I'm about to get my Catalina 22 hull blasted down to the gel coat to get rid of years and years of paint. Question is, what should I do from there? A couple of coats of ablative? Or is there something I should treat the gel coat with before that?
Hull Treatment after Sand Blasting
- Thread starter ppm411
- Start date
Assuming that you'll keep the boat in the water full time, this would be the perfect time to apply a barrier coat.
Even soda blasting is iffy depending on who is doing it. I hope he is having an experienced person do the work. I have seen hulls soda blasted through the gelcoat.
Is dry-ice blasting a good alternative? I wonder if it has been tried on boats. I'd consider it on mine if the cost is reasonable.
Best I have seen so far is sponge blasting. Dry ice is better than sand and about as good as soda if done right.
You can also consider epoxy like WEST System for a barrier coat. Their website should provide information on how and what additives to use. I think the interlux formula recommends multiple coats for a significant thickness buildup. The Epoxy may not require as many coats. Another option to that is a couple coats of epoxy then a couple coats of barrier coat to act as a base coat primer for bottom paint adhesion.
http://www.westsystem.com/ss/barrier-coating/
http://www.westsystem.com/ss/barrier-coating/
Unless you really have an experience person on sandblasting a Catalina 22, stay the heck away from that as most boats I saw sand blasted was a big mistake plus it will take gel coat off which is not good not to mention all the pit holes it puts in which epoxy fillers will have to be added and then sanded with sandpaper just to fill in the holes first.
The more educated I'm getting via all of your great feedback, reading, and conversations with the yard manager, sounds like my best option is to have the hull sanded. Blasting of any kind is great if you have blistering as it will blow away the loose chunks of gelcoat, etch the gelcoat and underlying resin to accept the epoxy. It doesn't appear that I have any blistering. The fact that my boat is on a trailer only complicates matters if I was to bring it somewhere. All told, I was quoted 1500 from the yard to sand it, epoxy it, and paint it on stands.
I might consider talking to other yards as that cost seems a little high to me. But you are in Oyster Bay so that could add a fair amount to the cost
. (I was in Oyster Bay two weeks ago, love the area but it did seem pricey.)I was able to have the yard to an aggressive power washing by giving the guys at the yard $100. That took almost all of the paint off. It was then sanded with a 6" random orbital power sander in less than 4 hours.
For barrier coat I went with the Interlux Interprotect. I did 3 thin coats but my Catalina is built after 1995 (Catalina changed from polyester to vinylester in 1995 and eliminated blistering). On a pre-1995 Catalina I would go with 6-7 coats of the Interprotect.
I "hot coated" my first layer of bottom paint. That means applying the first coat while the Interprotect is still tacky. I then did 3 thin coats of bottom paint. I used the Interlux Pacifica Plus. It lasted two years with that system.
Make sure the barrier coat and bottom paint are different colors. That way you can just sand down the bottom paint until you see the color change. Then reapply bottom paint.
Good luck and fair winds,
Jesse
I just went through the entire process of sanding (very thick) old bottom paint, blister repair, new epoxy barrier coat including a new layer of 8.9 oz cloth, Interlux Interprotect 2000 barrier coat, and bottom paint on my C-22. Its all in my restoration thread on the C-22 forum page.
I took off my gelcoat to facilitate drying the hull and making sure I got all the blisters. I also inverted the hull onto a wood cradle to make the task easier. This is the kind of job you hope to only have to do once in the lifetime of the boat, or in your own lifetime, lol. Besides the price of paint, epoxy, and consumable materials the job cost me zero dollars but it was a heck of a lot of sweat equity.
I would avoid sand blasting, period. For all the reasons mentioned above, just too risky. Dry ice blasting is very effective and from first hand experience (I have personally operated the machines) they are the least likely to damage the substrate. Good luck finding an outfit that does that job with good equipment, regardless of the benefits it still seems the industry has been slow to pick up on the technology (at least for small boats). I've had many things professionally soda blasted, but they were all steel. Great results every time, but I have no experience with doing it on fiberglass, but I would say it is way less risky than sand blasting.
I took off my gelcoat to facilitate drying the hull and making sure I got all the blisters. I also inverted the hull onto a wood cradle to make the task easier. This is the kind of job you hope to only have to do once in the lifetime of the boat, or in your own lifetime, lol. Besides the price of paint, epoxy, and consumable materials the job cost me zero dollars but it was a heck of a lot of sweat equity.
I would avoid sand blasting, period. For all the reasons mentioned above, just too risky. Dry ice blasting is very effective and from first hand experience (I have personally operated the machines) they are the least likely to damage the substrate. Good luck finding an outfit that does that job with good equipment, regardless of the benefits it still seems the industry has been slow to pick up on the technology (at least for small boats). I've had many things professionally soda blasted, but they were all steel. Great results every time, but I have no experience with doing it on fiberglass, but I would say it is way less risky than sand blasting.
