Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

A couple of things to consider:
-Keeping the weight down.....a couple of pounds is not a big deal,
just not 15 or more.

-How to apply graphics or even keep the natural look of the wood- do
you apply graphics under the fiberglass?

-Can I paint the wood? Before and/or after the application of the
fiberglass? The use of stains?

-How much stronger will fiberglass make the wood?

-Application?

-Prices?

-Where to buy?

-Other options?

Thanks, Jay.

On Sun, 10 Jun 2007 13:39:41 -0700, wrote:

-How much stronger will fiberglass make the wood?

Check out the fiberglass cloth they apply to wooden boats and
airplanes. You end up with an amazingly strong, lightweight
structure. Check this out:

http://www.roarockit.com/d_builder.php
http://www.lushlongboards.com/index.php?cPath=199_252
http://users.pandora.be/Toothless/To...ons_index.html

There are a few experienced boat builders here. I'm sure they'll
chime in with some really good information.

---------------------------------------------
** http://www.bburke.com/woodworking.html **
---------------------------------------------

wrote:
Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

A couple of things to consider:
-Keeping the weight down.....a couple of pounds is not a big deal,
just not 15 or more.

-How to apply graphics or even keep the natural look of the wood- do
you apply graphics under the fiberglass?

-Can I paint the wood? Before and/or after the application of the
fiberglass? The use of stains?


If you build a fiberglass/plywood sandwich, the plywood becomes a filler
and it's strength is of little value.

What you want to do is done every day; however, foam is the normal core
material, not plywood, to keep the weight down.

What are you trying to build?

Lew

wrote in message
oups.com...
Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

A couple of things to consider:
-Keeping the weight down.....a couple of pounds is not a big deal,
just not 15 or more.

-How to apply graphics or even keep the natural look of the wood- do
you apply graphics under the fiberglass?

If the fiberglass is thin it will be pretty tranparent. Thicker will get
milky.

-Can I paint the wood? Before and/or after the application of the
fiberglass? The use of stains?

The fg will stick to wood better than it will to paint. Probably best to
dye it, though a thin stain shouldn't hurt much.

-How much stronger will fiberglass make the wood?

It will make it much stronger, but not all that much more rigid unless you
make it quite thick. One of the nice things about fiberglass is how
flexible it is.

-Application?

A bit too difficult to get into here. I am sure there are many websites
that explain it.

-Prices?

Glass is cheap; epoxy is not. I buy it by the gallon for about $100, but I
am sure smaller containers are available.

-Where to buy?

Boating stores, or maybe woodworking stores.

-Other options?

Aluminum?
I just saw a TV show on making skateboards; quite interesting.

Thanks, Jay.

In article .com,
wrote:

Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

Check out http://www.epoxyworks.com/, specifically the article titled,
'Fortifying a spare-parts "Scootboard"'.

All of the strength is in the fiberglass (or, in this case, carbon fiber)
skins. A common boatbuilding technique is to laminate fiberglass top and
bottom skins over balsa. The balsa provides no strength by itself; it just
holds the two skins apart. Think torsion box.

wrote in message
oups.com...
Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

A couple of things to consider:
-Keeping the weight down.....a couple of pounds is not a big deal,
just not 15 or more.

-How to apply graphics or even keep the natural look of the wood- do
you apply graphics under the fiberglass?

-Can I paint the wood? Before and/or after the application of the
fiberglass? The use of stains?

-How much stronger will fiberglass make the wood?

-Application?

-Prices?

-Where to buy?

-Other options?

Thanks, Jay.


You might try TAP Plastics if there is one in your area, they carry the
cloth and the resin. I think if I was going to fabricate a skate board, I
would make the core out of Balsa wood, and in the area where the trucks are
to be fastened reinforce this area with either hardwood or even a plate of
steel that you can drill and tap to secure with machine screws..

The process is one where you mix the resin and then "paint" the goo onto
your core. While wet, you then lay the cloth over the sticky stuff and
smooth it into the goo.

