Why to rely on expensive (and SLOW) laser cutter to remove the resist when you can use the photoresist instead? Honestly, I don't get it.
Moreover, that sort of board could have been done easily using toner transfer too, if you really don't want to bother with photo-lithography.
And the etching itself, jeeeze!!!
That's waaay too concentrated, apart from etching away the traces, it is dangerous (ever had a pin-sized hole in the glove or the acid splash up?!)! Not to mention that the very corrosive fumes will likely attack and over time destroy whatever metallic he has in that room.
Please, kids, if you want to etch your own boards, do it as the sane people do, with ferric chloride, vinegar/salt or ammonium persulphate, using proper safety equipment, not like these two clowns! I certainly prefer having to wait a few minutes more for the board to etch than losing gear to corrosion or an eye to a splash of acid! I have used acid + peroxide once and never more. Just not worth it.