On 25 Jan 2007 17:42:46 -0800, "Greg Esres" wrote:

My tiling book says to sand the concrete with a coarse grit sandpaper
and then wash with muriatic acid. A friend of mine thinks muriatic
acid is way overkill and just washing the floor would suffice. I'd
rather avoid using the stuff. Any thoughts?

(BTW, concrete is interior slab...seems smooth. Troweled surface?)

I'd try to find an alternative.

Muriatic is (or turns to) Sulfuric (or is it Hydorchloric?) acid.
For a small job, it might be manageable. For major square footage,
it can get out of hand. Truly Nasty Stuff.

If you gotta do it, take muy mucho serious precautions. The
fumes are toxic. You could get a surface coat of rust on
any iron-based materials in the area.

And, yeah, after it's done it's work, baking soda or
any lye compound will help neutralize the acidity.

Good Luck,
Puddin'

"Life is nothing but a competition to be the criminal rather
than the victim."
- Bertrand Russell