How do you use muriatic acid to etch concrete?

Answer 1

For anyone interested in the TRUE HCl concentration of muriatic acid (sans WIKIfication) simply google "muriatic acid msds" and you will see that, while the concentration varies by manufacturer, it generally ranges from 33-40%. Furthermore, even if you order HCl by name from a chemical supply house, you order by concentration, usually some reagent grade, with fuming HCl starting at ~40%. No hardware store in the world sells 100% HCl for etching concrete.

DANGER / SEVERE HAZARD -- Muriatic Acid IS UNDILUTED (100% concentration) Hydrochloric acid.

Wear Eye and face protection, acid resistant gloves, rubber slicker suit, or be VERY careful as Hydrochloric acid is highly corrosive and can instantly burn holes in your skin and tissues, and right through all woven clothing.

When diluting ANY acids, it extremely important that you NEVER ADD WATER TO ACID, as the reaction between the two will result in an "explosion" throwing acid instantly in all directions.

The PROPER method of diluting acids is to very SLOWLY pour the concentrated acid into a larger volume of water.

For an additonal "layer" of safety, do not pour the acid from a large and heavy container, as it is more difficult to handle and control. Pour the needed amount of concentrated acid into a smaller, acid resistant, container which will be easier to handle and therefore control the pour rate.

When using baking soda for neutralizing acid residues, be VERY CAREFUL to NOT ALLOW the baking soda to contact the UNDILUTED ACID as the resulting reaction can be explosive!

1Bust out some protective clothing and a gas mask. Have a good supply of fresh water on hand in case you need to rinse any body parts.

Be very careful with muriatic acid; it's 30% hydrochloric acid, and is fairly hazardous.

If you only want to barely 'etch' a slippery concrete surface, it is best to dilute the acid with water, as acid straight from the bottle tends to be very aggressive with any concrete surface, and can badly damage the surface very quickly.

For a deeper etch Pour the substance where you want to etch the concrete and spread it out with a nylon broom. let it sit for a half-hour. Wash it thoroughly with the hose after.

I have used a small hand held spray bottle set to a fine misty spray, and skipped the 'rinse' step altogether with very good results.

'Baking Soda / water solution' is an acid neutralizer, and can be used around most landscape with safe results.

>>> Get used to the process FIRST. Buy a few cement blocks, bricks, or slabs that you can throw away. Different concrete blends, strengths,... react differently. New and old concrete of the same formula will also react differently. An new slab poured next to the exact same mix from the same company in an old slab will be different due to moisture content and curing time).

Good luck.

- tapalmer99@aol.com

#3, You follow the MFG directions on the product as with anything.

You use Ammonia to neutralize.