PJ Morrissey wrote:
> Baking Soda works great on steel but do you really want to use it on a 
> masonry project with substantial mortar?
Baking soda wet blast was used on the Montauk Lighthouse, sandstone, in 
February then it was coated with an acrylic material that was at least 
1/16" in thickness. Check the location of the lighthouse on your maps... 
it is out there in the Atlantic. Coating system was showing failure 
within months of application. The applicator of the cleaning and coating 
blamed the site stewards for letting them do it.

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