Plywood, OSB or pressboard

[kdk]

What are you guys using, pros and cons?
thanks for the help, im full of newbie questions

[russtrnmn]

I generally use plywood. I have also used OSB.
Like them both. OSB seems to strain my circular saw and dull my blades faster.
Years ago we built a club layout with press board . It was not the best thing.
The building we were in was damaged by a hurricane and got on the layout in some places.
The board expanded and crumbled over time. So we had to replace those areas. Over time the rest got to where it crumbled some.
The main reason we used the pressed boad was it was given to us.

My preference is using 1x4 pine for the framework and 1/4" plywood for the top. I like building my layouts as
modules that are put together so I like the light weight pine and 1/4" plywood.
Someone gave me some 2 4x8 sheets of 1/4" OSB and a 4x8 sheet of 3/8" plywood. So this is what I will use for future
modules.

[ranulf]

I like OSB personally. I use the cookie-cutter method and find it cuts with my sabre saw easily, easier than plywood IMO. It's also much, much cheaper than plywood.

[Michael Whiteman]

My Lionel layout is suppended from the ceiling on 1/2" OSB. I like it because it has no grain and you do not need to be concerned with the possibility of open spaces in the inner layers of plywood that you can not see. It's mostly glue and will kill your saw blade sooner. I like the way plaster sticks to it when doing scenery.

[69Z28]

Great advice from the members. For it's few faults I prefer to use plywood with 2" of blue/pink foam board on top. I also use 2x4's and either/both 18"-24" centers when building benchwork. When it fits the application I usually put my benchwork on wheels for ease of movement to all sides of the layout.

See ya

Ron

[kdk]

great tips guys, thanks

[aussie]

My other hobby is woodworking so when everything in my workshop isn't covered in sections of model railway in various stages of construction I'm creating sawdust. I prefer to use plywood for the base of my layouts. OSB is okay but it does have more of a tendency to warp than some ply. Now you'll note I said some ply. If you can get hold of it the best stuff to use is Baltic Birch which usually only comes in 5'x5' sheets and not the usual 4'x8'. Baltic Birch ply has many more layers than the equivalent thickness ply - no matter the surface layer wood - you'll pick up at a big box store. You'll usually find it at a lumber supply company and most of those will cut it down for you if you don't have a truck or van capable of handling the width. It is a little more expensive than the veneer core ply you'll pick up at the box store but there will usually be no voids and this stuff resists warping like you won't believe. It's why it's used to make many of the templates and woodworking jigs you see in the WW'ing magazines. Oh and you can sometimes get 5'x10' sheets!

Funny story I once knew a guy back in Oz who built a very nice looking HO layout in his garage. I went round to see it and after only 2 months he had the track laid and most of the scenery in place. I was impressed. But I did notice that he had a lot of mdf pieces laying about the garage and lots of dust. When I asked him it turned out he'd used 3/4" mdf as the base for all of the track and risers as well as off-cuts for scenery supports. Yes, he used paper towel dipped in plaster for his scenery and lots of watered down white glue to attach ballast and ground cover! About 2 weeks later I went over again only this time it was to try and salvage as much track and scenery as possible while demolishing the now warped and crumbling layout.

[Komata]

FWIW Aussie mentions MDF and its 'limitations'. My 'main' layout (the 'Kereru Branch') resides in a cabinet made of MDF (not sure of the US equivalent for this material) and the baseboard is also of MDF, albeit with a pine 'spine' running down its length as a scenic divider (although this was added later). The cabinet and layout baseboard all have been sealed and painted with acrylic interior paint, which may in fact (unintentionally) have 'saved' it from the fate of the layout that Aussie described. In the 12 years since it was built I have had no problem with the material (MDF) in respect of 'crumbling' or 'system failure'. BUT I do notice that it is a fairly accurate 'weather indicator' in that when a period of rain is due the baseboard and cabinet will imperceptibly 'swell' as the material absorbs moisture and cause the drawer to 'stick' for several days until teh atmospheric moisture departs. Aside from that, no difficulty has been experienced, due, I suspect, to the previously-mentioned 'protective' paint was applied. And why MDF? Ignorance (I didn't know that it was a 'no-no' for layout construction, because of the aforementioned 'crumbling') and cost - a friend had a lot of it lying around and I could get a good deal for relatively little expense. Knowing what I do now, I would not however recommend that MDF be used for this sort of situation. It CAN be used - but with limitations. . . ' When ignorance is bliss' truly applies in this sort of situation. As I said, FWIW. .

[ww2commander]

It CAN be used - but with limitations

Komata, I will agree with you that MDF is one of those products that keeps suprising me. Having used it when making wargame scenario, I noticed it holds up well when sealed with paint.

I even incorporated some MDF into my current layout for the same reason as you...I just had some available at cheap and felt it a waste to throw away. I did take some precautions in sealing the underside with oil based paint.

