Thoughts on optimizing cookie cutter roadbed?

[samusi01]

The more I think about this, the more I lean towards doing masonite splines.

Probably what I'd do... cheap, easy, the only waste will be the sawdust, should allow very nice curves. The CNC option is fairly time intensive for prep and requires access to the hardware, which I am very fortunate to have. It does allow for some very precise work which is nice. The entirety of the present layout was CNC produced, and the general thought would be for the next layout - long may that day be in coming - to use the same technology, provided I am still in the present area.

[CRL]

The more I think about this, the more I lean towards doing masonite splines. The good news is that I don't plan on there being any turnouts on any of the spline/cookie cutter area, so at least I've got that going for me.

I thought about foam, but because of the grade needed, I don't feel I could get the precision needed when cutting it.

Let me explain how I would combine cookie cutter with foam. I’d use the more structural blue or pink foam sheets of at least 1” thickness, but preferably 1-1/2” thick. Trace out the location of your tracks and mark your cut lines at least 1” outside of each edge of your ties. Do not separate the cut roadbed section from the level base foam section which is attached to your ladder frame. Start raising the section of foam roadbed allowing the first few inches of roadbed to form a smooth vertical easement using bamboo kabob skewers pushed through the elevated roadbed at an angle into the flat section in the opposite side every 3 or 4 inches and resting on the flat section on each high side. If course, you’ll need to figure how much rise you need per foot of travel.

Or you can carve your grades out of solid foam... if you’ve got the cojones to pull it off. I’ve done it a few times for moderate distances on mostly straight track but I was working with foam glued over a plywood/Masonite base and used a bamboo skewer pushed down through the foam as a storyboard to measure the height at regular intervals above the hard base to keep the grade consistent. I’ve pulled it off with good results, but I’d rather find an easier method if I had a longer grade to build or didn’t have perfect 360° access to any curved sections. It was a great character building experience though. 

Or you can leave the foam sub-roadbed flat and use the woodland scenics foam inclines to form your grades. I don’t know how they do the vertical easements though.

[nickelplate759]

Woodland Scenics foam ramps work, but do not have vertical easements at all.  That's fixable - at the top of the grade you need to sand the foam to a smooth curve 6-10" on either side of the top of the grade.  At the bottom you need to fill  - I used layers of masking tape, just as I do for superelevation.

The other challenge with Woodland Scenics ramps is the grade choices are somewhat limited - 2%, 3% and 4%.

[Lemosteam]

The more I think about this, the more I lean towards doing masonite splines. The good news is that I don't plan on there being any turnouts on any of the spline/cookie cutter area, so at least I've got that going for me.

I thought about foam, but because of the grade needed, I don't feel I could get the precision needed when cutting it.

Why not just use 1" thick foam and cut it into 1" wide strips on a table saw. These should flex to your min radii and will naturally flow into vertical transitions.  Easy to test with some scraps too.

Attach them to 1x4 risers at optimal locations and use that to position the plan view curve and side view rise as you go.  As long as the 1/4 is cut square at and angled for the grade, and the foam is glued and screwed to that, and the riser is installed vertically, the roadbed will be horizontal at all locations.

[Ed Kapuscinski]

Why not just use 1" thick foam and cut it into 1" wide strips on a table saw. These should flex to your min radii and will naturally flow into vertical transitions.  Easy to test with some scraps too.

Attach them to 1x4 risers at optimal locations and use that to position the plan view curve and side view rise as you go.  As long as the 1/4 is cut square at and angled for the grade, and the foam is glued and screwed to that, and the riser is installed vertically, the roadbed will be horizontal at all locations.

I don't like the fragility of even 1" foam for something like this. Maybe if it was just a couple feet it wouldn't be bad, but it's gonna be around at least half the layout so I want something with some cajones, ya know?

[Lemosteam]

This from the guy who once convinced the world that having an entire layout supported on wall brackets spread 16" apart was OK, LOL.   

Well because you are using risers, you could add as many as needed to support the places you might think would be fragile. Once in place you could use Masonite to form a T or a U under it to support the foam between risers. Because you are using risers, you could add as many as needed to support the places you might think would be fragile.

My concern with Masonite splines is vertical transitions over curves.  It will be difficult to coax even 1 tall Masonite strips into a rise, especially at the beginning of the transition. Also keep a belt sander handy because you will have to clean off the top of the completed laminated spline, all of the oozed glue, etc. , all while trying to keep it level.

