Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

I am about to retuckpoint my exposed brick wall with a custom mortar mix (1x hydraulic lime, 2.5x sand). Once I am done, I plan to clean the residue and other dirt from the bricks using muriatic acid.

My question is: what is the minimum amount of time I should wait for the mortar to cure before it is safe to apply muriatic acid over it? Is a couple of days enough? I have heard that masonry mixes (concrete/mortar) take as long as two weeks to fully cure, I was unsure whether it is safe to bring it in touch with a substance as potent as muriatic acid during that time frame.

share|improve this question
    
Curious about the lime mortar.. is it a NHL based? Do you have old, soft bricks or some other reason for using a lime mortar outside? –  HerrBag Jul 5 '13 at 21:45
    
yes, the house (and its bricks) are 104 yrs old. also, i think the lime-based mortar (white) looks better. also, it is inside, not outside –  amphibient Jul 5 '13 at 22:22

1 Answer 1

up vote 2 down vote accepted

I would scrub with water only @10hrs - 48 hrs.

I wouldn't use muriatic/water until 3-4 weeks. Be sure to add acid to water, not water to acid. An 8:1 (water-acid) mix is a good place to start.

Pre-wet the wall and any plants nearby. Rinse off then neutralize with ammonia or baking soda and water.

Old clothes, rubber gloves, eye protection. If you use it any more concentrated, organic respirator.

share|improve this answer
    
i have added water to acid before and had no problem. why do you say the opposite? –  amphibient Jul 5 '13 at 22:26
1  
Small amounts of water (into acid) could potentially boil, spraying a (mostly) acid solution. –  HerrBag Jul 6 '13 at 0:22

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.