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Post by dralyagmas on Feb 15, 2015 23:27:33 GMT
Hi I am about to antifoul my hull for the first time (for me) its got 10 years of antifoul build up and I am keen to take it right back, fair the hull and then reapply.
I have heard some horror stories using paint strippers and blasting about effecting the gel coat but I am also not keen on sanding all the way back. I will be doing the work myself and not keen on spending a bomb but if there is a quick and easy solution I am keen to hear it. Reading some literature there seems to be lots who use paint strippers and some locations totally prohibit sanding anyway.
What are peoples thoughts?
37 ft hull, copper based antifoul in Australia
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Post by ianpowolny on Feb 16, 2015 7:41:49 GMT
We added copper coat last season. Take a look at the thread Copper Bottom. All our old anti foul was taken off by hand right back to the gel coat. Then Copper Coat painted on. It took 6 weeks in all.
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Post by sailbleu on Feb 16, 2015 7:53:07 GMT
In my view the only proper way to get the old AF off is a ( high quality) scraper an lotsbof elbow grease. The scraper way is the cheapest method , but afterwards you will still slightly need to sand the hull down to get the small remains off. Blasting can be done with different substances , like sand , salt or CO2 . Rather expensive though , and sand blasting is very intrusive and damaging for the gelcoat. Some yards do not even allow sandblasting.
Scraping my hull took me a week on my own.
Regards
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Post by On y va on Feb 16, 2015 8:56:21 GMT
You hear horror stories about boob-jobs too. Doesn't mean they are all bad!!
If blasting is done professionally and correctly, in my (professional) view by far the best method. It is not really a DIY job, as also the material used in relation to your hull is important. Usually a very fine silicon sand is used.
In Holland they generally peel the gelcoat (all of it!!) of boats and then rebuild with layers of epoxy. This in my view is total madness. Same for doing a 37 ft boat by hand with a scraper.......but I tend to be lazy and always look for the least tiring solutions. What I like about dust blasting, is that it does expose the weak areas in your hull. A little anekdote:
We had to re-coat a 10 year old Hallberg Rassy some years ago, which we prepared for the owner for a world cruise. So, blasting commenced (silicon sand) and all went well till at one stage the guy doing the blasting came out of the tent around the hull and a white face appeared when he pulled his mask off. He blasted right through the hull at midships. To cut a long story short, production error and in the end a hole of approx 30x40cm was taken out and had to be rebuilt. Initially HR denied all ofcourse. Impossible! Our boats never bla bla bla. In the end and after two independent surveyor confirmations HR sent two guys who repaired it all, eventhough the boat was 10 years old.
Also, dustblasting exposes any osmosis too, but just in the affected areas. It's amazingly efficient in that respect. If a boat has osmosis, after blasting the hull looks like a youth with acne. So these areas are washed with fresh water, then dried and then epoxy filled, then 5 coats of epoxy coating and 3 coats of antifauling and good to go.
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Post by hoppy on Feb 16, 2015 9:47:46 GMT
You hear horror stories about boob-jobs too. Doesn't mean they are all bad!! I hope the OP does not get confused and give his boat a boob job but I tend to be lazy and always look for the least tiring solutions. Last winter I discovered that the lest tiring approach to stripping the antifouling was to sit in my office at the computer earning money whilst paying someone else to do the work From what I understand they scraped 12 years of paint off then sanded back to the gelcoat before applying some sealant (epoxy rings a bell)
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Post by ianpowolny on Feb 16, 2015 10:55:18 GMT
You hear horror stories about boob-jobs too. Doesn't mean they are all bad!! I hope the OP does not get confused and give his boat a boob job but I tend to be lazy and always look for the least tiring solutions. Last winter I discovered that the lest tiring approach to stripping the antifouling was to sit in my office at the computer earning money whilst paying someone else to do the work From what I understand they scraped 12 years of paint off then sanded back to the gelcoat before applying some sealant (epoxy rings a bell) I have to say I'm also in the make money and pay someone to do the work. That way I get the job done, keep someone in work and then have money to buy some other item I don't really need.
