acrylic priming

[bosco07]

hey folks just joined the site and must say to all involved BRAVO. some fantastic knowledge and actual tiling on show

Basically im using aquaboard with BAL powdered addy, 500x200 ceramics. to be on the safe side i always prime every substrate i tile onto except splashbacks onto plasterboard etc. Am i right in doing this or are there certain situations where i dont need to use bal APD OR SBR. im only asking as a chap whith far greater experience said i didnt need to put it on cement boards and i was wasting my money.
so could anyone please explain which surfaces need it with which addy and id be much appreciative.

cheers

dom

[whitebeam]

I'd prime all gypsum products if using a cement based adhesive, the cement would not need priming.

[bosco07]

cheers for that white beam, so he was right, aquaboard and the likes dont need priming when using cemet based adhesive, on the other hand the ones i have primed would not cause a problem will they.

[pjc]

Or paper as in plasterboard just the plaster bits