composite using aluminum windowscreen layer

[Allan Morrison]

Can anyone see an advantage using aluminum windowscreen for a layer or
layers in a composite structure.
The outer layer(s)could be fiberglass where exterior smoothness is
required.
At ~0.5 oz per ft^2 it should be useful for something where high
strength to weight is desired.
Has it been used in some previous design?
Comments please.

[Orval Fairbairn]

In article >,
(Allan Morrison) wrote:

> Can anyone see an advantage using aluminum windowscreen for a layer or
> layers in a composite structure.
> The outer layer(s)could be fiberglass where exterior smoothness is
> required.
> At ~0.5 oz per ft^2 it should be useful for something where high
> strength to weight is desired.
> Has it been used in some previous design?
> Comments please.


If you count on the aluminum adding strength to the structure, be sure
that it has the same modulus of elasticity as the rest of the composite
material, else one will be taking up far more load than the other.

Example: If you have a 2 lb brick and attempt to support it with a
rubber band that will take 1.5 lb and a spring that will take 1.5 lb, in
parallel, the arrangement should support 3 lb, right?

WRONG! The rubber band will carry very little of the load until the
spring breaks; then the rubber band will carry more load than it can
handle.

[Ed Sullivan]

On 26 Jan 2005 19:41:26 -0800, (Allan Morrison)
wrote:

>Can anyone see an advantage using aluminum windowscreen for a layer or
>layers in a composite structure.
>The outer layer(s)could be fiberglass where exterior smoothness is
>required.
>At ~0.5 oz per ft^2 it should be useful for something where high
>strength to weight is desired.
>Has it been used in some previous design?
>Comments pl

I used it to form a small fairing between the leading edge of the fin
and the fuselage on my Jungster. The reason being when stretching the
screen on the bias it will form a very tight compound radius. I taped
it down and applied fiberglass over it, then trimmed it to fit. I
don't know that I would use it in an area that was under stress.

Ed Sullivan

[......... :-\)\)]

I don't see the point from a structural point of view.

The only reason you would do this is for lightning protection. Copper and
alumnium meshes are commonly laminated into composite laminates of
certificated airplanes to disipate electical energy associated with a
lightening strike.

However I wouldn't use flyscreen mesh for this. There are products available
for this exact prupose from Astrostrike and Delker (I think they just
changed there name). They are cheap and have a proper surface treatment for
bonding to the epoxy (they are cocured).



"Allan Morrison" > wrote in message
om...
> Can anyone see an advantage using aluminum windowscreen for a layer or
> layers in a composite structure.
> The outer layer(s)could be fiberglass where exterior smoothness is
> required.
> At ~0.5 oz per ft^2 it should be useful for something where high
> strength to weight is desired.
> Has it been used in some previous design?
> Comments please.

[[email protected]]

Allan Morrison wrote:
> Can anyone see an advantage using aluminum windowscreen for a layer
or
> layers in a composite structure.
> The outer layer(s)could be fiberglass where exterior smoothness is
> required.
> At ~0.5 oz per ft^2 it should be useful for something where high
> strength to weight is desired.
> Has it been used in some previous design?
> Comments please.

I've used this several times to build quick and dirty scoops for wind
tunnel tests of oil coolers. We have a very powerful fan and simulated
airflow equivalents of 230 mph with no degradation of the scoop. I
keep a can of a product we bought several years ago called "Tigerhair"
I think it's made by bondo and usues a standard hardner and catalyst in
a tube...it's mixed like bondo. I used to use window screen but now I
use a stainless mesh with 1/2' grid and .015 dia wire. It's much easier
to form and hold the shape. I only use stainless because we use it on
other stuff and it's available to me, but if aluminum mesh of the same
grid spacing and wire dia. were available it would be perfect. I've
managed to make thin wall sections some as thin as 3/8" using a
combination of tigerhair and bondo, but I see no harm in epoxy gelcoat
for your application, I never trim the excess mesh away because I use
that to form clips to mount the scoop to wind tunnel, but would also
make a good blend skeletin...good luck!