Fiberglass vs. Fabric

cavelamb wrote:

Once the fabric touches the resin - it's stuck.

Get your surface all good and preped, then spray it with a light
dusting of hair spray. It's just tacky enough to hold the fabric in
place, but let you peel it off and reposition it.

But how to wet it out?
On a vertical surface too?

Well, glass this thin, might just be able to spray it(?)
HVLP?

That's an interesting idea. Maybe one of Vdubber's Harbor Freight
touch up guns, with the disposable jars.

rocky wrote:
Lou wrote:
Ok, I just finished reading Tony Bingelis's "sportplane builder"
section on covering a wooden plane with fiberglass instead of the
intended fabric. Has anyone in this group ever done this or some who
knows someone who has done this? I'm building a wooden place that
calls for
a fabric covering. I've tried to do as much homework on this subject
as I can but still can not come up with a weight difference between
fabric and a thin coat of fiberglass. I know that the fabric is not
structural so why can't I subsitute a lightweight fiberglass for the
fabric?
Any feedback?
Lou

The fiberglass you're refferring to goes by the name of RAZORBACK.
Various military planes used it like the PT-19B

Razorback is it's own covering system, using dope on fiberglass cloth
IIFC. Bingelis' technique is to use light fiberglass over plywood,
using the same resin one normally uses.

--

FF

Richard, won't the hairspray interfere with the adhesion of the resin?
Lou

Lou wrote:
What you described is what my plans call for. Wooden ribs with plywood
over but
routed inbetween. Then on top of the plywood I'm to install the fabric.
This is just one
of the areas that I want to replace the fabric with fiberglass. It is
obcviously not structural.
So replacing with fiberglass should give me a smoother, harder finish.
Also, I would like to know if this finish will give me a better gph for
trips not to mention maybe, just maybe a few more knots. Yes I would
love to talk to your friend.
Lou

Ahh so the fabric is to be a non structural skin over open bays like any
normal fabric covering. If you apply a rigid glass/epoxy skin it will
be the same as skinning the entire wing in plywood.

The ply is routed out between the ribs to save weight in an area where
the ply provides no structural benefit. If you want to create a rigid
glass/epoxy skin over an area that is normally covered with flexible
fabric it will have to be stiff enough to support air loads without
deforming. It will be much heavier than a fabric layer would be.

You might as well skin the entire wing in ply and use a minimal glass
layer as a protective coating. Either way you are going to end up with
a much heavier wing.

A rigid skin in the area aft of the spars designed for open bays with
flexible fabric will make no significant difference in speed if the a/c
goes under 150 mph, and it will cost you many pounds in weight.

Use a polyurethane covering process on those areas intended for fabric
over open bays. Only use glass/epoxy only on fully skinned components.


John

Hi John,
One of the idea's I came across was to insert styrofoam into the wing
under the routed plywood to keep the wing shape. Then apply the
fiberglass over the entire wing. Do you think this will be a waste of
time?
Lou

Lou..........

I have read most of the postings and replies on your idea. The thing that
comes to mind is why you would want to do such a thing? It makes no sense
whatever. Keep in mind the homebuilder's mantra:

"Follow the plans, add only lightness.

Follow the plans, add only lightness.

Follow the plans, add only lightness."

Repeat this every day as you begin your work.

Rich S.

J.Kahn wrote:

...

You might as well skin the entire wing in ply and use a minimal glass
layer as a protective coating. Either way you are going to end up with
a much heavier wing.


Having read his book, I think that is exactly what Bingelis did, with
either the wing, or the fuselage, or both.

The advantages were a smoother surface, though I daresay proper
wood finishing technique would produce as smooth s surface
with considerably less work and wieght, and improved resistance
to the elements.

I believe he said it added 10 to 15 lbs to the plane.

--

FF

wrote in message
oups.com...

J.Kahn wrote:

...

You might as well skin the entire wing in ply and use a minimal glass
layer as a protective coating. Either way you are going to end up with
a much heavier wing.


Having read his book, I think that is exactly what Bingelis did, with
either the wing, or the fuselage, or both.

The advantages were a smoother surface, though I daresay proper
wood finishing technique would produce as smooth s surface
with considerably less work and wieght, and improved resistance
to the elements.

I believe he said it added 10 to 15 lbs to the plane.

--

FF

I wonder if the thin glass skin, over the plywood, would eliminate the
sagging 'tween rib bays that a Pulsar builder experienced. He was skilled
at woodworking, IIRC, but complained about sagging 'tween rib bats in humid
weather. I don't know the details, unfortunately.

As I indicated in a previous reply to this thread, he routed out the plywood
and fabricated sheets of fiberglass/epoxy as a thin "skin" that he then
applied as if it was plywood skin material. No sagging and he liked the
result. I have no details about weight penalty, engineering changes (extra
thickness all around because of the plywood over the ribs, spar, etc.).

I am trying to locate the Pulsar builder to see if his experiences could be
made available for this thread.

Michael Pilla

On Mon, 19 Jun 2006 13:22:00 -0600, "Michael Pilla"
wrote:


--

FF

I wonder if the thin glass skin, over the plywood, would eliminate the
sagging 'tween rib bays that a Pulsar builder experienced. He was skilled
at woodworking, IIRC, but complained about sagging 'tween rib bats in humid
weather. I don't know the details, unfortunately.

Probably coating the entire plywood covered wing, inside and out with
cladding epoxy would eliminate the changes brought on by humidity
variations.

Probably coating the entire plywood covered wing, inside and out with
cladding epoxy would eliminate the changes brought on by humidity
variations.


You may be familiar with "Wood/Epoxy Saturation Technique"
That has been used in boat building for decades?

How about "WEST systems" epoxy?

Yep - that's where the "WEST" in WEST systems comes from.

The wood gets soaked all the way through, so the wood is just there for
support, and it seems to last forever.
I BOILED some samples for 24 hours with no degradation other than a bit of
color change. Add light fiberglass over that...