Glueing foam core

Phil was kind enough to ask how I was glueing the layout together. I should have included these thoughts in my posts before so I thought I’d put something together now.

The layout base is made from 3/16″ foam core sheet. Corner joints are butt-joined together. For these foam core-to-foam core joints I used yellow carpenter’s glue. I used Lepage but really any brand would work – I’ve just always used Lepage. One neat option for fabricating these joints that I have done before but didn’t do this time, mostly out of laziness on my part, is to actually create a dado in the sheet by cutting away one sheet and removing the foam leaving behind a groove and the outer paper layer.

I scanned in Ian Futers’ track plan for Victoria Park from the Railway Modeller article and printed out a full-sized version. To glue this to the benchwork I used spray contact adhesive. Again, I had Lepage product on hand so used that. Be careful with this product as it is oil-based and will attack the foam if it comes into contact with it.

I used ties made from PC board strip and styrene strip. Each of these ties was individually glued into place with medium CA. Again, as with the spray contact adhesive, CA will attack and melt the foam core. I gambled that I was only applying enough to attach the tie in place. If you’re using CA, you can buy these really neat little extension tips that fit on the end of the glue bottle. These tips protect the original tip so it doesn’t get fowled over time and also makes it much easier to control the amount of glue you’re applying. I purchased the ones I use from Great Hobbies but most hobby shops would have a similar product. Click here to see the ones I used, on the Great Hobbies website. For what it’s worth I did try using yellow carpenter’s glue to hold down the ties but it just didn’t work at all so I used CA.

Now that the main layout is operational my thoughts are turning to scenery. Typically this stage involves a lot of water and I worry that this won’t work well with the amount of paper I’m using here. I may try sealing the whole thing beforhand. The next thing on my to do list is painting track so perhaps this sealing process becomes a part of this task.

I hope this helps. I hope it makes sense.

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5 comments

  1. Thanks Chris
    The reason I asked and you kind of brought it up was using strong chemical based glues. I had used rubber cement to glue bottom joist to firm up the deck… The edges that were exposed parts (after cutting) melted from the adhesive. I haven’t tried rubber cement on the sealed surfaces but I won’t take the chance. I haven’t tried carpenters glue yet. I suppose that would work as its water based.

    1. Glueing the butt joints at corners remains tricky. CA or any solvent-based glue will only melt the foam so we are left with water-based glues. What I’m gambling on is the bond made out the outer edges, between the paper layers where yellow or white wood glues will work perfectly. You’ll notice in some of the pictures I’ve tried to include a lot of blocking made from scrap to reinforce these joints.

      My last large layout was framed entirely with 1″ extruded foam (Styrofoam Blue) To bond those sheets I used latex panel adhesive. This product is sold in the hardware store and is used to bond rigid foam sheets to concrete walls when insulating a basement. The glue comes in a tube and you use a caulking gun to apply it. In Canada, Lepage call it their 9000 and I’ve seen a Home Hardware brand equivalent. The glue works perfectly. It tacks quickly and cures within 24 hours. However it’s a little messy to use and it’s thick.

      1. I framed the outside of my foam board with some foam wainscoating I had left over from redecorating the bathroom. For that I used clear Silicone adhesive. It worked well, but is not the strongest for adhering the foam board. With a little force you can pop off any glue bead you’ve created.

      2. Years ago, when I built my first foam layout I used a thin bead of clear silicone to glue down my track. I liked that it didn’t attack the foam but the working time was slow since silicone doesn’t really tack. Needing some better than silicone led me to the panel adhesive.

        The hard part with the 3/16″ sheet I’m using is the small glueing area made even smaller since most of what I think I’m getting is from the paper outer layers. So far I haven’t noticed too many brittle joints so I think I’ll continue with the yellow glue and reinforced corners for now.

    2. Glueing the butt joints at corners remains tricky. CA or any solvent-based glue will only melt the foam so we are left with water-based glues. What I’m gambling on is the bond made out the outer edges, between the paper layers where yellow or white wood glues will work perfectly. You’ll notice in some of the pictures I’ve tried to include a lot of blocking made from scrap to reinforce these joints.

      My last large layout was framed entirely with 1″ extruded foam (Styrofoam Blue) To bond those sheets I used latex panel adhesive. This product is sold in the hardware store and is used to bond rigid foam sheets to concrete walls when insulating a basement. The glue comes in a tube and you use a caulking gun to apply it. In Canada, Lepage call it their 9000 and I’ve seen a Home Hardware brand equivalent. The glue works perfectly. It tacks quickly and cures within 24 hours. However it’s a little messy to use and it’s thick.

      The contact adhesive I used is solvent-based. To laminate the track plan I used an aerosol spray contact glue. I think that if used sparingly and only in places where it doesn’t come into contact with the foam it should be okay.

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