Sodablasting reveals "the pits!"

[DamoNomad]

Hoi all!
So I had my newish-to-me S2 9.2c (bought late last summer, and bottom paint was decrepit) soda blasted so I could hit this season with fresh everything down there. I figured I'd attack any blisters I found before hitting her with from scratch barrier + bottom paint.

On seeing the result, I see the hull is peppered with significant pitting of varrying size and depth. I'm wondering a few things:
- are these the aforementioned blisters that the soda blasting tore open? If not, what gives?
- what's the proper "prep" for painting?
- Do I need to grind these out/sand smooth etc or...
- Fill with fairing compound or will the new barrier coat do that?

Also, the bottom is pretty rough textures now. What FIRST step do you rec? Quick sand of the whole bottom to get is smooth or is rougher better for adhesion?

Thanks yall!

[Celestialsailor]

Looks to me like the gelcoat let go from the pressure of the blast. There is almost zero strength with gelcoat, just because it is not supported by fibers. It's not a big deal but still has to be addressed. If it were me, I would mix a little cabosil with epoxy to the consistency of cake frosting or lighter given the small size and use a small flexible plastic spatula, forcing the shmoo into the tiny craters. Not too heavy as you will want to sand D/A with 100 grit and not want to turn this into a sanding job.

[Ballsnall]

Doesn't look like blisters but that bottom coat is trash. I would thoroughly course sand the coating off back to good substrate to do it properly.

[MicHughV]

I agree with post # 2 !! Do that, and you will be fine. There are various epoxies on the market. Not sure where you are at, so check your local marine stores, ask them for advice which is the best for your purposes.

[Celestialsailor]

Originally Posted by MicHughV

I agree with post # 2 !! Do that, and you will be fine. There are various epoxies on the market. Not sure where you are at, so check your local marine stores, ask them for advice which is the best for your purposes.

I would also add to check with a working boat repair yard, if the OP is in one already. Asking an actual repair person might be a good choice. While picking up the odd item at West Marine, I will see a floor person that gives advice by reading off the the product label.

[MicHughV]

I kinda havta agree with you there..some people that West Marine hires to run their stores seem to have dubious maritime qualities or experience...

[Celestialsailor]

Originally Posted by MicHughV

I kinda havta agree with you there..some people that West Marine hires to run their stores seem to have dubious maritime qualities or experience...

I suppose they couldn't make the cut at the Golden Arches...

[Tetepare]

If you have the cash, pay the marina. If not grab a belt sander and go to town. You’ll have to fill and fair, then barrier coat. $20k for the marina or $1k and a bitch of a self job. If you go the latter we can step you thru it.

[mlydon]

Get som system three quick fair. It’s the perfect consistency. Apply as if you were doing drywall, with a fairly flexible 10” drywall knife. You’re looking to to leave just a skim coat behind. Sand smooth, barrier coat the whole bottom, and bottom paint.

Yes, it’s some work, but certainly not impossible, and your bottom will be trouble free for many years to come.

Matt

[Celestialsailor]

Originally Posted by Tetepare

If you have the cash, pay the marina. If not grab a belt sander and go to town. You’ll have to fill and fair, then barrier coat. $20k for the marina or $1k and a bitch of a self job. If you go the latter we can step you thru it.

Tell me you didn't mean a Belt sander!

[Ballsnall]

The original coating looks defective to me which could be why the soda blast has caused so much damage. Give it a scrap with a hard scraper or coarse sandpaper and if it is chauky it all needs to come off. If there is a problem with the hull coating this needs to be resolved first. If you can, have someone knowable look at it or post more details.

[Fore and Aft]

Celestial Sailor "Belt Sander" I had the same reaction as you. They are way too heavy for overhead work and then the gouging if you don't know what your doing!
I also had the same reaction when you said cabosil as a filler. That sands like a SOB if you don't flush fill it. There should be a better premixed epoxy filler that Sands easier. Preferably with a bit of colour so you can see the areas you missed sanding.
Cheers

[Celestialsailor]

Originally Posted by Fore and Aft

Celestial Sailor "Belt Sander" I had the same reaction as you. They are way too heavy for overhead work and then the gouging if you don't know what your doing!
I also had the same reaction when you said cabosil as a filler. That sands like a SOB if you don't flush fill it. There should be a better premixed epoxy filler that Sands easier. Preferably with a bit of colour so you can see the areas you missed sanding.
Cheers

I should have elaborated and said that I also use West Systems 407 with the Cabo-sil. Over the years I have learned to apply with a flexible squeegee, making sure not to over apply. Then use a 60 or 80 grit to finish. It goes pretty quick and if you're rolling on bottom paint, you never see it.

[Fore and Aft]

Celestial sailor I was going to say microballoons with epoxy resin. I like the premixed filler for amateurs, the constant consistency makes it easy to use.
Cheers

[Tetepare]

Looks bad to my eye so yeah belt sander for fast take down. Soda blast will leave pits, so take it all down or fill and fair the whole hull? Properly used the sander can do the job and eliminate lots of fairing.