What is this on the block?


#1

On a job cleaning a building with some split cinder block ( at least that it’s called around here). What it is not-
Mold, algae, mildew or anything organic or soot.
I have used straight SH, 30% Sodium Hydroxide.

Not sure what to do? Acid?


#2

I have also tried heat up to 190 degrees with no dice.


#3

turbo nozzle ?


#4

It looks like its part of the color from the casting. Maybe just me and my screen…


#5

No on turbo nozzle.

Not sure about casting color. It is not consistent in that only a small% of the total blocks have this. It only shows on the north side of the building where the mold/algae was the heaviest. But it is not mold/algae - I put 12.5% on it and continually reapplied for 30 minutes (while doing other things) just to see if anything would happened.

Showed my Prosoco shop here today and they are at a lost as well. He gave me a stain remover sample to try which I believe is just muiratic acid solution of sorts.

I almost positive is was nothing I did, as I used the same chem and process over the entire building and only in this one area was it showing.


#6

Scrape it with something and see if it’s part of the block?


#7

Send the pic to info@eacochem. Mike is the guy you will talk to, incredibly knowledgeable about all things stone and rocj cleaning related. Also very willing to help.


#8

Acid burn ?


#9

Maybe. I am going to test a small area with some acid and see if it either cleans it or duplicates it. Will let you know.


#10

Maybe light efflorescence? Could try some 600 by prosoco or some Muriatic. If you already finished the job, what did you end up using?


#11

Following…


#12

Might be efflorescence.

At first I was thinking someone before had cleaned with an acid or something, but I noticed it on a newer building the other day that I am fairly positive has not been cleaned with the same appearance.

I have not yet done anything to my job (commercial property and PM has not brought it up) but in the next day or so, I am going to try a Muriatic solution to see what happens. I am also running by the Prosoco shop here in a bit and ill see if they have any 600 samples that I can get 1 of and try that as well.

Will update