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Trev
Posts: 160
Joined: Thu Jan 15, 2009 2:56 am
Location: Moruya NSW

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Post by Trev » Thu Jul 29, 2010 3:20 am

Hi,

this question is for anyone but mainly the builders using Duflex, I want my 10mm acrylic windows to finish flush which means rebating the duflex panel, I'm thinking approximately 60mm wide(the designer wants 20mm clearance around the windows) to a depth of about 13-14mm. My question is do I have to remove all the balsa in this rebate and replace it with thickened epoxy? has anyone done anything similar?

Any advice



Cheers

Trev

mahnamahna
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Location: Gosford NSW

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Post by mahnamahna » Thu Jul 29, 2010 5:21 am

Not sure of the exact details of what I am doing yet. I have a professional builder doing my windows, and he is talking about making mouldings that the windows will be fitted to with recesses that form a flush fit on the outside, fitting them to the boat once the windows have been formed to them, then fairing the outside of the boat to them. I will also be having internal linings so these frames can also be made to accomodate these linings abutting them. This method removes the need to decore as these frames get glassed into the boat and have re-inforcing glass in them (not sure of the layup yet), but I am also under the impression that you need to de-core and then back fill with uni rope to add strength to the opening if not glassing in a frame such as I am.



I also have no mast in the middle of my boat so I will have a wide span of window across the front and I was initially going to have 3 larger window spans, one up each side and part of the way around the front curve, then one wide one across the front starting part of the way around the curve and across the front, but having said that we are looking at having a lot of narrow carbon mullions rather than the normal schionning wilderness method of wide (300mm) areas of duflex between smaller window spans. Our carbon mullion method is more like the window set up on the schionning Alaskan and besides a more panoramic window effect, the other major advantage is the window panes are smaller which helps with cost as well as minimising any issues of movement (expansion) that a wider single window span increases. Not that a well fit window should have issues but tis method minimises the chances of them. And of course one other advantage is that should I ever need to replace a pane, it will be a much smaller pane and help with cost.



Hope this helps. My guy is planning my window/mullion set out now and I should have something on my website in the coming months. Cheers Paul

judy
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Post by judy » Thu Jul 29, 2010 10:55 am

Trev, I agree with Paul, you would need to decore and reinforce with unidirectional glass, not just epoxy. We have not done a rebate as such, rather, doubled the duflex to create the door jamb for our back cabin wall door, which is flush with the outside. See here for some details: http://scrumbleproject.wordpress.com/20 ... cond-wall/



These two earlier posts may help explain how we got to this stage:

http://scrumbleproject.wordpress.com/20 ... or-basics/



http://scrumbleproject.wordpress.com/20 ... or-making/

Trev
Posts: 160
Joined: Thu Jan 15, 2009 2:56 am
Location: Moruya NSW

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Post by Trev » Thu Jul 29, 2010 9:19 pm

Hi,

Thanks for the replies, I want to make such a wide rebate (so that the panel looks like its all window) I don't think decoring and reinforcing is going to work for me? what would you reckon about re applying a layer or two of glass back onto the exposed balsa?? I would wrap this layer of glass all the way around the window opening?

does that make sense? I would make my desired rebate in the duflex and re-glass it, would that work? after all the Duflex only has a layer of glass on the balsa anyway. any thoughts?



Trev

Trev
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Location: Moruya NSW

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Post by Trev » Sat Jul 31, 2010 10:29 pm





This is what I want to do, any thoughts?



Trev

mahnamahna
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Post by mahnamahna » Sun Aug 01, 2010 12:31 am

I think you have a weak point at the place where the 2 curves (inside and outside) are closest together. I think you remedy that by running your foam doubler inside further (wider) so that you maintain the width at that narrow point.

Trev
Posts: 160
Joined: Thu Jan 15, 2009 2:56 am
Location: Moruya NSW

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Post by Trev » Sun Aug 01, 2010 3:08 am

Paul,

I see what you mean, and I'll do that. I will probably change the 600 gsm laminates to 400 to get around the curves easier?

Well that's another bit I can stop worrying about :) Thanks for the feedback



Trev

44c
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Post by 44c » Sat Feb 26, 2011 5:40 pm

A bit late to this, but..... what i did was to remove all the balsa, undercutting the outside laminate by around 12mm. Then glue filled, made a fillet from glue, and glassed the two laminates together.



I added 2 x 600 gsm tape to the inside to reinforce the flange.



You want a deep bed for the glue that will hold the perspex on. 5mm or more preferably. When the perspex expands/contracts, it puts the glue in sheer - the thicker the bed of glue the better it will cope.

Trev
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Post by Trev » Sat Feb 26, 2011 9:38 pm

The rebates worked OK, I will do a few things different on the next boat :) Hows the sailing?

Trev

44c
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Post by 44c » Sun Feb 27, 2011 4:09 am

Awesome. :D



In Sydney harbour just now, watching all the dickheads performing. Geez there's some morons in mono's!

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