hi everyone
I was fixing some flag stone at my house, everything was going great until the cement dryed and left a film on the flag stone. I have tryed to get it off but it is not working. my qestion is, what can I do if anything to get the film off and how can I stop this from happening if I try fixing the flag stone again.
thanks everyone
Replies
Try muriatic acid (hydrochloric acid). Available at any decent masonry supply or brickyard. Mix per instructions, wear appropriate eye protection, rubber gloves, yadda, yadda, yadda.
"A job well done is its own reward. Now would you prefer to make the final payment by cash, check or Master Card?"
I'm not sure that there are instructions for use on masonry printed on those muriatic acid bottles. Not all of them anyway.Here's how I use it. Start off using about 1 part acid to 10 parts water. apply with a stiff nylon bristle brush. the mortar or grout should fizz slightly if the mix is right. if it's not fizzing, it needs more acid. This only works on cement/lime products for a few days after it sets. Don't go stronger than about 1 to 2 acid to water. ventilation, rubber gloves to the elbow, eye protection, lots of clean water around, rinse it really well when you're done.If that doesn't work, I use a knotted wire wheel on a 4 1/2" grinder, it does a pretty good job removing haze, but can damage the stone if you're not very careful with it.zak
Do you add the acid to the water, or the water to the acid?
Yes, this is a test.
Spheramid Enterprises Architectural Woodworks
" Iam not a poet, but your hat is singularily inadequate"
I add acid to water, so I don't have a bucket full of full strength acid. I'm not sure if that's right, I can't remember if anyone ever showed me how it ought to be done. just makes sense to me.
what say you?
zak
Always add acid to water.
Never add water to acid (not even a drop).
Adding water to full strength acid can cause the acid to react violently with the water.
"A job well done is its own reward. Now would you prefer to make the final payment by cash, check or Master Card?"
Not only that, but it can melt the bucket and create a whole new mess...
Actually, I've used full strength (well hydrochloric usually comes at 10-12% in retail bottles) to strip galvanizing off of bridge cable, and we do that in a plastic bucket. it doesn't affect the bucket or the steel (much) but it takes the galvanization off quick.
zak
Ah, reminds me of "glory days" . . . long gone by.
Anyway, of course, don't smoke (and stay clear of any ignition source) when you do that. (I'm sure you know it generates hydrogen gas). ;-)
"A job well done is its own reward. Now would you prefer to make the final payment by cash, check or Master Card?"
When you add water to acid (as opposed to acid to water), it creates a LOT of heat. I've seen chemistry students forget this and melt the bottom off of a pyrex beaker...
If it is already mixed, no worries...
"Always remember to do what you oughter
to cut its molarity, add acid to water"
Came from my college chemistry professor, back in the days when we used to have glass bottles with ground glass stoppers filled with 6 Molar HCL and 12 Molar H2SO4 sitting on our lab shelves. Whew! Bet you won't see that today!
BruceM
Don't use that nasty acid. My floor installer uses white vinegar mixed 50/50 with water and it removes all the grout and thinset from the tiles.
busta