Hello everyone, Does anyone know how much bottom paint it takes to cover our c22? And does anyone suggest what type of paint for a boat that is going to spend time on the trailer also....thank you...Don
Bottom Paint Questions
- Thread starter little breeze
- Start date
Bottom paint depends on what "growth" you are trying to prevent. The plants and animals that are in your area are susceptible to different poisons in the paint, so you need to match the poison to the pest. First, ask around local sailors what they use - most local yacht clubs or marinas are filled with people who would be happy to give advice. Posting your location on your profile here would help - we don't even know fresh or salt water.
Second, many bottom paints are destroyed with drying, and all are poorly adhering paints, so repeated trailering works against them. Some will not even tolerate one complete drying, so read the web pages. On my trailer-sailor, I used Pettit's Vivid because it is relatively tough (for bottom paint) and I could trailer several times in a season, but still depend on coverage when I left it in a dock for a month or two. That said, I'm in fresh, cold water so it was not exposed to the most agressive growth on the planet.
As far as quantity, my Hunter 21 used about one quart of Vivid paint per coat, but coverage will vary by paint. You will probably want two coats for the first application, and priming may be necessary to increase adhesion. Application is by a low-nap roller following (religiously) the manufacturer's directions.
Second, many bottom paints are destroyed with drying, and all are poorly adhering paints, so repeated trailering works against them. Some will not even tolerate one complete drying, so read the web pages. On my trailer-sailor, I used Pettit's Vivid because it is relatively tough (for bottom paint) and I could trailer several times in a season, but still depend on coverage when I left it in a dock for a month or two. That said, I'm in fresh, cold water so it was not exposed to the most agressive growth on the planet.
As far as quantity, my Hunter 21 used about one quart of Vivid paint per coat, but coverage will vary by paint. You will probably want two coats for the first application, and priming may be necessary to increase adhesion. Application is by a low-nap roller following (religiously) the manufacturer's directions.
As far as coverage it may range from 100 sf to 400sf per gallon. Read on the can the manufacturers recommended coverage for the type of paint. A hard cooper based paint should not be used for a boat that will sit on a trailer or on a lift as the paint's outer layer will oxidize when out of the water and loose effectiveness to repel organisms. It may sound counter productive but the recommended paint is of the ablative type. Yes you will loose some in the bunks but it will retain its effectiveness. The oxidized outer layer will peel off revealing a new layer of protection. Now the hard paint will last longer than the ablative type but it really all depends on what kind of usage and protection you expect from the paint. For a boat that is pulled frequently out of the water and the bottom cleaned the hard paint may be a better choice as far as cost and longevity but for a boat kept in the water for months at a time the ablative paint will work best.
Don......Big question, how much time are you talking about being on a trailer, and how much time will the boat be in the water? You may not need to apply any bottom paint if you anticipate the majority of the time the boat being on the trailer, and say occasionally up to two weeks in the water.
Don
Don
Basically there are two types of paints. Single season and multi season paints. Single season paints mean they have to be applied each year and that is mostly because they have cuprous oxide as a biocide. Cuprous oxide takes on a chemical change when the boat is hauled which renders it not as effective. They are usually harder paints and the toxicant sluffs away from the paint application leaving the paint behind (which eventually builds up). You can look at an old application of a single season paint, which might show lots of paint, but you cannot assume there is any toxicant left because it leaves the paint behind on the hull of the boat while it sluffs (does its work). Multi season paints are often referred to as ablative. An example would be Interlux' Micron technology. The paint and the biocide or toxicant sluff off at the same rate, which means eventually you will have a bare hull. The good part about that is you don't get a build up over the years. The other good part about that is because the paint application has a biocide in it that are like time capsules in a cold pill, as the paint wears down, more biocide is exposed which keeps on working until the paint is gone. It is like a bar of soap. As the soap bar gets smaller with use, it continues to clean until it disappears. The other thing about multi season paints is that you can pull the boat out of the water and let the hull dry and then put it back in and get good antifouling properties (unlike cuprous oxide single season paints) as there is no dreaded chemical change that renders the paint useless. Therefore, for a trailerable boat that is in and out more than once in a season, the multi season ablative paints are preferred. They are a bit more expensive and they recommend usually 3 coats, which means more cost, but the paint lasts longer and as long as you see paint you can assume that you have good antifouling properties working for you. So, I have written extensively about this in the past, but peeps, I guess, don't like to delve into the past looking for answers. You are lucky I am a fast typer. ;-) Hope this helps.
