I have tried Joe Fugate’s spline roadbed and vermiculite mix on a testmodule. The problem I have is that the scenery close to the spline roadbed cracks. It’s where the spline roadbed meets the ground terrain. I do not want that to happen on the real layout. How can this be avoided? Look at the picture:
Sure-fire solution - DON’T BUILD SCENERY!!!
(just kidding)[:D]
Maybe you can just groom the edge of the ballast so it covers the crack.
You mean cover it with ballast? Do you think the ballast will crack if I do it that way?
When you put your ballast/grass/dirt down for your scenery, it will hide it. Brush a pretty thick layer of white glue over the crack before applying your ground cover and balast. Mine did the same thing and now you can’t tell.
loathar,
Is this something that will be the same a couple of years down the road? Is it a long time since you did your ballast?
With most any type of scenery mix , did you put it down really thick ? Thin coats with plenty of drying time usually prevents cracking.
I really don’t remember how thick to be honest. It was a long time since I did it.
It might be that the bare wood on the splined road bed is drawing moisture from the plaster mix and causing the cracks. Maybe a coat of latex paint to seal the wood before you apply the plaster would prevent that.
I’ve had some of mine down for about a year and it’s still O.K. Train room temperature ranges from 20F-110F. White glue is pretty flexable even after it dries. The only other thing I could think of is to wipe some latex caulk over the crack.
PS-My cracks are mostly covered by grass and ground foam. Where the scenery meets the ballast along the side of the tracks.
Electro:
I just put a narrow strips of masking tape down over the cracks and ballast right over it. The ballast held down with white glue isn’t going anywhere and in 40 years of model railroading and bonding ballast with diluted white glue I’ve never had the ballast crack later. [swg]
What are you using for your base and how are you attaching it to the spline? If you’re using foam or cardboard strips or any other method that doesn’t have a continuos bond to the spline these areas will always show some cracking. Joe’s method of masking tape or any other mesh or screening glued or stapled to the spline will stop any cracks. We use various methods of scenery base at my club. The layout is a pine spline and 3/4" ply subroadbed mix. The cookie cutter plywood base will never crack, the scenery is attached to the ply and up to the roadbed. The spline, however, has the scenery base of wire screening stapled to the side of the spline. Some areas where the scenery base maybe plywood meeting the spline, or between double track splines expandable foam can be used to fill the void. This foam has never allowed any cracking in 5-6 years. Other odd spots were spanned by stapling screening accross the joint.
This pic shows 3 methods of the attachment. Wire screen is seen at the unfinished area to the left, the ballast between the double track was done with expandable foam and the lower plywood base(to be muddy pond) has mesh tape stapled and glued then plastered over showing the initial coat.
Thanks guys for your suggestions. I think I will try Joe’s method and see what happens.
If that doesn’t work for you, definitely try latex caulk.
Any time two dissimilar materials join, there is a chance of unequal expansion/contraction leading to cracked plaster. It happens in houses too. The caulk has plenty of “give”.
electrolove, most of my home layouts have been small so I have had little occasion to use spline roadbed; I did build a test track using it one time back in my HO days and it worked okay. About twenty years ago I was anticipating the purchase of a new house - it fell through on some technical grounds - and I was designing a layout to fit a 20 foot by 30 foot auxiliary building - that was the ‘technical ground’ - and I was planning to spline my (N Scale) subroadbed. I was in a club one time back in the sixties when spline roadbed was somewhat of the rage and it seemed to work out okay for the new roadbed being constructed on the club layout. I am, at the current time, anticipating a larger space for my next layout and, again, I am giving consideration to splining my subroadbed.
Over the years I have used the tried-and-true Hydrocal soaked industrial-strength paper towels over crumpled newspaper hardshell scenery technique. I have found that the majority of my problems with cracking scenery was caused by using too thick a mixture of Hydrocal; I have, subsequently, developed the practice of soaking my industrial-strength paper towels in a VERY THIN gruel of Hydrocal and letting it dry for 24-36 hours before applying a second coat; scenery construction goes slow with this technique but I have had a minimal of problems for many years. One thing I almost always do before painting my ‘groundcolor’ is I paint a mixture of very thin Hydrocal over the hardshell.
By the way, your photograph accompanying your post is worthy of recognition.
Plaster shrinks when it dries. The bigger the continuous pour, the greater the shrinkage. So does concrete, and many water based construction materials. That’s why building plans usually specify exapansion joints at seams, or the use of expansion controlled grout in critical areas, like under steel columns and between finished tile work joints.
Goop a fillet in that crack with your fingertip and see if it cracks again.
If not, you’re good to go.
If so, you have unrelieved stress, probably due to thermal or moisture induced differential exapnsion/contraction.
My money says the repair will fill the crack for good, but if it comes back, you’ll need to identify, isolate, and relieve the stresses to get rid of the crack for good.
An “expansion joint”, simply covering the crack with ballast, grass, dirt, or shrubs, is one possibility.
Joints at other areas, easier to hide perhaps, may work too.
Patch it first though, odds are you’ll be done with the issue.
Scenery looking good.
Very good.
Where’d that talus/riprap south of the tracks originate?
Brought in frome offsite or blasted off the canyon walls?
As good as it looks “as is”, prototype would have it matching the source in color and texture.
Not easy to do, sometimes, but something to think about.
First class layout, but who are those two scary looking characters on the far side?
Have they been cleared by corporate security?
Great thread [:D] Covers about all the bases. [:D]
Except the crack that just will not go away… even when you’ve taken out all the stresses, filled it, taped it, moved the spline… AAARGH! [banghead][banghead][banghead]
[Edit [#oops] Jeffers_mz mentions covering the crack with tallus… you could also use rip-rap in a suitable location… or, come to think of it, if a ballast cleaner has gone through it may have sprayed out a line of dirty ballast - where permitted - that conveniently covers the crack… and everything else: weeds, bushes, battery boxes, ties and rail at the lineside…]
The solution (short of building a different layout) is to bury it… If it’s small enough plonk some spare ties and/or bits of rail on it. If it’s too big have the MoW gang dig a drainage ditch there.
I guess that, if you’re modelling the San Fransisco area, you could make it an earthquake fracture if it’s really big. Hmm… put this in “humourously” originally… but cuts and fills do get problems with seperation which doen’t always lead to a full scale slip or washout. What they will do is cause remedial work - which might be fun to model. In earlier times this would tend to be cribbing or digging out and back-filling (vile job by hand). More recently a back hoe would do the work -clear of the trains. More recently still “difficult” banks can be grouted by pumping in a slurry of concrete. Some banks get a bonding net put over them and grassed with binding grsses (like sand dunes get stabilised). Sometimes steel piling gets huge bolts through it
I just took another look at the picture…
Brakie will undoubtedly tell me off for advocating covering a crack that close to the ties with anything at all!
Okay, so my ideas work for cracks 6’ (1.8 metres [ish]) from the rail… use a wider spline so that the crack comes where you can hide it?
Actually my first thoughts were to just stuff the crack full of a flexible caulk that takes paint… then I moved on to wondering why it was cracking and came up with the plaster shrinking because of water loss (too fast while drying) and then stress in the spline structure… all of which got covered by other posts.
[sigh]