I put my lead to the turntable down with latex caulk (about two feet). All was well until I removed the weights but the rail now stands proud of the turntable rim by a small but annoying amount.
I dug out the foam and caulk under the track for about two inches and there is now some space for new glue. Question is, what can I use to reglue the track? I think something that I can put inbetween the ties that will flow under and set up while the weights are applied and the rails are resting on the TT rim.
Bruce, you will get lots of suggestions, and hopefully one or two more positive than mine, or less draconian. However, I would rip it up and start over. You need to maybe rethink the entire grade of the lead if your (properly) caulked rails wanted to lift free. You must be imposing on the rails a configuration they dislike rather intensely for this to happen, or perhaps the caulk is the wrong stuff.
It’s what I would do.
However, if you need to, slide some styrene shims under the tracks with some Weld Bond or other super white glue, or you could try something like Gorilla Glue. GG likes to expand like a curing foam spray insulation, though, particularly if you do what they say and wet one surface with water to catalyze it properly. So, just a light sheen of this amber glue. But it is very strong. Once the styrene strips set up, apply more GG and a water wipe and then place filled tin cans over the rails and hope for the best.
Bruce, it sounds like you’re trying to bend the rails through a fairly sharp vertical curve; something a t-shaped rail is specifically designed to resist. What needs to happen is to either raise the turntable, or to relay the track, at a lower level. Two inches won’t be enough. You’ll need at least a foot, because latex caulk is specifically designed to be flexible. If you carve out about a foot of foam and caulk, about 1/8th inch below the surface, lay caulk in the resulting trough, and lay your track on that, and weigh it down lightly, it should lay right down on the TT rim.
I don’t ever glue flex track down to roadbed. It is spiked down (with spikes) and then ballasted. The thinned glue in the ballast holds it if the spikes don’t. Been using flex since 1960, no problems.
Cutting back and totally replacing the track in this situation is probably the best way to avoid having some nagging issue occur again and again in the future, since by this time the track itself might be a bit distorted.
I do use adhesive caulk to lay my track and thus far, no problems. I don’t rely just on weights but on selective and strategic placement of track nails and pins, which I remove once the caulk is really and truly set. And I give it all the time it needs.
I suppose if the track would otherwise be ripped out anyway it makes sense to try one last ditch effort at salvage in which case this idea of a shim of plastic (black styrene might work well) with glue on both surfaces makes some sense. You may be understandably gun shy about adhesive caulk (that is what you used isn’t it? not just sealing caulk but adhesive caulk?) but I still think it is a good option. But again strategic track nails that really hold it where you want it while the caulk dries and sets, and are then removed, work better for me in critical locations than do weights. I use weights too but for broad expanses of track, not finicky areas.
Try putting some wooden or styrene shims under the track and operate your trains. My guess is that you will have derailments, stalls, and other unpleasant issues. If your trains will handle the trackwork with the shims under it, simply ballast over them and you’re done.
My bet, though, if I understand the picture you’re painting, is that you will have some serious operating issues due to a major kink, and should rip out the area and try again. There’s no shame in that, really, because you want your track work to be bulletproof.
The problem is the large empty space under the track. Empty space = no good, you need to fill in with some styrene shims so the track has a solid surface to rest on. If the track is actually pointing somewhat skyward withotu any weights on it, then it liekly has been bent vertically. Even if the turntable lip raises the track slightly above the roadbed, if it was just laying there with no fasteners of any sort, it should lay flat witha slight gap near the turntable, it shouldn’t be lifting up. I have never EVER had a problem with latex caulk letting loose when I didn;t want it to, and the whole process is WAY faster than using track nails.
