Andro, Acid, the muriatic bought in stores, is a very dangerous substance. You must be aware of all the pitfalls BEFORE using it. It's the combination rattlesnake/cobra/rabid skunk of household chemicals. Treat it with fear and respect and you wont have too many problems. Do not be casual about it at any time. It's a big subject to cover but here are some links to go to. Know what you want to get into. It however can do what you want, cheaper too. Remember above all- ALWAYS pour acid into water NEVER water into acid.

http://www.eezimmermanco.com/products_files/MuraticAcid.html

Here is a link that might be useful: ACID !

Thanks very much, Rock. The site was very useful. It mentions the use of phosphoric acid (apparently considerably safer) instead of hydrochloric acid. For my purposes (pH reduction), I should not be using a very concentrated solution, rather, I had in mind to use a weak solution and soak the project for an extended period to allow for penetration and subsequent leaching. However, I have no experience in this matter (in other words, I donÂt know what IÂm doing) and, thus, ask for guidance.

Andro

Hi Andro
I have great fear of acid especially if you use it like I do.
I brush my work with vinegar. I have tried muriatic acid but I figure over the long haul the chances of having an accident, getting it in my eyes is too great. So I won't be using it.
Vinegar can be bought very cheap, but not a the local grocery.
I still buy the stuff by the gallon but a few months back I found a whosaler (not in my area) selling it in 5 gallon containers for $8.50.

Acid, any acid can be dangerous. Know the percentages of the product you are dealing with. Household vinegars and this includes pickling vinegar can have a range of 4% to 7% acid. Muriatic acid is a 30% acid, which means you can dilute to the same range as vinegars easily.

* Skin Contact: Contact may cause mild injury and burns from vinegars of 11% acetic acid and greater. Dilute solutions may cause dermatitis in some individuals.
* Eye Contact: May cause severe burns and permanent corneal injury from concentrated vinegars. May be followed by blindness. High vapor concentrations may result in conjunctivitis.
* Ingestion: Concentrated vinegars may cause pain, irritation and burns in mouth, gullet and stomach.

People that are more sensitive than others may experience problems at lower percentages. Be careful no matter what you use.

"Ingestion: Concentrated vinegars may cause pain, irritation and burns in mouth, gullet and stomach."

You should try my neighbors home made wine. Pickling vinegar is smoother and has a better nose.:)

Muriatic Acid is very handy stuff and almost a necessity if you work with cement-based materials...but it must absolutely be understood & treated with the respect it deserves. Just like any other tool you use.

First off understand that "Muriatic Acid" is basically nothing more the much more aggressive and thoroughly dangerous "Hydochloric Acid" that has been diluted with water to create about a 28% acid-to-water solution. Even at this rate of dilution it is still a very hazardous material that has the potential to blind, burn and attack the lungs. In fact, it is very often the "fumes" potential for harm that is underestimated and results in serious injury. I have actually wintessed people who were acutely aware of its reputation for burning & blindness casually open a bottle, and for whatever reason almost instinctively ...take a whiff!...as if they were checking to see if the "milk was still good". (???) DO NOT DO THIS! EVER! The fumes alone are adequate to cause severe burns to the lungs & eyes!

Muriatic acid can be further reduced by the addition of more water...but always...always...always!...remember this old trade rule..."Do like you oughter', add acid to water!".

NEVER combine the two by introducing any amount of water into a measure of acid!!! Add the acid to the water and everything is fine. Add water to the acid and it has the potential to spontaneously "boil" and explode in your face! Let me repeat so that you might memorize this phrase..."Do like you oughter', add acid to water!".

And as for relative "strength"... remember that Muriatic acid reduced to a 15 to one water/acid solution will still etch concrete. That's a pretty powerful Ph. And what is a "safe" solution? Well, I'm not exactly sure, but consider this...two gallons added to my 55,000 gallon swimming pool are more than adequate to raise the Ph as much as a couple of points to an acceptable & safe level of solution. One more gallon would push the entire solution to an unsafe level. I've never done the math, but I don't think you ever want to get a solution on you that's much stronger than whatever that works out to be.

Acid is like any other "power tool". Understand it, respect it's potential for harm and use it properly...and it can be very beneficial. Abuse it, be negligent and ignore that potential...and sooner or later you will pay the piper.

So, take care...stay safe...and be afraid. Be very afraid.

All my best --- Tango

Sorry folks. I said above that adding acid would "raise the Ph as much as a couple of points". First, I meant to say "REDUCES IT". Second, it's the "H" that gets capitalized, not the "P"...er, make that "p". I don't know if I'm just getting old...or if all those years of sniffing acid bottles is finally catching up with me.

Anyway, here is the full (correct) definition of pH...

(from potential of Hydrogen) the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is more basic and less than 7 is more acidic)

And remember the words of our friend Mr. Molecule..."Always play it safe with acid, because seeing and breathing are fun!"

All my best --- Tango

Ron, If you're just trying to leach the lime out of a planter; don't worry about vinegar or acids. Place it in a water bath for a couple of days and change the water daily. I use a plastic tub. Wear rubber gloves when removing the planters from the water while the lime is leaching out. Billie

Very interesting product.

I would really love to try this stuff. I'm sick of efflorescence.

Here is a link that might be useful: MetaMax

Evidently one of the big plusses to using GGBS (I think those are the letters! Otherwise known as ground granulated blast furnace slag) is that it gets rid of efflorescence - the material is too dense for the efflorescence to make its way to the surface.

At the moment I'm adding a diluted SBR (styrene butadeine rubber, which I think is more or less like latex) to my mix in the hope that it will prevent lime leaching out, keep it trapped within the body of the material. I make planters to sell commercially, so I'm keen not to sell a product that will kill anything planted in them! :D