Bottom paint and questions

[Bob Loewenstein]

I'm about to redo the bottom paint on my 81 CD27 (hull 218). I haven't done this before and have a few questions:

1. The old paint is most likely Red Hand
2. I'm looking at either using Red Hand or BottomKote or Interlux CSC
3. If I use Red Hand again, I probably can just clean the bottom and apply. Do I need to sand it first?
4. If I use CSC, I suppose I do have to sand down to gelcoat before applying. Is this really true?
5. I haven't seen any evidence of blisters. The boat is fresh water sailed and hauled out every season. If I do sand down to gelcoat, would it be wise to put a barrier coat on first?
6. I notice that Interlux recommends launching within 48 hours of applying the sloughing paints. Why? Is this REALLY necessary? I don't think our boatyard can guarantee to within a week of launching (if past history is any judge).

Any other words of wisdom would be appreciated.



rfl@yerkes.uchicago.edu

[Walt Bilofsky]

I'm about to redo the bottom paint on my 81 CD27 (hull 218). I haven't done this before and have a few questions:

<snip>

6. I notice that Interlux recommends launching within 48 hours of applying the sloughing paints. Why? Is this REALLY necessary? I don't think our boatyard can guarantee to within a week of launching (if past history is any judge).

Yards around here (S.F. Bay) tell me that if you're out of the water over 48 hours, the potency of the bottom paint declines. Possbily this may vary among types of bottom paint - we've always used modified epoxy. My insurance company paid for repainting the entire bottom when I had to be out of water for a couple of weeks, so they must believe it.



bilofsky@toolworks.com

[Neil Gordon]

Check with Interlux or whoever makes the new paint you put on, or check the booklets at your marine store. To put soft paint over hard, a lite sanding might be all you need.

CSC Micron Extra gives multiseason protection that lasts even if the boat is hauled. So no rush to get it launched. But check the booklet!



103355.34@compuserve.com

[Matt Cawthorne]

Bob,
I have used Micron CSC and Woolsey Neptune II bottom paints on my CD36 used in the Chesapeake bay. The paint has NEVER gone on within a week of launching and the boat is hauled each winter for about 4 months. Some years I add a coat and some years I don't. The bottom has always remained spotless (except for the prop and shaft). Do your best to follow the manufacturers recomendations, but don't worry too much about the 48 hour thing.

Matt

6. I notice that Interlux recommends launching within 48 hours of applying the sloughing paints. Why? Is this REALLY necessary? I don't think our boatyard can guarantee to within a week of launching (if past history is any judge).

Any other words of wisdom would be appreciated.

mcawthor@bellatlantic.net

[Dana]

Bob,

We should be a little more clear. With a hard epoxy paint like Interlux Bottomcote, you do want to get that boat in within the hours specified. The exposed copper content exposed on the surface of the paint is the protection.

When the boat is exposed to air, the copper on the surface oxidizes and loses its antifouling abilities. Because the oxidized copper is suppended by the hard paint surface, "fresh" copper under that layer is not available until some wear occurs. Thus if you launch late and the copper is oxidized you have poor protection.

The Interlux CSC is more forgiving. It is designed to wear but is not as soft as a real sloughing paint like Red Hand. Thus fresh antifoulant is always renewed to the surface due to microscopic wear but its wear rate is far superior to that of sloughing paint. It does not take much movement thru the water to expose new antifoulant at the microscopic level. Because the wear is even and the paint does not appear to dry and peel like the expoxy paints, sanding in the spring is really minimal.

Dana



darenius@aol.com

[Dana]

Bob,

I'm sorry...about your other questions.

You must know what type of paint is on it now.

If it is a soft sloughing paint like Red Hand you will need to get it off if you put Bottomcote or CSC on.

If it is Bottomcote on it and the paint is good condition, i.e. not peeling, then Bottomcote or CSC can be put right over it. You will probably have a little sanding to do just to rough it up a bit and make sure all the residue is off before applying that paint.

Dana



darenius@aol.com

[Rick Parish]

I suggest you visit a local marine retailer that sells Interlux and get a copy of an Interlux brochure called "Boater's Painting Guide". It answers your questions. Also, borrow a copy of "This Old Boat" by Don Casey. These two sources (I'm sure there are others) will give you excellent advise.

I'm about to redo the bottom paint on my 81 CD27 (hull 218). I haven't done this before and have a few questions:

1. The old paint is most likely Red Hand
2. I'm looking at either using Red Hand or BottomKote or Interlux CSC
3. If I use Red Hand again, I probably can just clean the bottom and apply. Do I need to sand it first?
4. If I use CSC, I suppose I do have to sand down to gelcoat before applying. Is this really true?
5. I haven't seen any evidence of blisters. The boat is fresh water sailed and hauled out every season. If I do sand down to gelcoat, would it be wise to put a barrier coat on first?
6. I notice that Interlux recommends launching within 48 hours of applying the sloughing paints. Why? Is this REALLY necessary? I don't think our boatyard can guarantee to within a week of launching (if past history is any judge).

Any other words of wisdom would be appreciated.

parish6@ibm.net