Phosphoric acid

I have seen some mention phosphoric acid as a way to get mortar , concrete off glass, whats the method and is there a dilution rate or a mixture that works best, also where is it available

Have you read through these?

Thanks LLarry

Phosphoric acid works good for mortar,stucco & plaster,loosening the bonding agent in them. I prefer using a hog hair brush along with applying it(making a point not to let it run down onto anything below the windows for sake of possibly etching certain substrates.

No dilution is needed,just straight from a squeeze bottle,i like 16 oz plastic bottles.Normally i like to make 2 to 3 horizontal squirts along the affected glass then using the hog hair to lather it up & blading as needed.

In some cases you may need to hold the brush next to globs of debris and use concentrated squirts directly onto them along with a single edge razor commonly known as a #9.

I get mine from Surtec,same place Dan gets his.Although im sure you can find it at several janitorial supply houses. Bottom line dont forget the waiver!! link below

I allways get a waiver Craig, I don’t think phosphoric acid would be much use to me as all the windows I do are cut-ups with painted wooden frames, I think it would be too difficult to control the liquid in such a small area consistently

Good point although i’ve run into situations where i needed it on cut-ups i used a sea sponge and dabbed it on that way,catches the excess and gives you the ability to get stubborn debris off those smaller panes.

excellent Idea , thank you

Yeah, it works. Another option is utilizing a spray bottle to apply either phos acid or in some cases Safe-Restore as well,truly one of my favorites in my arsenal.

Craig: As previously mentioned, the solution we purchase from Surtec (I buy direct from Dan) is, in fact, diluted phosphoric acid.