Plywood for my grades

Your question is a little confusing - ramps and trusses are two separate things.  Trusses are the triangle shaped units that make up the bridge itself.  Ramps, I'm assuming are the inclines and declines to get up to and down from the bridge.   My apologies if it's me that's off base. 

If you are referring to the inclines/declines unless you have a standard gauge layout I wouldn't use plywood for any grade, especially with fastrack.  It's much easier to use foam and just put the track on top.  For O scale, it looks much better if you use two sets side by side for extra width, especially with track which has built-in road bed like Fastrack.  Here are some pre-made:

https://woodlandscenics.woodla...com/show/item/RISERS

https://woodlandscenics.woodla...how/item/INCLDECLSET

Here is an old picture of my old layout while under construction -  the entire rise up to the bridge was made using the products in those links:

Regards,

Greg

Timothias, I installed the 7/16 “homasote” over the OSB (no plywood) on all grades for a uniform look; where damaged, “homasote” can be painted with a latex dark charcoal (had mixed at Lowe’s) or a lighter color for the Fastrack bed. I utilized 7/16 OSB for strength in all directions instead of plywood, which can get tricky/weak at curves (directionality of plywood layers). OSB throughout. It is strong- I get up and walk around my layout (12 X 24 + large yard) for painting, repairs, maintenance, etc. Generally the distance between supports/bench work does not exceed 30”. If you are not going to be on your layout, then you could use ⅜” plywood instead of the OSB. Maybe 5/16 or full ¼” ply on ramps if supported closely and well. I like the quieting effect of the insulation board; my layout is totally quiet (you hear every feature) in part due to the sound driving down through my open tubular track into the “homasote”. The high-volume resonating noise of Fastrack is well documented here on the Forum. Very difficult to reduce. Someone suggested adding spray foam underneath; the “homasote” may help as well. Too bad for a nice product but Fastrack is too noisy for me. I’m not a scale modeler but Ilike to get close when I can.

Good luck.

Wally

I didn’t see Greg’s suggestions, good ideas but a little expensive.

Wally

I agree with ally.  7/16 OSB the way to go.  Even 3/8 OSB is OK.  

Don't get the OSB wet!

Another reason I used the OSB was because I wanted the space under much of the "ramp" to be open as in concrete/metal supports. I have one long continuous loop with a crossover/"over and under" portion standing above other tracks below.

Wally

On the moisture thing, I used "regular" OSB in 2012 in my basement, no problems at all. There is an OSB-3 (water resistant) that some builders use for exterior underlayment; also read that there is, or to be, an OSB-4. My basement stays around 50% relative humidity year-round.

Wally

Hi Timothias,

Use ramps where you want make it appear like rock or an earthen incline. 1/4"ply is fine. The nominal is like 3/16" or 5mm. Cut one end of the supporting block on a bevel to match the slope of the incline. Then, the wood sits flat on top. You'll never get the splinters out of you after working with OSB.

many do not put deck where the inclines will be. Just attach the supports to the framing crossmembers.

I am not a big fan of homosote. It does provide an easy surface to attach layout objects. It is messy to cut, drill or generally work with. You must seal it with 2 or 3 coats of cheap latex. It will absorb humidity. 
The sound absorption factor of homosote is minimal for FasTrack. Carpet padding works best under FasTrack The thick upgrade type. Just a little wider than the width of the track. Use ballast to hide it.

Check out this build thread for some nice techniques Hidden Pass Junction RR

I use 3/4 inch cabinet grade ply from HD.  I also use a Kreg pocket hole jig and screws to make the joints.  Russ

Some grade work done with 1/4" luan.  (two layers), easier to bend. 

Also I made a little tool for easy setting of my grades.  I wanted a max 2% grade which is a 2 inch rise in 100 inches.  So the piece is 25 inches long and has 1/2 inch block under one end.  I set that on top of the ply with a small bubble level on top of it.  Pretty simple.  Russ

gunrunnerjohn posted:

Don't get the OSB wet!

Ask me how I know this.......Pat..

Sorry this request is off the topic but.....Mike,

Your photos caught my eye as identical to my own layout which is in the planning stage.  Will you share/post  your layout plan with a few dimensions?

regards,  Jim

gunrunnerjohn posted:

Don't get the OSB wet!

There are different grades of OSB.  The OSB stamped  "WATERPROOF" is as good and even better than marine grade plywood.  We use it quite a bit at the marina to rebuild transoms and decking on boats.  You won't find it in the box stores but some of the lumber yards carry it.  

All I can say is the OSB that was used to build most houses in the past 10-15 years must not be waterproof, it's coming apart all over the place.  One only has to watch the news! 

ChiloquinRuss posted:

I use 3/4 inch cabinet grade ply from HD.  I also use a Kreg pocket hole jig and screws to make the joints.  Russ

 

 

 

Russ - how do you like using the Kreg system?

My wife is giving me a set for Christmas and I'm looking forward to working with it.

Orion the Hunter posted:

Sorry this request is off the topic but.....Mike,

Your photos caught my eye as identical to my own layout which is in the planning stage.  Will you share/post  your layout plan with a few dimensions?

 

regards,  Jim

Track layout.  12'8" X 11'8" as pictured. Original/first

First add/remodel. Turntable roundhouse. 

Coal tipple Last addition. 

Camera walk around.    Click on the underlined phrase. 

Mike, Great work and very inspiring!  Thanks for posting.

Jim

Sean -"using the Kreg system"  make a couple of test pieces before doing layout work.  Follow their really good instructions and the system works well.  Having the pieces flat and level to each other is important.  I have not glued any of the joints and it has held up quite well.  The layout is in a room 20x40 and is a triple deck ON30 railroad.  Have fun.  Russ

Sean:  I have had the Kreg System for butt joints for over ten years and have made many bookcases and assorted other projects using it and I love it. I think it works better and is stronger than a biscuit joint. But it does have it's limitations I am currently building shelves for the new train room out of 1x4 pine and it does not do a very good job, the wood is to think and soft. Also follow Russ's advice and make test joints using the same material the finished product is made of.

I appreciate all the input so far.  I went ahead and did some more bench work and added a higher level to remove elevated trusses and have a tunnel.  I have not anchored anything down yet, track or construction.  I will be working on the grades coming up to it next.

Thanks again for all the great ideas and what has worked for you all.