Special Finishes

Architectural and Decorative Coating Specialists

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Acid Etch Preparation

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For New or Existing Concrete Floors


Before painting any concrete floors, new or existing, they should always be Acid Etched to remove all partially cured cement that has been floated off on top surface (laitence).  This process is essential or adhesion failure will result.


Acid Etch all new or existing concrete with 2 parts water to 1 part Hydrochloric Acid or Phosphoric Acid.  Apply with sprayer or plastic watering can at approximately 5m² per litre, completely flooding the area.  DO NOT broom any dormant or excess acid over any dry concrete as the acid's performance will be inadequate.  Allow 10 minutes until foaming ceases.


  1. Waterblast total area removing all loose sand, cement, etc., to achieve clean substrate.  Allow to dry.
  2. Ensure concrete is totally dry and dust free.  Test concrete with masking tape for dust deposits.
  3. Apply 1 coat of Optiseal Epoxy Sealer or Polyfloor as per specifications.
  4. Apply 2 coats of: Armescreed - Armepoxy - or Polyfloor as required, as per specifications.  Allow 48 hours cure time before heavy traffic.


Phosphoric Acid or Hydrochloric Acid can be used.


Protect all areas not requiring etch.  Use gloves, goggles, protective gear, etc. Refer to Materials Safety Data Sheet before use.

Observe New Occupational Safety & Health (O.S.H.) Instructions

Warranty / Liability

Special Finishes (NZ) Ltd provides all the enclosed information in good faith but without warrantee and is to assist your application. However the use of this product being used is beyond their control. The manufacturers can accept no responsibility whatsoever for any damage or failure arising from its application or use. It is totally the responsibility of the user to insure that the product is suitable for its intended use.