When the resin cures, you then paint on a another layer of goo, and
completely saturate the underlying cloth. Another layer of cloth is then
applied and smoothed over and then recoated. You keep this up until you get
to the desired thickness, and then you change to a finish coat that tends to
dry a little less sticky than the undercoats. The finish coats can be clear
or it can be pigmented. For a skate board you might also get some additives
that you sprinkle on the top to give you some traction.

Alternatively you could finish the whole thing smooth and apply traction
tape.

If your goal was to make a thin board you might forgo the core and make
yourself a female mold to form the board into. Here you have to be careful
to maintain the appropriate draft angles, and the process would be to make
the mold smooth and then you wax it or spray a mold release agent. Now you
paint on the finish coat or gel coat, and then work your way backwards by
then applying the resin, glass and resin, and any blocking for attaching the
wheels, and finishing with a finish coat for the bottom when you have built
up the board to the desired thickness.

It stinks to high heaven, and mucking about with the fiberglass cloth will
give you little micro-cuts that will leave you itching for a while, but by
doing it yourself, you can get anything you want.

--
Roger Shoaf

If knowledge is power, and power corrupts, what does this say about the
Congress?

Sun, Jun 10, 2007, 1:39pm (EDT-3) stumbles in and
mumbles:
Hi,
********I'm trying to make a board similar to a
skateboard. snip
-Other options?

"Similar" to a skateboard, eh? And, "other" options? We don't
even know what you want to do, so how can we offer options? So many
questions; so few details. Makes one wonder. How about some details?



JOAT
If a man does his best, what else is there?
- General George S. Patton

When the resin cures, you then paint on a another layer of goo, and
completely saturate the underlying cloth. Another layer of cloth is then
applied and smoothed over and then recoated. You keep this up until you
get
to the desired thickness, and then you change to a finish coat that tends
to
dry a little less sticky than the undercoats. The finish coats can be
clear
or it can be pigmented. For a skate board you might also get some
additives
that you sprinkle on the top to give you some traction.

Works better if you apply all your layers before anything cures. That way
it is one structure instead of multiple structures glued stuck together.
I have never heard of this finish coat you refer to. Since hardened epoxy
isn't the least bit sticky, how could the finish coat be less sticky?

"Toller" wrote in message
...
Works better if you apply all your layers before anything cures. That way
it is one structure instead of multiple structures glued stuck together.
I have never heard of this finish coat you refer to. Since hardened epoxy
isn't the least bit sticky, how could the finish coat be less sticky?



Have you ever installed a fiberglass shower stall?

The gel coat is hard and smooth, but the back side has sort of a sticky feel
to me.

You could be correct about the best technique for laying up the glass, my
experience was only onetime helping my brother fiberglass a plywood boat and
that was done in several stages.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

"Roger Shoaf" wrote in message
...

"Toller" wrote in message
...
Works better if you apply all your layers before anything cures. That
way
it is one structure instead of multiple structures glued stuck together.
I have never heard of this finish coat you refer to. Since hardened
epoxy
isn't the least bit sticky, how could the finish coat be less sticky?



Have you ever installed a fiberglass shower stall?

The gel coat is hard and smooth, but the back side has sort of a sticky
feel
to me.

The shower stall might have been polyester resin. The base resin never
cures where it is exposed to air. You can either cover it with poly or use
a top coat that will cure with air exposure. Epoxy isn't like that.

You could be correct about the best technique for laying up the glass, my
experience was only onetime helping my brother fiberglass a plywood boat
and
that was done in several stages.

You can do in several stages, but then you are relying on each layer to
stick to the one before. It is much better to do it in one pour, if
possible.

On Sun, 10 Jun 2007 13:39:41 -0700, wrote:

Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

A couple of things to consider:
-Keeping the weight down.....a couple of pounds is not a big deal,
just not 15 or more.

-How to apply graphics or even keep the natural look of the wood- do
you apply graphics under the fiberglass?

-Can I paint the wood? Before and/or after the application of the
fiberglass? The use of stains?

-How much stronger will fiberglass make the wood?

-Application?

