First of all, an apology, this is about our Mk 4 Golf GTi that I bought new in 1998!!

 

I have asked for assistance in all the right places about this but no joy. 
This forum has been a great help to my Fabia so hopefully with this too but please forgive this VW intrusion. 

The GTi has an upgraded turbo fitted and so needed to be mapped to suit. It has the old AGU engine with a basic ecu and needed to be bench flashed rather than live mapping through the OBD port. 
So I removed the wipers and pulled the plastic scuttle away from little channel at the bottom of the screen to get to the ecu hidden underneath. 
Disaster, the little channel that is reinforced with aluminium just crumbled away. 24 years of oxidation meant the aluminium turned to white dust and the plastic disintegrated. 
 

Now there is nothing to hold the scuttle to the windscreen and it will just rattle around not to mention, little to protect the ecu from the weather. 
I’d say there is about 1.2 cm of overlap between the scuttle and the bottom of the screen and it will sit flush if held lightly in place but will move away if let go. 
 

My question is what can I use to seal the scuttle to the bottom of the screen using that overlap?
it needs to be swift to act as I cannot stand out all night holding the scuttle in peace until the glue etc sets. Also waterproof and able to withstand daily live on a car. 

Regarding the remap it all went smoothly and so the car is now at about 225 BHP and the torque capped at 280 lbs ft  to reduce the chance of bending a rod! Well worth doing as it is a bit of a sleeper now. 

 

 

Many thanks!

Edited 29 April, 20224 yr by prt57

There are many knowledgeable experienced people on here who I have come to respect over the past couple of years.
I just need the best type of fixing material to allow the plastic scuttle to bond to the glass windscreen. 

problem with using tiger seal / tec7 etc is - you will never get the scuttle out again without smashing it.

 

do you have any pics? it might be possible to get some thing made to fill the channel and let you reclip it. (3d printers to the replicate the original is what im thinking)

It is actually possible to buy the channel from VW. It just pushes onto the bottom of the windscreen to be held in place. 
However, the mastic bonding the screen to the car prevents me getting the remnants off the back and therefore cannot get a new one on and into place. 
Simply, all I need is some sort of adhesive to keep the scuttle stuck to the bottom of the windscreen via using the overlap of about 1 cm. 
Good point about the Tigerseal. Other folks have talked about Windscreen fitting companies using a bonding material that locks everything in place for ever.
At the moment I am thinking about a bead of Butyl tape. Very sticky and it should be possible to separate it if I need to access the ecu again. 

Good morning, how about a strip of double-sided tape? - Gorilla glue would work, but is likely to be very difficult to remove in future. 

Carpet tape is insanely sticky both sides and cloth reinforced.

Apparently Gorilla glue is not good with most plastics. 
my best thought so far is butyl tape. Very sticky and water proof.  

If it were me I'd use 3m double sided automotive foam tape...   The sort that is used for sticking badges on.  I have a roll of the stuff and it's never let me down for that sort of thing

13 minutes ago, skomaz said:

If it were me I'd use 3m double sided automotive foam tape...   The sort that is used for sticking badges on.  I have a roll of the stuff and it's never let me down for that sort of thing

That was my other option but I tried something similar but it would not stick to the plastic. Fine on the window side though. This was the 3M double sided tape used to stick uPVC glazing bars to double glazed windows. 
Does your foam based tape stick to the type of plastic used for the scuttle?

7 hours ago, prt57 said:

That was my other option but I tried something similar but it would not stick to the plastic. Fine on the window side though. This was the 3M double sided tape used to stick uPVC glazing bars to double glazed windows. 
Does your foam based tape stick to the type of plastic used for the scuttle?

 

I've found it stick to most plastics yes so it should do but the plastic needs to be cleaned with an alcohol (isopropyl) wipe first.