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#1
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Barnacle removal
I really left the Paceship in too long this time and have a fair amount of
barnacles. I've done many bottom jobs and have never tried to get every last bit of the barnacle off as long as it was relatively smooth. For a hull speed boat, I can't see the harm. I'm using a very high quality ablative bottom paint this time and want to be sure that it's a lasting job. Any INFORMED comments? TIA QL |
#2
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On Sat, 22 Jan 2005 11:23:47 -0600, "Sail-n-Dive"
wrote: I really left the Paceship in too long this time and have a fair amount of barnacles. I've done many bottom jobs and have never tried to get every last bit of the barnacle off as long as it was relatively smooth. For a hull speed boat, I can't see the harm. I'm using a very high quality ablative bottom paint this time and want to be sure that it's a lasting job. Any INFORMED comments? =========================== I had ablative bottom paint on my small boat and had good luck removing marine growth of all kinds using a standard Mark I, Home Despot pressure washer (~~$450 variety). Of course it also removes most of the bottom paint, at least the ablative active ingredients, but if you're getting ready to repaint that's not a problem. I've now gone to a hard paint with a biocide in it that seems very effective, believe it's called Micron Extra with biolux slime blocker. |
#3
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Wayne.B wrote:
On Sat, 22 Jan 2005 11:23:47 -0600, "Sail-n-Dive" wrote: I really left the Paceship in too long this time and have a fair amount of barnacles. I've done many bottom jobs and have never tried to get every last bit of the barnacle off as long as it was relatively smooth. For a hull speed boat, I can't see the harm. I'm using a very high quality ablative bottom paint this time and want to be sure that it's a lasting job. Any INFORMED comments? =========================== I had ablative bottom paint on my small boat and had good luck removing marine growth of all kinds using a standard Mark I, Home Despot pressure washer (~~$450 variety). Of course it also removes most of the bottom paint, at least the ablative active ingredients, but if you're getting ready to repaint that's not a problem. I've now gone to a hard paint with a biocide in it that seems very effective, believe it's called Micron Extra with biolux slime blocker. It "does" matter & probably even more so with a displacement hull, so getting all the old barnacle off is worth the effort, although granted it's depressing job:-) Get all the old loose paint off with a water blaster as above, then scrape all the barnacles off. As you are obviously aware, it's difficult to get the base of well established barnacles off with a scraper & not cut into the underlying paint so it's best to give the whole bottom a "quick" sand with an orbital sander. So long as you water blasted all the old loose or soft antifoul off, it shouldn't clog & you'll quickly see which grit of paper suits the surface (use as fine as will not clog but still knock the high spots off the existing paint). You're not trying to remove or even sand through the remaining paint, just flatten the surface & rough it up a little for the repaint. When you come to a barnacle base left after the scraping, just slow down on that till you sand it away, they're hard & orbital sand off pretty easily. If you're changing to a new style of anti foul say going to soft ablative from the harder types then; when it's sanded smooth & surface slightly roughed give it a couple of barrier coats & another very quick light sand before the anti foul. Wear a mask when sanding antifoul even if there doesn't appear to be much dust. K |
#4
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K,
you sound like you have some experience with bottom jobs and I'm not being smart here, but HOW does it matter? Drag? Poor adhesion of the paint? I doubt if there is laminar flow over the bottom of a boat with ablative paint and surely the few thousands of an inch left would not have much if any effect. I'm going to get as much as I can without spending too much time. One real problem that I have is getting the centerboard slot in the short cast iron keel well prepped. I'm going to try sand blasting it this time but it is very narrow and I'm not sure that I can do that. I used hammer and long chisel last time but I was fighting growth 6 months after I put it in the water. I'd really like to put a lift on my pier but it's tough to do. QL "K. Smith" wrote in message ... Wayne.B wrote: On Sat, 22 Jan 2005 11:23:47 -0600, "Sail-n-Dive" wrote: I really left the Paceship in too long this time and have a fair amount of barnacles. I've done many bottom jobs and have never tried to get every last bit of the barnacle off as long as it was relatively smooth. For a hull speed boat, I can't see the harm. I'm using a very high quality ablative bottom paint this time and want to be sure that it's a lasting job. Any INFORMED comments? =========================== I had ablative bottom paint on my small boat and had good luck removing marine growth of all kinds using a standard Mark I, Home Despot pressure washer (~~$450 variety). Of course it also removes most of the bottom paint, at least the ablative active ingredients, but if you're getting ready to repaint that's not a problem. I've now gone to a hard paint with a biocide in it that seems very effective, believe it's called Micron Extra with biolux slime blocker. It "does" matter & probably even more so with a displacement hull, so getting all the old barnacle off is worth the effort, although granted it's depressing job:-) Get all the old loose paint off with a water blaster as above, then scrape all the barnacles off. As you are obviously aware, it's difficult to get the base of well established barnacles off