What is the plaster compressive strength of a mix 1:4 ratio?

 The compressive strength of a plaster mix with a 1:4 ratio is typically in the range of 3,000 to 3,500 psi (pounds per square inch). This means that a 1-inch cube of plaster made with this mix would be able to withstand a compressive force of up to 3,000 to 3,500 pounds before it would break.

The actual compressive strength of a 1:4 plaster mix will vary depending on the type of cement used, the quality of the sand, the water-cement ratio, and the curing conditions. However, in general, a 1:4 plaster mix will have a compressive strength that is sufficient for most interior applications.

Here is a table of the compressive strength of a 1:4 plaster mix after different curing periods:

Curing Period	Compressive Strength (psi)
7 days	2,500
14 days	3,000
28 days	3,500

As you can see, the compressive strength of the plaster increases with the curing period. This is because the cement in the plaster continues to harden over time. So, if you want the strongest possible plaster, you should allow it to cure for at least 28 days.