Technically, Aquasure is a repair compound, not a cement. It is also excellent, if used well.
There's some good advice above but I'd add:
* Clean the area with an organic solvent cleaner first (after first roughening with sandpaper, to provide a key, as suggested).
* If supporting a tear with stitching then applying a bead of Aquasure, first apply a strip of adhesive tape on the inside to prevent the viscous liquid from slowly flowing through tiny gaps (as removal of set Aquasure from a carpet is a real drag . . . .).
* Don't make the bead of Aquasure too thick - this would reduce flexibility of the repaired area, eventually leading to cracking of the repair compound - probably resulting in further tearing.
* The advice above about flattening the area is very important because Aquasure has a habit of running off the repair area as soon as you turn your back. The advice about doing one repair at once is good. If it's impossible to lay our the repair area perfectly flat (e.g. a curved seam) then you need to make several thin applications of Aquasure, allowing each one to set first. This game of patience can be made easier by purchasing an accelerating compound which needs to be mixed with Aquasure. I've never tried this (as it sounds messy) but I know others who have, apparently with good results.
* If applying a patch, use the purpose designed PVC cement. Roughen & (solvent) clean both suit and patch. Use cement as per instructions on tin / tube. Place patched area between two thick pieces of wood and compress overnight in a vice.
The above has given me very good results but I admit I've never actually tried Braveduck's suggestion, which (knowing him) is also probably good advice.
Finally, as with the repair of all caving equipment, the old adage "A stitch in time saves nine" definitely applies.
Good luck!
