On a recent project one of our customers decided to put a number of stain resistant sealers to the test. The goal was to see which stain resistant sealer would be best to use on marble bench tops and splash backs for their clients project. Guard Industry products ProtectGuard® and ProtectGuard® Marble and Granite were independently tested against 4 leading brand penetrating sealers. These products were Actichem AP176, Du Pont Bulletproof, Dry Treat Stainproof and Lithofin Stain Stop Plus.
A fair sealer review requires an independent evaluation. As such all test work was carried out by “Stone Initiatives” A NATA (National Association of Testing Authorities, Australia) accredited testing facility. They are also members of the ASAA (Australian Stone Advisory Association) and ASTM (American Society for Testing Material – Worldwide Standards).
The staining test results in this sealer review are derived directly from Stone Initiatives results. Information regarding application methods, lifespan and VOC’s data has been derived from manufacturers published information. These include Technical Data Sheets (TDS), Application Guides and/or Safety Data Sheets (SDS). Average retail pricing, as published on Australian online retail stores has been used for all cost calculations and comparisons.
Samples of stone were treated with the required coats of each stain resistant sealer in accordance with the manufacturers application guidelines. The sealers were allowed to cure for a minimum of seventy two hours. Following the curing period the surface of the samples were subjected to 20 scrubbing cycles with a red nylon floor pad. This simulates in service cleaning processes. It also removes any excess sealer which did not fully penetrate the surface. The samples were allowed to air-dry before application of the following staining agents to the surface finish:
- Red Wine (acidic)
- Olive Oil (stain leaving a film)
- Black Coffee (stain leaving a trace & slightly acidic)
- Coca Cola (stain leaving a trace & slightly acidic)
- Soy Sauce (stain leaving a trace & slightly acidic)
Staining agents were allowed to dwell on the surface for periods of one hour and twenty four hours before attempts were made to remove the stains.
Cleaning was attempted firstly by rinsing the surface with running hot water for a period of 5 minutes followed by wiping with a damp cloth. Any stains still visible were then cleaned vigorously with a red nylon pad and neutral detergent. Then rinsed under hot water. The surface was air dried and then re-evaluated for staining or damage to the surface.
The reason for testing both 1 and 24 hour stain exposures is to determine performance in different situations and applications. In general, most spills will be cleaned up immediately or very shortly after the spill is made. The one hour result best simulates this type of event. Bench top and indoor flooring applications would generally fall into this category. The 24 hour exposure better evaluates what happens when a spill goes unnoticed for a longer period of time. In most instances this would result in the stain drying out on the surface.
Elegant Grey Marble stone samples were used for this test work as per the project requirements. However, marble is notoriously difficult to seal. As such it provides a rigorous performance test of the stain resistant sealers in question. It provides an excellent benchmark. If a penetrating sealer works well on marble it generally performs as well, if not better, on other materials.
As such, the results presented in this sealer review are representative rather than definitive. Sealer stain resistance may vary when applied to different types of stone or other sealed materials. However, for the purposes of comparing the relative performance of different stain resistant sealers, the results are fair and representative.
The following graphs display the results as determined by Stone Initiatives.
Scores are of 1 – 5 are determined according to the below scale:
5 – Stain removed after cleaning procedure (scrub with red nylon pad, detergent and hot water).
4 – Stain very slightly visible (not noticeable upon casual viewing).
3 – Stain slightly visible (noticeable at close range at casual viewing).
2 – Stain moderately visible (conspicuous).
1 – Stain highly visible / permanent damage to surface finish (e.g. etching).
Stone Initiatives state a Stain Index Uncertainty of ± 0.5.
Sealer Stain Resistance Results
The following 4 graphs illustrate the ease of cleaning of stone after being exposed to the 5 stains over both 1 hour and 24 hours. Graphs show individual testing results per stain for both 1 and 24 hours. And an average score rating for both 1 and 24 hours stain exposure time.
Sealer Stain Resistance After 1 Hour Exposure
Sealer Stain Resistance After 24 hours Exposure
In addition to staining, Stone Initiatives analysed the surfaces of the cleaned samples to evaluate the extent of surface etching. Etching is caused by acid attack and is a permanent defect. To remove etching the stone needs to be cut back and re-polished. After such a process sealer would need to be reapplied. The results of the etching analysis are presented in the table below.
|Unsealed||Antichem AP176||Du Pont Bulletproof||Dry Treat Stainproof||Lithofin Stain Stop Plus||Protect Guard||Protect Guard MG|
Visibility of Etching
Slight to moderate
slight to moderate
slight to moderate
slight to moderate
slight to moderate