Bottom Paint or Just RePaint?

[balistikb]

Ok I have an issue that I have been debating for a while now and I am looking for suggestions.
I have a 20ft Cobia that I bought last year. It came with bottom paint on the boat.
The bottom needs to either get repainted with bottom paint or regular paint.
In either case I will need to sand the current bottom paint off.

I need suggestions please? The boat is never kept in the water and is trailerable.

[Marsh Mallowe]

One thing my Uncle told me about bottom paint: It's always easier to repaint bottom paint with bottom paint. If the bottom paint is still mostly on the hull (not completely bare to the gelcoat in places), it will take much less prepwork to go back with bottom paint; I don't think you would need to sand it completely off, just rough it up evenly and recoat with bottom paint. I would suggest using hard bottom paint if you don't plan on leaving the boat in the water for any real length of time- it tends to stay on the hull longer if you're launching from a trailer often...

[EndlessOcean]

but don't use a hard (non-ablative) paint on "roughed up" bottom paint. It wont stick.

If I were u, and the gelcoat under the bottom paint was still good, I would use a chemical stripper like the west marine bottom paint stripper or Interlux 299E and remove the bottom paint. Then polish out the gel coat using 3m super duty rubbing compound and a buffer. U can use 3M Finesse It if you still need even more shine.

[balistikb]

EndlessOcean, thanks for your reply. The reason why I am not painting over the current bottom paint is because I don't know what kind it is. I have been reading that if you don't know what kind of bottom paint you have than you might not get the right bottom paint to go over it.
So since I have to remove the current bottom paint anyway, this is where my original question come from. I may take your suggestion and look into the chemical stripper for the bottom paint.

[Marsh Mallowe]

Not knowing what kind of paint is on there now changes things a bit... Is there no way to find out? I would see if you could take a sample to someone who might know because it will save you a LOAD of work getting that bottom paint off, even with the stripper. I've heard differing experiences with the stripper: some say it worked great, leaving behind only a few remaining splotches of the original paint, and some say it didn't work at all, but ALL have said it was a tough, messy job, but hey, so is bottom painting. If I were you, I'd try to eliminate at least half of the work.

I just finished sanding the old bottom paint off my 73' Aquasport (it was very uneven and splotchy, so I took it back down to the gelcoat), and it was time consuming, awkward work, but it wasn't so bad. I'd say you can get all the paint off in a weekend with DA sander, even if you take a lot of beer/smoke breaks

I'd say, ideally, find out what paint is on there, rough it and smooth it, and go back with the same type of bottom paint. It would be the easiest solution.

Now, if you're not looking for easy....

[balistikb]

I think I want to try to take all the bottom paint off to see what is under there. I just don't know what to do afterwards. When sanding should I got with 80grit?

[balistikb]

Here is a picture of my boat before I start any work.

[prober]

Looks nice as is. I would use it and let the water and trailer take as much off as possible before doing anything else. Then strip and polish. Use as little grit as possible since you will have to sand out the sand scratches with progressively lighter grit paper before polishing.

[Marsh Mallowe]

Depending on how thick the paint is (I'm at work and my company blocks third party pictures), you could use 80g to get all the paint off. I tried 40g on the thicker patches, but it didn't work as well as the 80g (go figure).

What will probably be under the bottom paint is a barrier coat (if they used one prior to applying the bottom paint) which you'll have to sand through as well to get down to the bare gelcoat. My boat was so old that I guess they never used a barrier coat as my bottom paint sanded right down to gelcoat, but most likely you will run into a barrier coat. SO, if you did decide to go down to gelcoat and then went back with bottom paint, you should use some kind of primer. Being that you don't plan on keeping the boat in the water, an expensive barrier coat wouldn't be necessary, just some primer and bottom paint... but, at that point, there would really be no reason to go back with bottom paint. If you are set on taking all the bottom paint off, to repaint with new bottom paint would be more work for no real purpose.

So... if thats what you want to do, you could buff out your original gelcoat after removing the layers of bottom paint and barrier coat, but my guess would be that it probably wont look like you'd want it to. Just repaint the bottom with new gelcoat when it's ready, and be done with it.

Me- I'm going back to bottom paint because I simply don't have the desire to prep my 35 yr old hull to the point that gelcoat would look good. Bottom paint goes on thick and somewhat dull, which is what my boat is- thick and somewhat dull , this way I wont need to bother with a labor intensive prep job to have a good looking painted hull.