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Author Topic: how to shape bulkheads and stringers,chines for sheeting?  (Read 444 times)

Gazzalene

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how to shape bulkheads and stringers,chines for sheeting?
« on: May 13, 2019, 01:02:22 PM »

I do not even know the correct term for this,i am a new builder.
I am building from a plan and the bulkheads are on a chine with stringers lower down.
I am at the stage for side and bottom sheeting and need to shape these parts for the ply/balsa to butt up.
I do not know how to do this OR find a clear tutorial.
thanks.
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dreadnought72

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Re: how to shape bulkheads and stringers,chines for sheeting?
« Reply #1 on: May 13, 2019, 09:24:59 PM »

Thin card (brekkie cereal packets) is good for working out the shapes of the sheeting you require. Trim to fit with scissors. When you're happy with the shape (you've got smooth, fair curves on the edges) use these as templates - but do cut the sheet material a little oversize so that you can sand them down to fit once they're on the boat.


For the chine join, aim to run one sheet edge accurately into the inner surface of its neighbour. The neighbour's excess can be sanded down later for a crisp edge.


Much easier to show than type!


Boats with chines stiffen up enormously once the sheets are on - do make certain the keel, bulkheads and stringers are really well braced and solid before sheeting, else you'll end up with a banana-shaped boat. Which is not good.


Andy
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RST

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Re: how to shape bulkheads and stringers,chines for sheeting?
« Reply #2 on: May 13, 2019, 09:39:25 PM »

Have a look at the Boothbay Lobster fishing boat thread on here at the moment, plenty of pics.  For beginners, any day I also thoroughly recommend a book and Model Boats Magazine -most of the model boat books cover basic construction techniques (nothing much has changed over the years), worth every penny, try and see if your library has one first.
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malcolmfrary

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Re: how to shape bulkheads and stringers,chines for sheeting?
« Reply #3 on: May 15, 2019, 10:02:00 AM »

Assuming the drawings for the bulkheads were correct, and are correct on the building board, the chine stringer should fair itself into a nice curve which is a good 3D guide line.  Card templates as suggested by dreadnought72 are very good, but best a bit oversize.  Start from the centerline, get a good fit there, then trim the excess back to the cine rail.  The side sheets are then a matter of having a bit of overhang which can then be trimmed back, hiding the edge of the bottom sheet.  Much as detailed in the various books and articles in past magazines.
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grasshopper

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Re: how to shape bulkheads and stringers,chines for sheeting?
« Reply #4 on: May 15, 2019, 10:27:21 AM »

Do you mean shaping the rails and chines?
Long piece of timber or aluminium extrusion, whateverís dead straight stick some sand paper on it and gently sand across chines and rails are at same angles as bulkheads, then skin as previously mentioned
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SailorGreg

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Re: how to shape bulkheads and stringers,chines for sheeting?
« Reply #5 on: May 15, 2019, 03:38:30 PM »

I think your original query was about fairing the chines and stringers so that your sheeting will lie flat and not perched up on an edge somewhere.  I suggest you take a piece of thin ply, glue some fairly coarse abrasive paper to it and apply it as in the picture below.  I used 80 grit paper, but 120 would probably be a little safer - less likely to take too much off somewhere.  The little wooden handles are essential to keep the board evenly pressed down on the stringers etc.  You can make up several of different sizes if your hull has lots of different curves/facets.  If you run a permanent marker lightly over the chines and stringers, you get a good indication of when you have faired them in sufficiently.
Hope that helps.
Greg


fairing-board.jpg" border="0

Gazzalene

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Re: how to shape bulkheads and stringers,chines for sheeting?
« Reply #6 on: May 15, 2019, 05:52:08 PM »

Thanks Greg, that was what I was after. the angles seem to go in all directions,the flexible sander will now be made.
Many thanks
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