I'm planning a spline sub-roadbed in laminated 1/4" x 1" marine ply strips. (The lower-grade plywoods I can get locally all have too many voids to get uniform curves when cut into 1" wide strips. Hardboard only comes in 1/8" here, and both it and MDF suffer about twice the expansion with humidity as plywood.) On top of that will be a Homabed roadbed followed by wooden ties and code 55 rail, spiked with 0.25" spikes. The Homabed comes in two thicknesses: mainline (0.218") and branchline (0.125"). I think the thinner will be closer to my prototypes (D&RGW & DSP&P). But with a 0.011" rail flange, 0.06" tie and 0.125" roadbed, my 0.25" spikes will be sticking 0.064" in the plywood splines. As the splines are edge-on, they will be going into the plywood's end-grain, which I expect will be soft enough. It will however make it pointless to use a flexible adhesive between the roadbed and sub-roadbed. Anyway, better to go with the thicker Homabed (so the spikes don't go all the way through), or is spiking into the spline sub-roadbed a "normal" thing to do? Thanks, Jeff.
Hi Jeff. I have never had much luck trying to make spline sub-roadbed. I expect it is my lack of talent to do so, but it also has something to do with radii of the curves on my railroad. I guess spline works better and easier with larger radius curves ... I donno. Sorry that I can't be much help with you on this one! As for spikes, it is a typical problem for hand laid rail modelers for the spike to go all the way past the "soft stuff." My personal remedy was to use a micro-drill and pre-drill the spike hole. Just makes more work though. Good luck. Bill
Hi Bill, I was also talking to a carpenter friend today about this. We were mainly discussing the expansion issues, and he suggested using hardboard or MDF for the splines so that the splines and roadbed expanded/contracted at more-or-less the same rate. That way if I spike through, the differential movement won't constantly be trying to loosen the spikes. But, as you point out, spiking through into hardboard or MDF is definitely going to be a pain (and even spiking through into the plywood end-grain might be). So either way, I think I need the thicker roadbed. If it looks too tall, I can always fill in a bit of dirt at the edges of my scenery to bury part of the roadbed. (And once I go with thicker roadbed and don't have the spike-through issue tying the two together, I think I'd lean back toward plywood splines in the interests of a stable-as-possible sub-roadbed.) Cheers, Jeff.
Have you considered using Masonite as a source for cutting those splines? Fellows I know who have tried it, seem to really like it.
Yes, that's what I'm calling "hardboard". (Masonite is actually a brand name for hardboard. Kind of like Kleenex instead of facial tissue.) FWIW, I am leaning back in that direction, mostly because it seems to be more widely used than plywood for splines, and will therefore have been tried in more different environments. Cheers, Jeff.
For anyone else following this (or finding it through Google at some later date), here's a very informative thread I found on the subject: http://model-railroad-hobbyist.com/node/7403 (In particular, don't miss the post from Douglas Meyer on page 3 of that thread.) Cheers, Jeff.
OK. I was not clear on what you meant by "hardboard". Straight on against the finished surface, it can be a bit tough for something small such as track spikes, but on edge it works quite nicely. Glues up easily, in flowing curves and it solid when adhesive dries. Only very minor drawback is ripping it, can be a little dusty at times. If you ever pass through southeastern Ireland, say hello to the ghosts and memories of my Irish ancestors!
I hate to go in a completely different direction...but...what was the reason for splining your curves in the roadbed? I used 1/2" 5 ply finish plywood that I cut to the curves and supported every foot or so with pine to the incline that I needed. Cutting the plywood worked best with a jig saw with downward facing teeth so that the blow out was on the bottom. Finish plywood has a reasonably smooth surface and the 5 ply is less likely to warp. I also painted the bottom of the plywood so as to reduce the moisture that might seep in. Track has been set up for just over a year (which is not much) but we HAD to set it up in our garage (no basement or spare room). Temperature shifts have gone from a low of maybe 10 deg F to a high of 95 deg F. Track still looks like the day that we laid it. I predrilled the ties with a micro drill (Peco flex track has no holes anyways and the holes in the Atlas are too big). Small spikes go right into the plywood easily. I started out using a small hammer with a mechanics drift with a nice flat tip. After a while, I found that I could just use the drift and push the spikes in. Maybe 1 out of 10 will bend over by accident but it is usually easily straightened. I figured that it was a small price to pay for not swinging a hammer. Maybe I am just not understanding what you are trying to do. I am a carpenter though......
Hi stew_d, I think the theory is that splines are better at controlling noise, and give you nice curve easements without having to calculate them or do the bent stick method (the spline itself is essentially the bent stick). I did my last layout with an elevated plywood roadbed. I didn't do any curve easements (that was pre-internet, and research was a lot harder so I didn't know about them). It was a bit noisy, but mostly it just seems like adding curve easements is a good excuse to try out splines. Cheers, Jeff.
Sounds good Jeff. We have not wrapped up the scenery etc. on the layout, but I could definitely see how an elevated plywood layout might act like a drum, especially once you close it up! Make sure to post some pictures on this thread as you progress and experiment! Good luck bud!! Have fun!!! Stew
