walnut shell blasting is an awesome way to get 4 to 5 layers of old bottom paint off your boat. enviromentally friendly fast and easy to do. scraped one small spot approx 1 foot square in 1/2 hour down to gelcoat
compared to 2 hours blasting to do whole boat
.it took 250 lbs of media or five bags @30$ a bag compressor rental @ 75$ and sandblast guy at a secret discounted rate vs a month of scraping and sanding = priceless . they are cleaner than soda blasting and wont hurt the gelcoat.