If the paint is very thick try using a paint scraper and just scrape it all off. You have to really press down and it is a lot of effort but a lot less messy and cheaper than sanding. I did a Catalina 25 that way and it worked well. The final sanding is a lot easier and a lot less exposure to toxic sanding dust. I used a scraper like this one, it scraped the gel coat a little but if you plan on putting an epoxy barrier coat that's not a problem.
http://www.zoro.com/i/G4791114/?utm_source=Bing&utm_medium=cpc&utm_campaign=PLA
http://www.zoro.com/i/G4791114/?utm_source=Bing&utm_medium=cpc&utm_campaign=PLA
Its easy! I did it and so can you.
I did my P303 30foot with great success!
BACK TO NATURE Aqua Strip Paint StripperFormulated to remove up to 10 thick layers of marine antifouling paint, Aqua Strip is a heavy-duty yet environmentally safer alternative to caustic and methylene chloride strippers and other noxious compounds. It stays wet for extended periods of time to penetrate and lift multiple layers of paint—making it possible to strip large areas at one time.
InterProtect® 2000E is a unique two-part epoxy coating developed to protect new and used fiberglass hulls from water absorption which can lead to poor hull performance and osmotic blistering. Formulated with Micro-plates® that create an overlapping barrier to eliminate any direct path for water migration. In addition to use as a barrier coat, Interprotect 2000E is also an excellent fiberglass topside primer.
Quart and Gallon Kits are offered and consist of separate containers of base and reactor. When mixed, kits yield either a quart or a gallon. We also offer, as separate purchases, “short-pour” 3-gallon containers and separate containers of reactor, which when mixed yield three full gallons. The low-VOC formulation, Interprotect 2000VOC, meets all VOC regulations and can be applied in any air quality management district.
•Total Thickness Required: Above waterline: 2 coats; below waterline: 4–5 coats (10 mil minimum)
•Drying Time: To overcoat: 3 hrs.–6 months @ 73°F (time period applies to overcoating with InterProtect 2000E; min./max. time to overcoat varies with temperature and substance applied, that is, bottom paint, filler, etc.)
• Coverage: Brush: 60sq.ft/qt., 240sq.ft./ gal.; spray: 45sq.ft./qt., 180sq.ft./gal.
•Application Methods: Brush, roller, airless/conventional spray
•Thinner: Interlux 2316N (Model 198598), (10% reduction limit)
NOTE: Myself I put 8 coats of barrier coat 2000E on first to dry then around 30 days later put 6 coats of ablating paint and do far.. great! should last 10 years so I'm told.
good luck, Capt. Rob
I did my P303 30foot with great success!
BACK TO NATURE Aqua Strip Paint StripperFormulated to remove up to 10 thick layers of marine antifouling paint, Aqua Strip is a heavy-duty yet environmentally safer alternative to caustic and methylene chloride strippers and other noxious compounds. It stays wet for extended periods of time to penetrate and lift multiple layers of paint—making it possible to strip large areas at one time.
InterProtect® 2000E is a unique two-part epoxy coating developed to protect new and used fiberglass hulls from water absorption which can lead to poor hull performance and osmotic blistering. Formulated with Micro-plates® that create an overlapping barrier to eliminate any direct path for water migration. In addition to use as a barrier coat, Interprotect 2000E is also an excellent fiberglass topside primer.
Quart and Gallon Kits are offered and consist of separate containers of base and reactor. When mixed, kits yield either a quart or a gallon. We also offer, as separate purchases, “short-pour” 3-gallon containers and separate containers of reactor, which when mixed yield three full gallons. The low-VOC formulation, Interprotect 2000VOC, meets all VOC regulations and can be applied in any air quality management district.
•Total Thickness Required: Above waterline: 2 coats; below waterline: 4–5 coats (10 mil minimum)
•Drying Time: To overcoat: 3 hrs.–6 months @ 73°F (time period applies to overcoating with InterProtect 2000E; min./max. time to overcoat varies with temperature and substance applied, that is, bottom paint, filler, etc.)
• Coverage: Brush: 60sq.ft/qt., 240sq.ft./ gal.; spray: 45sq.ft./qt., 180sq.ft./gal.
•Application Methods: Brush, roller, airless/conventional spray
•Thinner: Interlux 2316N (Model 198598), (10% reduction limit)
NOTE: Myself I put 8 coats of barrier coat 2000E on first to dry then around 30 days later put 6 coats of ablating paint and do far.. great! should last 10 years so I'm told.
good luck, Capt. Rob