Brick/old fire escape black marks

mtngoat

mtngoat

Member
I have the exterior of a brick builbing I may do if I can find the correct chemicals for the job.
A old iron fire escape was removed from the exterior and there are black marks running down the side of the building.
I tried sodioum hydroxide,it made no difference.

Any help greatly appreciated.
 
Hello mtngoat,

Since you have already tried a base, next try an acid. We use 24% hydrofluoric.

Dave Olson
 
24% hydrofluoric. With this acid can I run it through the pressure washer or should I apply it through a pump up sprayer?
The windows are wrapped in aluminum should this be a concern? And how about glass?
Will it etch the glass?
Thank you Dave.
 
Hi Tim,

Yes it will etch glass. This product is for aluminum brightening. For example we use it after we have cleaned an exhaust fan assembly that has caustic burns. Can make the fan look new again.

Be careful this product is a Bad Actor!!

Be sure to test a small spot first.

Dave Olson
 
Tim, are the black marks from the fire escape black paint possibly?? If you can avoid the HF acid, you'll be better off - that not only will etch glass, if used in the wrong dilution, you can burn the brick as well. Before you determine what chem to use, you need to be clear on what you're removing from the brick face :)

Celeste
 
Ok, Will look into this some more before chooseing a chem.
 
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