I used to own a company that performed high pressure wet sand blast and have prepped many bottoms, so I thought i would add my two cents for what its worth. There are many different mediums (Sand, garnet, walnut shells, glass beads, Co2, baking soda, etc.) that can be added to blast equipment
to strip, cut and clean surfaces depending on the material to be removed and the type of substrate involved.
Baking soda cleaning was oriogionally introduced as a much gentler and more environrmentally friendly method. For the right type of application baking soda will clean with out damaging the surface (No stipple) and as the soda eventually liquifies there is one less aspect to the clean up.
Where we live in NY there are two outfits perfoming blast work for stripping bottoms. One shoots plastic beads the other soda. As the soda is the latest and greatest it tends to cost more. Bead blasting has been going on for years and is a very accepted meathodology for removing bottom paint
We bead blasted my buddies Cape Dory
27 this spring prior to doing a blister job. For $800.00 the company came in with a self contained box truck with a three man crew, completly tented the boat, ran powerful vacuming equipment
into the tent to capture the old paint
and had the boat prepped in about an hour. I would say that that due to environmental concerns, (Making sure the toxic paint
that is removed is cleaned up and disposed of properly) it is a job best done by the pro's.