-Prices?

-Where to buy?

-Other options?

Thanks, Jay.

Use balsa instead of plywood, slice it to your thickness on endgrain,
use more than one piece, edge glue the pieces together just to hold to
make a rough panel (flat board with wax paper helps here), then cut
your final shape . Glass it all around, be sure to wet in the glass
to the balsa endgrain, it will soak up a lot of the epoxy and because
it is on end, will give you very good compressive strength. Tensile
and torsion strength comes from the glass/epoxy, balsa does nothing
there.

That is the way many fiberglass boat decks are constructed and they
are very strong. Other method is a foam or honeycomb core, but more
expensive, don't know if you can get a small quantity of honeycomb.

Internet for prices and sources of glass and epoxy resin. Most
recently I bought from U. S. Plastics, they had the best price. Hobby
shops for balsa. I managed to get a 4 X 4 piece of balsa to slice
into my tiles for some boat deck repair.

Don't paint the wood. will seal off the endgrain and it's not pretty,
so you don't want to see it. Paint the component afterwards or put a
coloring agent in the final coat of epoxy. Final coat will probably
need a thickening agent to get the build up you need to not be sanding
into the glass cloth.

my $.02 worth

Frank

On 10 Jun, 21:39, wrote:

I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on.

Fibreglass is generally used with polyester resins, not epoxy. Epoxy
is used for the really high-end stuff, but it's expensive and a pain
to work with. Unless you've tried GRP already and found it wanting,
then you're best sticking with the cheap stuff.

Although this stuff is easily available, the prices for small
quantities in car spares places are ridiculous too. Any reasonable-
sized city will have a fibreglass specialist selling it far cheaper.

As to the "adding strength" issue, then you have to think carefully
about what "strong" means in your case. Simply adding a bit of resin
and maybe mat to plywood will make the surface harder and may make
attachment points less likely to pull out. However for real strength
in bending, and especially stiffness and resistance to bending, then
you're more likely to make a double-layered fibreglass beam with two
strong surface skins and a weak filler material between them that's
there as a former, not for strength. You can make surfboards and
airplane wings with just a foam core, so you don't need to be using
heavy plywood any more. You might well find yourself going from "GRP
as an addition" into a full-blown GRP structure design, using a core
that's just the lightest wood (or foam) you've got.

There's an awful lot already published about this stuff. Search for
boat or surfboard building advice.

Plan to make several. Most people find it quicker to get it right
second time around, after some pratice. 8-)

Others have given you a lot of good how-to information that should help you.

If you want some idea of how strong a piece of plywood becomes when covered
with fiberglass, here is an example.
I have a manufactured trench cover that is 4' wide and 8' long. It was made
for placing over a ditch in a roadway so traffic can pass over it. My trench
cover was made from a sheet of 3/4 void free 11 lamination birch plywood
covered on both sides with about 1/4 inch of fiberglass cloth and resin. It
is rated by the manufacturer to carry 3500 pounds per axle across a 4 foot
span, and I'm sure that this is a conservative rating, as it has seen quite
a bit more than that a few times without suffering any damage at all. When
spanning a 7' gap I have had 6 people standing closely together in the
middle of it and it has only bowed down about 1 inch. It's heavy though. It
weighs about 90 pounds, which is over 2X the weight of a similar sized
un-fiberglassed sheet of plywood.

A 1/4" piece of plywood covered on all sides with fiberglass cloth and resin
should make an extremely tough scateboard, but it might not be thick enough
to hold screws for attaching the wheel assemblies. You could go with thicker
plywood or place metal inserts in the fiberglass/plywood assembly and then
attach the wheels to these pieces of metal.

How are you planning to bend up the ends? Skateboards that I have seen were
manufactured by gluing the plywood laminations in a form. In other words,
they make the plywood to shape and then cover it.

Charley


wrote in message
oups.com...
Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

A couple of things to consider:
-Keeping the weight down.....a couple of pounds is not a big deal,
just not 15 or more.

-How to apply graphics or even keep the natural look of the wood- do
you apply graphics under the fiberglass?

