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Author Topic: 3 layer ply splitting?  (Read 423 times)

tizdaz

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3 layer ply splitting?
« on: January 12, 2022, 12:43:52 am »

hi guys,


so I'm making my bulwark supports using 5mm ply which is 3 layer.


Problem is no matter how careful i am, the top layer of the ply begins to peel or chip a little when im cutting it, I'm using a very fine tooth saw to try eliminate the issue but its still doing it slightly, so what's best method to avoid this, and how can i fix the pieces ive already cut to size!?


i need to make 38 of these supports so ideally i would rather eliminate this issue rather than having to fix each piece after I've cut them!


Cheers
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BrianB6

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Re: 3 layer ply splitting?
« Reply #1 on: January 12, 2022, 01:38:47 am »

Sorry! but it sounds like you are using a cheap plywood.  5mm. should be at least 5 layers.  You could try masking tape on both sides of the plywood.
Better to start again with some better quality material.
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tigertiger

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Re: 3 layer ply splitting?
« Reply #2 on: January 12, 2022, 05:14:19 am »

Firstly I agree with BrianB6, about the quality of the board. However, if it is what you have, then it is what you have.

I would check the outside edges of the sheet of ply to see if it is delaminating. If the edges are still sound, it should be OK. If the edges are splitting, then long term, any piece you cut may also split.


For cutting, I would try this. Tape both sides of cut location with tape, I prefer carpenters tape (this is the blue stuff that will not leave a residue). I would mark my line with pencil and then score the the cut line heavily with a sharp modelling knife or marking knife, before you saw. This will cut the fibers that are causing your surface splintering.


I hope this works for you.

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Colin Bishop

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Re: 3 layer ply splitting?
« Reply #3 on: January 12, 2022, 11:39:39 am »

5mm sounds a bit thick for a bulwark support. What scale is the model?

Colin
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tizdaz

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Re: 3 layer ply splitting?
« Reply #4 on: January 12, 2022, 03:04:51 pm »

5mm sounds a bit thick for a bulwark support. What scale is the model?

Colin


1/12 according to my plans, thats abbut corre0ct width.give or take about 1/2mm which im not fussed about  :-))
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Re: 3 layer ply splitting?
« Reply #5 on: January 12, 2022, 06:32:09 pm »


1/12 according to my plans, thats about correct width.give or take about 1/2mm which im not fussed about  :-))

I am not sure what 1/12 is but if it is 1/12 inch that would be 2.1mm wouldn't it?
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tizdaz

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Re: 3 layer ply splitting?
« Reply #6 on: January 12, 2022, 07:04:42 pm »

I am not sure what 1/12 is but if it is 1/12 inch that would be 2.1mm wouldn't it?


2.1mm would be way to thin, thats what they are on my 1/24 plan, so double that as mine is 1/12 scale
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RST

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Re: 3 layer ply splitting?
« Reply #7 on: January 12, 2022, 09:37:56 pm »

Hi,

I'm no expert these days but is 5mm right -that would give a plate thickness of 60mm in real life?  Normally, something like bulwark supports are from thin plate with a 90 degree turn on the inner edge which gives a "stronger" section than an equivalent thicker plate over the full thing. Given that TID's were constructed P.D.Q. in war time -I may be wrong, but 60mm thick plate sounds too thick (and a very heavy fitting, would probably be more difficult to weld as well needing allot of heat).  I don't think that's evident on pics from google either.

You're probably better-off going from thinner ply / polystyrene sheet or something similar and adding the 90 degree turn on the inner side from an added strip a few mm wide.  That would look closer to the pics I just looked at anyway.  It would make your cutting allot easier also.

Rich
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tizdaz

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Re: 3 layer ply splitting?
« Reply #8 on: January 13, 2022, 02:11:32 am »

ok I've decided to use 3mm ply and as Rich pointed out the supports have a strip on the inner, i didn't realise this was a strip as the plans i have didn't show that! so cheers for info :) ..also after looking at more pics i notice that the supports have a small hole in each one for drainage, so i will be sure to add them also! :)


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RST

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Re: 3 layer ply splitting?
« Reply #9 on: January 13, 2022, 04:36:30 am »

Hi,

That seems much more sensible.  I see from your other build you cut a good few since.  I hate making things like this as not good making more than one thing exactly the same  -look for a cheat wherever I can.

The rat holes in the corner help also -if you use thin CA you migt be able to run in from one end to secure a good few at a time, at leat a thin film joining the bottom of the bulwark to the deck anway.

Tich
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tizdaz

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Re: 3 layer ply splitting?
« Reply #10 on: January 16, 2022, 11:02:06 pm »

Hi,

That seems much more sensible.  I see from your other build you cut a good few since.  I hate making things like this as not good making more than one thing exactly the same  -look for a cheat wherever I can.

The rat holes in the corner help also -if you use thin CA you migt be able to run in from one end to secure a good few at a time, at leat a thin film joining the bottom of the bulwark to the deck anway.

Tich


hiya buddy, managed to make them all & they fit good! ..i surprised myself actually on how well they turned out!


Im now going to cut out the holes for each & also make the thin plate for the front of each one :)
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