Black beauty is the abrasive material that goes into the mix its ground up coal slag , its used for traction . If you are serious about striping and sealing , demo a line lazer by graco , some sherwin williams dealers carry the machine , its the caddy of stripers. That unit you purchaced is the bug sprayer I was refering to in my previous post ,its a trusco , I had a school want to give me one that they used 1 time . It took them a week to stripe a lot with 1000 spaces . They had to thin the paint it only lasted 2 months . I told the maintenance guys it would be good for spraying round up along the fence line. We came in , sprayed all the spaces in 5 hours with 2 machines and didnt cut the paint , job still looks good 3 years later. Go to www.parkinglotplanet.com get the real scoop on machines there . I still use air atomizing ( air compressor and paint pots ) they consider these machines antiques . But they still work . ( I have a 1973 model Wald that still works great) I also have 2 of the airless which are lighter and therefore faster .