Time for me to a ask a question that's been bugging me for the last year or so: Is "light sanding" really needed before applying new bottom paint?
Breakin' Away is due for fresh bottom paint this year. I keep her in a DIY yard and will do the job myself before launching. Last year I bought her with a virtually paint-free (heavily sanded) bottom, and the yard put one coat of single season ablative on before launch. The finish is very smooth, with absolutely no loose spots that I can see. After a 14 hour trip to her winter storage (which looks to have sloughed off all the slime), the boat came out of the water almost perfectly clean. I didn't even bother to pressure wash like I normally do - I just scrubbed a slight scum line off last fall. There are some thin spots that definitely need new paint, so I plan to re-coat the whole bottom with a multi-season ablative (either Hydrocoat or Ultima SR-40/PCA Gold).
I've checked the compatibility chart for these paints, and they all say a light sand is all that's needed. I know from having done this job three times before on my prior boat that sanding is the most disgusting, toxic, dangerous part of the whole job. I have a pretty nice vacuum system that pulls 95% of the dust into a Shop-Vac, but it still really sucks.
I've read on a few sites that the main purpose of light sand is just to clean and identify any loose spots. With temps heading into the mid-60s this weekend, I am tempted to pull out my really nice pressure washer and use it to go over the bottom to remove any last traces of slime stain. In my experience, 3100 psi water does a pretty good job at exposing any loose spots.
Pressure washing is ergonomically superior to getting under the boat and sanding, and given that my bottom has no heavy accumulation of paint after having been stripped last year, it might be good enough.
Do any of you have comments from your own personal experiences?
Breakin' Away is due for fresh bottom paint this year. I keep her in a DIY yard and will do the job myself before launching. Last year I bought her with a virtually paint-free (heavily sanded) bottom, and the yard put one coat of single season ablative on before launch. The finish is very smooth, with absolutely no loose spots that I can see. After a 14 hour trip to her winter storage (which looks to have sloughed off all the slime), the boat came out of the water almost perfectly clean. I didn't even bother to pressure wash like I normally do - I just scrubbed a slight scum line off last fall. There are some thin spots that definitely need new paint, so I plan to re-coat the whole bottom with a multi-season ablative (either Hydrocoat or Ultima SR-40/PCA Gold).
I've checked the compatibility chart for these paints, and they all say a light sand is all that's needed. I know from having done this job three times before on my prior boat that sanding is the most disgusting, toxic, dangerous part of the whole job. I have a pretty nice vacuum system that pulls 95% of the dust into a Shop-Vac, but it still really sucks.
I've read on a few sites that the main purpose of light sand is just to clean and identify any loose spots. With temps heading into the mid-60s this weekend, I am tempted to pull out my really nice pressure washer and use it to go over the bottom to remove any last traces of slime stain. In my experience, 3100 psi water does a pretty good job at exposing any loose spots.
Pressure washing is ergonomically superior to getting under the boat and sanding, and given that my bottom has no heavy accumulation of paint after having been stripped last year, it might be good enough.
Do any of you have comments from your own personal experiences?