Sure-fire solution - DON'T BUILD SCENERY!!!
(just kidding)
Maybe you can just groom the edge of the ballast so it covers the crack.
Mark P.
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Jerry SP FOREVER http://photobucket.com/albums/f317/GAPPLEG/
electrolove wrote: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?
I've had some of mine down for about a year and it's still O.K. Train room temperature ranges from 20*F-110*F. 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.
Joe Fugate Modeling the 1980s SP Siskiyou Line in southern Oregon
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.
Modeling B&O- Chessie Bob K. www.ssmrc.org
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".
The mind is like a parachute. It works better when it's open. www.stremy.net
From the far, far reaches of the wild, wild west I am: rtpoteet
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.
bogp40 wrote: 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.
First class layout, but who are those two scary looking characters on the far side?
Have they been cleared by corporate security?
Great thread Covers about all the bases.
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!
[Edit 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 that go right back into the slope until they find a grip or are grouted with a gripping material... and earlier way of doing this was to put in a big screw auger and then hook the piling onto it. (Sorry that's a rubbish description... but you could get spare piling and/or the big augers stacked ready by the line).
One other thing... where the ground is playing up a slow order may be imposed on the line... this means that you get more time to watch your trains go by.
Talking of which, an event that amazed me was that we had all of the fill from a northbound track wash out for about 60 yards... but the southbound stayed completely good and the speed restriction applied was more to re-assure the public than as a precaution. Ther was no damage to the surviving line at all. The engineers even stayed in the hole while trains rolled by above on the good line. So a half-way house on this would be to have the line on the side with the track slow ordered while the far line ran normal speed.
In short - hide it by highlighting it.
electrolove wrote: Look at the picture:
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.