Soda blasting and barrier paint

[wingman]

We're considering soda blasting while on the hard this winter to remove 20 years of paint that is flaking and peeling to get down to gelcoat, and then painting with barrier coat and bottom paint next spring.

I'ver researched the board and would like any other experiences/opinions with soda blasting and barrier paint on Catalinas.

Any lessons learned?

[Ted Pounds]

I had mine corn-blasted. They used ground up dried corn kernels. It worked well. One thing I should've done was close all the thru-hulls.    My head sink filled up with corn kernels and paint flakes! 😵

[Jim Hardesty]

Look here.

https://c34.org/bbs/index.php/topic,10176.msg78333.html#msg78333

I think Northern Tool has the attachments for a pressure washer to use the coal slurry may be able to use other media with it.  If you keep your boat where you can do the work may be a good option.   
Jim

[Ron Hill]

Wing : When you are finished just make sure that your final coat of bottom paint is ablative!!

A thought

[wingman]

Wing : When you are finished just make sure that your final coat of bottom paint is ablative!!

I like the idea of alternating color as well so you can see exactly what layer is showing

[Stu Jackson]

Wing : When you are finished just make sure that your final coat of bottom paint is ablative!!

A thought

My understanding is that you can put ablative over hard but not the other way around.

Thus, if you do so, consider the implications.

[wingman]

My understanding is that you can put ablative over hard but not the other way around.

Yes, that is what I was told and it makes sense. Once you go ablative, you're committed.

[Jim Hardesty]

I like the idea of alternating color as well so you can see exactly what layer is showing

I also like the idea.  But didn't work for me when I painted red VC17 over blue VC17.  Paint is so thin and the new coat dissolves then mixes with the old coat.  That was rolling, possibly spraying would give different results.
Jim   

[Ron Hill]

Jim : I believe that the blue VC17 was not dry (set) when it was painted over the red.  I found that it's best to let it the first coat dry for 48 hrs. before rollering over with a new paint!!  Sometimes Yards try to do thing tooo fast!!

A few thoughts

[oldcatsailor]

After buying moody blue had 22 years of paint ,had a service use crushed walnut shells to take down to the gel coat without damage,,then put three barrier coats on. And use abalitive since still looks good.

[Noah]

Back in the day, when I owned wooden boats, crushed walnut shells was the go to thing for non-skid. You would paint deck, then sprinkle on crushed walnuts, then paint over.

[MarcZ]

Few years ago I had my boat soda blasted in the fall by the boat yard (or their specialized sub contractor) and I was quire happy with the result (walnut blasting was actually priced higher)
From what I understand any blasting gets more expensive every time "regulatory" wheels turn.
There was no blisters so following spring I did some "light" sanding followed by 4  coats of Pettit Protect Epoxy primer (use alternate gray and white colors to ensure even coverage)

Lessons learned:
Even light sanding of the bottom becomes way more unpleasant each time I'm doing it.  - I'm sure age is irrelevant   they just don't make the sandpaper like they used to
Having extra jack stands makes moving them around easier and safer
If you are painting solo - time required to finish single coat of Pettit Protect Epoxy primer in ~ 80F on c34 wing keel   is about the same as the minimum recoat time
4 coats + 1st antifouling = rather long day

[Phil Spicer]

Jim, the different result if you spray is you can see the dollars floating away in the over spray. I haven't seen anyone spray VC in many years and I winter in a marina that stores mostly sailboats. People are rolling on VC.

[Jim Hardesty]

the different result if you spray is you can see the dollars floating away in the over spray. I haven't seen anyone spray VC in many years and I winter in a marina that stores mostly sailboats. People are rolling on VC.

Phil,
In Erie VC17 is the most used bottom paint for sailboats.  I rolled for years, a couple of years ago my friend loaned me his sprayer.  Used about half the VC17 was quicker and easier.  Don't get much overspray.  Probably the paint isn't on as thick but it lasts a season. I bottom paint every year so that's not an issue.   Of course don't spray on a windy day.  The sprayers are HVLP.  I'm embarrassed to say I bought mine at Harbor Freight, same sprayer as my friends.  I do wear a respirator spraying that I didn't do rolling.

https://www.harborfreight.com/high-volume-low-pressure-spray-gun-kit-44677.html

I figure the sprayer paid for itself in saved VC17 the second season.
Jim

[LogoFreak]

Hey wingman,

I did exactly that this year on the new to me C34. Sandblasted down to barrier coat. Some before and after pictures, the cost wasn't bad ($1500 Canadian).