I used 3 Sika products in the construction of our composite 4WD motorhome body.
The body is totally held together with Sikaflex, without screws or bolts or other mechanical fasteners.
"252" for the highly structural requirements. Needs to be used with the appropriate cleaner and primer to achieve best adhesion, so takes more time but is exceptionally strong. When gluing dis-similar materials you also need to take differential expansion into account for long joins and adjust the thickness of the glue joint accordingly.
"11FC" described as an adhesive/sealer for less structural joints. More flexible and easier to use. Cheaper. Totally adequate to attach sail track, for instance.
"Pro" which is technically a sealer only, but has sufficient strength for wider area adhesive jobs (our windows are held in with "Pro" - no screws).
More recently I have used "Construction AP" which is also just a sealer, but again it is good for lower strength adhesive jobs and is even cheaper than "Pro".
Buying in sausages instead of tubes is considerably cheaper.
I built our rig in 2004. I have never had a Sikaflex join fail.
Cheers,
Peter
OKA196 motorhome