During the flying session yesterday, I had a new flyer with zero stick experience (even on the sim) on a trainer cord, and we were flying the AXN Floater.  Since the new flyer also had ordered one of these, the discussion moved to the material used on this.  From the website of the original manufacturer of this model (http://www.rc-model.cn/802.htm), I remembered that it was made of "Elapor" foam, but our friend Murali was not convinced.  I noticed that the website also now says EPO instead of "Elapor", although I was convinced that the word Elapor was mentioned somewhere there earlier.

Anyways, Murali sent in this clarification via PM this morning, about the differences between such materials.


Hi Anwar,
I was searching for more info on elapor, other foams and found the following. Though to share as it might help  others modelers here.

Elapor is proprietary composition and Multiplex Robbe models use it. Many RC model companies may switch to this
ELAPOR and ARCEL are not EPP.

EPP (Expanded Polypropylene) stands on its own as the toughest, most resilient foam, great in compression, will tear in tension. Needs strapping tape to carry the tension loads. Downside is it is difficult to mould.

Arcel is a composite of EPS (Styrofoam) 70%, and PE (Polyethylene) 30%.

EPO: Expanded Poly Olefin , see below for more info

Elapor is probably similar to Arcel but its mix is not revealed.

Both of these are a bit softer in compression than EPP, but are nonetheless VERY good, with the tremendous advantage of being able to be molded for mass production.

You put Elapor Foam together with regular CA glue so I just fixed all the cracks and broken parts with that. Boiling water makes the Elapor Foam beads swell up and after dipping the nose in the hot water and using my hands to help remold, the cells got back their "memory" and with the back of a spoon to smooth out the surface cells again and a touch up of paint, the Twister looks almost as good as new.

EPO is definitely not EPP. It looks similar to Elapor but it has a greasy feel to it.

What kinds of glue work on EPO?
"Regular CA?" Yes but needs kicker.
"Epoxy?" No
"Gorilla Glue?" Yes
"White and yellow glues?" No
"Others?" GWS Glue or Polyurethane glues

"Can we use fillers with EPO to get smoother finishes? What kind?" Fillers are not needed and possibly would not stick well.

"What kind of sanding considerations? Will it sand?" Yes it sands well, but the kits need very little sanding. The surface finish is almost as good.

"Any special considerations for paint? Water based?" Solvent based? You can use any type of paint that will stick. Both water and solvent based will work but some paints require a primer.

"Can I apply Monokote or similar coverings to it?" no reason to as the finish is pretty smooth.

"A common repair method with Elapor is to heat it with hot water to expand it after a hard bump. Will EPO work the same way? Probably

if they say to use foam safe CA, then it's definitely NOT Elapor. Multiplex, who came up with the stuff (or at least it's name) makes it quite clear in their Elapor plane instructions NOT to use foam safe on their planes, as it will not provide a sufficient bond. Although I have heard of people using Gorilla Glue successfully.

EPO: Expanded Poly Olefin
Polyolefin - Polyolefins are the largest group of thermoplastics, often referred to as commodity thermoplastics, they are polymers of simple olefins such as ethylene, propylene, butenes, isoprenes, and pentenes, and copolymers and modifications thereof. The term polyolefins means "oil-like" and refers to the oily or waxy feel that these materials have. Polyolefins consist only of carbon and hydrogen atoms and they are non-aromatic. Polyolefins are usually processed by extrusion, injection molding, blow molding, and rotational molding methods. Thermoforming, calendering, and compression molding are used to a lesser degree. An inherent characteristic common to all polyolefins is a nonpolar, nonporous, low-energy surface that is not receptive to inks, and lacquers without special oxidative pretreatment. The two most important and common polyolefins are polyethylene and polypropylene(EPP::$) and they are very popular due to their low cost and wide range of applications.

Some links for more info

http://www.ides.com/generics/Polyolefin.htm
http://www.rcgroups.com/forums/showthread.php?t=684387&highlight=epo
http://www.eflightwiki.com/eflightwiki/index.php?title=Elapor

Cheers
Murali

 

Foam board (biofoam?), Insulation styrofoam and EPP.

Is there any source of EPO in India...?