-Can I paint the wood? Before and/or after the application of the
fiberglass? The use of stains?

-How much stronger will fiberglass make the wood?

-Application?

-Prices?

-Where to buy?

-Other options?

Thanks, Jay.

Andy Dingley wrote:

Fibreglass is generally used with polyester resins, not epoxy.

Not true.

There are a lot of epoxy/glass laminations out there, including my boat.

Epoxy
is used for the really high-end stuff, but it's expensive and a pain
to work with.

Again, I take exception.

Slightly different methods of layup, but it ain't rocket science.

Glass/Epoxy ratios of 50-50 are quite common. Higher with vacuum bagging.

Glass/Polyester ratios of 35-65 are about as good as you can get.


Bottom line....................

Glass/epoxy is much less weight for the same strength.

Simply adding a bit of resin
and maybe mat to plywood will make the surface harder and may make
attachment points less likely to pull out.

Mat is strictly for polyester, not epoxy.

It adds weight, but not strength.

However for real strength
in bending, and especially stiffness and resistance to bending, then
you're more likely to make a double-layered fibreglass beam with two
strong surface skins and a weak filler material between them that's
there as a former, not for strength. You can make surfboards and
airplane wings with just a foam core, so you don't need to be using
heavy plywood any more. You might well find yourself going from "GRP
as an addition" into a full-blown GRP structure design, using a core
that's just the lightest wood (or foam) you've got.

Yep, which is why I asked the question, "What are you building?"

Lew

On Mon, 11 Jun 2007 17:09:14 GMT, Lew Hodgett
wrote:

Andy Dingley wrote:

Fibreglass is generally used with polyester resins, not epoxy.

Not true.

There are a lot of epoxy/glass laminations out there, including my boat.

I'd suggest that you're unusual in this, being significantly more
experienced than most. Maybe boatbuilders are fussier.

Certainly here in the UK, for "hobby" levels of work or even small
dinghy makers, polyester is _far_ more common than epoxy. Just the price
of resins is enough to swing it.

Epoxy
is used for the really high-end stuff, but it's expensive and a pain
to work with.

Again, I take exception.

Slightly different methods of layup, but it ain't rocket science.

I've never used epoxy that didn't need vacuum and controlled moderate
heat. This has been with either prepreg carbon, or Kevlar. I've never
used a grade of epoxy that wasn't fussy enough to require this -- when
I've been working at that level, with glass, or 20-30 years ago it was
always just polyester. There are certainly such epoxies around that
aren't so fussy (I use West System for general gluing), although I've
never used it seriously for fibreglass.


Glass/Epoxy ratios of 50-50 are quite common. Higher with vacuum bagging.

Glass/Polyester ratios of 35-65 are about as good as you can get.

Glass/epoxy is much less weight for the same strength.

If you have the skill to achieve that sort of wetting out. "Typical" UK
amateur skill levels (I'm coming to this from the kitcar world) are
often distinctly heavyweight, certainly on the first projects.


Simply adding a bit of resin
and maybe mat to plywood will make the surface harder and may make
attachment points less likely to pull out.

Mat is strictly for polyester, not epoxy.

What do you mean by "mat" ? I'm referring to weaves, as well as choped
strand. Maybe this is a local terminology issue?

Incidentally, there's an epoxy thread in rec.knives at the moment. How
do you best attach scales to a metal frame ?

Andy Dingley wrote:

I'd suggest that you're unusual in this, being significantly more
experienced than most. Maybe boatbuilders are fussier.

Naw, just set in their ways and scared to death of $$ signs.

Just look at initial price of materials, not finished cost of laminate.

OTOH, you tend to get a little fussy when you are building for
yourself, which is what I did.

Certainly here in the UK, for "hobby" levels of work or even small
dinghy makers, polyester is _far_ more common than epoxy. Just the
price
of resins is enough to swing it.

Again, got to look at finished laminate cost.

Yes, epoxy is more costly than polyester.

Yes, knitted glass used with epoxy is more expensive than 1/2 OZ mat
and woven roving.

