I use 5 glues
Mostly PVA, I buy it in 2 litre bottles, and transfer it to a 500ml bottle to use. Great for foamboard, card, wood and polystyrene foam, even my metal hand rails get PVA'd to the structure.
AMOS glue stick, I have tried other brands but they dont work as good, used in warning signs etc.
Contact adhesive _ Selleys Kwik grip, dont use this unless metal is involved, wouldnt use this on foam!
Super glue - I usually drip it out onto a plastic surface and then use a toothpick to transfer small amounts
GW plastic Glue
Some people use hot glue for foam, thats something I havent tried yet.
I have undercoated the Gas storage, pleased that the weld lines are still visable, thinking about using this on my smaller tanks but not sure it rivets and welds would look right on the same peice, will paint this when I sort out the pipe bends on the four small storage tanks.
Second pic is the end cap on the tank before its cut, turn this over to cut, trim of small bits to get a nice rounded end.