Foam Types

[Solitaire]

Does anyone have a quick explanation of the different types of foam available today for planes and their advantages?

EPO
EPS
EPP
Depron
Z Foam
BluCore
FanFold
Any others?

[BTCat]

Don't forget Dollar General foam. It is just foam board used for presentations. Strip the paper off of each side and you have very cheap foam to build a "throw away" or combat plane. About 5mm thick.

[akent]

What I know:

1. Depron is a very light brittle foam, usually white or gray in color that comes in sheets of various sizes.
Pros: Very easy to work with. Cuts cleanly with a sharp knife. Sands well.
Cons: Very brittle. Crushes and breaks very easily. It is eaten by many paints and glues.
Water based paints work well.
Epoxy, gorilla blue and hot melt glues work well. Welders does not work.

2. Blue core and Fanfold are generally one in the same. These are blue or pink in color and come in folded piles of sheets. These are very similar to depron, but slightly less brittle. This has the same pros and cons as Depron with one extra con: It usually comes warped.

3. EPP is a light to medium foam that is very flexible and durable. It comes in white or black and in various thicknesses and densities.
Pros: Easy to work with, but not as easy as Depron. A plane made with this will survive many many crashes. It is VERY durable and does not crush. Almost all paints and glues work with EPP. I have used Rustoleum, plastic paints, Krylon, and others without issue. All glues that I have used work with EPP, including epoxy, Welders, gorilla glue, and hot melt.
Cons: This foam is VERY flexible, requiring a lot more carbon or other reinforcement than depron, especially with the 1.3# density foams. The 1.9# density foam is much more rigid, requiring less carbon. A very sharp knife is a must, or the cut edges will tear. This foam tears easily, but is easily repaired. It is difficult to sand. It is heavier than Depron.
===========
I believe the EPS, EPO, and Z foams are all molded. I have planes made from EPS and EPO. I think they are very similar. These are crush resistant and fixable to most extents with epoxy, gorilla glue, or hot melt.

That's about all I know!
Kent

[Gabe]

Good info Kent!

[Solitaire]

Thanks, Kent.
I actually thought BluCore was just standard blue styrofoam, like they use in construction.
I'm still unclear on the exact differences between EPS, EPO and ZFoam and why one is used over another.

[19000rpm]

I'd agree with Kent. Although, I don't have any experience with the Blue core, fan folds or foam core board types in aircraft.

[akent]

I have never played around with the Dollar General foam board. It is also available from Michaels and the stuff I saw is made by Elmers. I don't know if that is the same stuff that BT was using.

BT is the expert on this stuff!

Bluecore is available in thick stuff, too, so I think you are exactly right, Sol. I saw some thicker stuff at Home Depot. I felt it and it felt the same as the fan fold blue core. This stuff would probably work great for wings cut with a hot wire into an air foil.

Hey BT, there's something to try with your new hot wire cutter!
Kent

[BTCat]

May 11, 2010 16:46:50 GMT -6 akent said:

I have never played around with the Dollar General foam board. It is also available from Michaels and the stuff I saw is made by Elmers. I don't know if that is the same stuff that BT was using.

BT is the expert on this stuff!

Bluecore is available in thick stuff, too, so I think you are exactly right, Sol. I saw some thicker stuff at Home Depot. I felt it and it felt the same as the fan fold blue core. This stuff would probably work great for wings cut with a hot wire into an air foil.

Hey BT, there's something to try with your new hot wire cutter!
Kent

I have an idea about how to cut wings. IF I EVER GET TIME I'll try it.

Dollar tree foam is slightly less dense than the Elmers stuff, but not so much to make a functional differance. You have to remove the paper covering from both and the Elmers has a very thin plastic membrane that is a little of a pain if you don't get it all off in one big hunk. The DT foam is easy to strip. I dump water on it or even stick it in the shower for a minute. Then after it soaks in, I can peal it. If I am in a hurry, I get the iron and steam it. It literally takes 2 minutes that way. If carefully warmed, DT foam is moldable. I used it to form the Clark-Y airfoil on the Fidget. It is also very easily shaped with sandpaper. Great for combat planes. One dollar plus time and electronics and you are in the air. It is not durable, though.

[Solitaire]

So, if somebody decided to shape a fuse out of BlueCor, what would be a decent covering for it? That foam needs some kind of sealant to keep it from disintegrating.

Some type of non-reactive lacquer, I suppose. Is that available?

[19000rpm]

Maybe Krylon Fusion or an Acrylic.

[Gabe]

I was told by my LHS guy not to paints with laquer. It will eat the foam.

[akent]

If you don't want to use paint, you can use packing tape!!

I ordered 8 rolls of different colored very thin and light packing tape online from somewhere. It is very light tape that sticks very well to blue core or depron. That's what I used on my little delta. This stuff does not stick very well to EPP. I understand that you can spray the foam with a light coat of 3M 77 and it will then stick well.

The combat planes the Austin club flies are only one type of plane, so everyone is playing fairly. It is depron unfortunately. I have two of them cut out. I plan on using this tape for them.

Ah, I just looked at the box, and the tape is from Fastpack Packaging, Inc. in Lee Florida. The website is www.fastpack.net.
Kent

[Solitaire]

Yeah, Krylon may work or possibly a water based type of sealant that can be painted afterwards. Looks like it's experimentation time.

Now I see another type of foam available called Elapor. MultiPlex uses that and I suppose it's their name for EPO, or something.

[19000rpm]

Yep, it's EPO. The J10 I'm building is made of it. It's similar to the Z foam Parkzone uses. Not quite as tough, but I've used regular CA on it so paint shouldn't be a problem. I'll let you know after I test a spot.