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Building with foam board

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  • Member since
    October 2010
  • From: outside of London, Ontario
  • 384 posts
Building with foam board
Posted by lone geep on Saturday, December 3, 2022 8:05 PM

I finally made a big jump and purchased some model railroad R.O.W with a house on top. Though the basement isn't nearly as large as I would like, the price was right, I gotta start somewhere and it beats paying rent. Even though I have plenty of other work to do on the house and building a model railroad is lower on the priority list, I want to plan my strategy on building my 3rd layout. For this one, I will be using 1X4 for benchwork framing and would like to use foamboard instead of plywood for the base. I plan on using 2" for the majority and stacking 1" for scenes I would like to take off the layout to work on, like the roundhouse. Since this will be my first attempt at using foam, I have some questions.

1. can I lay the foamboard directly on the 1X4s or do I need to glue it to to plywood.

2. what cutting tool would you recommend to cut the it?

Lone Geep 

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Posted by rrebell on Sunday, December 4, 2022 8:50 AM

That was exactly how I built my last two railroads and never had a proublem. I built my 1x4 frame and glued down the foam with siliconized latex caulk, weighinging down the foam till the caulk set. I used beaded foam on mine, as it is cheaper, easier to hot wire and will not shrink once stabilized (all foam shrinks once made but most of that happens in the first 3 months or less) and it dosn't tend to warp. 2" is what you need. I caulked down cork where the track was going (cork can be sanded for smooth transitions) then used clear latex caulk to glue down the track. I used plaster cloth for anywhere there was no cork, very cheap if bought in bulk.

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Posted by PennCentral99 on Sunday, December 4, 2022 8:50 AM

lone geep

1. can I lay the foamboard directly on the 1X4s or do I need to glue it to to plywood.

Yes, you can lay the foamboard directly on the 1x4's and they should be secured to keep from unwanted shifting or movement. I used latex caulk to secure the foam to the benchwork. I found it unnecessary to use plywood between the benchwork and foam. It makes it easier to run feeder wires, turnout controls, etc without going through a layer of wood.

lone geep

2. what cutting tool would you recommend to cut the it?

I used a drywall knife to cut the foamboard, and just about any knife will do. Try to avoid using power tools to cut the foam as the bits/pieces of foam will be spread around. You'll find it necessary to keep a shop vac close by.

Terry

Inspired by Addiction

See more on my YouTube Channel

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Posted by MisterBeasley on Sunday, December 4, 2022 10:54 AM

It's a good idea to glue the foamboard to the benchwork, particularly if you ever plan to move it.  Don't make the benchwork sections too large for the same reason.  The largest section of my old benchwork wouldn't make it into my new train room and had to be scrapped.

I trim the pink foam with a hot wire cutter if the pieces are small enough, and cut it with a knife otherwise.  If you measure and score both sides about as deep as you can with a utility knife, you can probably use a score and snap technique on larger pieces.  That way you get no mess.  A drywall saw leaves scraps all over the place.

It takes an iron man to play with a toy iron horse. 

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Posted by BATMAN on Sunday, December 4, 2022 12:21 PM

Being able to remove things to work on them makes life easier. I used some scrap Kerdi board for my RH/TT. Once I got to the point where I thought I would not be removing it again I taped over the cracks and added ground cover. If I ever move or need to take up the structure I can run a knife through the tape and lift it out. 

I used PL300 to glue my foam to the 1" x 4". I would use caulk next time.

For cutting, I generally use this large box cutter but also use anything and everything.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

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Posted by MidlandMike on Sunday, December 4, 2022 10:02 PM

BATMAN
I used PL300 to glue my foam to the 1" x 4". I would use caulk next time.

The PL300 is compatible with foamboard.  Maybe you already knew to use foamboard compatible caulk, but for those who might not know, incompatible sealants may melt foamboard.

  • Member since
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  • From: Bradford, Ontario
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Posted by hon30critter on Sunday, December 4, 2022 10:39 PM

lone geep
can I lay the foamboard directly on the 1X4s or do I need to glue it to to plywood.

Hi lone geep,

Someone suggested in a previous thread that all you need to do to securely attach things like turnout motors to the foam is glue a small square of 1/4" plywood to the foam where the screws will go. The 2" foam doesn't need the plywood itself. It will be plenty strong enough.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by rrebell on Monday, December 5, 2022 8:55 AM

hon30critter

 

 
lone geep
can I lay the foamboard directly on the 1X4s or do I need to glue it to to plywood.

