I am using 1 1/2" Dow Blue Foamboard with 1/4 inch plywood glued to the back as my track support. I have been using Locktite Foamboard adhesive to fasten the two together. Basically, it works some times. This one from Lowe’s was chosen in part because it was for foamboard with a rapid set… The problem is it doesn’t always adhere to either piece and the rapid set isn’t quite true. The pieces are clean and dust free before gluing. The latest aggravation is that yesterday I glued a strip of plywood to the foamboard strip. A short while ago I removed the weights the plywood popped right off the foam.
However, just before Christmas I put some 12 running feet of track together with no problem.
When working on the other half of the layout last spring, there were a few times that the foamboard plywood bond didn’t hold. Regluing worked. During that time I glued foarmboard to foamboard without any issues… Well that I know of.
So has the Locktite adhesive gone bad?
To glue some plywood segments together for curves, I used some Liquid Nails. It seemed to work well but needing clamping until dry. I finished the Liquid Nail tube gluing foam board to plywood. The bond held. The Liquid nails now says it is foam board compatible.
All of the Locktite adhesive was from the same box. I still have several tubes left but am a little concerned about using it.
So now that you have heard my story, has any one else had this issue? How did you solve it? What is your choice to bond foam board to plywood? What is your choice to bond foam board to foam board?
What you need to get is DAP3.0 Latex Adhesive caulk, I have used foam glue in my shop when we added a second layer of insulation, yes this stuff really is a building material believe it or not. it worked ok but I did notice it had some sag to it as it didn’t seem to set up quickly. we remedied that problem by sticking finishing nails through the outer foam to the inner pieces. Well as luck would have it we ran out of glue and Lowes was closed so I went to the train room and brought back several tube of DAP 3.0 well they advertise that it sets up in about 3 minutes and their not lying. It has excellent bonding qualities as well. A bit pricey but not as bad as having to do the job twice.
I used Elmer’s yellow carpenters glue for mine. I got like a 1/2 a gallon for about $10. I placed lots of weight to hold in place until the glue set (I gave it 48 hours since it is hard for air to get in there).
I tried the caulk for gluing the foam together and to plywood to foam but found the porous foam took to much caulk for my liking making, it too expensive to me. I did and loved using the caulk for track to cork.
I also used the glue to put the cork onto the foam for the same reasons.
Elmer’s yellow glue is what I use for attaching my foam to the plywood. And foam to foam - I used two layers of foam. My old MR collection is in plastic magazine racks so I just take those and line them up on top to privde weight untilt he glue dries - generally I leave this sit at least 2 days before removing the weight. There’s very little air penetration with the foam so it takes longer than it typically does for any adhesive to set up.
I use Foamboard adhesive from Home depot to glue foamboard to wood or to more foam. It works but can take a LONG time to dry - like weeks if it is all sealed away from any air. I have cut a section I did weeks before and the adhesive was still not dry in places.
Lately for smaller pieces I have been using DAP Latex caulk but don’t know yet how good or bad it is.
I didn’t use glue. I just used drywall screws with fender washers to secure the foam down. The washers and screws are easily covered with plaster cloth.
I used Elmers wood glue and works fine . However, when I looked at the foam board,it was obvious it had a plastic coating on one side and I removed it,but the other side had plastic coating also but it was hard to tell. I found out when the glue didn’t stick.
Because the items you’re gluing are flat surfaces mated together, you need to have an adhesive that will cure in an almost airless environment. I’m not familiar with all the products in question, but I do know some things about general construction.
All adhesives are not created equal – each is designed for specific purposes. Humidity, temperature, the porosity of the material (and if you’re using the right foam for construction, it’s NOT porous, at all) all affect their adhesive properties. If it doesn’t say you can use the adhesive on wood, then you run the risk of it not bonding correctly – clean and dry or not.
When bonding two planes together, put your adhesive down in an “S” pattern. If you use a spiral or a broad smear, the adhesive on the outside will actually seal up the adhesive on the inside, preventing it from curing and weakening your bond.
When a manufacturer provides a curing time, that’s usually under more or less ideal conditions (70 degrees Fahrenheit and 50% humidity) with plenty of ventilation and the recommended amount of adhesive. Less than optimal conditions increase curing time substantially. While a 1/4" bead of the stuff on your workbench may indeed set in 3 hrs, a 16" smear an eighth of an inch deep between two pieces of foam may take a few days.
Thanks for the tip. I have used several tubes of DAP 3.0 Adhesive Caulk and it works great. It seems to take about 2 to set up sufficiently so you can work with the pieces. It works well enough that it is being used for the tops of risers in place of hot glue because of longer working time.
BTW, it took me a bit to identify which on of the offerings to buy at Home Depot. One DAP 3.0 label just extolled the virtues as a bath room and shower caulk with a 3 hours till use. The other one had virtually the same label but also indicated it was an adhesive. It was the later one that I am using.