Ground throws on foam board

[jecorbett]

I built the first town on my layout on 2" foam board before going back to plywood for the rest of the layout. I now need to add ground throws (Caboose Industries) to several industrial spurs. Obviously I cannot mount them directly to foam board and exect them to hold. I'm thinking the solution is to mount a small block of wood to the foam board and then mount the ground throw to that. I'm also thinking it of mortising the foam board to hold the block and give it more stability. I'm trying to decide what type of adhesive would be best to join the small block of wood to the foam board. I'd appreciate any thoughts others may have on tackling this problem.

[cregil]

I like your mortise idea.  As for glues:

Gorilla Glue:  It foams a bit as it dries, but glues anything to anything, and the foam may be a plus when gluing foam board.  Any cured foam that oozes out scrapes or carves off easily enough.  It has a good working time and I don’t think it has a problem with porous surfaces.  I’d check the label for you but can’t find mine—must be out.

I like epoxy.  I use T-88 (made by System Three) because it is the only one I can clean off my hands with soap and water—and no matter how careful I am, I always get epoxy on my hands.  I have not tried it on foam board but my only concern would be that epoxy generates some warmth when curing—especially the faster setting type.  I doubt that there is enough heat in curing to cause any melting in the foam board, but I would test first.

Cyanoacrylate (a.k.a., CA, Superglue, Jet Glue, etc.) won’t work.  I wanted to mount my ground throws to the cork, and thought the thick (slow setting) CA would be perfect to hold them in place while I tacked them down through the cork into the plywood roadbed.  But the glue wicked up, somehow, into the mechanisms.  Those levers are not going anywhere!

 

Two warnings concerning CA glue:

1) I keep a CA solvent within reach whenever using it (once, my ear itched while holding two pieces together as they set... well, we won’t go into that).  I may be able to rescue the ground throws (neither Gorilla Glue nor epoxy react to any solvent) because the CA solvent appears to work even after setting up.

2) If you use CA; then use a respirator—the risk, although slim, is too great.  A small percentage of persons have severe pain and breathing problems lasting hours to days from inhaling even small amounts of the vapors of the substance when it is still in liquid form.

Good luck,

Crews

[pcarrell]

Yeah, you're going to have to mount it on some wood or something.  Gorilla glue may be the best way to go to get the wood to hold.  Once you get that going on, I'd take a look at this article (http://www.conrail1285.com/news.asp?storyid=31) and think about doing something like that.  It's about N scale, but it should work well in any scale.

[nbrodar]

I glued scraps of cork roadbed to the foam, to bring the the ground throws up to track level, then used 1" long nails to secure the ground throws.   I put a dab of Tacky Glue on the nails before driving them into the foam.

Nick 

[mls1621]

I've used the following method on two project layouts for our local NMRA division with very good results.

Cut .080" stryrene to fit under the base of the ground throw.  I glued these to the foam after carefully drilling them to accept self tapping allen head screws, found in the model airplane area of the LHS.  The holes in the ground throws may need to be openned slightly to accept the screws.  I used double stick Scotch tape to hold the ground throws to the base and a bit that fit the existing holes in the ground throws to drill into the base styrene.  The screws I used required that the holes in the ground throws be enlarges slightly,  Once the holes were drilled in the styrene, I enlarged the holes in the ground throws, this insures exact alignment. 

The track on these layouts was mounted directly on the foam with no road bed.  This required shortening the pin in the throw bar to clear.

The screws I used were long enough to extend through the stryene and pierce the foam.  This allowed me to position the ground throws when gluing them in place with Elmers yellow carpenter's glue.  For gluing, I postioned the ground throw with the throw bar vertical, mid-position, and the points of the turnout shimmed to center them in their throw.  I put down a layer of glue then placed the ground throw.  Once in place, I flowed the glue around the base, creating a fillet of glue.  Let the glue set overnight. 

The yellow carpernters glue is waterproof so once dried, you can remove the ground throw and paint the plastic base, add ground foam or ballast around it and have it blend in.  Once painted and scenicked, re-install the ground throw on the base and you're finsihed.

I especially like this method as it allows replacement of the ground throw if some shlub breaks the throw bar.

I'd recommend using the sprung ground throws, they help simplify the process.

