Author Topic: Scratchbuilt hull material  (Read 7259 times)

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des

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Re: Scratchbuilt hull material
« Reply #15 on: August 29, 2019, 04:04:07 »
Steve - photos coming soon, I hope.  Every time so far that I thought it was ready to photograph I found some issue that has required almost complete dis-assembly again;  all due to my own inexperience as a hull-builder, not due to the material.

I thought of you this afternoon - see my later post ref Kort nozzles.  I was hoping you might be able to give me some tips ref 3D design & printing.

Capt.Towline

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Re: Scratchbuilt hull material
« Reply #16 on: August 29, 2019, 12:13:20 »
Itíll be good to see some photos Des. Iíve often wandered about using that method but three possible issues always held me back. The first being accurate placement of pieces the second being twisting and the third finding a good way of glueing whilst avoiding 1 and 2.

Iíll be watching your progress with a keen eye.

Capt.Towline

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Re: Scratchbuilt hull material
« Reply #17 on: August 29, 2019, 12:14:47 »
But I really like the idea of building frames and shell plating as ship builders would with steel!

des

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Re: Scratchbuilt hull material
« Reply #18 on: August 29, 2019, 13:51:17 »
Surprisingly, accurate placing is not really much of an issue, as long as you use at least three "3rd hand" tools to hold a frame in position whill you measure it all up and make adjustments (which WILL be necessary).

But I made two mistakes before I even got to that stage.

Firstly, I cut all of the notches in each frame for the stringers - located at the top outboard corners, and at the chines.  (I had thought that placing the stringers at these locations would stiffen the hull, as well as giving me somewhere solid to cement the "plating" in place later, and provide a watertight seam.)  So I lost these corner setout points even before I started.

Secondly, a lot of the frames are "open top" - they are roughly U-shaped in order to leave the deck openings clear.  So I lost the top centre marks as well.

Good thing it's easy to fill and file styrene without causing distortion.

sea monkey

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Re: Scratchbuilt hull material
« Reply #19 on: August 30, 2019, 07:09:22 »
If you make the frames with closed tops the whole thing will be much stronger and more rigid when you put the plates on. Itís easy enough to cut the Ďtopsí off when finished and the hull is nice and true.
I usually attach the deck (with access holes already cut) before I start plating/planking. Really stiffens up the keel and ribs.
Warped hulls can be very difficult to fix.

des

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Re: Scratchbuilt hull material
« Reply #20 on: August 30, 2019, 14:34:28 »
Yeah - thanks.  I already worked that out.

I had to dis-assemble the whole lot.  I put some masking tape over the tops of the open frames and marked out the top centres.  Then I put the keel into a jig to hold  it straight (there's another lesson there, too), then used some milliners elastic thread to stretch a top centreline fore-and-aft, and re-assembled the whole lot again.  When it was all lined up I glued it all together again.

Then, when I tried to line up the next frame I couldn't get it right, so I measured everything, and found that one side of everything was 3 mm higher than the other, even though it was all lined up correctly along the centres top and bottom.  It took a while to work out that I had to ease the slots in the bottoms of the frames where they engage with the keel, in order that the frames could be "rotated" a bit to get each shoulder height right.  Then set it all up, measure it several times, then glue it all again.

I am now uncertain about whether or not the frames are still symmetrical, so I have made templates for each frame so I can ensure both sides are the same.  I have had to ease one side of several frames, and fill the other sides of those frames, to get them right again.

So, many lessons learned.  Whether or not my original reasons for using styrene were correct, I am still glad I used it,  due to ease with which I can carry out the reworks needed, at only the cost of another bottle of styrene cement.

Des.
« Last Edit: August 30, 2019, 17:53:08 by des »