Self polishing or hard bottom paint??

[Petar]

I own a 29 year old sailing boat that I purchased two years ago and am planning on hauling it out this spring to renew my bottom paint. Currently it is painted (unknown number of layers of self polishing paint) and last painted three or four years ago.

I need sound advice if it is better to just power wash and repaint with another layer of self polishing paint or remove the whole thing and apply new coat of either self polishing or hard paint.

If removing the paint what is the best way of doing it? What are pros and cons of self polishing and / or hard bottom paint?

please advise

Mirage

[dmurray]

Petar,

My experience is that you can remove most, if not all, of the ablative paint with a pressure washer. I did this last year on my boat which had not been repainted for about four years. I then sanded with air tools in my driveway and applied three coats of West System expoy and repainted with VC17 (now a freshwater boat).

Results are excellent.

What do you have to lose by trying the pressure washer approach?

Doug

[Fstbttms]

Originally Posted by Petar

If removing the paint what is the best way of doing it? What are pros and cons of self polishing and / or hard bottom paint?

It is not necessary to remove an ablative (self-polishing) paint before applying a modified epoxy (hard) paint over it. Generally, a good sanding and then paint will do. But if a pressure washer will remove most of the old paint, why not try that?

The pros and cons of one type over another will vary depending on where you sail and who you ask. I clean hulls for a living in the San Francisco Bay Area and have seen virtually every type of anti fouling available in this country. In my opinion, ablatives have only two advantages over other types; 1.- Ablatives do not build up successive layers of old paint each time the the bottom is painted. 2.- Ablatives can withstand extended periods exposed to air, making them a good choice for trailerable boats.

All that being said, I think modified epoxies are a better choice in almost all cases. A good epoxy paint (like Petit Trinidad SR) will have excellent anti fouling characteristics. Ablatives are not superior to epoxies in this regard and in regions of moderate-to-high fouling, ablatives are certainly not "self-polishing". Modified epoxies are durable and easily withstand several years of repeated in-water cleanings, something that ablatives have trouble claiming. Modified epoxies can be burnished to an ultra-smooth finish (although a sprayed-on ablative is very smooth as well.) But maybe most important, ablatives are tougher on the environment than epoxies, in that they shed much of their matrix along with their biocide. Epoxies do not do this. The argument can be made that the chemicals being shed by ablatives are inert and do not harm the environment, but I don't buy into this. Many state and local water quality regualtory agencies have stated that ablative paints should not be cleaned in-water. In fact, the State of Washington has banned the practice.

Your best bet is to ask other sailors in your area what products work for them and why. But I hope you'll keep in mind the points I made when making a final decision on what to paint with.

[ollie820]

I recommend ablatives. I used modified epoxy for a number of years but got tired of sanding and was not happy with the build up of paint. I switched to Micron Extra(with biocide) and never looked back. I can get at least two seasons out of the application and then just touch up the waterline, front of keel bow and rudder and I am good to go. I sail on Narragansett bay and I consider that a high growth area. All you need to do for the next season is scrub lightly with a scotch brite pad to reactivate. Actually, one year the yard launched the boat before I had a chance to scrub it with the pad and it worked fine. I would recommend a coat of modified epoxy in one color, say red, and then two coats of Micron. When you see the red flag coat coming through then you know it is time to reapply. This is what I have done and I only have a couple of areas to repaint this year, and that is due to chafe from my mooring ball and on the front of the keel from the lift straps. I have a 42' boat so I plan on getting a couple of years out of 1 gallon.

[sailingdog]

A couple of caveats...

1) Pressure washing off the old ablative paint and not treating the water used is probably against the law in most states. If caught doing so, you're in for some nasty fines from the EPA.

2) It is generally much wiser to remove an ablative paint before painting with a hard epoxy paint. Most of the paint manufacturers say this as well.

[pigslo]

I used Micron 66 for saltwater and it has workedout well in Galveston Bay area. Been on 3 years this July. It is self polishing. Not cheap but worth it to me.
pigslo

[Fstbttms]

Originally Posted by sailingdog

A couple of caveats...

1) Pressure washing off the old ablative paint and not treating the water used is probably against the law in most states. If caught doing so, you're in for some nasty fines from the EPA.

This is a good point. However, if done in a boatyard, it would likely not be an issue.

Originally Posted by sailingdog

2) It is generally much wiser to remove an ablative paint before painting with a hard epoxy paint. Most of the paint manufacturers say this as well.

Here is the West Marine Paint Compatibility Chart. It says that ablatives do not need to be removed before applying a modified epoxy:

Bottom Paint Compatibility Chart Old Paint to Remove Modified Expoxies Copolymers & Ablatives Vinyl Paints Sloughing Paint Thin Film Paint Vivid & Tri-Lux 33 Modified Expoxies Sand & Paint Sand & Paint Sand Well Sand Well Remove Sand & Paint Copolymers/Ablatives Sand & Paint Light Sand & Paint Sand Well Remove Remove Sand & Paint Vinyl Paints Remove Remove Sand Well & Paint Remove Remove Remove Sloughing Paint Sand & Paint Sand & Paint Sand Well & Paint Sand & Paint Remove Sand Well & Paint Thin Film Paint Remove Remove Sand & Paint Remove Clean & Paint Remove

[TrueBlue]

Most of the cruising sailboats at my marina use ablatives. We use Micron Extra, which lasts for two to three years before needed a recoating - with only a light scrubbing necessary beforehand.

I do understand why professional bottom cleaners prefer hard bottom paints though - ablatives create a toxic cloud to divers when scrubbed in water . . . have first hand experience with this fact.

[sailingfool]

If the paint on the bottom is still adhereing properly, i.e. not flaking off in numrous sections, touch up where needed and then apply another coat of ablative paint. If paint is flaking off then you need to figure out how to remove it, its either a terrible job or an expensive job, depending on who does it (you or a yard). Good luck.
Put ablative paint back on, you'd be nuts to use anything else. Consider a hard finish only if you race the boat and want every edge. Many racers I know still go with the ablative paint.