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plastering walls

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  1. #1

    Join Date
    Sep 2018
    Posts
    14

    plastering walls

    I am plastering some walls, and I've seen the workers use white limestone powder mixed with a brown gel. I've asked at the hardware store what it is and the responses ranged from "don't know" to "gel".... does anyone know what this stuff is? I CANNOT find it on the internet anywhere.


  2. #2

    Join Date
    Jan 2018
    Location
    Taiwan and HK
    Posts
    6,158

    Would it be a silica-based gel/gel that includes silica of some kind? Lime and silica will make a reaction product (like they do in concrete) that would likely make a good wall surface...

    Not sure what the "brown" is from...

    Lot of technical papers on the Internet about silica and lime reaction products, again, mainly concrete researchers (I deal with concrete composition patent applications from time to time which is why I keep mentioning concrete...).

    From what I have seen even from PhD researchers is that there seems to be a lot of DIY-type mixing of various ingredients that is less than 100 percent scientific...

    Good luck!

    Edit:

    Or just buy some pre-mixed waterproof plaster- something like this with some polymer in it...this is a local HK company and I am familiar with some of their repair mortar compositions...but they seem to gear their products for the local environment:

    https://www.optimix.com.hk/?route=pr...l&product_id=2

    Last edited by MABinPengChau; 17-04-2019 at 08:20 PM.

  3. #3

    Join Date
    Aug 2006
    Posts
    11,884

    I think the brown gunk is derived from algae, not completely sure of this though.

    It seems to make a pretty terrible wall surface, it's very soft. Suspect it's chosen for being cheap and easy vs good. Like many things in HK.

    MABinPengChau likes this.

  4. #4

    Join Date
    Sep 2018
    Posts
    14

    many thanks for that... I already have this gel and bag of white limestone powder, and currently doing some test mixes with the hardener. You're right, be easier to buy the premixed stuff, but didn't know it existed at the time = oh well...


  5. #5

    Join Date
    Sep 2018
    Posts
    14

    that sounds like it... but why buy something cheap, when limestone powder is usually mixed with the cheapest product of all = water... must be a reason for it. I may start applying tomorrow if the test batches harden well overnight = fingers crossed.


  6. #6

    Join Date
    Sep 2018
    Posts
    14

    yep, that's the stuff... they call it "choi gua"... or whatever sounds like that.... still can't find out anything about it... oh well... if anyone can ask, and get back to me, it might help