Anyone know the weight difference?

[Lou]

Does anyone have the knowledge of what the weight difference is between
1 square ft. of 3 mil. plywood and 1 square ft. of 1/2" styro core
composite?
Or maybe someone could give me the weight of the 1 square ft. of 1/2"
styro core composite?
Lou

[Roger]

On Wed, 04 Jan 2006 19:05:51 -0800, Richard Riley
> wrote:

>On 4 Jan 2006 18:08:58 -0800, "Lou" > wrote:
>
>:Does anyone have the knowledge of what the weight difference is between
>:1 square ft. of 3 mil. plywood and 1 square ft. of 1/2" styro core
>:composite?
>:Or maybe someone could give me the weight of the 1 square ft. of 1/2"
>:styro core composite?
>: Lou
>
>Sorry, not enough information to be accurate but we can wing it :^)
>
>The core's going to be around 2 - 3 oz. Bidirectional fiberglass will
>be about 1 oz per ply plus 1/2 oz per ply for epoxy. 2 or 3 plies per
>side, so about 8 to 12 oz. YMMV

You can make it a whole lot more compact if you use Vinyl Ester Resin
though. I'm assuming you are talking about Styrofoam (TM) the blue
construction foam. (has a styrene solvent in it)

I was using some Styrofoam as spacers under one corner at the front
end of the G-III. I "dripped" a little excess Vinyl Ester resin on
the *stuff* and it just plain vanished. I guess there is a reason
they don't use that stuff on wet lay-ups over Styrofoam cores. <:-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Rich S.]

"Lou" > wrote in message
ups.com...
> Does anyone have the knowledge of what the weight difference is between
> 1 square ft. of 3 mil. plywood and 1 square ft. of 1/2" styro core
> composite?
> Or maybe someone could give me the weight of the 1 square ft. of 1/2"
> styro core composite?

The weight difference between Okume or Mahogany plywood and that of Finnish
Birch is significant as well.

Rich S.

[Lou]

Thats true, the plane I'm building calls for 3 mil Okume. I've come
across a website of a kr2 builder who decided to install the
composite/foam instead of plywood. Unfortunatly he didn't weight
anything before he made this change. Also he oversized everything on
the plane and made quite a few modifications. His plane is overweight,
but doesn't know if it's from the redesign, the oversize, or the
material change. I like how it's coming out and it promises to be a
very slick machine.
Lou

[Rich S.]

"Lou" > wrote in message
ups.com...
> Thats true, the plane I'm building calls for 3 mil Okume. I've come
> across a website of a kr2 builder who decided to install the
> composite/foam instead of plywood. Unfortunatly he didn't weight
> anything before he made this change. Also he oversized everything on
> the plane and made quite a few modifications. His plane is overweight,
> but doesn't know if it's from the redesign, the oversize, or the
> material change. I like how it's coming out and it promises to be a
> very slick machine.

Sure hope he registers it as a "Swiftfoam Special" or something other than a
"Rand KR2". I can understand the toothgrinding that a designer suffers when
someone substantially alters their design, yet keeps the name the same.

2 mm Finnish Birch is the equivalent in weight and strength to 3 mm Okume,
IIRC.

Rich S.