MV Catapult Windows

Any see-through bits
seamad1250
Posts: 19
Joined: Wed Apr 27, 2011 10:46 am

Re: MV Catapult Windows

Post by seamad1250 » Fri Aug 30, 2013 4:17 pm

This is how I did mine.
Marked windows and routed trench, filled this with uni glass 450mm wide rolled up into rope and pressed into trench with 403.
Cut out windows.
Taped windows up and made mdf mould 40mm from edge to create neat flange ,and then put back so that they protruded 4mm internally ( to give flush fit of windows when finished)
Coved with 411 around cutout to give smooth transition.
Layed 150mm wide dbias, then 10 X 75mm wide dbias then 150mm wide double bias.Applied some 411 to give neat finish.
Waited 3 days then popped out window cutouts ( will keep to make windows)
Mullions then glued in with 30mm flange to finish flush with window flange. Mullions are dbias, 90carbon uni, 5 X 0 carbon uni, 90 carbon uni, then double bias.
Used plain weave ( 2 layers) on mullion flange, around window flange then 75mm onto cabin side.
Trying to see if I can get some of this acrylic in 10mm, looks good for reducing heat and very abrasion resistant http://www.spartech.com/CES/Polycast%20UV-SC.pdf

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV Catapult Windows

Post by groper » Sun Sep 01, 2013 7:46 am

thanks for the reply mate, but ive read it several times and still dont understand how you made those flanges! Any chance you could clarify what you did in order to make a flush fit window flange?

That low heat transfer acrylic looks like good stuff too mate, where can you buy it in australia? perhaps through some aircraft material suppliers? Looks expensive tho...

seamad1250
Posts: 19
Joined: Wed Apr 27, 2011 10:46 am

Re: MV Catapult Windows

Post by seamad1250 » Sun Sep 01, 2013 11:47 am

I should have taken some piccies.
Boxed the cutout first, 30mm mdf taped up, set in 40mm from edge(or whatever size flange you want). Attached 90 degrees to window cutout with blocks and hot glue, fairly easy on the straight sections but lots of cuts on the curved cutouts. This lets you get a good solid glass edge to the flange and very little tidy up required on finished flange.
The gap between acrylic and flange is dependent on size of your windows and thickness of acrylic , I found with mine to allow for expansion the thickness of the double sided tape meant the windows would protrude from the cabin side.
To flush fit the windows ( or recess the flange) I hot glued some 4mm material at multiple points on the outside of the window cutout. Then you screw some short battens through the 4mm packer into the cutout with the batten extending from the cutout edges to stop the cutouts from falling into the boat, secure cutouts by screwing the battens to the cabin sides. So when inside the boat you should see the whole cutout poking through 4mm.
To get the glass to lay down nicely i coved the cutout with 411 along the 4mm step before taping up.
Hope that's a bit clearer.

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV Catapult Windows

Post by groper » Sun Sep 01, 2013 5:11 pm

Yep, im with you now... thanks for that.

How about the acrylic, did you manage to source some of that stuff in the PDF? Id be interested in getting some too if the price is reasonable...

seamad1250
Posts: 19
Joined: Wed Apr 27, 2011 10:46 am

Re: MV Catapult Windows

Post by seamad1250 » Mon Sep 02, 2013 2:13 pm

Still chasing it up. Will post back here when i get some more info.

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV Catapult Windows

Post by groper » Mon Sep 02, 2013 8:06 pm

Ok, my cabin sides have a 15mm core... if i use a 6 or 8mm window pane, then i have 9 to 7mm of take up. If i make the flange 3mm thick, then i have 6-4mm take up in order to get a flush finish. I figure 4mm is about right for the MSP adhesive flexible joint?

So this means i dont need to recess the flange inside the boat, i was hoping i can just rout out 40mm around the edge of the window, taking away the core and outside laminate. This leaves just the inside laminate intact, then layup the flange on this by building thickness with a few layers. The transition from the flange to the outside laminate would be smoothed with a cove then over the UD filled trench with some dbias. This way i dont have a huge bump of glass to fair out on either side of the panel...

What do ya think?

mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: MV Catapult Windows

Post by mahnamahna » Mon Sep 02, 2013 10:28 pm

It is very difficult to lay up a glass stack and get the edges exact on each layer, so make your flange oversize to start with so you can grind it back to size and have a nice even thickness and straight (or curved but you get what I mean) edge. I made my tapes stagger from 120mm on the bottom layer to 110mm for the next 2 then 100mm for the top layer but tried to tape to the flange edge as flush with the layer below so that the transition to the outside skin is staggered and a gradual taper. So I initially made the flange 50mm but ground it back to 40mm after the layup had set.

http://yikes.com.au/wp-content/uploads/ ... trim-1.jpg

I found that if I layed up 4 full width tapes, that is from the edge of the flange (so glassing to the core side of the inside skin) over a cove against the core and over the rounded outside edge (rounded with a router) onto the outside skin by about another 50mm I ended up with a ridge of about 2-3mm to fair out.

http://yikes.com.au/wp-content/uploads/ ... urve-1.jpg

Between each full width tape I added a 50mm tape to just the flange and it ended up about 6mm thick. Each tape layer whether full width or just flange was one single length wet out on a table then rolled up then rolled out on the job and consolidated at each layer. I staggered the join place around the window so that there was no weak point. For some reason my kit came with about 10 rolls of 50mm double bias tape, I have found few uses for it but it was perfect for the window frame flanges.

