Doesn't really matter, because I build all my benchwork as 2x4 foot sections (some will be smaller). For legs - indeed, a straight 2x2 doesn't exists. So I uses a 1x3 and 1x2 to make an L, and I take one of those twisted 2x2's and cut it up into short sections which I screw and glue to the bottom of the leg so I have a place to drill in for the leg levelers.It may not be the cheapest way to buld benchwork but it works, it's solid, and I haven't had any expansion/contraction problems nor have I had any problems with the wood itself.
--Randy
Modeling the Reading Railroad in the 1950's
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