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Author Topic: How to remove a prop shaft from a hull - without damage to either  (Read 3691 times)

andrewh

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I have had recently to remove the prop shaft from my brushless trial boat for transfer to another hull - took some in-process pictures and wondered if it would help to share them.

By the way - if you follow Glyn Guest's advice and fit prop shafts using balsa cement there will be will be problem in removing and re-using them.  Just drip acetone or  cellulose thinners on the area till the shaft comes loose!

If anyone has fitted a shaft with PVA (woodworkers glue) as the fixative (and that would not be a silly idea) it will soften with heat - I would suggest touching a soldering iron or similar to the prop shaft tube for several minutes and see it the glue softens and frees the shaft.

Most people, I guess, will have fitted shafts using a resin - either polyester (the smelly one) or epoxy.  I had used my favourite 151 epoxy with lots of microbaloons to fill holes and stiffen the mix.
Neither epoxy or Polyester resin are thermoplastic, but they both soften considerably with moderate heat - around 100 degrees but I don't expect that they will soften enough to get the tube free.
Neither resin has any easy solvents which would free the prop tube.

So
It must be a physical metod of removal!
pictures follow - I do not have my camera with me :((
equipment required:
One  tube which fits over the prop shaft tube - either the next largest K&S brass tube, or a length of aerial tube
One hand or battery drill
One patience to read the next post with the pics
andrew
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Proteus

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Re: How to remove a prop shaft from a hull - without damage to either
« Reply #1 on: February 09, 2009, 02:48:43 PM »

I found the easy way to do it is to knock the bush out knock a bit of dowel in the shaft to stop it collapsing and grab with some mole grips and give it a turn, this normally works as long as you don't want to re use the shaft , this way you don't damage the hull.
it works for me anyway.


Proteus

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Martin [Admin]

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Tug

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Re: How to remove a prop shaft from a hull - without damage to either
« Reply #3 on: February 09, 2009, 07:30:49 PM »

hi,
My last removal was done with a tap wrench over the inside end of the tube and warmed the outside end with blowlamp, keping a wet towel over the hull, 'perseverence' and patience won over. [wasn't a boat called that?]  Tug.
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andrewh

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Re: How to remove a prop shaft from a hull - without damage to either
« Reply #4 on: February 09, 2009, 09:18:33 PM »

I realise there is more than one way of killing the proverbial cta,
 I apologise if I am covering old ground - I am finding the contributions interesting


Tube is a section of a dismantled aerial (chrome-plated brass) which fits over the prop shaft freely
End where it is chucked is plugged with wooded dowel to allow it to be chucked without crushing
I have cut serrations in the end with a file - any shape will probably do - I think they make heat rather than cut like sawteeth

Drill - fwiw is a 300 RPM old Bosch, which does slow jobs which a dremel don't

 
The tube cuts and softens the adhesive around the prop  tube assembly
Boat is 1mm styrene so flexible and not capable to taking much force


after 20 sec or so of rotating - out it comes for installation in the next BL trial boat - a white Dwarf
andrew






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