Screws for Aquapanel Exterior

[Comedydave]

Hi
Knauf Aquapanel Exterior recommended screws are about £70 for a box of 250.
I only have a small job and can't warrant paying that much and for an amount I don't need.
I have these for a different job:
"SPAX T-Star Plus Facade Screws Stainless Steel A2"

Façade screw, stainless steel A2 | SPAX

www.spax.com

Now before anyone kindly points out that it says they're wood screws, predrilling a hole in the Aquapanel would work (I tested it).

The question is: these are A2 steel; will the cement be too acidic and cause them to rust? Would A4 steel screws be better? As fixings they will work, but I don't want big filthy rust marks appearing in a couple of years/months...

Thanks!

 

[noseall]

Hi
Knauf Aquapanel Exterior recommended screws are about £70 for a box of 250.
I only have a small job and can't warrant paying that much and for an amount I don't need.
I have these for a different job:
"SPAX T-Star Plus Facade Screws Stainless Steel A2"

Façade screw, stainless steel A2 | SPAX

www.spax.com

Now before anyone kindly points out that it says they're wood screws, predrilling a hole in the Aquapanel would work (I tested it).

The question is: these are A2 steel; will the cement be too acidic and cause them to rust? Would A4 steel screws be better? As fixings they will work, but I don't want big filthy rust marks appearing in a couple of years/months...

Thanks!

Those Spax screws look like the mutts nuts. They are your typical self drilling, clad screw. Crack on.