As a first time boat owner, I am going through the school of hard knocks, but thanks to this forum not enough to knock me out! I have recently been schooled in bottom paint. I began removing the bottom paint down to the gelcoat in an area maybe 2' by 4'. After much thought and upon further inspection of the bottom paint, I have decided the bottom probably only needs some light sanding to remove the oxidation and any rough flakey spots. We had a blast of warmer weather here in Wisconsin and yesterday I sanded the bottom and keel area lightly for about three hours. This action seemed to confirm my thoughts about the bottom paint. It likely doesn't need to be totally removed before I paint in the spring, but only lightly sanded with an orbital sander. My Question: Should I add a barrier coat to the areas where I am now down to the gel coat before I paint two layers of new ablative anti-fouling bottom paint in the spring? I will be using a different color. I have also fully stripped the rudder down to gel coat! Your thoughts/comments welcome. Greg W.
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Yes, barrier coat the area that you have removed.
Greg: That is a good idea to apply some epoxy barrier coat over the area that you have totally removed the bottom paint. There is a good chance that the boat had a barrier coat when it was new. You are in fresh water and if you pull the boat each year two coats of bottom paint is adequate. I would check with some local yards and other boaters to see what works best in your area. We are also in fresh water in the west and have excellent luck with the Pettit SR paints. The SR if for 'slime reduction' which is our biggest problem. Be sure to inspect your rudder for any cracks in the gelcoat. Patch any cracks in those areas before applying the barrier coat. It would not be a bad idea to apply some caulking around the rudder where the post and the rudder meet. This will help prevent water from entering at that point.
Greg: That is a good idea to apply some epoxy barrier coat over the area that you have totally removed the bottom paint. There is a good chance that the boat had a barrier coat when it was new. You are in fresh water and if you pull the boat each year two coats of bottom paint is adequate. I would check with some local yards and other boaters to see what works best in your area. We are also in fresh water in the west and have excellent luck with the Pettit SR paints. The SR if for 'slime reduction' which is our biggest problem. Be sure to inspect your rudder for any cracks in the gelcoat. Patch any cracks in those areas before applying the barrier coat. It would not be a bad idea to apply some caulking around the rudder where the post and the rudder meet. This will help prevent water from entering at that point.
Well, if you really want to do it right...
...finish stripping the entire bottom and rudder down to the gelcoat, thoroughly prep the surface, apply your epoxy barrier coat per manufacturer's instructions, then use your choice of bottom paint to finish the job. The problem you will run into by "patch-coating" is overlap of barrier coat on ablative paint. The barrier coat will not adhere and you'll just end up doing the entire job again next year. You're much better off starting with a clean slate. Just my eversohumble opinion. Cheers, Bob
...finish stripping the entire bottom and rudder down to the gelcoat, thoroughly prep the surface, apply your epoxy barrier coat per manufacturer's instructions, then use your choice of bottom paint to finish the job. The problem you will run into by "patch-coating" is overlap of barrier coat on ablative paint. The barrier coat will not adhere and you'll just end up doing the entire job again next year. You're much better off starting with a clean slate. Just my eversohumble opinion. Cheers, Bob
strip it and use vc17
wish i did, always envious in the spring watching those guys adding a new coat in a few minutes and having that super slick bottom. mike
wish i did, always envious in the spring watching those guys adding a new coat in a few minutes and having that super slick bottom. mike
Bottom Paint
Greg- Whatever you are going to do has to wait till next spring if you are outside. You can't take a chance on your windows of time now, plus your hull temp is too cold. If I was you, I would sand it all off and put a barrier coat on. Then throw a couple of coats of VC on her and go sailing. Rob
Greg- Whatever you are going to do has to wait till next spring if you are outside. You can't take a chance on your windows of time now, plus your hull temp is too cold. If I was you, I would sand it all off and put a barrier coat on. Then throw a couple of coats of VC on her and go sailing. Rob
check out the slick bottom paints
Here on Wheeler lake in Northern Alabama my main problem is a black scum that coats the bottom. When the water is warm I take a sponge and wipe it off. I have ablative paint that was needed when I was in salt water last year. But if you are going to stay in freshwater and haul every year the slick paints may be all that you need. On my last freshwater boat I used hard antifouling paint that stands up to being trailered better. But even in the cleaner lake scum was the scum problem and washing was the solution. I really like ablative paint to keep off oysters and barnacles. I guess if you have Zebra Muscles the ablative paint may be required. But since you have some time ask around locally. I did have some problem with algea depositing calcium on the hard paint. Normally with an ablative paint all you need is to pressure wash and a light sanding. Then just use a roller to roll on a couple of coats. My boat stays in the water year round and I haul every other year to repaint. Probably could go three years. A trick that I use is to put the roller in a couple of plastic bags and stick it into the freezer. Then it can be thawed to put on the next coat. At $100/gallon the paint in the roller is more valuble than the roller. Plus you have less hazardous waste.
Here on Wheeler lake in Northern Alabama my main problem is a black scum that coats the bottom. When the water is warm I take a sponge and wipe it off. I have ablative paint that was needed when I was in salt water last year. But if you are going to stay in freshwater and haul every year the slick paints may be all that you need. On my last freshwater boat I used hard antifouling paint that stands up to being trailered better. But even in the cleaner lake scum was the scum problem and washing was the solution. I really like ablative paint to keep off oysters and barnacles. I guess if you have Zebra Muscles the ablative paint may be required. But since you have some time ask around locally. I did have some problem with algea depositing calcium on the hard paint. Normally with an ablative paint all you need is to pressure wash and a light sanding. Then just use a roller to roll on a couple of coats. My boat stays in the water year round and I haul every other year to repaint. Probably could go three years. A trick that I use is to put the roller in a couple of plastic bags and stick it into the freezer. Then it can be thawed to put on the next coat. At $100/gallon the paint in the roller is more valuble than the roller. Plus you have less hazardous waste.
why a barrier coat?
The main reason to do a barrier coat is to prevent osmotic blistering. If that is not an issue, a barrier coat is generally not needed. Some boats are constructed with a type of resin that is resistant to osmosis. Some boats have high water content in the hull but minimal or no blisters. It is hard to figure sometimes. My dad's 1972 Bristol 40 has high readings on a meter for years but never has had a blister. My 1981 Mirage unfortunately had both moisture and blisters. If that is not an issue, a barrier coat is not definately needed. Check the moisture content of you hull with a moisture meter. If it is an issue and you have blisters, in short, sand off all the paint, dry the hull by waiting or tenting it with plastic and keeping a dehumidifier underneath, grind our the blisters, patch with glass if needed or just epoxy with microbeads, then barrier coat. A lot has been written about this issue.
The main reason to do a barrier coat is to prevent osmotic blistering. If that is not an issue, a barrier coat is generally not needed. Some boats are constructed with a type of resin that is resistant to osmosis. Some boats have high water content in the hull but minimal or no blisters. It is hard to figure sometimes. My dad's 1972 Bristol 40 has high readings on a meter for years but never has had a blister. My 1981 Mirage unfortunately had both moisture and blisters. If that is not an issue, a barrier coat is not definately needed. Check the moisture content of you hull with a moisture meter. If it is an issue and you have blisters, in short, sand off all the paint, dry the hull by waiting or tenting it with plastic and keeping a dehumidifier underneath, grind our the blisters, patch with glass if needed or just epoxy with microbeads, then barrier coat. A lot has been written about this issue.
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