resealing perspex windows

[pappaecho]

A couple of windows on my Evasion 32 have to be replaced. I intend using Sikaflex to provide a gasket between the Perspex and the GRP.
There is an anodised outer aluminium frame and a correspondiing inner frame within the cabin. Each frame is screwed together by "inter*" something screws (M4 set screws with a stainless ferrule which is the Inter* bit). There are about 20 screws per frame
The screws mostly came out without problem. How do you rebed the window, without getting Sikaflex over the screw threads?

 

[Talbot]

Check with Sikaflex cause there is a specific product from them for this task which has a much higher resistance to UV than the standard Sika - in fact done correctly with this product there is actually no need for the bolts

 

[T_S]

The only drawback is if you have to remove something bonded with sikaflex!

 

[Talbot]

True, but if you are replacing a window it is normally cause either the window is leaking cause the seal has gone - if the seal has gone then your problem is not a problem, the other reason is if the acetate has become to end of its life, so doesnt matter if it gets broken when being removed- again not a real problem!

 

[Grandad]

On my Waston motor sailor ALL my windows and fore hatch are sealed by seating on Bedding Tape. The wheelhouse and main cabin windows are Alloy framed and I obtained the tape from the supplier (Technautic). my fore cabin windows are Plain Perspex fastend with 5mm Pan heads tapped into the cabin side (GRP) agin these windows are bedded directly onto tape (left over from main cabin window fitting).
This tape is self adhesive on one side only and I fitted it to the windows prior to installation. Strange stuff though, it feels more like putty than foam. Sugest you contact the likes of Seals direct etc, or window suppliers for recommendations.
Adavantages.
1. No Mess. 2. Easy to fit. 3. Easy to remove. 4. No leaks (WH windows have been in for 14 years).
Disadvantage.
1. Edge of tape, where visible can get mouldy, but this easiy cleans off.

 

[pappaecho]

I removed my two windows today, with two huge screwdrivers as levers. The window Perspex had been bonded to the grp with an adhesive tape about 25mm wide, and about 2mm thick. The windows are being replaced because of crazing, not because of leaks.
I am re thinking the Sikaflex route and will try using this thin adhesive mastic tape, as it is easy to control, and leaves no mess. The sandwich of bolted aluminium will provide the strength.
Some years ago I saw a Westerley yacht which had to make port in La Rochelle, having had two cabin windows ripped out in a force 9 in the Bay of Biscay - these had been "glued in", and so I am strongly in favour of belt and braces

 

[LeonF]

Do a search on my previous postings.. I had a very bad leak on my Sigma 33 and rebedded the perspex on to neoprene tape, self adhesive on one side glued to the coachroof. Interscrews replaced the old self tappers and the job was a great success. I was wary when the neoprene tape was suggested but it works and is a lot less messy than Sikaflex and if you break a window it would be easier to replace. Do not drill into the tape once affixed to the coach roof as this will shred it..a mere pencil point is all the starting that is needed. And 3mm neoprene is all that is needed.

 

[Rubberman]

Have a look at Seals + Direct at

http://www.sealsdirect.co.uk/bbCMS/shopping.asp?intDepartmentId=1

Also on thier hints and tips page it will tell you how to do the job