PS,

I used wood for this purpose on my layout.  The wood has a tendency to split when the screws go in.  If I had to do it over, I'd use the method above,  The styrene is much more forgiving.

[ARTHILL]

I use 1/8 inch plywood scraps. I score them to look like planks, add a little grain, stain them dark and inset them in the foam. I use either caulk or hot melt. I would beware of gorilla glue, it foams and can make a big time mess.

[bnsfjoe]

Don't give up so quickly on attaching the ground throws directly to the foam. I'm in the process of building my current layout and have attached the Caboose Industries ground throws directly to the foam. Some have been in place for 6 months so far without any problems. I use a small spot of Gorrilla Glue on the bottom of the ground throw and then hold them in place with track nails until the glue sets.

[jellybean]

Don't forget about silicone caulk. I mounted all of my tortises through 2'' foam 2 years ago and there still holding. Try to use a clamp on it and tighten it as much as possible. Let it go at least 6-8 hours.

 

      Jellybean

[DeadheadGreg]

wouldn't a small dab of Liquid Nails do the trick?  this is an issue i'll be running into shortly.  i actually just finished up the benchwork for the table of my layout (its still sitting on sawhorses, but its still done!) and i'm gonna be putting foam board over the top of my plywood because the plywood comes from a 'layout' i built when i was a little kid, and i had stapled this paper grass mat thing to the entire layout, and had also stapled on black posterboard for roads 'n whatnot, so instead of trying to get out every one of those nails, i'm just going to put foam board over the entire thing.

is foam board sold in 4x8 sheets?  and is there any specific type i should go for (pink vs blue)?

[abbieleibowitz]

I got a 4X8 sheet of blue foam at my local Lowe's but they only had a sheet this big in the 3/4 inch thickness. I live in the Northeast and it's winter here. The big box stores in different parts of the country stock different varieties of foam (if they have it at all). Most of what you can find it 2X8 foot sheets of pink foam in 1, 1 1/2 and 2 inch thicknesses.

I'm planning to try liquid nails or caulk on my ground throws. The idea of carving out a depression in the foam for them is interesting, but too much work when you have dozens to do.
Abbie

[sparkyjay31]

I also glued scraps of cork roadbed to the foam, nailed and glued them down.  Never had a problem.  My throws are also the spring kind that I thought might give more of a problem, but no sweat so far...

[saronaterry]

I use 1" by 3" frames with 11/2" and 2" foam stacked, cork roadbed and caboose throws.All of it is attached with PL300(blue tube for foam-OSI is the manf.).I even use it for the track.Mylocal HI store carries it in the caulk aisle.

Terry in Sarona.WI

[nucat78]

Before I went to Peco turnouts I used doublesided squishy foam tape to attach Caboose throws directly to foam. I forget what the official name of the tape is.  Make sure you get the correct thickness so the throw isn't too too high or low.

[dand200]

I'm a little late on this thread, and I'm not adding anything new, but anyway......

I mounted Caboose Industries ground throws on cork roadbed that was glued to the foam board with yellow carpenters glue.  I made sure the cork was level with my roadbed and slightly larger than the base of the ground throw, then glued it after aligning the throw to the switch rod.  When the glue dried overnight I installed the ground throws with track nails and a dab of glue as was previously mentioned.  It's only been about 3 years on my layout but I have had absolutely no problem with any of them.  Also balasting around the throw and its base will add to its stability.  Good luck.

Dan

[bearman]

This is a timely thread for me.  I am thinking of using gorrilla glue to attach the groundthrow to the cork base and then using track nails dipped in white glue to keep the ground throw in place while the gorilla glue cures.  Anyone know if there might be any reaction between the gorilla glue and the white glue?

[ham99]

I, too, glued pieces of cork roadbed to the foam with yellow carpenter's glue, then nailed the CI ground throws with track nails.  Lines up well with the track that way.  Ballast around the ground throw adds stability.  Never had problems.  Watch out for Liquid Nails -- it can melt foam unless you are careful to get the "For Foam" type.  I would second the suggestion to avoid Gorilla Glue.  Messy and permanent.  I also avoid the waterproof yellow carpenter's glue.  I want to be able to re-use items when I change the layout [which I always do].