but, its very messy and requires a good sturdy “tent” to be errected around the area.
If you have a compressor then you can either rent or buy for the same amount of money the tool. The sand is dirt cheap and can be re used over and over again if its strained of the paint chips.
Get all the safety gear and be very patient on this, it will take a while. The paint will come off the rocks easily, BUT the paint on the mortar will be another issue. Be ware of chemicals.