What are the best materials for supporting a foam based layout.

[Denver Road Doug]

Purple is Corning Foamular 250,got it at Home Depot..It's only a slightly different color than the pink.Seriously,it's WAY stronger than the blue.I have really strong hands.I can take a piece of blue and squeeze it between my thumb & forefinger,and sink both fingertips in it 1/2 inch or more.I can't even dent the purple doing that..

Huh, I wonder if I didn't get the Dow version of that.  The place I bought it from (an industrial freezer/vault company of some sort, ref'd to me by a fellow model railroader in the area...and still the only place I've ever seen 2" foam available for sale) had what they termed a "more dense" version that was actually pretty pricey but I popped for it since I was only buying one sheet.   At the time I thought I might have been hoodwinked but it *did* look different from the other.

[C855B]

Huh, I wonder if I didn't get the Dow version of that.  The place I bought it from (an industrial freezer/vault company of some sort...

I suspect this may have been "Freezermate". It is a higher-density version intended for walk-in freezer floors - you can apply flooring materials over it, and the compression resistance is much higher than the other stuff intended for walls and attic spaces. It's also available in 3"!

There is a huge selection of the "pink" and "blue" foam sheets, all with different characteristics. The home improvement stores typically stock the lowest, cheapest grades. Gauging from the discussion here, apparently the cheapest Owen-Corning is stiffer and has better compression resistance than the cheapest Dow.

EDIT: Just for the comparison, Lowe's carries "Dow Styrofoam UTILITYFIT", which is the lowest-grade "blue" product. It has a compressive strength of only 15 psi - that's pretty grim. Freezermate is 40 psi, and "Dow Styrofoam HIGHLOAD" is available in 40, 60 and 100 psi grades. Strong stuff!

I do know the Owens-Corning Foamular line is an uptick from the regular pink stuff, and also has many grades. Foamular 250 is 25 psi, and they have up to Foamular 1000, which... yes... is 100psi. The simple bottom line is, of the stuff you can get conveniently, Foamular 250 will be stronger than Dow UTILITYFIT.

[DKS]

Just for the comparison, Lowe's carries "Dow Styrofoam UTILITYFIT", which is the lowest-grade "blue" product. It has a compressive strength of only 15 psi - that's pretty grim. Freezermate is 40 psi, and "Dow Styrofoam HIGHLOAD" is available in 40, 60 and 100 psi grades. Strong stuff!

I do know the Owens-Corning Foamular line is an uptick from the regular pink stuff, and also has many grades. Foamular 250 is 25 psi, and they have up to Foamular 1000, which... yes... is 100psi. The simple bottom line is, of the stuff you can get conveniently, Foamular 250 will be stronger than Dow UTILITYFIT.

This is very useful information--thanks for posting.

[C855B]

BTW, "Styrofoam" is a Dow trademark! Everything else is "expanded polystyrene". I guess it's another "Coke" and "Kleenex" situation.

[Chris333]

I used the 250 foam last time. To me it seems to be more dense than the regular stuff and it is only like $2-4 more per sheet.

[VonRyan]

A friend of mine uses blue foam that he gets from a refrigerated container outfit as offcuts.
It is probably 1.5 to 2" thick (I'll have to take a measurement on Monday night) and is backed with 1/2" plywood and has a plastic on it.
The foam is permanently bonded to the plywood and the only way to get it off is with a bandsaw.
No noticable sag, and the section that i'm using as a reference has maybe 2mm of sag in the middle yet is spans a 3ft gap as a freestanding shelf that supports all its own weight.



-Cody F.

[SkipGear]

A friend of mine uses blue foam that he gets from a refrigerated container outfit as offcuts.
It is probably 1.5 to 2" thick (I'll have to take a measurement on Monday night) and is backed with 1/2" plywood and has a plastic on it.
The foam is permanently bonded to the plywood and the only way to get it off is with a bandsaw.
No noticable sag, and the section that i'm using as a reference has maybe 2mm of sag in the middle yet is spans a 3ft gap as a freestanding shelf that supports all its own weight.



-Cody F.

My dad has a 12 x 20 storage building made of something similar. There was a guy in Somerset, KY near him that was getting trim offs from a refrigerated trailer manufacturer. It is 2" high density foam laminated to an aluminum skin, The cut offs are 2-3' wide by about 12' long. This guy assembles them into a barn style shed. They are light, strong and easy to cool (it's a big cooler really). I'm sure the plywood backed stuff is similar.

