Window fixings

[CliveG]

Another little job I am doing over the winter is replacing the cabin windows and the internal lining to the cabin.
The existing windows are perspex set in a molded recess in the cabin molding
The lining was foam backed vinyl on ply.
I am using 5mm perspex again for the window and a 2.5mm plastic material called whiterock that is normally used to line commercial kitchens for the cabin lining.

I have 2 questions.
The existing windows are bedded on a silicon mastic.
They came out very easily and there was a lot of dirt between the mastic and the GRP molding.
What should I bed the new windows in?

I intend to bolt the new windows in and the internal lining in place by drilling through the lot and putting a countersunk bolt through from the outside with some sort of nut on the inside.
I could use a dome nut but this would protrude into the cabin a bit and would not look very nice.
I would like to use something like a threaded bit of tube with a flat head in the end that would go part way into the assembly.
It that called a tube nut?
I would like the fixings to be in Stainless steel.
The total depth of the fixing would be about 15mm.
Can anyone tell me where I could get this sort of fixing?

 

[damo]

Interscrews

One supplier is www.eagleboatwindows.co.uk

 

[VicS]

Also a2a4 and Seascrew
Other window suppliers as well probably. Project Plastics in Colchester might be worth a try if that's a good place for you.

Any of the window suppliers should be able to supply a tape (not used it personally though) that is frequently recommended for bedding the widows on.
Sikaflex do special UV resistant compound for plastic windows if you want to bed on a "mastic" again: Sikaflex 295 UV

 

[Cruiser2B]

Screws are bad as: a) they let water in; and b) cracks start at the screw-holes. The tape previously mentioned is a double-sided foam tape (3M makes it) - it holds the windows in place, then you seal around the edge, inside and out with 295 or similar UV-resistant glazing adhesive. How serendipitous - a thread on this very topic has been revived on another forum with a link to these instructions: http://www.thecoastalpassage.com/windows.html

Cheers,

Kevin

 

[damo]

Don't you think that every fixing system has its problems?

Mine are 30 years old and screwed (several are curved, so other methods aren't practicable ) with panhead s/tappers, and there are no cracks starting from screw holes (though there are cracks and crazing, hence the new ones waiting to be fitted). The secret is to make sure that the perspex holes are large enough so that expansion of the plastic doesn't cause stresses.

 

[FullCircle]

Clive, try and avoid countersunk screws in Perspex as they put a high cracking stress load in the material. which is brittle. If you use Polycarbonate/Acryluic, it is softer and wont suffer from cracking.

 

[VicS]

[ QUOTE ]
try and avoid countersunk screws in Perspex

[/ QUOTE ] Panheaded screws can be used from the outside with interscrews (the nuts) inside. As far as i know the interscrews are only available countersunk but i could be wrong.

 

[dazautomatics]

I used the grey sealant provided by Eagle Boat Windows, which I don't know the product name but Mr EBWindows recommended it very strongly. It had a silicone appearance when applied by tube, but when dried turned to putty and the excess was removed very quickly.

I also used A2A4 fixings for the screws and got some 5mm dome headed A4 studs with an alien key head in them, they looked very professional.
Sealant / fixings and new windows 8mm perspex, survived being smashed to bits by a F10 storm and being submersed for a considerable amount of time without leek or movement. Good stuff for confidence building

Darren