OCR 1,2,3 any difference

[camnz]

i was wondering if there was much difference in how hard the 3 different weber OCR renders set.ive been using OCR 3 but it seems chalky whens its dry even a few months later.are the other ones a bit more durable?

 

[S a plastering]

Think the numbers are for diff exposures just like diff strenghts but not too sure my friend

 

[Rigsby]

The lower the number the stronger the mix. 3 may be the safest against cracking and crazing. Like any sand and cement mix, let it dry out slowly.

 

[plasterjfe]

yep riggers is right, it is the strength

good for ocr 2 scratch coat and ocr 3 top etc if the background needs it