ZXRJon – I used a general purpose bonding paste from Glasplies:
http://www.glasplies.co.uk/2-5-Kg-Bo...white2.5kg.htm
This required a catalyst and starts off blue.
Then, before it starts to set fully, it goes brown.
I actually came across my test piece the other day…
( Box section steel and fibreglass. )
Three years on and it is still as solid as a rock.
Hope that helps, Paul.