removing anti fouling paint

[rbh]

good morning-
well just got back from working out of town and have a couple of days, so its time to tackle the boat issues before the boating year starts. The 4th thing I have to tackle is getting rid of the anti fouling paint, the stuffs like the texture paint you see on ceiling and must slow you down quite a bit, and not very good for the fuel economy? (at least it should be better).
Anyway we are on a fresh water kake and I do not believe I require it. What is the best way to remove it and get back to the original paint without screwing it up to much?
(and you know the next question will be I screwed it how do I fix the jell coat)
thanks rob

 

[Gelcoat-jon]

Re: removing anti fouling paint

Hi Rob, They do sell stripper but that can be very messy and hazardess. there is sandblasting, big machine to get the pressure you want. Otherwise 40 grit 8" pad on grinder with soft pad and go to work. Careful to only go close to gelcoat then change grit 100 then 180. by now you should be to gel everywhere. Now change to a DA orbital sander and use 400 grit. Now wet sand with 800 and buff out to shine. Depending on how nice you want it to look, you can skip the 800 and just buff with 3M heavy duty rubbing compound 2 X it will shine. You could even start with 80 grit if you wanted then180. Just takes longer but you can be more careful and your mistakes aren't as bad. You are probably go to have repair spots unless you TAKE YOUR TIME. If you do go through the gel I can lead you through that also. Gelcoat is my specalty hence Gelcoat-Jon Ha-Ha Good Luck Happy and SAFE Boating

 

[rbh]

Re: removing anti fouling paint

hello jon thanks for the input-
I get the orbital and the wife gets either the palm sander or the block (ya like thats going to happen).
rob

 

[Bob_VT]

Re: removing anti fouling paint

I would avoid sand blasting and look into soda blasting which is less aggressive.

Now here is a tidbit to confuse the issue...... a textured surface will help a boat through the water since the turbulance it creates and carries air bubbles along the surface. It is the same design as a golf ball having dimples. Many of the "high end" boat hulls have special hull designs just for that purpose.

 

[rbh]

Re: removing anti fouling paint

hello bob-
thanks for the imput, as for the dimples/anti fouling paint why do peaple clean their hulls of barnicles etc and wax and buff till it glows.
I understand the concept of aeration around a hull, but these are not dimples
but pimples!
I think I will go with a slite smoothing, just to get the high spots down.
The black anti fouling paint still looks OK,( its below the water line) and I dont have to worry about the white jell coat.
rob

 

[ImNu2Boats]

Re: removing anti fouling paint

hello bob-
thanks for the imput, as for the dimples/anti fouling paint why do peaple clean their hulls of barnicles etc and wax and buff till it glows.
I understand the concept of aeration around a hull, but these are not dimples
but pimples!
I think I will go with a slite smoothing, just to get the high spots down.
The black anti fouling paint still looks OK,( its below the water line) and I dont have to worry about the white jell coat.
rob

There is a point of diminished return where the drag coefficent becomes destructive to performance characteristics of the hull.

Hyper cavitation is critcal in achieving maximum top speeds. The initial lifting effect is caused by forcing a heavy object (boat) against an uncompressable substance (water). Newtons Second Law. The less resistance you have to that lift the better off you are and that's why the smooth hulls. Once you've achieved maximum lift, you can go faster if hyper cavitation occurs and the boat rides on a cushon of air. You need a lot of HP to get there but that's a layman's explanation of how its supposed to work.

 

[Gelcoat-jon]

Re: removing anti fouling paint

I agree 100% the shinnier the hull [smoother] the better. Dimples? golfballs? This is boats!!! There is such a thing as lift when you accell. At that point of initial take off is when [air bubbles] do there job. Your right, a barnacle boat does not go faster than a boat with a shinny surface. We use to put teflon on the botom of our race boats. Super slick. Take off the bottom paint the way I stated and you'll be just fine. I know there is alot of good advice here but some people should stick to there area of expertise. Instead of supposedly haveing an answer to every ? on the web site. Then people would not be confused as to which way to go.

 

[Bob_VT]

Re: removing anti fouling paint

Perhaps you have never seen the results of someone who made an error with the "sand blaster" and destoyed a fiberglass surface.

The smoothness of a hull is part of the equation. I will bet that rbh is contending with mostly algea and growth and not barnacles.

I am against bottom paints and think a clean gelcoat is nicer (personal preference).

Yes dimples and golf balls have nothing to do with boats but the physics principle does. Fountain boats have a positive lift hull as a result of design changes.

 

[Yacht Dr.]

Re: removing anti fouling paint

I would HIGHLY recommend that you do NOT sand bottom paint with a soft pad ! Not as a DIY ..

Bottom paint is Very bad for you. You would also have to Tent your bottom b4 you sand.. unless you want it all over your boat, car, the ground, yard, blowing in neighbors yard etc.

If not properly using the best safety equip. then bad things could happen.

Let a professional do it IMHO.

If your just gonna burnish the bumps down then I would wetsand with 80g on a drywall sanding pole. Some anti-fouling requires you to do this every season if kept out of the water more then 30 + days.

Just FYI..

YD.