Every box of ARTO tile notes that the installation is not finished until sealed. While it is no doubt important to seal your (porous) concrete tile installation, sealers have always come with trade offs. Penetrating sealers give a natural look but could be better at protecting against stains and scratching. Topical sealers provide more protection but typically have a glossy finish and are less than ideal for exterior installations (glossy surfaces are sometimes slippery plus they can trap moisture and efflorescence from the substrate).
We have found Master Seal 100 by Desert Brand combines the best aspects of topical and penetrating sealers. While it does have a slight sheen (“satin” per the manufacturer) it still has a natural look compared with glossy sealers. The surface is also breathable so it can be used outdoors without moisture and efflorescence being trapped below.
Like just about every other concrete product, cleaning with acid is not recommended. However, we did a test where we sealed our 4×8 Smooth brick veneer with Master Seal 100 and then dunked one half in full strength hydrochloric acid. As the photos show, the back side of the tile shows the pitting and exposed aggregate that can be expected when concrete is acid washed.
Back side (unsealed) of 4×8 Smooth Cotto Dark untreated (L) and submerged in acid (R).
By contrast, the front side sealed with Master Seal 100 was almost completely unaffected. Without the labels, it would be hard to determine which half was dunked completely in full strength acid.
Front side (sealed) of 4×8 Smooth Cotto Dark untreated (L) and submerged in acid (R).
You can purchase Master Seal 100 direct from ARTO and the brief video below is a further testament to its durability.