sprayman

I am new to the area (Moved down from NY), and this red clay is something new for me. Ive recently got in with a custom home builder, who calls me frequently to take care of the newly built homes. The driveways are always absolutely covered in this red clay, and its nothing short of a b**** to get cleaned. The first house I "cleaned" for him, was an absolute disaster and the driveway was still stained. I quickly learned about the beloved muriatic acid. Ive done many new homes for the company since using the acid. They have all came out okay looking. I am able to get the driveways cleaned, however it is a very slow process, and I believe it still comes out looking like.. poop. I use a "weed sprayer" I picked up at Home Depot. You can kinda see the lap marks where I spray the acid.. 18:1 I pre-wet the concrete, keep it well saturated, spray small sections at a time, use the fan tip and go back and forth at a respectable distance. I recently picked up the Original X-Jet, and I want to try it on the next upcoming job. Using it to obviously apply the acid in small sections, but hopefully it has a more even spread and you will not be able to see the application marks. Any recommendations from someone who has experience with red clay on new concrete? Do you use the muriatic acid? How do you apply it? Should I be mixing stronger? What should I be doing differently? Any kind of help would be greatly appreciated!!