Yes, but there are two MAJOR factors to consider before using factory made premixed high-temperature mortar for our Mattone Barile series ovens.
First, you need to consider the cost of the high-temp mortar per bag. Since the joints on the firebrick ovens are larger than a typical 1/8" joint, you will be using (7) bags of mortar for the Mattone Barile Grande and (6) bags of mortar on the smaller Mattone Barile. Those bags of mortar can quickly add about $200 (or more) to your oven project.
Our low-cost high-temperature mortar recipe is very inexpensive, works extremely well and is used all over the planet!
Second, if you do decide to go with premixed mortar, you MUST MAKE SURE that it can be used outdoors. Many high-temp mortars are designed for indoor fireplaces and ARE NOT designed for outdoor ovens. Look for the phrase “NON-WATER SOLUBLE” on the bag of dry mortar.
Third and Most Important - NEVER USE PREMIXED / WET HIGH-TEMP MORTAR IN A BUCKET OR PAIL! THIS TYPE OF MORTAR WILL NOT SET PROPERLY AND WILL REMAIN SOFT / PLIABLE!!