Now here is the really interesting part....I am currently cleaning up my second mold attack in the basement (happens every summer) and I noticed that the plywood is not dealing with it well at all....however...the MDF survives untouched and with no significant warping! This observation has done my head in as I figured that the 'crappy' MDF would be the first to suffer but the pieces holding track, the backboard and the fascia have all gone through two moldy seasons without any problems. Of course there is some minor 'warping' in the fascia and backboard, but thats because the plywood they sit on has expanded or shrunk!

I think the leason here is that a properly sealed and protected MDF layout is possible, but you would have to observe very strict rules such as how far apart support braces are placed and what materials you use on it.

[aussie]

FWIW Aussie mentions MDF and its 'limitations'. My 'main' layout (the 'Kereru Branch') resides in a cabinet made of MDF (not sure of the US equivalent for this material) and the baseboard is also of MDF, albeit with a pine 'spine' running down its length as a scenic divider (although this was added later). The cabinet and layout baseboard all have been sealed and painted with acrylic interior paint, which may in fact (unintentionally) have 'saved' it from the fate of the layout that Aussie described. In the 12 years since it was built I have had no problem with the material (MDF) in respect of 'crumbling' or 'system failure'. BUT I do notice that it is a fairly accurate 'weather indicator' in that when a period of rain is due the baseboard and cabinet will imperceptibly 'swell' as the material absorbs moisture and cause the drawer to 'stick' for several days until teh atmospheric moisture departs. Aside from that, no difficulty has been experienced, due, I suspect, to the previously-mentioned 'protective' paint was applied. And why MDF? Ignorance (I didn't know that it was a 'no-no' for layout construction, because of the aforementioned 'crumbling') and cost - a friend had a lot of it lying around and I could get a good deal for relatively little expense. Knowing what I do now, I would not however recommend that MDF be used for this sort of situation. It CAN be used - but with limitations. . . ' When ignorance is bliss' truly applies in this sort of situation. As I said, FWIW. .

It could have been worse. He could have used chipboard!

Komata, I will agree with you that MDF is one of those products that keeps suprising me. Having used it when making wargame scenario, I noticed it holds up well when sealed with paint.
I even incorporated some MDF into my current layout for the same reason as you...I just had some available at cheap and felt it a waste to throw away. I did take some precautions in sealing the underside with oil based paint.
Now here is the really interesting part....I am currently cleaning up my second mold attack in the basement (happens every summer) and I noticed that the plywood is not dealing with it well at all....however...the MDF survives untouched and with no significant warping! This observation has done my head in as I figured that the 'crappy' MDF would be the first to suffer but the pieces holding track, the backboard and the fascia have all gone through two moldy seasons without any problems. Of course there is some minor 'warping' in the fascia and backboard, but thats because the plywood they sit on has expanded or shrunk!
I think the leason here is that a properly sealed and protected MDF layout is possible, but you would have to observe very strict rules such as how far apart support braces are placed and what materials you use on it.

If you use a good undercoat and top coat of paint applied evenly you can seal mdf fairly well but it will still react to humidity. The reason the stuff resists mold better than ply is because of the glue. OSB is the same way. With osb and mdf there's so much glue mixed with the wood the mold can't survive. Ply on the other hand only uses glue to join the veneers.

[ww2commander]

If you use a good undercoat and top coat of paint applied evenly you can seal mdf fairly well but it will still react to humidity. The reason the stuff resists mold better than ply is because of the glue. OSB is the same way. With osb and mdf there's so much glue mixed with the wood the mold can't survive. Ply on the other hand only uses glue to join the veneers.

You learn something new everyday. I always wonder why this was the case...given I dont have a clue about how MDF or plywood is made. So all we need now is a 'super' product that has the best qualities of each product and we are set!.

[Komata]

FWIW: For railway modellers, MDF seems to be the stuff from which horror stories are made - especially the one which says it sags like crazy and needs bracing to within an inch of its life, to even remain viable. My previously-mentioned 'Kereu Branch' baseboard is a single MDF sheet measuring 6ft 3in x 2ft 5in. On top of this is a 'sub-baseboard' of a New Zealand-manufactured soft-wood product called 'Pinex' which is like glued and compressed sawdust and used for building interiors as it provides insulation and has sound-deadening qualities. (Our Australian-originated US/Canadian members might be able to identify the North American equivalent) Because it is a 'fold-away layout, the baseboard has a 7/8in- wide steel strip placed cross-wise underneath it at a point 1ft 11/2in from one end - and only to act as a pivot for the folding mechanism. That is its only 'bracing' as such. When folded out the 'exposed' section of teh 'board is supported by a pole at one end. this being centred at a point 12in in from that end, and another pole placed against the layouts' underside at the back-end of the layout that remains inside the layout cabinet. These 'supports' constitute the only support for the structure, yet there is no visually-evident sag. In my last posting to this thread, mentioned the existence of a 'spine' down the layout. This is relatively new, and was installed after three years of operation, but only as an after-thought as I needed a scenic divider. it effectively has no structural significance for the base-board's support. And the point of all this? M merely to illustrate that it IS actually feasible to use 'unsupported' MDF for baseboards, and that, at least in my experience, it does not 'sag' as of right. I suspect that the 'Pinex' may contribute to this 'lack' but cannot say with certainty that that is the actual case. However, having said that, I wouldn't recommend that you follow my way for a large, fixed-in place layout, as I strongly suspect that the previously-mentioned' 'gravitational effect' would cause some difficulties. And as for 'Bison Board'? It may be where we live, but in New Zealand, the larger scales (Nine-mil Sn3 1/2, NZ120 along with OO/HO and TT) use this extensively, though with the rider that they also use 'Pinex' on top of the Bison board sheets, again with no evidence adverse-effects. As I said, it may just depend upon where you live, although as we have a wide variety of climatic-types in this country, this may not in fact be an accurate assessment . . . It's an 'Interesting' topic

