Foam Question

[JoeG]

Is it common practice to use foam on top of your plywood?
And what thickness and type shoud be used?

 

[Dougget]

That's exactly what I'm doing. I went with 2" foam (14.5 feet in HO scale). I figured if I need to dig down for low areas, river, pond, ditch, whatever... 14 feet would be sufficient.

Doug

 

[JoeG]

Ha i never thought of how many feet that would be in scale size!
Id like to make a turn table and some rivers, and i was thinking that would be the best way to go below grade.

 

[kenw]

it's an excellent way to go, that's why I did it, too. Mine is the blue foam (~1") used for home insulation around here, it stacks for where I need more (glued with elmer's). You need to peel off the thin plastic vapor barrier tho.

You CAN use it without plywood underneath but you will need a much thicker foam. The right combo of thin plywood and moderate foam is economical, lightweight, strong and easy to use.

 

[UP2CSX]

2" of extruded foam is the way to go. Not only is it much easier to make below grade features, it makes it much easier to place things like trees, utility poles, and road signs. Just stick them in, they make thier own hole, add some white glue, and you're done. You can easily experiment with different placements of scenic elements as well, something that's tough to do with just plywood.

 

[lmackattack]

I also use foam base. it not only helps when you need to make a river below grade but when you want to make the tracks climb a grade. just cut next to both sides of the track and rase the grade as you wish. I suggest getting a foam cutting tool to give smooth cuts in the foam.

Trent

 

[JoeG]

Is there a density that i should be looking for

 

[kenw]

the stuff used for home insulation (pink or blue) will work fine. I scavenged all of mine from construction sites (ask 1st!) for free when they were building in my neighborhood. You can buy it in 4x8 sheets and sometimes in narrower widths to fit between studs.

Florist's foam (dark gree) is another animal and doesn't work as well (it deteriorates over time, crushes easily and it is outrageously expensive).

 

[lmackattack]

the stuff used for home insulation (pink or blue) will work fine. I scavenged all of mine from construction sites (ask 1st!) for free when they were building in my neighborhood. You can buy it in 4x8 sheets and sometimes in narrower widths to fit between studs.

Florist's foam (dark gree) is another animal and doesn't work as well (it deteriorates over time, crushes easily and it is outrageously expensive).

I used the pink stuff also. its weather insulation and has a vapor guard as well. I dont have plywood under neath I just used bracing under neath at 2' intervals with 2x4 studs also found at job sites If I did it again I would have used 1/4" plywood under the foam to have a solid surface to screw things into (like switch machines.)

Trent

 

[GWT&P]

I also have plywood with foam on top. I can only find 3/4" foam around here, so I have to stack it. I put 2 levels (1 1/2") over 3/8" plywood.

 

[nmaniac]

Why use plywood?(is this a home layout ?) its heavy when I build layout's I use soundboard then put your foam on top.One issues I have found with the foarm both blue and pink is it can get dented really easy!!I found by placing plaster cast cloth ( I get mine from my doc) when it expires and it works jsut like the stuff you have to pay for at the hobby shop

 

[leghome]

The only time you need plywood under the foam is when you are going to attach something on the bottom side as Trent has said, tortis switch machines or even brackets to holdup wiring. The thickness of the foam on my layout is the 1 1/2" pink stuff with no wood backing. I made a frame out of 3/4" plywood ripped into 5" strips and then screw and glued together with cross braces every 2 feet.

 

[bigford]

so the 5 sheets i have of 4'' blue foam is to much???
that stuff is real heavy a 4'' thick

joking about above, the 4'' foam is used for house foundation pours

 

[mike8693]

yes imo It would be a real pain to install under the table switch machines and to wire it.

 

[nof]

I have built my layout of 2" blue foam reinforced with a frame of the same kind of foam. I have mounted my tortoises in the foam with screws and plastic plugs glued in the foam. The only problem is that the 2" foam makes the tortoises to come too much under the switches. I have also tried to recess a piece of plywood in the foam directly under the switches and mounted the tortoise in that piece of plywood. The plywood is glued to the foam. This way to use recessed plywood seems to be the best way to mount the tortoises.
My layout and the supporting "table". The layout is built in two pieces in order to make it easier to move out from the apartment when I move out.

 

[leghome]

I just remembered a friend of mine built a layout out of blue board. He cut some 2" foam into pcs. of 2x4 and made a frame and then topped it with more 2". It was very solid and portable. This mini layout was 30" wide by 4' long. I have not seen him is a while so I do not know if he still has it but I know it was around for over two years being transported to different shows and other model RRing outings.

 

[n-scalejohnnie]

I used to 2" pink foam on my HO that I Just finished.And I loved it. When making rivers or ponds just remember to coat the dug out area with plaster because the water epoxy will eat the foam like the flesh eating virus.
N-scal Johnnie
See you Sunday at the Springfield Ma train this weekend!

 

[hfd]

I use Bachman EZ track...how difficult woud it be to remove it from the foam after it has been glued down...

 

[hamltnblue]

Shouldn't be hard at all. You don't have to use much. Just put a small bead of silicone caulk on each piece of track. You don't have to hit the whole track.

 

[hfd]

Thank you...