Hi. If you've read my OP, and since the dimensions are rather small, is it alright to skip the plywood sub-roadbed and just use Homasote, alone (not to be confused with "Home Alone" )? I've never used Homa, but have always heard how well it holds spikes (And I will never, EVER again spike track on plywood !). I'm aware too that Homa can develop dips. The only higher elevation sub-RB (not to be confused with Arby's subs ) is the main line along the back which has a LH switch for the decent to the switchback-tail, half way down, and where it has a RH switch to final decent into main scene at ground zero and where the Homa will of course lay atop the open grid bench...
No , you will need some kind of plywood under it . Homasote is a paper based product and any kind of water that you will use for scenery will warp it if it's not secured to the plywood......Mike
The press for the hobby tends to have trends. You'll see all kinds of things appear as "The one true way" to do whatever it is is that needs doing. Homasote was popular, but it added extra work and weight to a layout. It would be used in place of cork as a sound barrier too. It seems like homasote was also more ideal for handlaid track. The common thought is that you need some kind of sound barrier to absorb motor and wheel noise. Most people use pre-made cork roadbed. Yet these days you can get cheap cork sheet at dollar stores. The Brits tend to favor cork sheet over pre-made on their layouts.
OH, right; water in plaster, acrylic paints, white glue !! Didn't consider that as a detriment to the Homasote ! As this entire layout (except for upper main) will have no shouldered ballast (no cork/foam). It's all secondary and tertiary rail which will be flat on the muddy ground with a flat-ballast depiction. Oh, well, so much for solo Homasote !! Maybe I will use ply, but will glue, instead of spiking the track to it ... I've always used 1/2" ply SRB, but I'm going to go with 3/8" this time and 1x3 open grid pieces. Not really sure yet how it will be supported; Thinking of diagonal 2x2"s from front edge stringers to molding on walls at floor, instead of vertical legs.. Rear stringers will be screwed into wall studs....So tired of wishing for so long to see my engines and rolling stock back out on the rails again; seeing my PowerCab lit up again..I'm sensing a star-up is finally in view, now ! Elvis Presley's "It's Now or Never" is the 'sound track' of my hobby life now !! M, Los Angeles
Mark: I used 1/2 inch thick Homasote only--no plywood or OSB under it--on my first bowl-shaped helix, and the 1 inch wide ramp sagged between the supports (which were at the 8 points of a compass). To prevent sagging, I had to put supports at the 16 points of the compass (longest span between supports at the top of the helix = 7.5 inches. This first helix was in a narrow alcove and I needed to use the narrower ramp to get enough loops in a 44 inch diameter to make the climb. On the next 3 helices, I had more room for the helix footprints, so I used a 1.5 inch wide ramp instead of 1 inch, and I cut the ramps (continuous spirals from the bottom of the bowls to the top) from 4x8 sheets of Homasote and 1/2 inch OSB (AKA wafer board or strand board) screwed together before I cut the ramp. I used stair-step supports at the 8 points of a compass...longest span between the supports at the top of these 3 helices is 14 inches...and I have not had any sagging in almost 15 years. If you put stringers on 12 inch centers along the length of a piece of Homasote forming a 24 inch deep shelf, and if you cut a 2 inch wide Homasote strip which will be lifted up on risers for an elevated track at the back of your shelf, then the elevated Homasote piece will probably need risers on each stringer plus an extra riser screwed into the back frame halfway between each of the stringers. If your stringers are on 16 or 24 inch centers, then you may want to consider adding 16 or 24 inch long cross pieces between all the stringers (so there is support in the middle of the shelf 10 or 11 inches from the front of the shelf) and also at 21 or 22 inches from the front of the shelf (so the back edge of the 0" elevation Homasote is supported). I would encourage you to use the cookie cutter method when cutting the strip for the elevated section because it is easier to make a gradual vertical track easement over 8 to 12 inches from 0% grade (level) to slanted at whatever grade you prefer by bending a single piece of Homasote upward, rather than abruptly changing from level to a grade where the ends of 2 pieces of Homasote meet (one level and the other slanted at the desired grade). [Mark, you probably already know this, but for other viewers who may not, a vertical track easement improves reliability and appearance when track transitions from level to a grade in exactly the same way a horizontal easement improves reliability and appearance when entering a curve on level terrain.] Another reason to use the cookie cutter method to cut the Homasote for the elevated track: when you drop feeders from the elevated tracks, you will be able to drop those wires directly through the frame/grid/stringers (which you won't be able to do if you run your Homasote from the fascia/aisle all the way to the back of the frame/grid)...Yep, the Voice of Experience.
