Building Foam Baseboards

I’m slowly working my way towards being able to lay track on my model railroad.  One big step that I’d been putting off due to the finicky nature of getting it right, was final assembly on all the foam baseboards.  Since I live in an apartment and the layout will eventually need to move, the baseboard is divided into three equal sections.  That creates two joints that will have many tracks and a large expanse of “water” spanning them.  I have a little experience building modules, and I know that if the joints have large gaps and don’t line up vertically, it’s a huge headache later in the building process, so I’m trying to get everything as tight as possible from the very beginning.

I tried a couple of different adhesives.  The one I ultimately settled on was Loctite Premium Construction Adhesive.  It doesn’t attack the foam and it dries hard as a rock.  I found the hardness of it to be particularly useful as it allowed me to set the panels at exactly the right height, then when it cured, they wouldn’t move up or down.  I did try some Liquid Nails adhesive that’s designed specifically for foam insulation panels, but I discovered that it stays very flexible and doesn’t create a very tight bond.  I was able to pull two test pieces of foam apart even after they had cured for 24 hours.

Each baseboard consists of 3 pieces: a 1″ thick base, a 2″ thick section that the track rests on and a 3/4″ section next to the 2″ section that will act as the base of the water.  This will put the surface of the water about 1″ below the top of the 2″ foam.  I found that the 2″ foam was not terrible consistent in it’s thicknesses and the piece on the middle baseboard had to be shimmer slightly to bring it closer to level with the baseboard on one end.  A little sanding and everything should line up nicely.

Before laying down any adhesive, I traced out the locations of all the switch motors.  The adhesive dries very hard so I wanted to make sure there wasn’t any in locations that I would have to cut through later (note the circles in the photo).  I applied adhesive thinly to the shims and in thick zigzags to the rest of the foam, then I sandwiched the two pieces together, moved them to my kitchen table and weighted them with books for 24 hours.

Overall I was pretty successful getting the baseboards even and with a minimal gap, however they’re not perfect.  It’s going to take some fairly messy cleanup with a palm sander.  I’ve also decided to fill the gaps between baseboards with caulk.  When it’s time to move, I’ll just slice the caulk out of the joint and reapply it once the layout reaches it’s new home (which will hopefully be permanent).

– Chris