According to the folks in the baths forum, he's over at the John Bridge forums these days.

Thanks, writersblock!

I think he had been there for some time, and came over here initially to warn people about an aerosolized tile sealer, available at that time through one of the big-box stores, that made the grout sealing process much quicker and easier, but which had the minor, unfortunate side effect of permanently damaging your lungs or killing you.

He stayed and helped GW people for several years, but I think writersblock is correct that he's returned to John Bridge. On the plus side -- enough people learned enough from him during his time here, that we can answer some of the easier questions.