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Post by On y va on Feb 16, 2015 15:01:35 GMT
but I tend to be lazy and always look for the least tiring solutions. Last winter I discovered that the lest tiring approach to stripping the antifouling was to sit in my office at the computer earning money whilst paying someone else to do the work From what I understand they scraped 12 years of paint off then sanded back to the gelcoat before applying some sealant (epoxy rings a bell) Ok, on the sealant topic there are many options and opinions too. If you have a pre-isophthalic polyester hulled boat (so orthophthalic polyster) and you do make the effort to go all the way back to gelcoat, you will need 5 coats of epoxy primer (ie Interprotect of International) to get the correct water resistance. Same goes for the steel keel. Less than 5 coats is just not waterproof and makes the excercise more or less a waste of money. Last spring I had my keel blasted to bare metal and had, after a 2 component metal primer coat, 5 coats of Interprotect applied. The dents and scratches were then filled with epoxy filler, next an intermediate coat and then 3 coats of antifauling. However, I will have my hull (so the GRP) done later this year with only 2 or 3 full coats of epoxy coating instead of 5, as the hull has a isophthalic polyester gelcoat (most boats built after 1995 have this, shortly names ISO polyester). Isophaltic polyster is a lot better than orthophthalic (standard) polyester in many ways. This material has a much better standard of water resistance, hence less chances of blistering. It is also stronger than normal polyester, i.e. the elongation to break (stretch) is several times higher than normal polyster (polyester 1.6, iso polyester 5.0). Tensile strength is 50 to 74 (N/mm2). This means reaction (also within the gelcoat) with humidity for ISO polyester is far less than afore mentioned orthophtalic polyster and therefore full waterproofing is not really needed. You can if you want ofcourse. So the age (and with that the polyster used) of your Jeanneau decides what system you need to apply and how to go about it.
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Post by dralyagmas on Feb 16, 2015 22:59:14 GMT
You hear horror stories about boob-jobs too. Doesn't mean they are all bad!! Cant afford to do both (
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Post by hoppy on Feb 17, 2015 7:49:22 GMT
You hear horror stories about boob-jobs too. Doesn't mean they are all bad!! Cant afford to do both ( She'll look a bit lopsided, so maybe you should wait and save until you can afford both
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Post by ianqv on Feb 18, 2015 21:08:28 GMT
When we copper coated we done it by hand! A very time consuming, back numbing, boring job! However, by doing that way I saved £750, plus I knew it was done correctly! It must of taken 8 weekends. Looking back - I'm glad its done and I'm pleased that I done it. Would I do it again.... probably not, it just took me soooooo much time.
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Post by Seagem on Feb 19, 2015 20:50:01 GMT
I stripped the AF from my SO42i using a simple scraper called Proscaper. (Google it) it can be attached to a vacuum cleaner to collect all the old AF. It's hard work but quicker than sanding. It took me a whole 7 days on my own to complete the job back to the gel coat. I then used an obital sander with some grade 20 discs to finish the job and provide a key for copper coat. A local boat repairer advised against soda blasting, does more harm than good in his opinion. A friend has tried the paint stripper option and it failed miserably.
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Post by On y va on Feb 19, 2015 22:05:53 GMT
So what harm does soda blasting do? As sanding with 20 grain on a gelcoat seems a lot more harmful to me. Or is grade 20 not the same as grain 20?
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Post by Don Reaves on Feb 19, 2015 23:00:39 GMT
I think the real issue with soda blasting is that it's too easy to remove too much material. But in the hands of someone who knows what they're doing and cares about the outcome, soda blasting can be a very good technique.
I had my keel soda blasted back to bare metal last summer, as the factory applied epoxy barrier coat was done very poorly and it was a real pain repairing the rust every spring. Of course, the keel is much less susceptible to damage than the gelcoat, so I wasn't worried about problems.
Don
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Post by rxc on Feb 20, 2015 23:19:02 GMT
I once sanded the bottom of a 34 ft sailboat, and decided "never again". This was followed by years of spot scraping and painting each year with ablative paint.
Next time my 43 needs to have the bottom scraped, I will pay someone to do it.
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Post by On y va on Feb 21, 2015 9:18:02 GMT
I think the real issue with soda blasting is that it's too easy to remove too much material. But in the hands of someone who knows what they're doing and cares about the outcome, soda blasting can be a very good technique. I had my keel soda blasted back to bare metal last summer, as the factory applied epoxy barrier coat was done very poorly and it was a real pain repairing the rust every spring. Of course, the keel is much less susceptible to damage than the gelcoat, so I wasn't worried about problems. Don Yes, but you also would't attempt DIY heart surgery, would you? It's a job for professionals who know what they are doing. And I mean professionals, not some Pablo or Alessandro who rents a compressor with a blasting machine.
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Post by Don Reaves on Feb 21, 2015 11:56:54 GMT
Yes, this is exactly what I was trying to say. I would never want to do this by myself. It requires real expertise.
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bigred
Junior Member
Posts: 19
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Post by bigred on Feb 22, 2015 13:44:47 GMT
Two of us hand scraped, sanded and repainted a bene 43 in 5 days... I will NEVER do it again.
