DO NOT WORRY ABOUT CUBE FAILURE DUE TO POOR MOULDS ANYMORE.(As your fellow engineer l got all of us the best solution you need to try your self)
Durable plastic, cast iron and steel 150x150x150 moulds with smooth and perfect shape to ensure regular cubes for better and accurate results in the "ultimate Compressive Strength test"(UCS test)
*My results improved as so will yours*