As Mike C correctly pointed out, Homasote is a paper product that is easily affected negatively by water in paints or glues (and, seasonally, even by changes in the amount of humidity in the air). But, I have noticed that any Homasote sheets which I painted on both sides and all edges before installing on my layout, seem much less vulnerable to swelling or shrinkage than my unpainted/unsealed pieces. I also saw a dramatic reduction in seasonal swelling or shrinkage (much more on unpainted than on painted pieces) after we installed a humidifier on our furnace/AC and set the household humidity to a consistent 35% humidity. I suspect Homasote-only shelves will be more likely to sag when large unsupported areas between stringers and cross-pieces are excessively soaked for long periods of time; however, sagging would be less likely, if scenery is added in several small areas that are not near each other, and those areas are allowed to completely dry before starting scenery on the remaining areas.
Homasote does have advantages. But ithas the same problem as Masonite. It has no grain. Plyood does--wood grain going both directions (with layers glued together with grain running 90 degrees from each other), which makes it pound for pound stronger than steel. Because they lack wood grain, none of those pulp products can match plywood for resisting sagging between supports.
Gents, thanks much for all the 'recipes' for success. Yes, I very much have been thinking 'cookie cutter' and am aware of horizontal and vertical easements. I think with all the info thus far I'd better go plywood again. Other than White or yellow glue, is there a better glue that holds Delryn (Atlas) ties ?
I've had great results with a thin smear of clear silicone caulk, but I'm intrigued by John Moore's posts where he uses white glue and if needed, gives it a spray with water and then a short wait before the track comes right up.
On my second layout with homabed, pre-cut road bed. Love the stuff. After its down, I put on one coat of latex paint and it does just great with whatever scenery stuff you can throw at it. Here's a before and after shot.
Kitbash/others, thanks again for the studious suggestions... Since it is a very small space for HO; 2 wings 90 Deg. apart = 2' x 2' in center, each wing tapering to 6" at their ends, I'm now thinking 3/8" ply mostly covered with cork sheets for subroadbed, depicting unshouldered secondary and tertiary track around a few industries. Again, the only shouldered ballast will be the raised main line in rear with a #6 LH switch which begins the descent to the switchback tail, half way down into said industries in frontal areas, with 1x3" framework . Jury is still out on legs or brackets for support. As I too like to look across at trains, not down on them, lowest track will be about level with my shoulders.. Control is NCE PowerCab... A little note to those with same controller: Do not push inward/downward on speed wheel; something we might do when a fast stop is needed and we don't want to do an instant, non-realistic stop with the red panic button.. Pushing inward on the wheel axle eventually ruins it electronically where we, until repaired, can only use the 4 push buttons on either side of the wheel...Better, when panicking TO use the red button..I found out too late. But NCE did send me another wheel/axle free...M
Above should have read #6 RH switch, not LH..'edit' no longer available today. Also thinking all extrapolated foam for entire surfaces/sub roadbed. Main reason is the easability of digging drainage and othe ditches and puddles I never had in prior railroad. I have read about the mess foam makes. I usually am against foam, as I still like the old screen stapled to wood blocks and plaster, method. But it may be time to give it up and go all foam where likely no risers will be needed (upper main line supported instead by layered, foam rocks and hills, and a bridge/trestle here or there..$ is preventing the startup right now... M
