Questions About DEPRON Foam Material ?

[Ez2cDave]

I have never used Depron foam ( not EPP ) and I have some questions about the material.

What is its weight, compared to Balsa ?

How rigid / flexible is it ?

Does it break easily?

What adhesives are compatible with it and which are not ?

Can it be sanded ( airfoiled ) and used for Glider wings ( Competition gliders ) and fins ?

In those applications, would it need to be "braced" ( carbon fiber strips ) and / or vaccum-bagged with light FG cloth ?

What are the best sources to get it from ?

Thanks, in advance !

Dave F.

 

[burkefj]

Only one source in the US for 3mm and 6mm, rcdepron.com

I have only used foam safe ca, 3m77 and uhu por contact cements.

It can be sanded. You would need some reinforcing for a thin wing.

6mm is about 2.43 lb per cubic foot or around .7 oz per sq foot, 3mm is slightly denser.


It has some flex but thats a relative term.

Frank

I have never used Depron foam ( not EPP ) and I have some questions about the material.

What is its weight, compared to Balsa ?

How rigid / flexible is it ?

Does it break easily?

What adhesives are compatible with it and which are not ?

Can it be sanded ( airfoiled ) and used for Glider wings ( Competition gliders ) and fins ?

In those applications, would it need to be "braced" ( carbon fiber strips ) and / or vaccum-bagged with light FG cloth ?

What are the best sources to get it from ?

Thanks, in advance !

Dave F.

 

[Ez2cDave]

Only one source in the US for 3mm and 6mm, rcdepron.com

I have only used foam safe ca, 3m77 and uhu por contact cements.

It can be sanded. You would need some reinforcing for a thin wing.

6mm is about 2.43 lb per cubic foot or around .7 oz per sq foot, 3mm is slightly denser.


It has some flex but thats a relative term.

Frank

Frank,

So, for an application like the photo's below, would it be a good choice or something like the "Blu-Cor" foam ? I am thinking about "hot-wire" cutting the airfoil.

Dave F.

 

[Amsterdam]

Incoming long reply.

I would recommend extruded polystyrene foam if you were looking into trying foam builds. it offers a lot of freedom and the material is easily locally sourced.
I've used XPS foam to make freeflight stuff not anything rocket powered yet but that's just from lack of time
I buy "Project Panels" from Menards, Home depot, Lowes. they are 2ft x 2ft and 1" thick
They typically have one brand, whether it be yellow, pink, green, or blue foam. most are R-5, 25psi and have a density of about 1.5lbs/ft3

I use Bob Smiths GOLD foam safe CA for all gluing, the accelerator hasn't hurt the foam either

A hotwire is a must. i use a simple handheld one from Amazon, and a larger one i built, its non adjustable, i use a DC adapter to control the power/ temp,
instead of hotwiring airlfoils (which i could), i cut sheets, then sand the foils in. its easier and more accurate when making 1/8th inch thick or thinner wings

I use aluminum tape for Hotwire templates. stuck directly to the foam,

bracing with either carbon or balsa gives a huge increase in strength, even carbon tow makes a big difference.
skinning is good if you can afford the weight, i have had good luck with an airbrushed coat of thinned polycrylic as a compromise

Here is a document showing how to make an XPS foam scale rubber band plane. all of the cutting and handling techniques are sound advice, but this for an incredibly lightweight indoor model, and they don't get into bracing/ skinning at all.

Indoor Foam Models

In the end I think an investment in XPS over depron is more worthwhile because XPS is locally sourced, potentially cheaper and it opens the door for much more than just wings.

 

[Ez2cDave]

I would recommend extruded polystyrene foam if you were looking into trying foam builds. it offers a lot of freedom and the material is easily locally sourced.

I've used XPS foam to make freeflight stuff not anything rocket powered yet but that's just from lack of time.

I buy "Project Panels" from Menards, Home depot, Lowes. they are 2ft x 2ft and 1" thick.

They typically have one brand, whether it be yellow, pink, green, or blue foam. most are R-5, 25psi and have a density of about 1.5lbs/ft3

In the end I think an investment in XPS over depron is more worthwhile because XPS is locally sourced, potentially cheaper and it opens the door for much more than just wings.

AGREED . . . 100% !

I have been doing more research on this . . . Thanks for the link !

Dave F.