Fiberglass tube

On Jan 11, 3:24 am, Bruce in Bangkok <b_paige_....TakeThisOut@gmail.com> wrote:
> On Wed, 9 Jan 2008 20:32:49 -0500, "Garland Gray II"
>
> <gg....TakeThisOut@nospam.com> wrote:
> >If I were to wax the outside of a piece of 2 1/2 inch pvc pipe about 6 feet
> >long, and then lay up several layers of fiberglass and epoxy, would the
> >resulting tube slide off the pvc easily enough after curing ? Or would I
> >need to first wrap the pipe with sheet plastic or similar ?
> >Thanks !
>
> I don;t believe that you could get the glass off the PVC. I have made
> fiberglass tubing by molding two halves inside PVC pipe split
> lengthwise and using several coats of mold release it still took
> significant prying to get the halves out of the molds.
>
> Bruce-in-Bangkok
> (Note:remove underscores
> from address for reply)

Wrap several layers of waxed paper instead of the newspaper. It never
occurred to me that it might NOT work. Shrug.
 >> Stay informed about: Fiberglass tube 

On Jan 9, 9:32 pm, "Garland Gray II" <gg... RemoveThis @nospam.com> wrote:
> If I were to wax the outside of a piece of 2 1/2 inch pvc pipe about 6 feet
> long, and then lay up several layers of fiberglass and epoxy, would the
> resulting tube slide off the pvc easily enough after curing ? Or would I
> need to first wrap the pipe with sheet plastic or similar ?
> Thanks !

After the goo sets up, running a source of heat inside the pvc could
soften it enough to pull out, or even to melt it out. Epoxy wouldn't
be bothered by the heat required, I suspect.

Alternatively, perhaps a plug of wax wrapped in a seperator would more
easily be melted out. It's called the "lost wax" process.

Or, a spiral coiled cardboard tube could be pulled out after set up.

When I relined my rudder tube, I used epoxy with graphite shaped with
a pvc pipe pulled out before setup and sanded inside after set up
using a balloon and sand paper. I was worried that I might need to
cut a tooth in the rudder post and use it as a tool to bore out the
hole, or to use a hole saw and guide setup.

I am told the "proper" way was to install top and bottom rudder
bearings, but that would have cost quite a bit.

Seems to have worked out, no more jamming or juddering under moderate
loads.

Terry K
 >> Stay informed about: Fiberglass tube 

One solution that I have tried on a smaller scale. Slit the PVC pipe down
one side on a table saw. The pipe should close up a little so the kerf will
be a little less than 1/8". Cut a strip of 3/16 or maybe 1/4" polyethylene
sheet maybe 1/2" wide and fit it in the kerf so that the edge is flush with
the pipe's outer diameter. That will expand the pipe over it's normal
diameter. Wax everything and spray on a couple of coats of PVA mold release.
Mist coat first then a fill coat.

Wrap your glass. If it is uni-directional, diagonally in both directions
then straight once or twice then a top ply of woven on the bias. If you are
vacuum bagging you have to pull all the diagonal and bias plies TIGHT and
tape them well or the fiber will bunch up as the bag pulls it down.

Once it is set up, knock out the poly strip out of the kerf and whack the
outside of the tube lightly to break the release agent and let some air in.
The pipe will spring back to its original diameter and drop out. If it
still sticks soak it in water to dissolve the PVA.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Garland Gray II" <ggray.DeleteThis@nospam.com> wrote in message
news:5Behj.29827$Ft5.7226@newsfe15.lga...
> If I were to wax the outside of a piece of 2 1/2 inch pvc pipe about 6
> feet long, and then lay up several layers of fiberglass and epoxy, would
> the resulting tube slide off the pvc easily enough after curing ? Or would
> I need to first wrap the pipe with sheet plastic or similar ?
> Thanks !
>
 >> Stay informed about: Fiberglass tube 

One other hint for wrapping a tube with uni-directional on an angle.
Multiply the OD of the tube by 3.14 to get the circumference and then by the
sign of the angle you want. For example for your 2.5" tube, the
circumference is 7.85". The sign of 45 degrees is .707 so cut strips of uni
about 5.5" wide. If you keep the edge of each turn next to the previous one
you will have a 45 degree angle.

