My bad about the tip size, meant 15050. Well, I've only been two-stepping for about 6-7 months and I'm still playing around with how I do it. I'm trying to figure out what mix the chems are going on the truck just for my curiosity. I didn't know if you had to measure it or if there was a formula. I've been trying to tweak my mix ratios a little bit that's all. I was actually trying to see if there was a way around using hot water but getting the same results as using hot upstream soap. I only use the burner when I turn the soap on but I keep burning the seals up in my gun......At what temp do most of you wash at or is there a way around the hot-water when two-stepping?