Re: [ATM] growing and weaving a tube

[Woodchuck <djv@bedford.net>]

On Wed, 16 Jun 2004, Ina Ron Lippard Renaissance Reproductions wrote:

> 1.thermal failure,trauma,and design flaw.A well designed joint that is
> assembled with the correct adhesive should withstand anything but a nuclear
> exchange.

.... preferably before the glue is added.  See Chinese furniture or
Japanese architecture for examples.

> process,the material is there for you,and it shouldn't corrode.Boat
> builders use 3 types of cloth: mat, it looks like a doormat or enlarged
> screen.has great strength,roving,a bit more refined to smooth out the form,
> and chop cloth,looks like bits of thread in a cloth.Many auto-body shops

My last foray into fiberglass was a visit (also in the '70's) to a
'glass fab shop in Wyoming.  These lads were laying up stock watering
tanks and suchlike.  Besides  the various cloth, roving, and so forth,
they had a compressed air gun that sprayed the monomer+catalyst, and
also chopped up, if I recall correctly, a continuous yarn of fiberglass
into 1" or so fibers and sprayed those fibers out along with the goo.
Now combine that with your lathe mentioned below...

> use this for places like rocker-panels.A series of layers of mat,
> roving,and resin are used on boats to give it the indestructibility the
> older wooden ones could not.Finishing the work can be accomplished by using
> wood veneer,or star-charts under a coat of,clear gel or gel coat.This is
> the top layer of any boat hull or bulkhead.A scope with a 3/8" thick
> tube-work made like this would be strong and stiff enough for most scopes
> under 24",OK I'm guessing that approaching 24" could require more
> under-pinning and strut work.Now here's the down side.It takes some
> hard,sticky work,and it won't be cheap.You need to have a good filtered
> breathing mask and work out of doors.You will be working with acetone and
> other fun stuff that is anti human until it goes off.The forms need to be
> accurate.BUT all the steps are simple.A well-thought out plan and a partner
> are a plus.You may wish to do this in halves.Then fit the 2 pieces
> together.If you can understand positive and negative shapes,your ahead of
> the game.
>     For the less intrepid,I'd stick to the apple-ply club.Use chop cloth in
> strips for all joints.You can wrap cloth around a strut for added
> strength.Round tubes made of 16 gage alum can be made much stronger by just
> 1 layer of fiberglass and resin.Thin 1/32" .032 2024 alum is very easy to
> roll.Another idea is to spin an octagonal tube.Ok, NOW Ron's on drugs! But
> think a minute.Build a form on a 3/4" steel shaft with a hand crank.Use it
> like a lathe to wind a fiberglass or kevlar thread on to the skeletal
> form,(use lots of mold release).Keep a couple of guys busy mixing and
> brushing on the resin as you wind the octagonal,or round tube.The first
> wind can be straight while the next can be spiral.I should think a very
> thin,very strong tube can be had with this method.You can very the layer
> over critical areas where you want extra support. This is a low tech
> approach anyone can do with a few things from a local hardware store.The
> form can actually be the baffle system and interior rib-struts of the

Have done this more or less, laying 'glass on top of a thin cardboard
tube.

> tube.If you could use a black linen cloth as a first piece tacked onto the
> ribs,it may serve as a light dampenner.The outside can be finished as
> described earlier.I'd try it on a small scale first to see just how much
> hot air I'm suggesting here.I cannot imagine this has not been tried
> already.If I can come up with this stuff,there must be hundreds ahead of me
> who already have.I'am sure there are some blanks to be filled in to make
> these processes work.My intent here is to get you to just think about the
> possibilities.
> regards, Ron

A lathe for this work need not be a toolroom LeBlond!  I made a tube
lathe with 3/4 pipe and a coupe of V-notched pieces of wood on sawhorses.
This was used to lay up using cloth and roving.  It would even become
powered, when sanding out the work, using a belt sander.  The sander
was held on a bias, which both sanded the work and turned it.  Since
a lot of the sander's efforts went into turning the work in the same
direction as the belt, the abrasive effect was attentuated and tamed.

The idea of laying up a tube using 'glass yarn is very interesting.
This might even justify an upgrade (spec creep :-) in the construction
of the lathe, even using real bearings, and *some sort of power
feed*, such as is used to guide wires when winding coils.  Maybe
something like the guide on a fishing reel.  Hmmm, "ready-thready-rod"
comes in 3/4D and 6 foot lengths, and would actually be *overkill*
for a lead screw, in terms of strength and precision, a threaded
wooden closet rod would be plenty. (Cobble up a die of old-tyme
design to thread it).  The lead screw could be "geared" to the
"headstock" in some kludged way, the chain and sprockets from the
neighbor's abandoned bicycle, perhaps, or even friction wheels
(gears of infinitely fine pitch :-).  THere is no *requirement* for
a lead screw, the "carriage" could be moved with chains and sprockets,
it could be as crude as sliding barn door hangers, we are not
grinding micrometer screws here.  I have in my mind's eye three
guys, one turning the flywheel (the "motor"), one laying on the goo
somehow (the "painter"), one attending and tensioning the yarn as
it is wound on (the "fish").  I think this would produce great
results, especially if a high helix angle were used, as in winding
an electronic choke.

After making telescope tubes, rent time on the device to those
who mess around with Tesla coils.

it would NOT be hard to automate the feed with stepper motors
and sensors, and any pattern desired could be wound on, including
"thick places" for cell, spider, mount.

This sounds silly -- but it isn't.  I know where to get (cheaply)
10' of 8" I-Beam for the bed of this "lathe" -- it's poltruded
plastic I-beam, pick it up by hand.  I was going to make a
quasi-optical bench with it.  Maybe I should go look at this stuff
again.

Dave
-- 
                 A need is a terrible thing to waste.

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