That said, you use less epoxy by weight and about the same amount of
glass, thus the total laminate cost is about the same.

It is also far easier to wet out knitted glass with epoxy than it is
to wet out mat and roving with polyester, thus there is some labor
savings once you ramp up the learning curve.

I've never used epoxy that didn't need vacuum and controlled moderate
heat. This has been with either prepreg carbon, or Kevlar.

Different world.

Never worked with either one, but understand they are a bear compared
to knitted glass.

I've never
used a grade of epoxy that wasn't fussy enough to require this -- when
I've been working at that level, with glass, or 20-30 years ago it was
always just polyester. There are certainly such epoxies around that
aren't so fussy (I use West System for general gluing), although I've
never used it seriously for fibreglass.

Standard WEST is laminating resin.

There are only 4-5 base resin (Part A) manufacturers world wide.

Shell, Dow, Ciba come to mind.

Lots of formulators for the hardener (Part B) like WEST.


If you have the skill to achieve that sort of wetting out. "Typical" UK
amateur skill levels (I'm coming to this from the kitcar world) are
often distinctly heavyweight, certainly on the first projects.

It's a basic problem with polyester, mat and woven roving.

Roving doesn't wet out easily, thus the mat is used to hold the resin.

OTOH, epoxy readily wets out knitted glass so it is easy to squeegee
out excess resin.

The trick is the knitted glass.

What do you mean by "mat" ? I'm referring to weaves, as well as choped
strand. Maybe this is a local terminology issue?

"Mat and roving" describes a glass that consists typically of a layer
of 24 OZ woven roving with a 1/2 OZ stranded mat stitched to it.

Been the backbone of the polyester boat building industry for years.

BTW, chopper guns in the USA are a thing of the past. Changes in the
environmental laws have turned them into antiques.

It's only been the last 10-15 years that knitted glass has started to
see some acceptance.

Old habits die hard.

Incidentally, there's an epoxy thread in rec.knives at the moment. How
do you best attach scales to a metal frame ?

What does the term "scales" mean in the above?

Lew

On 12 Jun, 00:42, Lew Hodgett wrote:

Incidentally, there's an epoxy thread in rec.knives at the moment. How
do you best attach scales to a metal frame ?

What does the term "scales" mean in the above?

Flat bits of wood or antler. Typically a folding knife will have two
thin metal "liners" between these and the blade itself.

If you're making a knife from scratch, then you rivet the scales to
the liners (easy), then you rivet the liners together around the blade
etc. (rather more work) If you're _repairing_ one though, you often
need to re-attach or attach new scales to liners that are already in
place around the blade, lock and folding mechanism. This is awkward,
as it's impractical to use the scale rivets, owing to poor access.

The temptation is to glue the scales to the liners, which is dead easy
but doesn't usually work too well. There's a lot of bending here and
an inelastic adhesive will tend to break off. As many liners are
brass, it can be a real problem. Personally (for repairs) I like to
leave the stumps of old rivets behind as crude dowel pins.

Andy Dingley wrote:
snip a tale of pocket knife reconstruction

The temptation is to glue the scales to the liners, which is dead easy
but doesn't usually work too well. There's a lot of bending here and
an inelastic adhesive will tend to break off. As many liners are
brass, it can be a real problem. Personally (for repairs) I like to
leave the stumps of old rivets behind as crude dowel pins.

Think I'll stick to boatsG.

BTW, might try some epoxy thickened with microballoons as an adhesive
for the scales/liners connection.

Yields a much better joint than plain epoxy.

Lew

In adition to what has been said befo in order to obtain the lowest
weight and the highest strenght, you must be carefull not to add too
much resin.
In commercial application, the parts are coverered with a plastic film
and then vaccumed, to eliminate excess resin and/or air bubbles. Your
option would be to press the layers into place using a roller.
For finishing, auto body primer/filler would be good, sanded after
each application, painted as desired, with a few coats of clear in the
end. Try to get the sort of paint that won't crack easily when bent.