Hire the best Concreting Expert

acid etching concrete

Results 1 to 5 of 5
  1. #1
    Novice
    Join Date
    Mar 2008
    Location
    heathcote junction vic
    Age
    43
    Posts
    34

    Default acid etching concrete

    Gday all, i am a long time reader who has gathered an amazing amount of info from this forum, but now it is time to post.

    After many years of dreaming about my perfect shed i have finally got it built, 9.15m by 11m barn with a mezzanine above the rear bay. I have got all of the wiring done now, heaps of power points, lots of lighting, all very neat and functional (well i have had about 3 years to think about it!!). The next stage is to paint the floor, I have done lots of research and finally purchased my paint (water emulsified 2-pack epoxy industrial flooring paint). As part of the preperation of the floor pre painting i need to scrub it with an alkaline cleaner, and then acid etch the floor. I have done a couple of test pieces on an old slab that is pretty clean and i found that while the acid did "fizz" when applied to the concrete it also appeared to stain the concrete.

    My questions are:
    1) Is it normal to "stain" the concrete?
    2) How do people ensure that all of the acid is removed before applying paint? Copious amounts of water?
    3) After etching and the concrete drys, i have heard that there is often a layer of fine dust on the surface that needs to be removed, have people experianced this, and if so what is the best way to remove said dust? Vacuum? Pressure wash?
    4) Any other hints/tips people can offer would be greatly appreciated

    Thanks all

    Yozza

  2. #2
    Tradesman Cementer's Avatar
    Join Date
    Dec 2007
    Location
    Newcastle
    Age
    52
    Posts
    86

    Default

    Hi Yozza,
    From experience I have found that acid washing leaves some sort of discolouration to the concrete. Usually the stronger the solution, the greener the stain. Using copious amounts of water removes the acid solution and helps dilute the run off but doesn't remove the residue or dust layer. That MUST be removed by pressure washer. I have seen so many jobs delaminate due to not pressure washing off the residue. At the very least, scrub with a firm broom and hose off. A water blaster will make sure though.
    My method is a solution of 2:20 (1:20 is the usual for etching but I like to make sure)
    Let the solution fizz before scrubbing with a stiff broom.
    I'm sure others will give you more tips but this is a start.
    Congrats on the new domain. Its a mans second home.
    Just because I'm paranoid, doesn't mean they're not out to get me.

  3. #3
    Diamond Member Terrian's Avatar
    Join Date
    Nov 2005
    Location
    Kilsyth, Victoria
    Age
    64
    Posts
    1,065

    Default

    ^^^ Sounds advice, take note

  4. #4
    Novice
    Join Date
    Mar 2008
    Location
    heathcote junction vic
    Age
    43
    Posts
    34

    Default

    Thanks Cementer for the advice
    My plan (at this stage) for painting the floor is
    1) Pressure wash floor
    2) Scrub with alkaline detergent and pressure wash off
    3) Mix acid and using a watering can apply evenly over floor, when it stops fizzing scrub with stiff bristled broom
    4) Rinse off, and then pressure wash and scrub with broom
    5) Let dry, then check for any crap left, and vacuum, pressure clean again
    6) Let dry again to check
    7) Moisten down concrete and then paint, very quickly!!!!

    In regards to wetting concrete before painting the agent i got the paint from said to do it as it is a water emulsified paint, having the floor moist helps the paint "suck in" to the concrete, giving better adhesion.

    The other problem i have got is that the shed is allready built and i am concerned about the acid reacting with the steel. I did some test pieces on scrap colorbond by scratching through to bare metal and then applying the acid sulution and then leaving it on there for times ranging from 5min to 20 min then rinsing off. So far after 2 weeks there is still no apparent reaction. Would it be safe to assume that provided i am quick with removing the acid there shouldn't be any real effect. I also did test piece on gal steel (simulate my posts) and there was a noticable reaction, with the final result that the gal dulled a little. Once again provided i am quick in removing acid solution can anyone envisage any issues with the gal?

    And one more question (sorry about all the Q's)!!!! I have read that if you apply a weak solution of ammonia after acid etch and washing, it should change the ph to approx an even 6 -7. is this correct and if so would there be any residue after lots of water flushing?

    thanks again for any help!!!!n

  5. #5
    GAM
    GAM is offline
    Apprentice (new member)
    Join Date
    Apr 2008
    Location
    Balmoral
    Posts
    15

    Default

    While on the subject, how would one REMOVE acid marks. I have a couple of yellow spots on outdoor granite tiles which I think may be due to hydrolchoric being spilt on to them.

    Thanks
    GAM


Similar Threads

  1. Help - Acid stained concrete
    By smidsy in forum General Odds & Sods
    Replies: 7
    Last Post: 21st Jan 2008, 06:31 PM
  2. Hydrochloric Acid on Concrete
    By billbeee in forum Concreting
    Replies: 23
    Last Post: 23rd Sep 2007, 06:27 PM
  3. Acid Stained Concrete
    By Metung in forum Concreting
    Replies: 1
    Last Post: 1st Jun 2007, 10:26 PM
  4. Replies: 15
    Last Post: 11th Jan 2007, 12:00 PM
  5. oxalic acid
    By Dan_574 in forum Decking
    Replies: 7
    Last Post: 10th Aug 2005, 12:24 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •