Bottom painting

Tips and posts general maintenance.
Ron
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Bottom painting

Post by Ron »

While the hard anitfouling paints have some advantantages, ease of maintaining it is definitely not one of them. I'd think seriously about any paint that eventually WILL have to be sanded off, noting that layers of dead paint will contine to build up until you break out the sanding gear. Work is work, and this is not one of the nicer jobs.

I thought I found a compromise with the Hydrocoat, noting that I used it in the Chesapeake for about 7 years - hauling and doing the bottom every two. Boat (big Catalina) was in Annapolis for 2 years and Rock Hall for 5. The bottom was pretty clean at each haul too. I did a short haul and power wash on the alternate years. I experimented with adding a slime resister too, against the recomendations of Petit, and that seemed to help with the soft growth. Did that on several paint jobs (over approx 10 years in the Chesapeake and NYC Harbor). Not sure if the stuff is still available - I believe that it was marketed by Starbrite. Supposedly the same stuff that Petit and Interlux adds to their paint. I would not use Hydrocoat in any warmer climate though - the copper level is a little on the low side for Florida or points south. The Telstar has Hydrocoat but it's out of the water half of the time (on a lift).

It's your call. There's nothing wrong with the hard paints as long as you have lots of extra time to sand them off. The paint that PC uses (or used?) is the epoxy based Bottomkote. Removal of that is based on what you wind up with. If it's vinyl or teflon based, better get the sanding gear out soon. The solvents in them will take almost anything off, and the new paint won't stick to the resulting mess.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Bottom painting

Post by Dan »

I sodablasted the bottom of the Pretty Gee two years ago. While I didn't find any blisters, I did find some small gelcoat voids. These were mostly smaller than the nail of my pinky and were dry voids between the gelcoat and the fiberglass. I filled them with epoxy and then put barrier coat over the bottom of the three hulls. :)

As Ron pointed out, hard paints can be a maintenance problem, since they do tend to build up and add quite a bit of thickness and weight to the boat. Most people would be better off using an ablative finish of some sort. That said, I did go with a hard-epoxy based bottom paint. However, it was not a typical biocide based hard epoxy, and it is designed to last through multiple seasons, so buildup of the bottom paint should not be much of an issue.

An alternative to stripping or sanding is sodablasting or blasting with corncob or walnut shell media. I had used sodablasting and highly recommend it. The amount of time it saved me was well worth what it cost me to do so.
wingman wrote:Thanks, Ron.

I talked to a local Pettit guy and he recommended Vivid, which is hard and can be burnished. The Micron guy recommended Ultra or Extra, hard and ablative, respectively. I see that Hydrocoat gets a single-season recommendation by Practical Sailor. The Micron guy said that 66 did not work in the Bay as the Bay was too brackish. Depending on which BottomKote PC used, Micron said it can either be lightly sanded or has to be removed completely. The Pettit guy said that we could probably apply over the Bottomkote, but needed to test it on a small section. I am still undecided.

Does anyone use a barrier coat?
Has anyone found any blisters?

I am debating sanding or stripping. Most stripping requires using paper and sounds very messy, but Pettit makes a stripper that does not require paper and is biodegradable, though, of course, the stripped paint is not. Need to buy a good sander if I go that way. A good excuse to buy a new toy!

One nice item about Vivid is that it comes in white, so the amas can be all white!

BTW, I tried to attach a pdf of the Pettit paint stripper, but it was disallowed by the site.
Ron
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Bottom painting

Post by Ron »

The powder that I had added to the Petit Hydrocoat ablative bottom paint was called Compund-X, marketed by Starbrite. Part number is 82510. As far as I can tell it is no longer available in the US, but is still sold in Europe. A review of the product calls it a "tetracycline hydrochloride, a relative of an antibiotic you may have taken to get well. It works by providing a bacteriostatic layer on the surface of the paint.".

It wasn't a controlled test. but my 4 or 6 years experience with it (2 or 3 paint jobs in the Chesapeake and NY Harbor) seemed to indicate that it noticeably retarded slime growth, as compared to the same bottom paint without it. Petit did not recommend the addition of the product to their paint.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Bottom painting

Post by Dan »

I'm not a big fan of using anti-biotics where they’re really not needed. Doing so can lead to resistant forms of disease-causing pathogens...something we really don’t need more of.
judy7clark
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Bottom painting

Post by judy7clark »

In the "for what it is worth" catagory, I have taken the boat off the trailer by blocking the Amas just aft of the forward ama pivot point and under the rudder trunk. I used large styrofoam blocks under the hulls. The amas were extended and locked in position. I jacked up the boat/trailer with a floor jack, put blocking under the amas and hull, let the trailer down, let some air out of the tires and slid the trailer out.
The reason I tried this was to paint the bottom and work on the centerboard. I don't have a marina with a travel lift handy and this seemed like a reasonable solution. It worked and I have not seen any adverse effects so far...
wingman
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Bottom painting

Post by wingman »

Thanks for the suggestion. We just hauled Bay Wings yesterday and I was wondering how to do the centerboard. Where did you get big enough Styrofoam blocks?

BTW, I have dimpling in the gelcoat (I think) below the waterline on both amas. Will at PCI gave a technical rationale for it having to do with the process that they use to keep down the weight allowing water absorption. The main hull so far appears fine, but I have not removed the paint, yet. the dimples are round, barely raised, and very close together.

Will has promised to provide a process for correcting this problem. I am assuming that we will have to remove the bottom paint, sand down the dimples, then put on a barrier coat, then apply new paint. I also showed Will how the current bottom paint does not cover the wetted surface when the amas are in and the 20-HP outboard weights down the port side.

John
judy7clark
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Bottom painting

Post by judy7clark »

Down here in the Keys the blocks are available at ACE Hardware or any where they sell/install davits. You only need 6 to 12 inch thick styrofoam where the blocks contact the hull. I use wood blocking for the rest of the height.
Dan

Bottom painting

Post by Dan »

John—

I sodablasted the hull two seasons ago for the same reason, the bottom paint didn’t cover the wetted area. If you have a sodablasting vendor nearby, I would highly recommend going that route with one major caveat. Don’t forget to seal off the rudder quadrant area inside the rudder/fuel locker. Otherwise, you can and will find yourself with a cabin full of baking soda and bottom paint... DAMHIK. :)

I used Interprotect 2000E for the barrier coat. The barrier coating process is pretty simple and takes about four coats. What I did is supported the boat on blocks, and "painted" the barrier coat on in layers, with a two-inch wide gap around the blocks. I alternated between grey and white barrier coating and left a two-inch wide gap for each layer at each of the blocks. At the end of the four coats, there was an eight-inch-wide border to the area where each support block/pad was located.

Once the four layers were dry, I moved the blocks and then filled in the area the previous blocks had been covering by repeating the color overlap. This way I was sure the entire hull was barrier coated. Then I bottom painted the boat in much the same way.

The tiny voids appear to be dry and exactly that, voids between the gelcoat and the laminate. I filled them with thickened epoxy and sanded them fair. I used an unusual paint from the UK called CopperCoat, which is a hard epoxy paint that uses pure copper rather than a copper-based biocide. Unlike most hard epoxy paints, it is multiseason capable, since it is pure copper, rather than a copper biocide. Last season, I had two barnacles on the entire bottom. Not too bad. It was rather expensive, but if it lasts as long as they say it will, it will have been a lot less work and effort in the long run.

If you have any questions, please let me know.
wingman wrote:Thanks for the suggestion. We just hauled Bay Wings yesterday and I was wondering how to do the centerboard. Where did you get big enough Styrofoam blocks?

BTW, I have dimpling in the gelcoat (I think) below the waterline on both amas. Will at PCI gave a technical rationale for it having to do with the process that they use to keep down the weight allowing water absorption. The main hull so far appears fine, but I have not removed the paint, yet. the dimples are round, barely raised, and very close together.

Will has promised to provide a process for correcting this problem. I am assuming that we will have to remove the bottom paint, sand down the dimples, then put on a barrier coat, then apply new paint. I also showed Will how the current bottom paint does not cover the wetted surface when the amas are in and the 20-HP outboard weights down the port side.

John
Jerry
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Bottom painting

Post by Jerry »

I am adding another bottom paint question to this string.

I not sure if I should had started a new string titled "bottom paint peeling"

The issue I am having is bottom paint peeling on the waterline of the main hull. Boat has been in the water about a month and a half now and last weekend I noticed two or three clustered - localized areas just aft of midship starboard where about 1 to 2 square feet of paint has peeled off in total right below the waterline. I did not dive the boat yet but will try this weekend to see if there is more.

I assume this has something to do with the difficulty in painting new fiberglass I have read on a few posts.

Question I have is - Assuming it is not more extensive when I dive the boat and it stops at this limit should I worry about it enough to pull the boat and do a touch up or just leave it to the fall?

Thanks,

Jerry
wingman
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Bottom painting

Post by wingman »

When I hauled my boat, I found a few areas where the bottom paint peeled off very easily as I pressure washed. The fiberglass was very smooth underneath those areas. My guess is that it was not properly prepared (sanded, prewashed, etc).

I wonder if a permanent bottom job can be done on new fiberglass. I agree with Dan that the hull should have a barrier coat applied first, then the bottom paint. The bottom paint that PCI used for mine had to be removed completely before using another paint. I understand that the new fiberglass is still out-gassing so any initial bottom paint is likely not to stick or show the small bubbles.

You should only have to apply the barrier coat once, then, if you use one of the multi-year paints that does not build up, you can just apply a few new coats every two years. Read the Pratical Sailor articles at your library if you do not subscribe to help choose a paint.

Remember, only a rich man can afford cheap paint!

John
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