 

Hi lone geep,

Someone suggested in a previous thread that all you need to do to securely attach things like turnout motors to the foam is glue a small square of 1/4" plywood to the foam where the screws will go. The 2" foam doesn't need the plywood itself. It will be plenty strong enough.

Cheers!!

Dave

 

Used to do that for my ground throws on top of my foam, found out that the cork held the screws fine.

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Posted by kasskaboose on Thursday, December 8, 2022 12:52 PM

I used liquid nails to glue the foam to the 1x4s. 

To cut the foam, I used a drywall saw.  I found it easier to use than a boxcutter.

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Posted by lone geep on Sunday, January 1, 2023 8:02 PM

A question for all fellow Canuks on the thread. Where do you get your suitable foam board from? The only decent boards I can find online are at Home Depot with interlocking boards made by Owens-Corning. 

Lone Geep 

 \

  • Member since
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Posted by rrebell on Monday, January 2, 2023 10:19 AM

lone geep

A question for all fellow Canuks on the thread. Where do you get your suitable foam board from? The only decent boards I can find online are at Home Depot with interlocking boards made by Owens-Corning. 

 

Home Depot have the pink stuff in varius thicknesses but their web site sucks and stuff is hard to find on their Canadian site.

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Posted by BATMAN on Monday, January 2, 2023 11:24 AM

lone geep

A question for all fellow Canuks on the thread. Where do you get your suitable foam board from? The only decent boards I can find online are at Home Depot with interlocking boards made by Owens-Corning. 

 

We live close to the U.S. border and will hop over to buy things as it is just as close or closer than heading to the shops in Canada. The price of foam is always all over the map but usually is much cheaper in the U.S. So I will grab a sheet when I am there. 

We have done a lot of renos including four bathrooms so the wife decides what fixtures she wants and checks prices on both sides of the border. Last time we found toilets way cheaper in the U.S. while the sinks and taps were way cheaper in Canada The same applied to window blinds we bought the first batch in the U.S. and the next sets in Canada, and there was quite a price swing.

Lows and HD seem to carry different brands. My local independent building supply store always has the best prices on everything by far.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

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Posted by Medina1128 on Thursday, January 5, 2023 3:16 PM

I used 2" beadboard for my base. I made the mistake of gluing the beadboard to a 1/2" sheet of plywood. It took some creative thinking to wire the track. I used a long 1/4" drill bit to drill a pilot hole directly vertically next to the track. I used that pilot hole to drill a bigger hole with a hole saw. I made a wire feeder from a clothes hanger. Now, I just glue the foam to the frame.

I ground a point on one end.

I flattened the other end and drill two holes in that end. I then thread the wire like thread, then push it through the foam and the hole. 

  • Member since
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Posted by CMattGo on Thursday, January 5, 2023 5:53 PM

Hi Geep,

An alternative approach I used - mainly because I don't know what the heck I'm doing - was to use GatorFoam. I was looking for a strong, thin and lightweight material since I'm planning on a non-permanent installation that can be easily moved. If you haven't heard of it, GatorFoam is "comprised of extruded polystyrene foam bonded between two layers of wood-fiber veneers", according to their website. You can get it in a variety of thicknesses. I found 1/2" to be strong enough for my needs. It's not cheap relative to the pink stuff though. A lot of art supply places carry the thinner boards, but I ordered from ULINE for the sizes I needed. They had the best prices at the time too.

The board is glued to several 1x4 frames for portability, the largest of which is 32x40. They are all latched together to make the layout. Frames are braced in the corners, but the foam is strong enough that there's no support needed in the middle, and I don't have to worry (much) about interference underneath from the bracing. The thicker pink foam is glued on top as a base for the landscaping.

So the jury's still out on the long-term benefits, but so far, so good.

Chris

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Posted by SeeYou190 on Friday, January 6, 2023 11:09 AM

lone geep
What cutting tool would you recommend to cut the it?

I did some experiments with the Bosch T313 blades in a variable speed jigsaw, and was very happy with the results.

-Photographs by Kevin Parson

It also works great with Homasote.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by BigDaddy on Friday, January 6, 2023 11:44 AM

I've used the same blades as Kevin with good success

The downside of just using 2" foam is you cannot create negative vertical space, i.e. if you want a truss bridge over a river or gulch.

Here I have used 5" of foam 2+2+1

 

Henry

COB Potomac & Northern

Shenandoah Valley

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