When mixing the Pettit 6455 Metal Primer with the 044 Activator, we recommend using a 4:1 volume mix in all cases. The reason for this is that if you add additional 044 Activator, you will wind up with excess acid in the primer film as applied and this excess, un-reacted acid can cause blistering, flaking and peeling of the primer and subsequently applied topcoats once the system is immersed in water.
If the user of the primer is going to make smaller mixes of the Metal Primer/Activator he should always follow the 4:1 guideline (i.e. 4 ounces Metal Primer to 1 ounce Activator or 2 ounces of Metal Primer to 0.5 ounces of Activator etc..)