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Foam

colorex

Rotor Riot!
Mentor
#1
I was checking today at local hardware stores for Depron or FFF, they've never heard of it. They did have Foam board. Foam, both sides covered in construction paper; they have a lot of (EPS) expanded polystyrene sheets.

What is the difference between Depron, FFF, Foamboard, EPS, etc?
 

JimCR120

Got Lobstah?
Site Moderator
#2
The FFF that I use is FanFoldFoam. Around here I can get the pink stuff at Home Depot and the blue stuff at Lowe's. Both are located back in the insulation sections of the stores. I think they are sold in bundles of about 25 sheets for around $40.

Another foam option is to go around construction sites and check out what they scrap. I've scavenged some thick foam scraps this way that will make a nice solid chunk if I need it. Considering where you are at I'm not so sure they have that down there. The temperatures you face there are not the cold ones we get here. I know when I was in southern Spain we just didn't see the houses insulated like they are here in the northern US. Even still though, foam can be used as a protection to transport many things. Maybe in that regard you could find some stuff that others have used and discarded.

By the way, the second link talks a little about foams which might answer your question too.

—Jim
 
#4
Foam board is the right stuff, it comes in 5mm sheets and is covered in paper. You can take the paper off to make it lighter, but it makes it less rigid. The EPS is flimsy and breaks.. you don't want that.
 

ananas1301

Crazy flyer/crasher :D
#5
I have no idea about your foams neither about yours colorex, but I can tell ya something about depron, as I use it.

The good thing about depron is that it can get very thin. If you get some 3mm Depron and you make a cut, the side will look like a sandwich. The outer bottom und upper side are "thicker" than the actual inside. This makes it rigid, but for a beginner you shouldn´t use depron. The thing about it is that even though many use it only for light weight, it can break much more easily then EPP or EPO.

In my opinion a beginner should be made out of EPP, because it gives you the flexibility you need as well.


Addition. 6mm depron will have the same look as 3mm. That sandwich type. That makes the weight per volume of 6 depron even lighter than the weight per volume is with 3mm. This is because the only difference is that the outer sides with 3mm and 6mm depron are both with the same thickness. Only difference is that wit 6mm you have more "filling" between them, which is much lighter than the outer sides. Hopy ou understand that just that you know. My english isn´t that good :/

Anyway, my two cents
 

colorex

Rotor Riot!
Mentor
#7
So no one knows the foam in the pic? I thought it was foamboard, but the covering is not paper, it's some kind of foam. It's hard to rip off. They had other sheets that were covered on both sides. Another shop has real foam board.
 

Heli-Yeah!

Gremlin on the Wing
#11
What foam is this?
Can you give a description of the foam, is it fairly rigid, does it have memory, does it snap easily, if so is a clean break?
It's hard to tell by the photo, but I don't think I've seen it before. If it seems light, and tough enough, and can be worked easily, you should be able to make something of it.
Give a sample of it the old torture test, to check out it properties.
 

colorex

Rotor Riot!
Mentor
#12
The material is covered with a thin layer of denser, colored foam, which stains if rubbed on paper. It breaks cleanly. If you compress it hard it will become ugly and unevenly surfaced, but it will be able to bend a bit more. The covering foam layer comes on both sides, and in phosphorescent colors. A sheet costs $4 and is about 100x60 cm. Approx. I did a superglue test, no problem. Cuts clean with a utility knife. Sanding seems OK. Overall very lightweight, but mistreated in the store. Looks like good foam for planes tho.
 

ananas1301

Crazy flyer/crasher :D
#13
if you can measure the weight for a specific volume we could compare it with other materials like depron!

3mm Depron has 40g/litre
6mm Depron has 33g/litre
EPP has 20g/litre.

So what would be yours? If it is light weight it should be comparable to some of those.

Edit: Yeah for bad explanation I just add the word density here because that is what it is all about here :D
 

FlyingMonkey

Stuck in Sunny FL
Staff member
Admin
#14
Andre, the edge showing, is that a cut you made, or from the factory?

Does it break apart at all when you cut it?

What is the foam sold as? What is it's original purpose?

On the left and right side, it appears to be compressed, is that the result of cutting? Does it dent easily?
 
#15
Dollar General has foam board for u guest it $1 and also hobby lobby/art and craft(not the R/c store) cheap that is better quality... And you can use the FFF method with this by scribeing a fold crease first...check rcfoamfighters.com great site
 

colorex

Rotor Riot!
Mentor
#17
if you can measure the weight for a specific volume we could compare it with other materials like depron!

3mm Depron has 40g/litre
6mm Depron has 33g/litre
EPP has 20g/litre.

So what would be yours? If it is light weight it should be comparable to some of those.

Edit: Yeah for bad explanation I just add the word density here because that is what it is all about here :D
Would be quite hard, I only have a small piece of foam, all tore up.

Andre, the edge showing, is that a cut you made, or from the factory?

Does it break apart at all when you cut it?

What is the foam sold as? What is it's original purpose?

On the left and right side, it appears to be compressed, is that the result of cutting? Does it dent easily?
I made that cut.
It does not break apart if cut with a good knife.
The foam is sold as foam. They don't know the name. Nor it's purpose. It's a small test batch they have bought.
The edges are a result of carrying it in the pocket of my jeans.

looks like epp with a coat of paint..but then again not a foam expert-
Nope, not paint.
 

FlyingMonkey

Stuck in Sunny FL
Staff member
Admin
#20
What is the difference between Depron, FFF, Foamboard, EPS, etc?
Let's see if I can get you the basics, and maybe someone smarter than I am can put together a good thread on this for people to link to in the future.

Polystyrene is the actual material the foam is made out of, from there the differences are the result of how it's formed. First of all EPS denotes that it is an expanded foam. Versus XPS type foams which are extruded.

You have two main types of the expanded foam. You have open cell foam, like you're used to with drink coolers. It has the flakey balls that stick to everything when they break. Then you have closed cell foams. These are the denser foams that at least here, are often sold in 4x8 sheets, in thickness from 1/2 inch up to a 2 inch thickness.

Depron is an example of extruded foam, it's what they use in foam board, the kind with the paper on both sides. So is the FFF that you often hear referred to. They differ in thickness and density.

Then you have EPP. This is the abbreviation for Expanded Polypropylene. This is the bouncy foam. This stuff can be bent double on itself and not break. It's great for planes because of this, it's also bad for planes, because of it's lack of rigidity. Often carbon fiber is used to reinforce this foam.


I think that covers the basics. Hope this helps.