In my case the core is about 18mm of the 20mm panel thickness (I also taped around the inside of the windows before removing the core because I found that if I didnt do so the original skin was so thin it would buckle and ripple along the flange once the core was removed, the extra layer of glass worked perfectly to prevent it) so with about 3mm padded out by additional 50mm flange tapes I still have about a 15mm window depth. I plan on 8mm polycarb windows and about 4mm for the double sided tape and sealant my windows should be recessed about 3mm to the cabin sides from the outside, and of course recessed by about 4mm of the double sided tape and sealant on the inside.

The double sided tape is about 10mm wide so I intend attaching it 10mm back from the edge of the flange leaving 20mm of sealant on the outside side of the double sided tape and 10mm of sealant on the inside side of the double sided tape. The double sided tape acts as a dam for the sealant so you can pack it in and ensure no voids or air bubbles. Most people use black sealant because they use dark polycarb, but I will probably use white sealant as I am going to use clear polycarb with a silver tint film. I will most likely have the film pre attached to the polycarb though.

44 warned that if using a tint film it is important to have the sealant overlap the tint film to seal the edges and prevent water getting under the film and creating runs in it. So having the window a few mm below flush will allow the sealant to overlap the front of the windows and still not protrude beyond flush. I will make up some coving tools to shape a slight trough say 1mm deep, in the expansion gap (about 10mm) between the poly carb edge and window frame all around whilst also overlapping the film by a couple of mm. No reason for the slight trough other than I think it would look better, but I will probably experiment with that first.

Sorry for the essay but its hard to fully explain in less words.

seamad1250
Posts: 19
Joined: Wed Apr 27, 2011 10:46 am

Re: MV Catapult Windows

Post by seamad1250 » Tue Sep 03, 2013 10:25 am

This link has a formula to work out expansion gap size required:
http://www.fixtech.com.au/images/Acryli ... -small.pdf

This link is for the tape:
http://solutions.3m.com/wps/portal/3M/e ... 7201&rt=c3

Will use the 4991. Will use a fixtech wipe either side of the tape to give a neat finish and a little extra retention. This is the tape used to stick glass to high rise building so it's plenty strong enough

seamad1250
Posts: 19
Joined: Wed Apr 27, 2011 10:46 am

Re: MV Catapult Windows

Post by seamad1250 » Tue Sep 03, 2013 10:29 am

Paul,
I'm using 10mm acrylic for my windows. After a fair bit of research I wouldn't use polycarbonate for large windows like ours, acrylic is better suited.
How's your build going ?
cheers
sean

mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: MV Catapult Windows

Post by mahnamahna » Wed Sep 04, 2013 10:58 am

Hi Sean,

Building is now progressing again, albeit slowly. Still seriously lacking in funds but not as dire as it was in Jan and Feb.

Am just applying ply pads around the boat for winches etc and cutting ports and hatches into boat and applying uni rope to de-core. Lots of air and light in now I have them all cut in. Just need to do the escape hatches and thats it for cutting holes in the boat!

Hope to hang the rudders and fit hydraulic steering next month (if my savings plan does not take a hit I should have the hydrive system purchased by then), then finish the sliders for the outboards (rig up the pulleys etc) but still have to figure out a trap door set up. But once that is all done the rear steps can finally be glassed in.

That will only leave the rig stuff to construct, (sheeting points and mast posts) before fairing will commence.

Back to topic at hand. I originally chose polycarb because I found a tint film called polygard http://www.tintgard.com/film/polygard which I had assumed, due to its name was designed for polycarb but upon revisiting their site after your recommendation I note that it is suitable for poly or acrylic. I too have found in my research that acrylic would be better than poly. My understanding is poly is too flexible and if you get a serious green hit it, it could bend and pop the seals, whereas acrylic being stiffer would not.

Does this concur with your findings?

Having said that, this video gives me pause for thought. I understand that the video is playing to the strengths of poly, ie its flexibility is what is saving it from breaking and that the flex is the problem in keeping it sealed.



Also encountering a lot of negativity toward silver tinting highly curved windows with external silver film from tint companies, even though they are talking themselves out of a job. With such warnings as metallic film will corrode fast in the marine environment to such films wont go onto highly curved windows, to such films (when applied to exterior) only last six months to a year before needing to be reapplied and then removing them without fogging the window is near impossible. Perhaps 44c can jump in with another progress report on his window tints and more info such as brand of tint and who applied it, was it applied on the boat or did he take his curved windows in to the tint shop etc.

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