Headlamp re-seal - what bonding agent?

Dear All,

As I drove through the one of Birmingham’s no-go zones, suddenly - something unusual happened:

Knowing that Birmingham is famous from unusual events, I couldn’t stop.
Frankly Jaguar engineers predicted this type of scenario including arise of no-ho zones - and implemented headlamp bezels in UK/Euro versions.

My question is - what experience you have with various bonding agents that can be used to re-seal the glass to the reflector - any comments highly appreciated.
It is worth mentioning thst Jaguar engineers used chewed off bread mixed with spat and chalk due to national scarcity of materials. I’m looking for something more effective… RTV silicone, butyl rubber, chewing gum etc…

RTV for me, a little dab will do ya.

Got wardobe full of those, however I am not entirely sure how that affects reflectors which are in pristine condition…
RTV silicone releases acetic acid vapour on cure :wink: don’t want to end up with dull reflectors - hence this topic

I once bought some aftermarket headlights and simply used some transparent silicone sealant, like you use for windows/bathrooms. Worked fine.

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I meant glass-metal bonding agent. This is the UV filter spray. Usually used by delusionists hoping that their faded plastic headlamps won’t go even more distress-yellow after quick polish… Same thing like the one you’re using on the beach in sunny day.

With real glass lid - this would be like application of mayonnaise on the unicorn…

I have absolutely no technical expertise.
Thanks for straightening that out.
I tried to be cute and botched it up.

OK, I’ll try again:

Was thinking about something neutral to reflector like butyl tape… Bombs away, clear rtv silicone and forced airfllow through the pipe stuck into position lightbulb holder. Effects to report shortly…

Have you tried this?!

Greg, unfortunately I haven’t…
Possibly this sounds so obvious to you, however I’m way below average age of Jaguar XJS owner…

The sealant should only be there for weather proofing to stop water ingress, and it definitely should be something that doesn’t out gas anything noxious that will damage the mirrored reflector. You need to use mechanical clips around the edge to make a solid physical connection.

Are those clips OEM? Or something you came up with?

I can’t remember for sure, it was a long time ago when I ditched those Euro lights, after going through the pain of trying to repair them a couple of times. There was a similar fixment on the SAAB 900 headlamps I rebuilt. I’ve also got a set from the local hardware store that mix your own paint colours, they use them as clips to hold the lid down when they put the tin in the shaker/mixer machine.

Done, left for 48hrs to release vapour until no smell evident. No sign of fading however lamps were vented with inserted tube and tiny flow from compressor. Silicone releases acetic acid which reacts with aluminium (guess what’s so shiny on the surface of the reflector…)
Tested today in the rain. Failed with sorrow. As there was no chance that lamp housings were leaking - I’ve checked this:

…and applied clear rtv silicone. That’s it. No sign of moisture after 25min ride in heavy rainfall:

And tiny advice. Never, ever apply Bilt Hamber Dynax with wind blowing towards your windscreen. 45minutes, half-bottle of WD40 Degreaser and 1.5 paper towel roll later:

Kirbert should mention it in his book for God’s sake…

I like your rusty bucket perfectionism!
All the best.


Banger, looking at Welsh Enterprises’ instructions on installing a new glass lens from them to an XJS fog light assembly, this is how it goes:

Apply white RTV 732 silicone sealant to frame evenly (This silicone can withstand temps up to
350F or 180C). If too much is applied use a knife or razor blade to carefully remove the excess

  • Align the glass with the frame and firmly push the two together. If any excess bleeds over the
    sides, use a paper towel to wipe away excess.

  • Let set for 24-48 hours

I recently used that procedure to re-attach my old lens after removing it to re-spray the reflector with silver paint … It is made by Dow Corning and works very well (presumably it is the OEM adhesive ?) … I ended up having to search for it online and found a vendor who was selling a N.O.S. tube of it … :+1: I am kind of curious though why Welsh does not recommend using their clear version of same, although perhaps it is not as strong and/or durable as the white stuff … (?) :confused:

Don’t forget, Banger emigrated TO the U.K. That shows he’s of un-sound mind right there … :smile:

So you’re saying the new lens just fell off the assembly??? :open_mouth: Are these the new glass lenses that someone was selling recently on their website?