This was old concrete and most definitely fully cured and I only used 2,000 PSI at the gun. I let my SC sit there for a second and it left this ring. I’m thinking it’s not etching and it probably just cleaned deeper than the rest of the concrete since it sat for a second. Do you guys think if I kicked up the PSI I could blend it? I need answers fast please. Thank you all in advance
Chances are when that dries you won’t be able to see it. You can always see “deeper” into wet concrete or wet wood than you can when it’s dry. I wouldn’t sweat it.
I cleaned this yesterday. The customer sent me this this morning asking if it was permanent. I believe it’s already dry by now but I can’t be sure
Ah, I see. I’m outside with glasses on and it looked wet. Well, in that case, you may be able to feather it out by going over that area slowly but not too slowly. You could maybe even get away with brightening that section with some oxalic but, in my experience, it will stand out from the other sections so I always end up doing the whole driveway.
Either way, that will eventually fade as the concrete gets dirt and residue build up on it. It doesn’t look etched to me.
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I’ve never seen 2000 psi do that to older concrete…….sure it was 2000 psi? Did you have a gauge? How did you get your pressure to 2000 psi? What size tips? What size machine?
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I’ve seen guys use f9 to blend concrete……I’ve never personally done it though.
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Why were you cleaning at 2000psi anyway? Drive doesn’t look particularly clean. I’d go back over whole thing at 5-600 more psi
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What degree tips are you using?
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there is quite a bit of cream runoff still on that part. likely there is some etching, but its not even rinsed well enough to be sure of its extent.
That ring is on their front patio so I think that oxalic strategy might not be a bad idea. Pretty much the entire patio is what you see in the picture so it wouldn’t be too hard to brighten the whole thing. I’ll try feathering it first and if that doesn’t work I’ll try brightening the whole patio with oxalic
Yeah I had a gauge right before the SC. That’s why I’m so so confused. I’m using 25025s on a 4GPM specifically because I’m still somewhat new want to become fully confident before risking etching with high pressure
I was thinking about using Craig Harrison’s f9 circle technique. That’ll be my last resort if feathering it with higher pressure, and/or brightening with oxalic doesn’t work
It was pretty clean. I used higher pressure with my wand on heavier areas. Just doesn’t look that clean because it’s a pretty bad concrete pour. Ugly concrete. I was using 2000 because I’m still somewhat new and scared of etching
25025s on a 20’ BE whirlaway with a 4000 PSI 4GPM machine
I didn’t see any cream at all coming off when cleaning. If that was the case wouldn’t the rest be etched as well? It’s a small patio so I’m 99% sure it’s fully rinsed but I could very well be wrong
it just doesn’t appear that way, but as you know it’s just a pic to me.
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My calcs may be off, but with 25025 I’m showing 2500psi.
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Yeah my machine has been running a little weak + friction loss from 300ft of pressure hose so I was only getting 2000 at the gun. I’ve been troubleshooting my machine for a little bit now and can’t seem to find the problem. I’ve toyed with a bunch of different things and I think I’ve narrowed it down to my unloader being bad. It’s been running weak, surging, and sometimes will turn off altogether when facing back pressure from letting off the trigger. I originally thought it was my gas/air intake on my carburetor being messed up but I’ve done a lot of work on that to no avail
Try using a 100’ hose and see if that fixes things, then you’ll know…something. The other guys can elaborate.
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I can tell you my 4gpm with a Honda 390 and 100’ of hose and those 25025 tips will only get 2200 at my gun. It was so slow cleaning at that pressure and it didn’t touch any lichen at all. I run 2502’s and its right at 3000 and I like the results with that pressure. A 390cc engine will not give you 4 gpm and 4000 psi.
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