Brightening concrete with oxalic acid

[WFSTOTT]

When brightening concrete with oxalic acid, what is a good ratio of oxalic acid powder to mix per gallon of water?

What ratio for using to remove rust?

Also, do you need to rinse it off? If so, how long should you let it sit prior to rinsing and finally, will it kill the grass?

 

[hadishon]

Try this:

http://www.powerwashnetwork.com/showthread.php?s=&threadid=373&highlight=oxalic+acid+concrete

The search function and prior posts are worth a fortune here!

 

[hadishon]

As for rinsing, if you use oxalic acid like citric acid, I don't rinse citric acid. I use it to balance the PH and to brighten, leave on.

As for will it kill grass... I know it's a poison, whether poison to grass... I dunno but I would guess it would be. Someone may be able to give a better answer on that one.

 

[chirobob]

Phosphoric acid

Try phosporic acid at 35%. It is the base of most rust converters and is a stronger ionizer than oxalic.
Regards
Jason

 

[Doug Rucker]

I wouldn't use oxalic for brightening concrete. Put down a nice house wash mix and it will brighten it as good as anything.

 

[Clean County]

Experience guys know that Oxalic can brighten Concrete nicely if you know what your doing. SH does is also but not always as good.

 

[Doug Rucker]

Oxalic as most acids do puts a white haze on it, changing the color of it. SH whitens it and along w the sun brightens it better than anything out there.