I'm not a person who is good with math so I would appreciate a little help.

My plan is to acid etch my concrete floor with phosphoric acid. The acid is 75% phosphoric acid. I read that I should etch using a 20% to 40% solultion.

So how much water would I need to add to get 20% and then how much water do I add to get 40% solution?

 

For every quart of the 75% acid you need water:

20% concentration: ~2.8qrt

40% concentration: ~1.4qrt

Edit: I had to do a damn formula on the paper to figure this out...lol!

0.75/(x+1)=0.2
=> 0.75 = 0.2x + 0.2
=> 0.2x = 0.55
=> x = 0.55*5
=> x = 2.75

Check: 0.75/3.75 = 0.2 = correct!

 

Big caution: your etching process will generate considerable toxic gas. Make sure you have very adequate ventilation!

 

Thank you

This acid is not nearly as bad as muriatic acid which has hydrocloric acid in it. Now that acid will make some fumes. Main reason for phosphoric acid to greatly reduce fumes that can affect paint and electronic already installed in garage.

I do where resprator mask with either acid.

 

OMG TITRATIONS! RUN FOR YOUR LIFE!

I hate chemistry...

 

Eric: Relax. No one does manual titrations anymore. We have fancy computer-controlled automatic titrators. Only lowly students might get stuck doing it by hand.

 

Always make dilutions by adding the acid to the dilution water .... slowly with stirring: start by making the 40% dilution, and if any is left over, further dilute to 20%.

 

I've used Muratic acid quite a few times indoors, not that bad. Just wear the proper gloves and protection etc.