I bought a 2x2 square of pink insulation board at Home Depot (I think it may be Homasote, not sure, but it’s pink and it cuts with a utility knife), and I want to experiment with stacking four layers together, then carving their face to form a vertical rock wall.
Besides the DAP caulk, which I always use too little of at any one time to make it cost-effective (the rest of the tube hardens no matter what I do), what are my glue options? I have barge cement and Elmer’s white glue. Either of those do the job? If not, what?
I have used low temp hot glue from a glue gun when in a hurry, but mostly use dap caulk. I like caulk because if the mountain gets bumped there is give in it and it doesn’t get damaged.
Whatever you use, keep the adhesive away from the edge you are carving as it can really put a damper on the carving when hitting glue. Figure out how much you are going to gouge out and add a cm or two as a margin.
How thick is your board? Never heard of 2x2, but then most of my foam has come from construction sights.
I use inexpensive laytex caulk for foam to foam, foam to wood, foam to cork, track to cork. I do not put adhesive under turnouts.
What I do to keep my caulk from hardening is to put a screw big enough to be screwed in, not pushed in the tip, then wrap the tip in several layers of cling wrap and secure it with a rubber band. I’ve had some stored over 6 months still useable.
Great tip, Brent, thanks for that. I would not have considered that. Your second photo is very instructive because I can see that you even used a peice of what looks like the same material I’m using standing on its edge. The area I want to carve is a sheer drop (which is why I want it to be rock, not a greensward) and there is very little room for the material, horizontal depthwise. I’m now thinking that I might consider mounting a piece of the foam standing upright.
Board is 1 inch thick. I have also used a similar method to try to keep the DAP from hardening, but I may use only one or two squirts once and then not need any again for a year, I work so slow. That’s why I was hoping to stay away from the caulk gun.
I’ve bought two tubes. The first one I bought I put a fat nail in and wrapped it with tape, which worked fine when I used it again 3 months later, but 6 months after that it was so hard in the tip that when I forced it using the trigger/ratchet mechanism the back of the tube exploded and I had DAP all over myself and the gun and everything.
I use liquid nails to secure layers. Whatever you use, put a long screw or unfolded paper clip to prevent the tube from drying out. This is speaking from experience of letting the tube dry out (yes, I covered it too).
I had a couple of spots where I had very little space to put a rock face. What I did was carve out the foam on the flat side to look like a rock face and then slice it off like a piece of bread to about 10cm thick and glued it in place.
You can score the foam to give the glue more grip. I’ve tried it with and without scoring and have not noticed any difference.
Spread the glue thin and even. Leave glue exposed to air for at least ten minutes. Press the parts together. Adjust. Pile weights on top until glue is dry which may take two days if it is a large surface with no air contact.
Do not use glue that expands like traditional Gorila Glue.
Do not use products like liquid nails or sillicone caulk on foam. They may either dissolve the foam or be catalyzed by the foam into drying too quickly and unevenly.
Be sure to remove any plastic vapor barriers on the foam. The glue will stick to the barrier just fine, but then the foam will separate from the barrier.
It holds very well, dries flexible, and is only $4 for a large tube. I’ve used it on foam-to-foam, foam-to-cork, cork-to-cork, and cork-to-work. It also doesn’t contain any nasty chemicals so it’s safe to use indoors.
That’s interesting. I use Liquid Nails (exterior grade) all the time for my bead board and I’ve never had a problem with it. As already mentioned, make sure it’s foam board compatible.
As to the hardening problem, Liquid Nails and such say on the tube that it should be used within a year of opening. For keeping it fresh, I have used caps specifically designed for that purpose and I have also put a piece of Duck Tape to seal the nozzle as well. All seem to work to keep everything fresh.
I think what you bought is not Homasote. Homasote is light brown with a fiberous surface and core. You bought pink foam insulation which is exactly what you want for what you are doing. Some people still use Homasote as sub-roadbed because it holds track nails well, but cutting it can generate a lot of fine sawdust which can make a real mess.
You all are correct. What I have is not Homasote, it’s the Owen’s Corning pink foam (extruded polystyrene, I think). My Home Depot sells it either in 4’x8’ sheets that are 2" thick and cost more than 50 clams a sheet or else in 2’x2’ sheets that are only 1" thick and cost less than a sawbuck each. I went with the small square because I just wanted to try foam out as a scenery base. I would rather have the thicker but I have neither the financial leverage nor the storage to be buying $56 sheets of foam just for experimentation.
The “caulk” I used turned out to be one of the Alex adhesive products. I don’t know which one offhand and I have “cat-lap” right now so I am unable to go and look. It worked well.
The DAP product I used – both tubes – turns out to be the Alex Plus that Tom shows above. This time I have put a long nail in the top and wrapped it very well. Also, now that I have started doing scenery, it’s likely I will use more of it more often, so I may not have to waste the rest of this tube.
