I've always used a masonry brush to do waterproofing. Was reading the MSDS on Thoroseal and it mentioned a Hopper. Don't know why that never occurred to me before. I use one for concrete fabrication and mold work. So after a miserable day working with brushes yesterday afternoon, I grabbed my hopper and compressor today. Put three GOOD coats on in about 2 hours... No muss no fuss...