Subject: Re: [harryproa] mast pipe
From: "David Howie" <>
Date: 1/26/2007, 3:26 PM

Thank you Rob, I have been puzzling over that for a long time. I need to
sleeve the main beams on Mbuli then glass the sleeves into the hull. I've been
putting it off coz I was sure I'd never get the beam out if I glassed it up.

------ Original Message ------
Received: Fri, 26 Jan 2007 07:41:15 AM MST
From: "Rob Denney" <>
To: <>
Subject: Re: [harryproa] mast pipe


For small pieces put it in the oven, or shove a heat gun in one end. When it
gets to about 80C, the tube shrinks and is easily removed.

For longer pieces, you can cut it in half lengthwise, remove the pipe then
glue the halves back together and wrap them with a layer of double bias. For
highly loaded, or minimum weight parts, wrap a single layer round the tube,
with an overlap. Place a piece of plastic between the overlap and the piece
under it. When cured, carefully unwrap the laminate to pop it off the
mandrel. Then apply a little glue to the overlap, place it back on the
mandrel and let it cure. Then add the rest of the laminate.

Do not put tape or plastic on the mandrel if you intend removing it
lengthwise. It will ball up and jam very tightly. Apply enough pressure to
balled up Gladwrap.Clingfilm/Saran Wrap and it will turn to white powder, but
still will not release.


----- Original Message -----
From: Doug Haines
Sent: Friday, January 26, 2007 12:50 PM
Subject: Re: [harryproa] mast pipe

G'Day Phil Keck,

Hi, I built and am still building as it needs improving an elemenatrry,
and have a query as well on the plastic pipe. This is also used for tiller
extensions and I used it as a mold for part of my masts.
My plans combine the pipe with reinforcing of glass for strength, so the
type of pipe is not important, though I beleive you can get thicker stronger
pipe you'd save weight by getting thinnest pipe with extra glass for strength.
The pipe provides a mold basically and a nice smoothe inside surface for
rotation of the mast.

However for say the tiller extensions and what I plan to do for the sun
shade frame, I would like to wrap the glass, or better carbon, round pipe,
then release the two parts to give a better strength to weight ratio. Even a
small thing like tiller extensions get quite heavy without some better
I do not know how to release the two - perhaps some one could advise.
Eg. a mast made spinning carbon on a , is it called a madrel or something?
must use some release wax or something. I read abot carbon compression or
something when you bang on some carbon, it was in a windsurfing mast are when
handling not to drop it on the ground literature.

Also Phil Keck, the Kiri is so weak that the glue is stronger so I think the
toungue and groove you're talking about will not do much. You couldn't fit it
in anyway as you go round the corners they meet on an angle - hence requiring
narrow strips.


pkeck2 <> wrote:
On this page:

Are the mast pipes just made of regular PVC pipe?


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