My missive above is contrary to a few comments before mine. I stick with my knowledge because I have been doing this for a long time. Hard paints last a long time, but as I explained above, they only last a long time as long as the boat is in the water. Once the hull dries they don't work so well because of this chemical change. You must read the product labels to understand whatever it is you wish to apply. If you have a relatively new application of a hard paint, and then the boat is removed from the water so the hull dries, there will be some toxicant present, but to release it, you have to lightly burnish or sand the hull to open up what is left. And, as I said before, once the toxicant is gone, it is gone, regardless of whether or not you have paint left on the hull. One person above said something accurate and useful, but at the end of his missive he/she gets it wrong and almost contradicts himself/herself. In regards to the application, sanding is the best thing to do to get good adhesion of the paint to the hull. Sanding is not a particularly fun thing to do, so peeps tend to get lazy and cut corners. With a new hull you want to make sure you have all waxes used for mold releasing off the boat. A good dewaxer is important, using a clean cloth often so as to not push the wax around, but rather to eliminate it. Then you can sand with an 80 grit and make sure the whole hull is frosty and there is no shine to be seen. That should provide you with a good tooth for the paint. Of course you want to clean the sanding dust off the hull before painting. If you wish to apply an epoxy water barrier coat, this is the time to do it. One of the most popular and proven products is Interlux' Interprotect and they have a few varieties, so read up on what they offer you. You can apply multiple coats (coat time depends on ambient temperature) and if you stay within the prescribed window, you can apply the antifouling paint right over the Interprotect without having to sand to get a good chemical bond. If you are applying new paint over old antifouling, then you must sand the old surface to get a good tooth (and of course clean up the sanding dust before applying the new paint). Which ever manufacturer of paint you use, they have lots of product info for you to read so you do it right. Or, pay someone else to do it (but make sure they know what they are doing).
@CaptDon01,
I keep mine on the trailer most of the time. I use it on weekends mostly. Plus I only sail on freshwater with this boat. Do I need any bottom paint? PO used Kilz oil base paint. I would like to smooth out the bottom to give it a slicker surface. I may someday race her. But for now just cruising. What would you recommend.
I don't think you need bottom paint. That said, if there is already paint on it, then you probably would be better off removing it. It seems like an odd choice for a boat paint. If you can strip it with paint stripper and get down to clean gel coat, then maybe you could just clean it and compound it and be good as new. If you can't get it off without sanding or soda blasting, then maybe you can use an epoxy barrier coat or some other hard paint that will leave a nice smooth finish. You don't need an ablative paint if you keep the boat on a trailer.
You don't need bottom paint.....What a putz the previous owner was applying Kilz on the bottom. What in the world was he thinking? You can sand that paint off, or use a paint stripper made for fiberglass. I understand generic paint stripper could soften and/or damage the gelcoat. My concern on sanding is damaging the gelcoat. But, after the Kilz is gone, several coats of an epoxy barrier coating could be burnished for a slick bottom. Unlike bottom paint, the barrier coating doesn't have to be recoated periodically, and Interlux offers it in grey or white.
After a weekend, or a week in the water, a quick trip to the quarter car wash on the way home and the bottom is good as new.
Don
I don't think the PO new any better and someone told him to use that. Thanks for your advice guys.
Just a follow-up for clarification ... if you do decide to sand or soda-blast, I expect that you would then have a rough surface that you would want to be smoothed down again and the gel coat would probably be compromised, that's why I suggest painting after that kind of paint removal procedure. Here is the texture of my bottom after sand-blasting to remove several layers of hard paint.
You won't have those pits (from surface blisters), but you may end up with an eggshell-like texture such as can be seen on the white gelcoat.
You won't have those pits (from surface blisters), but you may end up with an eggshell-like texture such as can be seen on the white gelcoat.
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Thank you guys for all your support. Great bits of info . I have a good barrier coat of epoxy and epoxy primer. I am going to go with a hard modified epoxy for starts just to have that tough finish for the trailer. I am not sure yet if its going to be in the water full time and I know this paint loses its effectiveness from sitting on the trailer but that's ok. After time when the hard paint is not doing its job sometime down the road, I will light sand and apply a ablative paint when I decide to leave it most of the time in the water. Once again thank you all for your feed back and all the info...Don
Don,
I used Interlux Micron CSC years ago because it gave me multi season use, and unlike many antifouling paints, long term storage like over the winter, or sitting on the trailer didn't affect it, and it had a hard surface for durability. All I had to do was give it a scrubbing and it reactivated the paint.
Don
I used Interlux Micron CSC years ago because it gave me multi season use, and unlike many antifouling paints, long term storage like over the winter, or sitting on the trailer didn't affect it, and it had a hard surface for durability. All I had to do was give it a scrubbing and it reactivated the paint.
Don
By "sometime down the road," I assume you mean about 72 hours, because that's how long it takes to ruin a hard paint by exposing it to air.