with a scraper & not cut into the underlying paint so it's best to give the whole bottom a "quick" sand with an orbital sander. So long as you water blasted all the old loose or soft antifoul off, it shouldn't clog & you'll quickly see which grit of paper suits the surface (use as fine as will not clog but still knock the high spots off the existing paint). You're not trying to remove or even sand through the remaining paint, just flatten the surface & rough it up a little for the repaint. When you come to a barnacle base left after the scraping, just slow down on that till you sand it away, they're hard & orbital sand off pretty easily. If you're changing to a new style of anti foul say going to soft ablative from the harder types then; when it's sanded smooth & surface slightly roughed give it a couple of barrier coats & another very quick light sand before the anti foul. Wear a mask when sanding antifoul even if there doesn't appear to be much dust. K |
#5
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Sail-n-Dive wrote:
K, you sound like you have some experience with bottom jobs and I'm not being smart here, but HOW does it matter? Drag? Poor adhesion of the paint? I doubt if there is laminar flow over the bottom of a boat with ablative paint and surely the few thousands of an inch left would not have much if any effect. I'm going to get as much as I can without spending too much time. With a displacement hull surface fairness & finish "is" important, indeed see the extraordinary lengths racing yachts or racing powerboats go to the ensure both. By giving it a quick sand with an orbital sander you repeatedly over time, knock the tops off the high spots & equally allow the low spots to become filled (with paint). Of course the opposite is true if you allow things like barnacle bases to remain, they get buried under layers of paint & so the uneven surface just gets worse with every season. One real problem that I have is getting the centerboard slot in the short cast iron keel well prepped. I'm going to try sand blasting it this time but it is very narrow and I'm not sure that I can do that. I used hammer and long chisel last time but I was fighting growth 6 months after I put it in the water. I'd really like to put a lift on my pier but it's tough to do. I hate to be the bearer of bad news but 6 mths is about right for the mid price antifouls, the much more expensive ones (ablative) will go 12 mths, however only if applied in the thicknesses as given usually on the tin, you'll be surprised how much is needed (at "least" two full on coats). You'll find the sellers of the paint always tell you "your" area is particularly bad for fouling but ................. K QL "K. Smith" wrote in message ... Wayne.B wrote: On Sat, 22 Jan 2005 11:23:47 -0600, "Sail-n-Dive" wrote: I really left the Paceship in too long this time and have a fair amount of barnacles. I've done many bottom jobs and have never tried to get every last bit of the barnacle off as long as it was relatively smooth. For a hull speed boat, I can't see the harm. I'm using a very high quality ablative bottom paint this time and want to be sure that it's a lasting job. Any INFORMED comments? =========================== I had ablative bottom paint on my small boat and had good luck removing marine growth of all kinds using a standard Mark I, Home Despot pressure washer (~~$450 variety). Of course it also removes most of the bottom paint, at least the ablative active ingredients, but if you're getting ready to repaint that's not a problem. I've now gone to a hard paint with a biocide in it that seems very effective, believe it's called Micron Extra with biolux slime blocker. It "does" matter & probably even more so with a displacement hull, so getting all the old barnacle off is worth the effort, although granted it's depressing job:-) Get all the old loose paint off with a water blaster as above, then scrape all the barnacles off. As you are obviously aware, it's difficult to get the base of well established barnacles off with a scraper & not cut into the underlying paint so it's best to give the whole bottom a "quick" sand with an orbital sander. So long as you water blasted all the old loose or soft antifoul off, it shouldn't clog & you'll quickly see which grit of paper suits the surface (use as fine as will not clog but still knock the high spots off the existing paint). You're not trying to remove or even sand through the remaining paint, just flatten the surface & rough it up a little for the repaint. When you come to a barnacle base left after the scraping, just slow down on that till you sand it away, they're hard & orbital sand off pretty easily. If you're changing to a new style of anti foul say going to soft ablative from the harder types then; when it's sanded smooth & surface slightly roughed give it a couple of barrier coats & another very quick light sand before the anti foul. Wear a mask when sanding antifoul even if there doesn't appear to be much dust. K |
#6
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On Wed, 26 Jan 2005 22:10:17 +1100, "K. Smith"
wrote: You'll find the sellers of the paint always tell you "your" area is particularly bad for fouling but ................. ================================================== = With water temps in the summer at 90 to 95 F, my area IS particularly bad for fouling... |
#7
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I had a long conversation with my sailplane Guru friend last evening and he
