Window Rail Rubber Insert

[zambo]

Has anyone the specific thickness for this rubber sheet they use for the insert into the window support rail?

I thought I’d matched the old decayed stuff to new material I sourced - but whilst a dab hand with a rubber mallet, I’m only getting the glass in about 2/3’s the way. 

 

Understand it’s a firm fit when pressed in - I removed the old one - but fitting these are not coming together as I think they should. And whilst a bit (little bit) of widening of the channel gap is a good suggestion I’ve read here, I though I’d check in case anyone had an as-yet uninstalled seal to hand they could run a verniers over. 
 

Just thinking I’ll take the obvious potential flaw out of the equation first. 
 

All typical lubricants, etc used to date and both guides are new. 

 

Thanks. 

[tzei]

When i did mine i sandblasted old rails & painted em. Old rubber went in easy (glued in as per oe), window went in easy, again with glue. Iirc rubber is about 2 mm thick.

 

[Mike Self]

The rubber piece is just an anti-rattle cushion, and when properly glued in, doesn't need to be a whang it with a hammer tight fit, just a tight-ish slip fit.  

 

mike

[zambo]

Thank you Gents - mine is 3mm thick so I will source some at 2mm and see how it goes. 
 

Any recommendations on the glue? Would something like a weatherstrip glue (black 3M) do the trick?

[tzei]

I used Bostik contact a3

[zambo]

I found that 2.5mm thick neoprene is ideal. A 450mm square sheet at Australia’s answer to Home Depot costs AUD7 - bargain.  
 

Ideal width of the rubber guide is 45mm if anyone’s thinking of cutting new ones for their situation. 
 

Still able to slide the glass in by hand but with resistance - no mallet required - which when coupled with the contact adhesive will mean everything will stay where it’s supposed to, once the entire window lifting mechanism is in place and operating. 
 

Thanks to the two responders. 

Edited March 5 by zambo