Again, pull it very tight if you are vacuum bagging.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Glenn Ashmore" <gashmore.RemoveThis@cox.net> wrote in message
news:463ij.33665$pq.20891@newsfe24.lga...
> One solution that I have tried on a smaller scale. Slit the PVC pipe down
> one side on a table saw. The pipe should close up a little so the kerf
> will be a little less than 1/8". Cut a strip of 3/16 or maybe 1/4"
> polyethylene
> sheet maybe 1/2" wide and fit it in the kerf so that the edge is flush
> with the pipe's outer diameter. That will expand the pipe over it's
> normal diameter. Wax everything and spray on a couple of coats of PVA mold
> release. Mist coat first then a fill coat.
>
> Wrap your glass. If it is uni-directional, diagonally in both directions
> then straight once or twice then a top ply of woven on the bias. If you
> are vacuum bagging you have to pull all the diagonal and bias plies TIGHT
> and tape them well or the fiber will bunch up as the bag pulls it down.
>
> Once it is set up, knock out the poly strip out of the kerf and whack the
> outside of the tube lightly to break the release agent and let some air
> in. The pipe will spring back to its original diameter and drop out. If
> it still sticks soak it in water to dissolve the PVA.
>
> --
> Glenn Ashmore
>
> I'm building a 45' cutter in strip/composite. Watch my progress (or lack
> there of) at: http://www.rutuonline.com
> Shameless Commercial Division: http://www.spade-anchor-us.com
>
> "Garland Gray II" <ggray.RemoveThis@nospam.com> wrote in message
> news:5Behj.29827$Ft5.7226@newsfe15.lga...
>> If I were to wax the outside of a piece of 2 1/2 inch pvc pipe about 6
>> feet long, and then lay up several layers of fiberglass and epoxy, would
>> the resulting tube slide off the pvc easily enough after curing ? Or
>> would I need to first wrap the pipe with sheet plastic or similar ?
>> Thanks !
>>
>
>
 >> Stay informed about: Fiberglass tube 

"Terry K" <tspragg567 DeleteThis @rogers.com> wrote in message
news:50b5b93d-d79b-407a-b605-11384b1da524@f47g2000hsd.googlegroups.com...
> On Jan 9, 9:32 pm, "Garland Gray II" <gg... DeleteThis @nospam.com> wrote:
>> If I were to wax the outside of a piece of 2 1/2 inch pvc pipe about 6
>> feet
>> long, and then lay up several layers of fiberglass and epoxy, would the
>> resulting tube slide off the pvc easily enough after curing ? Or would I
>> need to first wrap the pipe with sheet plastic or similar ?
>> Thanks !
>
> After the goo sets up, running a source of heat inside the pvc could
> soften it enough to pull out, or even to melt it out. Epoxy wouldn't
> be bothered by the heat required, I suspect.
>
> Alternatively, perhaps a plug of wax wrapped in a seperator would more
> easily be melted out. It's called the "lost wax" process.
>

What about making the core out of Styrofoam plastic, wrapped in release or
heavily waxed, and after the expoxy sets up dissolving the Styrofoam with
gasoline, acetone, MEK or some other solvent that attacks the foam but won't
hurt the epoxy?

A possible advantage of this approach is that it allows the production of
shaped epoxy parts that are more complex than a simple tube, should that be
needed.

Epoxy is fairly resistant to gasoline and many other common solvents, but it
certainly would make sense to "insulate" it from the solvent with the
release sheeting, heavy wax, etc., and then to thoroughly clean it after the
core is removed.
 >> Stay informed about: Fiberglass tube 

Alex wrote:
>
>
>
> What about making the core out of Styrofoam plastic, wrapped in release or
> heavily waxed, and after the expoxy sets up dissolving the Styrofoam with
> gasoline, acetone, MEK or some other solvent that attacks the foam but won't
> hurt the epoxy?
>
> A possible advantage of this approach is that it allows the production of
> shaped epoxy parts that are more complex than a simple tube, should that be
> needed.
>
> Epoxy is fairly resistant to gasoline and many other common solvents, but it
> certainly would make sense to "insulate" it from the solvent with the
> release sheeting, heavy wax, etc., and then to thoroughly clean it after the
> core is removed.
>
>
I've done this one several times.
It works quirw well.

Downside - the inside surface is goinf to be pretty rough - resin
seeping into the crevices in the foam.

If that is not a problem (and in this case it's probably not) this
is probably a reasonable approach.

But if I had to make this part?

I'd use a paper tube for the core mold.
Just make sure it's not waxed paper...

Richard
 >> Stay informed about: Fiberglass tube 

There was an article in Good Old Boat where the guy built a water lift
muffler. To do what you are asking, the guy wrapped one layer of glass
and epoxy around a well-waxed pipe. After it cured, he slit the glass
and removed it from the pipe. A little epoxy and he glued it back
together again and continued with the lay-up.
Article 3367 May/June 2007. Pages 33 - 36.
 >> Stay informed about: Fiberglass tube