On curves, I use some push pins to hold the track in place while the caulk dries. On straights, I’ll put maybe 4 pins in a whoel pice of flex track - one at each end to hold the joints in palce adn a couple more in the middle so I don;t accidently bump it out of alignment. The track instantly tacks to the caulk, and were it not for the natural tendency for it to spring back to straight, even the curves would barely need any temporary hold-downs. You also do NOT want to use so much adhesive that it bulges up around the ties. A very thin bead smoothed out is all it takes - probably why mine is fairly tacky right away, I spread it so thin that it almost looks clear BEFORE it dries (I use clear, it comes out of the tube white but dries clear).
I have the suspicion that you’ve made the same mistake I did when first using latex caulk (a cardinal sin) according to a friend. The only adhesive caulk to us in my O/P and some authorities is DAP3.0 Latex adhesive caulk. After about 5 minutes the stuff sticks like iron and once fully cured it has to be pried up with a tool. I do agree with Selector that you may need to glue some styrene shims to the bottom of the ties and for that I would use C/A.
I think some clarification is in order after reading some of the replys. First, I am laying the flextrack directly on 2" foam. Second, the track WAS flat and level with the TT rails before caulking. The thickness of the caulk is what caused the difference in rail height. I admit, it was old caulk and probably thicker than new would have been. I need to resolve this issue as there are three “whisker” tracks leading into the roundhouse that will have the same problem if I don’t do something different.
The bay radials will stay put if you use the proper adhesive caulk. Lepage’s PL300 foam board adhesive (light blue tube when I last purchased in 2006) and the appropriate DAP product will do.
Smear it, very thinly, lay the radials, and then weight with soda pop tins for about an hour or two. If the rails are too high when pressed firmly through the layer of adhesive, then scrape up the smear as best you can and then sand the foam to reduce its height. Then smear again and relay.
There are MANY latex adhesive caulks, DAP is not the only brand. I use Polyseamseal brand. They all work equally well. The hard drying adhesives are NOT as good, and pretty much defeat the purpose by forming a hard solid connection between the track and subroadbed, increasing noise.
FOr track, a very thin bead then smoother out with a putty knife, scrap plastic, or fake ‘credit card’ you get in those letters trying to get you to sign up for a new unwanted card until is it barely visible - for places where you are markign a centerline, you shoudl be able to see the line you drew almost as if there was nothing there. Yes, that is all you need to securely hold track in place
If you’ve dug out under the track, at this point I still say the best option is to fill in the foam surficae back level again and start over. Nothing you can flow in a gouged out area is going to work satisfactorily. If there was just a slight gap between the ties and the base at the turntable, a scra piece of plastic pushed in would have been sufficient - or if it was just a short stretch, it would have been fine as it was, when you add ballast it would have filled in just fine and been completely unnoticeable. So pull up the track, get back to a smooth surface, and lay the track again with a THIN bead of caulk, and if there is a slight area at the edge of the turntable where the track is not tight against the tabletop - don;t worry. If the joiners to the turntable are tight, and the table itself is securely mounted, it’s not goign to go anywhere. If it’s the opposite - the track is higher than the turntable, shim the turntable slightly to bring it level. The mounting flange for the turntable will be one thickness, depending on the track being used, the ties may be thinner, thicker, or the same.
At our club, we use a construction glue called WeldBond, available at our local hardware stores. Looks like white glue, goes on like white glue, provides great tack within about 5-10 mins, and dries solid in 12 hours. I’ve personally used it to attach track and roadbed directly to foam and wood, with no issues. Put a small bead along the path of the track, spread it thin with your finger or similar, and put the track down. We hold track in place with thumbtacks until it dries.
As Randy noted earlier, you will need a good solid base at the ends using Styrene or similar. I learned this the hard way building a removable bridge. Even if you get it working over time the rails will change if you don’t have a good base. Better adhesive will not be a good fix without this IMO
I always keep rail and wood ties on hand for odd problems such as this.
I would replace the flex track back 3 or 4 inches with wood ties and rails. Glue the ties down and after the glue sets, sand them to the thickness your rail needs to match up with your turntable. Spike the rail down.