[PhilNSF]

I use a plywood base with 1" to 2" extruded foam on top. I know there's supposed to be no stupid question, but what's OSB? (I haven't checked Widiped** yet.)

[kdk]

Oriented strand board, its made up of strips and chunks of thin wood plys, glued together, heated i think under pressure

[Jason Smith]

I use 1x4 pine framing with just some cheap wall paneling, then 2" of extruded foam on top. If I were to do it again, I wouldn't even use the paneling. Just 1x4 and foam. If you do enough 1x4 bracing, you can mount wires and stuff to it, typically ever 16" or so is plenty for support.

[ChicagoNW]

For my main layout I use 1x3 framing on 24 inch centers. The framing supports 3/16 inch foamcore board. The foam is strong enough to support N scale equipment with no problem. The foam center does not react to water in any way and the paper outside accepts glues and paint wonderfully. I can pick up the 6'x6' layout all by myself. White styrofoam and Woodland Scenics risers make up the hills. Sculptimold is used to smooth out the the white foam terrain and "cast" rocks.

On my traction layouts I just glue 1/2 inch pink foam to 1/4 inch cabinet grade plywood. The layouts are 1'x2' and 2'x4', no framing..

[aussie]

There's all kinds of ways to support the base of your layout no matter whether you use ply/mdf/osb as the base or not. If you use insulation sheet foam as the sub-roadbed then it depends on the thickness of that sheeting as to what center-to-center you space your supports. One trick with using the foam sheets on a shelf layout using the steel shelf brackets screwed into the wall or snapped into a support that's a screwed into the studs/wall is to use a solid material as the front and rear fascia and make sure it's attached to the foam sheets so that it acts as a support for the sheeting. Most wall studs are 16"o/c although you can find some basement installations at 24"o/c or 12"o/c. If you want more support along a wall then screwing a length of ply (or osb) along the wall(s) and securing your benchwork or shelf to that will stiffen everything along the rear of the layout. You can add more than one strip on the wall to allow you to attach brackets with tighter spacing for a shelf layout than the wall studs would allow.

Just remember that before attaching anything to a wall get yourself a good quality stud and electrical finder. Don't go cheap and buy something for under $20 and expect to get even adequate results. The first time you put a screw into a live electrical circuit believe me you'll regret not spending the money on a pro level finder! Pulling that screw back out isn't going to fix the problem either. Unless you go into the wall and see what damage has been done you risk burning down your house especially if the screw caused a fuse/breaker to blow/trip. It's likely you'll need to replace the wiring in that run - you can't just splice a piece in - and that will entail drywall cutting and repair plus pulling new cable from one junction to another. BUY THE GOOD DETECTOR!

[ChicagoNW]

Why don't more electrical codes require armored cable or conduit? If you rewire you don't have to tear the walls apart. Just use the old wire to pull the new one through. Instant built in ground if you use metal junction boxes too.

[ranulf]

Because building codes, like many laws, are created and overseen by the very industries they were intended to regulate.

Any further elaboration on that statement would touch too close to politics to comply with this forum's rules, but suffice to say: Running Romex wire without any conduit is cheaper for the contractors, and there is a general belief (very similar to a general belief in the tooth fairy) that the savings is passed on to the consumer. From a layman's casual glance it seems like a win/win. Whether it actually is or not. Codes DO require a metal plate between the stud and the drywall at places a cable passes through, but it's still possible to hit a cable. Good thing to be aware of.

And with that, I suggest we return to the topic at hand.

[aussie]

Because building codes, like many laws, are created and overseen by the very industries they were intended to regulate.
Any further elaboration on that statement would touch too close to politics to comply with this forum's rules, but suffice to say: Running Romex wire without any conduit is cheaper for the contractors, and there is a general belief (very similar to a general belief in the tooth fairy) that the savings is passed on to the consumer. From a layman's casual glance it seems like a win/win. Whether it actually is or not. Codes DO require a metal plate between the stud and the drywall at places a cable passes through, but it's still possible to hit a cable. Good thing to be aware of.
And with that, I suggest we return to the topic at hand.

We could have a very LONG and frightening thread on house wiring and the codes that are supposed to regulate the industry but that would be getting way off topic.