soda blasting hull.

[erice]

has anyone had experience with soda blasting for bottom paint removal? effectiveness, cost & effectiveness? did you then use a barrier coat prior to bottom painting? any help would be appreciated.

[Cape Codder]

erice,
Oddly enough, I had only the metals soda-blasted this spring. My bottom paint was in good shape, but the metals (rudder, tabs, strut, raw intake, bow thruster, etc) had big time barnacles. Not any more!!
I just pulled the boat for Earl the Wimp, and all metals were spotlessly clean. On the BARE metals I used, Pettit metal prep (2-part epoxy, 1coat, Tie Coat rubber paint, 2-coats, Pettit Vivid, 2 coats )
The rest of the fiberglass bottom is Pettit Hydrocoat water-based ablative paint......excellent results.

Back to the soda-blasting: A 2-3 hour job, because the prep work was nearly the same as doing the entire bottom.

Once the job was done, you would never know they were there. All soda/paint is captured in plastic curtains, and removed. They would NOT do any blasting in the open air.... NO MATTER WHAT.
If you do your hull (fiberglass) I'm sure it's like starting over with barrier coats, and then bottom painting. The soda guys showed me before and after pictures of their work...top notch.
If and when I need to remove the bottom paint, I would go that route for sure. With the ablative paint, I don't see that in my future for quite some time.
If you haven't tried Hydrocoat, I highly recommend it. So easy to use, and to clean up with soap and water. The Pettit Vivid is also awesome stuff. Very impressed. Glad I did all the work this spring...it has paid off in NO barnacles.

[DougSea]

Well, I had plans to go the soda blasting route as the bottom paint on my boat was in very poor shape. Each year when I would powerwash the bottom great big chunks of paint would flake off. Clearly whoever painted this boat when it was new never prepped the bottom properly. The gelcoat was all shiny under the paint! The paint really all needed to come off and a proper job done on the bottom. The problem with soda blasting for me was cost, estimated around $3,500 - 4,000, although after the CRAZY amount of time it took me to grind and sand the old paint off I might have reconsidered. (I spent the money on A/C and TV for the boat!)

I'll try and find some pictures of the boat after I prepped it. If you should decide to go that route I'd be happy to give you the details, for now lets just say that I used a LOT of 60 grit discs!

Either way you go you would absolutely want to barrier coat the bottom. The barrier coat seals the fiberglass, which IS water permeable, and gives the bottom paint a proper surface to bond to. I went with four coats of Interprotect, a "signal" coat of black alblative paint applied "hot", and a final coat of red alblative. I haven't pulled the boat yet but on a recent swim I passed my hand over my normal problem areas and found nice clean bottom.

[jumpjet231]

I had a hard coat with a lot of build up that I had my yard in Oxford take off last winter. They stripped it by doing a chemical peel and sanding. The yard put 5 coats of Interlux epoxy coat and 3 coats of Interlux ablative. The total bill was about $5k. It was an ugly job that I'm glad I didn't do myself.

[DougSea]

I had a hard coat with a lot of build up that I had my yard in Oxford take off last winter. They stripped it by doing a chemical peel and sanding. The yard put 5 coats of Interlux epoxy coat and 3 coats of Interlux ablative. The total bill was about $5k. It was an ugly job that I'm glad I didn't do myself.

You can't imagine how much I needed to see that $5K number there JumpJet! Now I can tell myself that I really did save the better part of $4,000 doing it myself.

Not that I will EVER do that again! What a long, hard, miserable job! But it paid for my A/C!