I had to paint some rough breeze blocks in my garden and decided to use Tikkurila Finngard Opaque. The wife chose her colour, and I placed an order with Tikkurila direct. I decided on the Silicon Protect variety, but they were out of stock and offered me the higher performance Opaque at the same price.
The good lady wanted to keep the rough brick shape despite my offer to coat it with render/plaster. It was about 4m x 3m, and I aimed to use the wall spray gun with my Wagner XVLP 5000. However, I wanted to test the paint with a large masonry brush so that I could get a fair test. It is a high opacity, and I could not believe how well it adhered to the surface. It was a pain to get into all the nooks and crannies, but I did three bricks using the brush, and it was reasonably straightforward.
I then did some testing on the XVLP gun and found a 5% dilution worked best. I had the material set at seven and the air also on seven. It sprayed like a dream, and I had completed the job in no time. I checked the coating and all looked good. I checked it an hour later, and it was touch dry and still no flaws showing.
I highly recommended if you have masonry to paint. It is not cheap, but my belief is it will last a long time judged on the first application; fingers crossed!