soda blasting

sbeer · Post by **sbeer** » Mon Dec 08, 2008 6:20 pm

This coming Saturday I am finally going to blast the bottom of my boat. 20 PLUS years of paint going bye bye. Has anybody done this? I do know that after it sitting all winter until may of next year she should be pretty dried out to do the barrier coat. Scary part is seeing the bottom naked, that is going to be a shocker. Mike

Rick · Post by **Rick** » Tue Dec 09, 2008 5:25 am

Mike, This is a project I'd love to do, but my winter marina will have nothing to do with it. As far I know, the bottom of our boats are gelcoat. Are we sure that soda blasting will scrape that off ? I'm wondering if you could away with going directly to paint. Rick Ticket 85 SF Merc 454 MPI's Falmouth, MA

sbeer · Post by **sbeer** » Tue Dec 09, 2008 7:48 am

Rick, the idea of useing Baking soda to take the paint off is to not take the gel coat off. I'll be down there all morning with the guy to make sure the job is done to my satisfaction. He also will open any and all of the blisters that I might have [ which are many ]. My marina only requires that the guy have at least 1 million in insurance coverage. I understand thats pretty common. It is definitly going to be a stressfull day. Mike

h2ojst · Post by **h2ojst** » Tue Dec 09, 2008 9:12 am

Piece of cake Mike, assuming the guy knows what he's doing. I did mine a couple of years back just to inspect the condition of the bottom. Thankfully, no blisters at all. Why do you have so many? This is uncommon in our boats. The soda blasting media is very fine & leaves a very smooth finish. I used interlux interprotect 2000E barrier coat applied with a roller to 10 Mils. (2 coats)Is the yard going to do the blister repair? Joe Tomaini 1988 Sportfish Attitude Adjustment II Fort Lauderdale, FL

Rick · Post by **Rick** » Tue Dec 09, 2008 9:44 am

A salesman's explanation of the process...about 7 mins... http://www.youtube.com/watch?v=fM-R2_Awgeg Rick Ticket 85 SF Merc 454 MPI's Falmouth, MA

sbeer · Post by **sbeer** » Tue Dec 09, 2008 10:13 am

Joe, I do believe the reason behind the blisters is that the boat was docked in southern waters its whole life and never was put on the hard except to paint the bottom. With as much paint that is on the bottom of my boat I can believe it, looks like the past ownwers just grabbed buckets and threw it on. Looking at that video that Rick posted the boat that they were useing as a model doesnt have any gel coat on it, interesting video. Mike

h2ojst · Post by **h2ojst** » Tue Dec 09, 2008 1:27 pm

Perfect video demo. This is the same product I used. Good luck this weekend. Joe Tomaini 1988 Sportfish Attitude Adjustment II Fort Lauderdale, FL

franklyprice · Post by **franklyprice** » Tue Dec 09, 2008 3:30 pm

I scraped mine off. It really sucked but worked. I also didn't use any barrier coat, figured if it hasn't blistered yet I'll give it more time to try. I wonder what will happen to the epoxy barrier coat when it decides to go bad in the future? Doesn't seem like blasting will take that off so easily.

Rick · Post by **Rick** » Wed Dec 10, 2008 6:18 am

Frank, I was waiting for you to weigh in on this one. I was thinking that if the gelcoat is still in good shape, do you really need the barrier coat ? It sounds like it's extra protection that could help preventing blisters. But like you said, the long term implications need to be understood. In Mike's case where he already has some blistering, I think he's got to use it. So Mike, you can be our beta site ! Rick Ticket 85 SF Merc 454 MPI's Falmouth, MA

Post by **dougl33** » Wed Dec 10, 2008 8:21 am

Bill Dunlop has his boat soda blasted when they did the re-power back in 2007. He seems happy.

buzzk · Post by **buzzk** » Wed Dec 10, 2008 11:18 am

Are you sure the blisters were caused by leaving the boat in the water? My boat doesn't have any blisters (knok on wood). It's never been left on the hard except long enough to have the bottom painted. I only haul her every other year to have her bottom painted. I use the paint that wears off as you run her. I do have the bottom cleaned by a diver every month. The guy I bought the boat from told me he had applied a barrier coat. I guess it's worth doing. Buzz

franklyprice · Post by **franklyprice** » Wed Dec 10, 2008 7:55 pm

Rick, I think that if blisters are a problem, the only choice is to barrier coat. If the gelcoat is in good shape then it's certainly something to consider but not a given. In my case I figured that if it made it 20 years then it might just last forever. If it doesn't I'll deal with it then. I have studied the causes of blisters quite a bit and while it's still debated a bit , they seem to be caused by a bad resin mix or defective resins or resins that were used when the chemical companies were trying to use less petroleum in the chemistry. Any or all of those seem to be the likely causes of blisters. For those reasons, our Bertrams are less effected than most boats, so I wasn't in a huge hurry to barrier coat. I will say it again though, bottom paint is relatively easy to remove, epoxy is super difficult to remove if it does go bad and prep is the biggest reason paints fail. So if you use epoxy (barrier coat), you'd better follow the directions to the letter.

IRGuy · Post by **IRGuy** » Thu Dec 11, 2008 6:13 am

When we hauled "Phoenix" for the pre purchase survey we found lots of small blisters (from dime to some quarted size, mostly dime to nickel size). The owner said he hauled the boat every winter for painting and inspection, but the marina guys said the boat hadn't been gone for years. I asked my surveyor about them.. his answer was that it is difficult to remedy this situation, and most attempts in removing bottom gel coat and recoating end up in failure, unless the applicators are very knowledgeable, and he didn't think many were. His advice to me was they had probably been there for years, and it would be best if I watched them for a few years to see if they were getting worse. I plan to haul in sometime before next summer so I will have a better idea then what I will do. Frank B - IRGuy@aol.com The weak will inherit only whatever the strong are willing to let them have! "Phoenix" 1983 FBC Cummins 6Bs - 315HP Wilmington, NC

Post by **dougl33** » Thu Dec 11, 2008 7:17 am

I stripped the bottom of my boat back in 2003. I used peel away. When I was done it looked like the boat had just popped out of the mold. As there had been no blisters in the first 17 years I saw no reason/need to barrier coat.

BECCA ROSE · Post by **BECCA ROSE** » Sun Dec 14, 2008 3:44 pm

They soda blasted mine a couple summers ago, it opened up lots of little (1/8th inch) pot marks. Is that a blister?? Not really willing to say that, wouldn't a blister have water in it? These were all dry. I filled every little hole with some two part epoxy putty. Sanded, barrier coated, and put two coats of bottom paint. If all those pot marks didn't show up I would not have barrier coated. I would have just cleaned, primed, and bottom painted. Barrier coating is time consuming because of the amount of coats and dry times, never mind expensive(materials only). It looks great though, anything would with 7 coats on it. 2 seasons later I still have not had to bottom paint or touch up any spots. It still looks great with no signs of wear. The pot marks might be due to a lesser quality of gelcoat Bertram used after 1997. My 1988 and 1989 Bertrams both have lousy gelcoat that just won't perform as well as earlier models. Doug and Frank can get their boats to shine like glass with minimal effort. Mine always look mediocre at best, no matter what you use. Maybe it's more brittle also and couldn't withstand the blasting.