wind screen bonding

Moderator: The Midas Forum Staff

wind screen bonding

Postby max midas » Mon Oct 17, 2016 10:07 pm

I'm about to remove my windscreen, partly to enable me to make a decent fist of re-trimming the dash, but also to replace the seal as it's leaking.
I see that the bonding sealant is available on ebay, with cleaners and primers for the glass.
My question is, as we don't have a frit (the black ceramic baked on edge to the glass) for the sealant to bond to, will it stick for any length of time (part of the frits job is to keep UV from degrading the bond)?
Would abrading the glass surface then applying the primer create a sort of frit for the sealant to bond to?
What has everyone else done with their screens?
max midas
 
Posts: 181
Joined: Tue Dec 02, 2008 11:32 pm
Location: somewhere under the engine - again!

Re: wind screen bonding

Postby Hans Efde » Tue Oct 18, 2016 7:59 am

Yes I did this with the rear quarter windows of my coupees. The primer is a black paint you apply on the glass to make a nice stripe on the inside. It's purpose is to block the sealant from the UV (and looks better as well). I got some from a local glass company, seems to be expensive stuff. For window bonding I used Sikaflex. For a small window it went okay bit I wouldn't want to bond in the front windscreen. It's a messy job and any voids left in the sealant will cause leaks. I advise to talk to a local glass fitter, get some primer from him so you can prep the window and let him glue the window.
User avatar
Hans Efde
 
Posts: 1731
Joined: Sat Dec 06, 2008 10:11 pm
Location: IJlst, Netherlands

Re: wind screen bonding

Postby mellors55 » Tue Oct 18, 2016 4:56 pm

I bonded in the rear screen on my Quantum saloon using one of the kits off eBay. It worked quite well. The screen has not leaked since and I did it 6 months ago. I wouldn't score the screen before priming because you will probably see the scratches through the primer on the outside of the screen. I will look up the make I used later. I picked one with clear instructions. John
mellors55
 
Posts: 23
Joined: Wed Dec 03, 2008 8:39 pm
Location: North Derbyshire

Re: wind screen bonding

Postby mellors55 » Wed Oct 19, 2016 6:44 am

I have checked - I used Wayside Adhesives. The primer and glue came to just less than £15
John
mellors55
 
Posts: 23
Joined: Wed Dec 03, 2008 8:39 pm
Location: North Derbyshire

Re: wind screen bonding

Postby ACourtney » Wed Oct 19, 2016 11:19 am

The glass only needs to be cleaned with a suitable degreaser and then primed. As John has suggested any scratching/abrading of the glass will be seen from the outside, so unless you had this gently sand blasted (as used to etch number plates onto glass and for decoration on some custom cars) it probably wouldn't look very pretty. If you take care masking up the inner edge for the primer then it should look okay.
One tip, that came from Alan Donowho when he did the heated windscreen group buy, is to prime the edged of the glass to make sure that the bonding agent seals across the laminate section. That will help prevent ingress of moisture between the glass and plastic layers of the screen.

The GRP surface of the screen surround should also be prepped by cleaning with a solvent and it would benefit from being roughed up with some coarse grit - P180 or P240. Failure to prep this surface properly is probably at the root of most of the leaks suffered by Midases. Our cars were all moulded with wax release agent, as that is what gives the gelcoat the gloss finish out of the mould. Consequently, the surface of new gelcoat is rich in wax. If you want to bond something to that gelcoat, or paint it, then you need to clean off the wax. Roughing up the surface will also improve adhesion.
User avatar
ACourtney
 
Posts: 488
Joined: Thu Dec 04, 2008 12:22 pm
Location: Oxford


Return to Mk 3 Convertible

Who is online

Users browsing this forum: No registered users and 3 guests