How to make fibre glass tube

Discussion in 'Fiberglass and Composite Boat Building' started by Frosty, Nov 8, 2011.

  1. hoytedow
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    hoytedow Carbon Based Life Form

  2. ancient kayaker
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    ancient kayaker aka Terry Haines

    I doubt there'd be much sag for a 4 m length of PVC pipe with no water in it. I just noticed that table has a column for fiberglass pipe which can handlea much longer span than PVC; if you can get some of that it would be a better mandrel, might even make an adequate mast . . .
     
  3. BobBill
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    BobBill Senior Member

    Glass Tubes

    Have comments on using glass or carbon sleeves, rolled back on itself. like rolled socks, and rolling out on prepared mandrel?

    I am planning to use a windsurfer mast above a aluminum Force 5 base, and intend to stiffen the windsurfer mast with carbon sleeves. I thought rolling the carbon out would be easier than pulling on to mandrel...
     
  4. P Flados
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    P Flados Senior Member

    Two very straight pieces of wood can make a quick temporary cradle to rest the tube in. You want to support it with two 45 degree surfaces that act like the vee blocks that machinist use to check shaft straightness. Build the cradle and use tight strings to check straightness. Shims can be used for vertical adjustments, 5 gallon buckets full of water can be set on the ground and pushed up against the sides for horizontal truing.
     

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  5. michael pierzga
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    michael pierzga Senior Member

  6. Frosty

    Frosty Previous Member

    Well-- wrapped a 2 inch PVC pipe in glass and a small 1 inch strip on the join. Only 40 inches more of an experiment .

    Now then who of you said it separates easily,-- you gotta be joking. I cant get it off banged it ,hit it ,prized at it. Yes coated it with boot wax.

    No way in hell is that coming off. Will have to rethink and glass over a PVC pipe and leave it. Incidentally one layer of glass makes for a surprisingly rigid tube and satisfactory with one layer.

    So--new plan is thin PVC pipe with a layer of glass only, actually lighter than the glass pipe.
     
  7. michael pierzga
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    michael pierzga Senior Member

    Slit with a razor knife and remove glass from PVC when the glass is in the rubbery stage. It will peel off the tube . Ive not used pvc as a form , i used mylar boxing tape covered steel pipe. My finished glass tubes were about 200 mm long. Once the glass is free of tube gently squezze back into shape and hold in shape with a few pieces of tape until it cures hard.
     
  8. sabahcat
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    sabahcat Senior Member

    as Michael said
     
  9. michael pierzga
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    michael pierzga Senior Member

    I have good luck using Brown Mylar tape as a mold release. Obviously its not suitable for some shapes and highly finished surfaces.
     
  10. CatBuilder

    CatBuilder Previous Member

    This may work a little better...

    Instead of using the pvc surface to glass on, tightly wrap a long length of line around the pvc, then cover that line with plastic film.

    Wrap entirely in glass and let cure.

    Now, pull the line out of the tube and slide the pvc out from your new tube.

    This is how Richard Woods suggested I make my dagger board trunk and may work just as well here.
     
  11. hoytedow
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    hoytedow Carbon Based Life Form

    This sounds logical. I am going to try this for my cross-beams.
     
  12. tunnels

    tunnels Previous Member

    Why are you wasting time wth all thoses things Pvc tube abs smear with petrolium jelly (vasoline ) wrap 2 layers of mylar round the tube and use the vacoline to hold the mylar wraps and then wind a layer of tissue and one of csm and wet it out !when wet and rolled then carry on with the rest of the layers you want to put on leave a space on the pvc tube to pass a steel rod at the opposite end of the glass tube glass on a piece of stout rope with a loop when is all hard then attach one end to a imovable object and the other end you might be able to pull by hand or simply attach to the back of your car and gentle pull !,it will slide off and when you take the mylar out from inside you have a shiney glossy tube
    The outside peel ply it or use a braided sleeve as the finished layer . Used to make 4 to 6 ,6 metre long tubes every day som off pl astis and some off steel . all came off quite easly !!
     
  13. Frosty

    Frosty Previous Member

    To be honest the PVC pipe wrapped with glass is perfectly suitable for the job. There is no need to remove the PVC pipe for my application and that is as supports for a rigid awning on the fly bridge.

    It will look like fibre glass and will be painted with urethane after fairing,I see no reason any more to remove a perfectly good inner pipe.
     
  14. ancient kayaker
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    ancient kayaker aka Terry Haines

    Something here on using Al tubing mandrel and dissolving it with swimming pool (muriatic, hydrochloric) acid. Other posts decribe using balloons and caution about mercury content when using fluorescent tubes.

    http://www.homebuiltairplanes.com/f...-tube-fabrication-methods-work.html#post50073

    I wonder about using PVC pipe, cutting a longitudinal slit in it, expanding the slit slightly with wedges then filling it with wax would work as a mandrel. Heating it up after forming the composite pipe should dissolve the wax, shrink the tube and make it a lot easier to remove. Anyone tried something like that? Possibly the slit could be held open with a rope that could be pulled out later; it would also provide support to the wax while it is setting.
     

  15. PAR
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    PAR Yacht Designer/Builder

    I wonder how much the epoxy exotherm would affect the wax during the cure.
     
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