[Ed Kapuscinski]

This from the guy who once convinced the world that having an entire layout supported on wall brackets spread 16" apart was OK, LOL.   

That experiment makes me an expert on the subject of using foam in construction! lol

Well because you are using risers, you could add as many as needed to support the places you might think would be fragile. Once in place you could use Masonite to form a T or a U under it to support the foam between risers. Because you are using risers, you could add as many as needed to support the places you might think would be fragile.

My concern with Masonite splines is vertical transitions over curves.  It will be difficult to coax even 1 tall Masonite strips into a rise, especially at the beginning of the transition. Also keep a belt sander handy because you will have to clean off the top of the completed laminated spline, all of the oozed glue, etc. , all while trying to keep it level.

Oh yeah, mechanical sanding is going to be a must.

I have been thinking about what other options exist out there beyond masonite. I feel like it might require a wander around Home Depot at some point to see what might be out there in the trim and insulation sections.

[davefoxx]

I always thought that splines for subroadbed was a lot of work.  When I was a member of the Southbound Model Railroaders' Club in Winston-Salem, North Carolina in the early 1990s, they started construction of a new HO scale layout using splines for subroadbed.  But they used strips of Masonite with small blocks of redwood (if I remember correctly) between the splines to get the proper width of the roadbed, and then they applied Homasote on top for the roadbed.  Those retired men made fairly quick work of it, but it seemed messy, complicated, and difficult to revise.

DFF

[amato1969]

Oh man, splines+homasote, that's old school...  "difficult to revise" indeed!

  Frank

[CRL]

That’s why I love foam construction. Want to make a change? Just cut out a section, insert new block of foam, cut & carve the revision.

[Ed Kapuscinski]

Oh man, splines+homasote, that's old school...  "difficult to revise" indeed!

  Frank

Haha, yeah, this is a homasote free zone.

That’s why I love foam construction. Want to make a change? Just cut out a section, insert new block of foam, cut & carve the revision.

Oh yeah, don't get me wrong, I really do love foam for many, many uses. But in this situation, I just don't think it's the material I want for this use.

The more I look at it, the more I think cookie cutter 3/4" ply won't be the worst solution. It basically has to cover the roadbed under the track visible here, and while there are some curves, I think it could work out ok.

I think I'd much rather work with the jig saw than have to worry about all those splines.

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[Sokramiketes]

For what its worth, I'm a big believer in masonite spline.  Besides the efficient use of material, it's a very positive construction sequence.  I'm not someone who can complete a very precise cad drawing of every track, and therefore every cookie cutter piece of plywood.  Too much measuring and templating and back and forth whatever.  With spline, I draw the track plan right on the plywood base, glue down photocopies of turnouts as needed, then run spline starting at the centerline and working out.  Everything flows.  Everything is a "positive" construction step.

[davefoxx]

The more I look at it, the more I think cookie cutter 3/4" ply won't be the worst solution.

Then, @Scottl's post is what I would recommend to minimize your plywood waste:

Why not rip strips of the plywood and cut angles on the ends to form curves?  Have a strip that is wider for turnouts. The notion of smooth curves on the plywood just seems like a way to waste wood to me. 

I've been contemplating the same thing for a helix.  Just cut the ripped boards at an appropriate angle and almost no waste.  And no printing of the templates.

DFF

[DKS]

OK, so this may have been covered earlier, but you can reduce waste by going with thinner ply and layering it for the curved sections of roadbed. Cut a series of arcs for the most common radii, and overlap them like very long, skinny bricks. You should be able to get a lot of such arc segments out of a sheet of ply with little waste, then glue and laminate them together in overlapping sections to make full arcs for long curves.

Does this make any sense to anyone, or do I need to get my crayons out?

[Jbub]

OK, so this may have been covered earlier, but you can reduce waste by going with thinner ply and layering it for the curved sections of roadbed. Cut a series of arcs for the most common radii, and overlap them like very long, skinny bricks. You should be able to get a lot of such arc segments out of a sheet of ply with little waste, then glue and laminate them together in overlapping sections to make full arcs for long curves.

Does this make any sense to anyone, or do I need to get my crayons out?

Someone made a helix like this recently.

Edit: I found it! If you zooooooom in on the picture you can see the glue weeping from between the layers and at the top of the helix you can see the two pieces overlapping.

https://www.therailwire.net/forum/index.php?topic=26212.msg705287#msg705287