insisted that the bumps left by the barnacles do indeed cause a fair amount of drag...I'm still not totally convinced but I guess I'll bite the bullet and sand all of those little suckers off today. Yuck! I do use the best ablative I can buy and the last bottom job lasted over 2 years with very little growth but during the last year(the 3rd year) there was a lot of growth down about 8" from the waterline but very little below the chine. QL "K. Smith" wrote in message ... Sail-n-Dive wrote: K, you sound like you have some experience with bottom jobs and I'm not being smart here, but HOW does it matter? Drag? Poor adhesion of the paint? I doubt if there is laminar flow over the bottom of a boat with ablative paint and surely the few thousands of an inch left would not have much if any effect. I'm going to get as much as I can without spending too much time. With a displacement hull surface fairness & finish "is" important, indeed see the extraordinary lengths racing yachts or racing powerboats go to the ensure both. By giving it a quick sand with an orbital sander you repeatedly over time, knock the tops off the high spots & equally allow the low spots to become filled (with paint). Of course the opposite is true if you allow things like barnacle bases to remain, they get buried under layers of paint & so the uneven surface just gets worse with every season. One real problem that I have is getting the centerboard slot in the short cast iron keel well prepped. I'm going to try sand blasting it this time but it is very narrow and I'm not sure that I can do that. I used hammer and long chisel last time but I was fighting growth 6 months after I put it in the water. I'd really like to put a lift on my pier but it's tough to do. I hate to be the bearer of bad news but 6 mths is about right for the mid price antifouls, the much more expensive ones (ablative) will go 12 mths, however only if applied in the thicknesses as given usually on the tin, you'll be surprised how much is needed (at "least" two full on coats). You'll find the sellers of the paint always tell you "your" area is particularly bad for fouling but ................. K QL "K. Smith" wrote in message ... Wayne.B wrote: On Sat, 22 Jan 2005 11:23:47 -0600, "Sail-n-Dive" wrote: I really left the Paceship in too long this time and have a fair amount of barnacles. I've done many bottom jobs and have never tried to get every last bit of the barnacle off as long as it was relatively smooth. For a hull speed boat, I can't see the harm. I'm using a very high quality ablative bottom paint this time and want to be sure that it's a lasting job. Any INFORMED comments? =========================== I had ablative bottom paint on my small boat and had good luck removing marine growth of all kinds using a standard Mark I, Home Despot pressure washer (~~$450 variety). Of course it also removes most of the bottom paint, at least the ablative active ingredients, but if you're getting ready to repaint that's not a problem. I've now gone to a hard paint with a biocide in it that seems very effective, believe it's called Micron Extra with biolux slime blocker. It "does" matter & probably even more so with a displacement hull, so getting all the old barnacle off is worth the effort, although granted it's depressing job:-) Get all the old loose paint off with a water blaster as above, then scrape all the barnacles off. As you are obviously aware, it's difficult to get the base of well established barnacles off with a scraper & not cut into the underlying paint so it's best to give the whole bottom a "quick" sand with an orbital sander. So long as you water blasted all the old loose or soft antifoul off, it shouldn't clog & you'll quickly see which grit of paper suits the surface (use as fine as will not clog but still knock the high spots off the existing paint). You're not trying to remove or even sand through the remaining paint, just flatten the surface & rough it up a little for the repaint. When you come to a barnacle base left after the scraping, just slow down on that till you sand it away, they're hard & orbital sand off pretty easily. If you're changing to a new style of anti foul say going to soft ablative from the harder types then; when it's sanded smooth & surface slightly roughed give it a couple of barrier coats & another very quick light sand before the anti foul. Wear a mask when sanding antifoul even if there doesn't appear to be much dust. K |
#8
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On Wed, 26 Jan 2005 09:00:44 -0500, Harry Krause
wrote: ================================================== = With water temps in the summer at 90 to 95 F, my area IS particularly bad for fouling... I hear all the barnacles up here headed to your boat for the winter... ========================== That was last year. This year they should head for someone elses boat if they know what's good for them. |
#9
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Wayne.B wrote:
On Wed, 26 Jan 2005 22:10:17 +1100, "K. Smith" wrote: You'll find the sellers of the paint always tell you "your" area is particularly bad for fouling but ................. ================================================== = With water temps in the summer at 90 to 95 F, my area IS particularly bad for fouling... Hmmm very good......... yes & that's why the paint never performs as advertised??? Seriously if it doesn't work in say Florida then they should say so on the tin, save that warning; when apply as directed in the thickness they say then they can pay for subsequent slippings, maybe forevermore???? Expensive ablatives properly applied will last 12 mths mostly , they still have some life after than but if it's a sailing boat or displacement boat etc you'll want to haul & clean. This life of anti foul thing is right up there with life of OMC OBs, there are exceptions of course which the spruiking sellers seize upon to tell of, but the majority don't last long, OMC nor antifoul, if Ficht is involved the anti foul will last longer:-) K K |
#10
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On Thu, 27 Jan 2005 12:38:29 +1100, "K. Smith"
wrote: Hmmm very good......... yes & that's why the paint never performs as advertised??? ================================== Actually the paint I'm using now seems pretty good (so far), but at $200 a gallon it darned well ought to be. |
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