[John]

That method doesn't make the attachment of fascia all that easy.

Just use some foam for the fascia .. paint it green ..

[John]

I've always been impressed by the fantastic benchwork I see on the Net and in magazines. Seems like some make that the focus of their layout!!

Thats because most of them never get beyond that stage .. gotta have something that looks good

[OldEastRR]

 

Freezermate is 40 psi, and "Dow Styrofoam HIGHLOAD" is available in 40, 60 and 100 psi grades. Strong stuff!

Apparently the guys who stated here that 4x8 extruded foam sheets can't support themselves did not have "absolute, unassailable" reasons for their assertions.

Let's not forget, folks, that the construction stuff at the big box stores is cheap lower grade priced to sell. If you only use that, it's like eating a Big Mac and saying, "Steak doesn't really taste that great." Fact is, you can't even buy the same grade of steak they have in restaurants at the supermarket.

[Denver Road Doug]

Apparently the guys who stated here that 4x8 extruded foam sheets can't support themselves did not have "absolute, unassailable" reasons for their assertions.

Let's not forget, folks, that the construction stuff at the big box stores is cheap lower grade priced to sell. If you only use that, it's like eating a Big Mac and saying, "Steak doesn't really taste that great." Fact is, you can't even buy the same grade of steak they have in restaurants at the supermarket.

I think that's a little harsh.  Not everybody is an expert on every material ever made, and honestly I've seen dozens of forum discussions on the topic of foam and this is the first one I recall ever mentioning the breakout of brand versus color and psi options.   I can tell you it was dumb luck that I bought a more dense version (pretty sure it was 60psi now that it was broken out like that....that number sticks in my mind now that I think back) and even the 4x8 sheet of 60psi doesn't hold it's shape as well as, say, 3/4" plywood.  Both flex, and they might be close.   But neither would be a good standalone 4x8 layout without some bit of bracing.   I'm sure it's been done, but that doesn't mean it's recommended.

[DKS]

Apparently the guys who stated here that 4x8 extruded foam sheets can't support themselves did not have "absolute, unassailable" reasons for their assertions.

I think it's quite unreasonable to expect anyone to have samples of every different type of foam to compare. Besides, the stuff at the big box stores is what most modelers will be able to buy--and probably be able to afford, as I would imagine the premium 100+ PSI stuff has a premium price tag. Given the circumstances, I stand by my assertions.

[robert3985]

I think it's quite unreasonable to expect anyone to have samples of every different type of foam to compare. Besides, the stuff at the big box stores is what most modelers will be able to buy--and probably be able to afford, as I would imagine the premium 100+ PSI stuff has a premium price tag. Given the circumstances, I stand by my assertions.

+1

[robert3985]

Being pretty lazy (not to mention unskilled when it comes to woodworking), I just used cheap Office Max folding-leg tables for my "benchwork". No complaints so far.



Cheers,
-Mark

Well, Mark and I agree that cheap folding tables are "it" for Rog.  I swear I read the whole thread.  Don't know why that got by me, but it's the logical conclusion to Rog's "given's & druthers and the size foam sheet he's gonna use.

Since I'm using foam (blue, pink, purple and some 3" stuff wrangled from a construction site that's pink and ultra dense) not as a structural component, but as a scenery base on my "battleship" L-girder portable sections/modules...the discussion of the merits of different kinds of foam as structural components doesn't turn my crank, although the information is good to know from an esoteric standpoint for me.

I'm sure it will benefit others here, and is one of the reasons I'm here at TRW...all that information that's available here and not many (if any) other place online.

Good luck Rog on getting your new Kato Unitrack layout up and running.  I'd advise you to open up them old ears a bit to what DKS is saying.  He knows his business and some of his suggestions might make a big, positive difference in your final plan.   

[rogergperkins]

  I have considered the folding table bench work approach instead of building a leg system, however the most recent time I priced materials it was more economical to buy the folding legs instead of the whole table. These banquet table legs are priced at less than $25 USD for a package of 2; i.e. $125 for the five sets.

They could be attached to the wooden box underframe constructed of plywood strips (instead of dimensional lumber) with extruded polystyrene foam as the working surface.
The one feature I have used is bolts in the bottom of the layout legs to help adjust for irregular floors.  This works very nicely in a basement layout room.