What isthe sand cement gravel ratio for making paving slabs, and what is the cheapest release agent? any tips?

Answer 1

I would use concrete mix ( Ashgrove ).

the veg oil thing may work ...but it also may discolor your pavers.
( it may be reactive )
The are some really economical release agents- Symons makes one that retails for around $28-32/5Gal.

Go to your local Symons dealer ( concrete supply house )

Answer 2

Why don't you buy premixed bags of cement? use one made with pea gravel so you don't get a big rock in your paving slab. The cheapest release agent you can use is vegatable oil.