Bottom Sanding

[BarryL]

Hello,I plan on painting my bottom (OK, the boat bottom, not mine).The paint on it is in OK condition, it's an ablative, and mostlyworn through. My plan is to sand w/80 grit, then paint.I don't have a power sander and there is no way I will handsand a 28' boat!What power sander should I get? I see there are belt, randomorbital, 6", 4.5", with dust collector, etc. So, what KINDof sander do I need. Then what MAKE or MODEL should I get?I also plan on polishing the topsides. Is there one unit thatI can use for both, or am I better off buying something elsefor that?Lastly, the boat is in the yard and supported by yard supllied jackstands. How do I move them to sand and paint underneath?All comments welcome!Thanks,Barry

 

[Paul (Affinity C320)]

Porter Cable

Random orbit, 6" is what I use. Probably should get the one that has dust collection, mine does not have it. I like it otherwise. Light enough, but big enough to get the job done.Paul

 

[Richard Bryer]

Excellent reference site

Here is an excellent reference site for tools for boatworking.

 

[Terry]

Bottom Paint

Any decent random orbit sander will work to sand the bottom. Clean well before sanding, you don't want to push any silicones or waxes into the fiberglass. Follow the paint directions for the grit size. Remember to wear a respirator, the bottom paint is as bad for you as it is for the critters your trying to be rid of. As for buffing the upper hull, a true buffer (I have a dewalt) is the best way. First clean as best as possible, then use a wool or wool synthetic compounding pad, with the appropriate compunding paste. They range from fine cut to heavy cut. Unless you have a very scratched up surface use the fine cut, it will remove any fine scratches or swirls. Clean well again after compounding, Next use a polishing pad with your buffer, and use a polishing paste, this is where the shine will come out. Any decent auto store will carry the compunding and polishing pastes as well as pads for the buffer.  To paint and sand the bottom the pads will need to be dropped one at a time and that area can be sanded or painted. It is time consuming letting the paint dry before raising the pad, but not much choice. Good luck

 

[Jentine]

Rent it

Buying a sander to do one bottom is a waste of resources. You may decide to never paint another bottom (both yours and the boat's) so why invest in a dust collector. Go to your local tool rental store and rent a 6" random orbital sander for the occasion. If all else fails, try Home Depot or the like.Jim Kane

 

[Jack]

Renting costs as much as buying

Link to Harbor Freight sander. Just an example. I don'tknow if this one is random orbital but they are out there for this kind of money.

 

[JOE NEWELL]

RENT IT AT MARINA

MOST MARINAS WILL RENT YOU ONE FOR A HALF DAYFOR ABOUT $15.00 THEY ARE THE DUSTLESS TYPE

 

[Gerry, GMJ Marine]

Barry,  I use a Porter Cable right angle sander. Great tool for this job and many more. If your ablative paint is in good shape but worn thin and you're going with more ablative, you could just use a Doodle Bug Pad. Similar to a Scotch Brite pad, only larger size and pores as well as coarser. I use these on a lot of my customers boats when I'm re-doing their bottom paint that's in good condition. Just scuff over the whole bottom consistently. You're not removing layers of paint, just scuffing for adhesion. Using a sander or a pad,... you're still doing it by hand. I'd recommend the sander if you were trying to level out old bottom paint in rough shape. How I deal with the boatstands is to sand an area for the pad next to the current location. Move the stand over to the sanded area. Do this to all stands first. Now the stands are all on a sanded spot so you can now sand the rest of the bottom, clean, and paint. When the paint is dry after 1, 2 or more coats, you can move the stands back to where they were. Put some old towels or rags on the wooden pads to protect your new paint. Now you can paint the sanded areas left and you're done. I use a Makita polisher for buffing. It's variable speed makes it a great tool for buffing and polishing. Hope this helps. Good luck with your project.

 

[David21629]

Pneumatic Orbital

I wet sanded with a 6” pneumatic orbital. I learned this technique from watching the professionals at the boat yard. Wet sanding is required at the yards here in California. I wore cheap rain-gear, a construction type hard hat with face shield attached, and rubber gloves. I taped a sprinkler nozzle to the orbital to provide a continues rinsing during sanding. This system works very well.Regards,David

 

[Daryl]

Buy it, use it, return it

Home Depot loves that action and takes everything back. That's what makes America great!

 

[Rick Webb]

Or Buy the One Daryl Used Once for Half Off

Thanks Daryl

 

[Fred Ficarra]

Wait a minute,,

You said the paint's ablative, why sand it off? It's sloughing off anyway. Just keep using the same stuff.

 

[Wright Ellis s/v WhiskyII]

I'm with Fred

Keep on painting over what's there. That's another beauty of ablatives!

 

[BarryL]

Additional information

Hi guys,Thanks for all the comments. Regarding why I want to sand: the directions on the can state that if the existing paint is in good condition to sand it with 80 grit, clean thoroughly to remove residue, then apply fresh paint. The paint that is on the boat is in good condition. It's an ablative, kind unknown, and worn off on the leading edge of the keel and rudder, and pretty thin on the rest of the boat. I believe it to be ablative because when I scrubbed the boat in the water, lots of paint came off. Also, the paint is very soft and you can rub it off with your finger.Anyway, do I need to use 80 grit, or will the doodle bug / scot brite pad work as well?Today it's close to 50 degrees and I'm dying to get back on the water! My last sail was in November and I'm going crazy.Thanks again,Barry

 

[Fred Ficarra]

Barry, you want it fairly clean of growth and

for best performance you might want to feather any raised edges. Other than that go for it. I've never had to sand old bottom paint and I've been using the stuff since the mid '70s. It'll adhere.

 

[Bill Hearsey]

Wet sanding

I wet sand the bottom as I pressure wash the bottom. I use a course drywall sponge (available at most lumber yards). It's a messy job, but much less so than doing it dry and much quicker. When I am ready to paint, it takes just a little sanding and you are ready to go.