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Post by sailbleu on Feb 22, 2015 14:15:19 GMT
Yes, this is exactly what I was trying to say. I would never want to do this by myself. It requires real expertise. Don , some practice on a friend's boat and you're ready to go. Regards
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Post by hoppy on Feb 22, 2015 17:21:00 GMT
Yes, this is exactly what I was trying to say. I would never want to do this by myself. It requires real expertise. Don , some practice on a friend's boat and you're ready to go. Regards Don't you mean, soon to be ex-friend?
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Post by DUET on Mar 2, 2015 20:35:10 GMT
On a 2010 50 DS, I used walnut shells to remove the paint and get to the gel coat. There is no damage or pitting with the shells and the process leaves a fairly smooth bottom. I used Sea Hawk Tuff Stuff for the barrier coat and painted with Sea Hawk Biocop TF (2 coats) with terrific results. Paint (ablative with little plume) lasts approximate three seasons (New England waters).
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debenboy
Full Member
Posts: 46
Country: UK
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Post by debenboy on Mar 4, 2015 17:34:55 GMT
Last year I started off doing my bottom with a scraper. It took me a morning to do one side of the rudder! After that I handed over to the yard - Foxs at Ipswich and they blasted the bottom. As others have said, blasting can be too heavy handed, leaving a damaged gel coat behind, but the contractor at Foxs is very skilled, leaving the gel coat undamaged and just a spiders web of residue to be removed by sanding. I did that with wet and dry and it was three days of back braking work. On reflection I should have got the yard to do that too with their air driven sanders as I saw them remove the residue from the bottom of an Oyster 405 in a morning!
Be careful of using domestic quality sanders with hook and eye attachments for the pads as the attachment interface clogs with dust very quickly and your expensive sanding discs go spinning off across the yard in no time- hence my wet sanding the residue.
I have seen AF removed using a well blunted 1" chisel reversed with the chamfered edge of the blade towards the hull supported with a forefinger behind it. This seemed a very quick and relatively painless method at the time, although the boat owner had two chisels and a hand driven grinding wheel to regularly fettle the chisels. He did an S&S 30 in about two days.
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Post by Don Reaves on Mar 4, 2015 20:25:20 GMT
It took me about 2 days to do a Catalina 30 with a 1-inch carbide scraper. It was the most intense physical labor I have ever done, and I won't do it again. Even so, it went fairly quickly because I had a hard paint on the bottom, and it was flaking off after seven or more coats.
I switched to an ablative paint and never again thought about scraping.
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Post by balticus on Mar 10, 2015 14:40:15 GMT
Well my latest experience: Had four hands with a scraper (2x Proscraper, 2x ordinary) and the old MICRON AF on my Sun Fast 36 was done in 5 hrs! No Joke!!!
It was exeptionally easy to remove but - Key is that you use sharp tools! If you decide to strip the AF with a blade / scaper make sure you use really high quality material, e.g. the PRO SCRAPER. Not only leaves it the poor working fellow rather clean behind, hence the dust ist immedeately sucked away, the blade remains sharp for a longer time. To give an example: The blade can be turned once and this is exactly what we did. No more! These thing really stays sharp for a long time...
Of course you need to finish the bottom off with a sander and you need some extra attention on the awkward areas...
In your situation: As many of the fellows here already mentioned- blasting maybe an option, but also an expensive one. (Provided it's done by pros) It depends what you want and expect.
On my two previous boats I used antifouling stripper with good success. If applied correctly you get a rather smooth hull within one day, and the residual work is still in range. But beware: IT'S A HELL OF A MESS !!! Be prepared to spend a good day in a rather poisonous environment with sticky and smelly paint residues all around you! No matter how carefull you are - after at max 1 1/2 hrs you will find the jelly every where. So good protection of your surroundings and of course yourself is imperative. Once you've survived the mess give your bottom a finish with the orbital ant apply whatever you deem neccessary (I use to use VC TAR, others rely on gelshield).
FYG I Used STARBRITE Antifouling remover. To see how It's working and how easy the job actually is (depending on facilities) check out this video from a fellow of mine:
After all - go for it! You will get a complete new relation to your boat ;-)
Cheers,
Michael
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Post by balticus on Mar 10, 2015 14:47:37 GMT
Noted I just posted the second part of the video...
Here's the first:
Hope you don't mind it's in german, but the pics speak for themselves...
Cheers,
Michael
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maf49i
Junior Member
SO 49i - Serenity
Posts: 11
Country: UK
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Post by maf49i on Mar 20, 2015 19:25:43 GMT
Balticus .... Excellent video..... I am looking at applying copper coat next season before we sail off as livaboards and I think stripper is the way to go....
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