Best tool for removing old hard bottom paint

[OldManMirage]

Well, I was planning to haul out tomorrow but I have put it off for a little bit longer while I get a few more of my ducks in a row.

One task I may be doing myself is the bottom job.

I would like to know what tools - such as disc grinders/sanders or whatever - you have had personal success with and can recommend for taking the old paint off/down. I'm not sure if I'll go all the way to gelcoat. I want to get it smoother than it is now, but if I don't HAVE to go all the way I won't. I don't have blisters.

These should be things I can still get today through Amazon or retailers.

Thanks for any help in advance.

[JimsCAL]

Removal down to gelcoat is a hard nasty job. Using a chemical stripper is probably the best DIY method, but still a lot of work. If just smoothing things out prior to adding a coat, a random orbital sander will work. Use a rough grit like 40 or 60. If you decide you want to remove everthing, hire a pro to come and do it.

[SailingHarmonie]

How ugly a job it is depends on the paint that has been on there. If it has been ablative paint, it's not likely to be too thick. If it has a dozen seasons of hard epoxy paint, it's a hard row to hoe.

You do NOT want to use a grinder. You will be left with a terribly uneven bottom. A good radom orbit sander is the best approach, and use good 40 grit paper if you have a lot to go through.

Get one with GOOD dust collection. For your own health, the cleanness of your own boat and that of your neighbor's boats. Coating the boats downwind of you with bottom paint dust is NOT a way to win friends!!!

The gold standard in boatyards all over is the FessTool 150 with matching vacuum. If you can't afford to buy one, (and they are pricey!) it is WELL worth renting one for the job.

[Bill O]

We use Porter Cable 5" variable speed disc sanders w/vac. attachment and a good quality 40 grit paper. With 2 of us doing the sanding, we can usually get our boat done in 2 days.

[OldManMirage]

Originally Posted by Bill O

We use Porter Cable 5" variable speed disc sanders w/vac. attachment and a good quality 40 grit paper. With 2 of us doing the sanding, we can usually get our boat done in 2 days.

Thanks, that is very useful info.

It sounds like I'm going to just try and smooth out what's on there.

[keepondancin]

You should still use a rotary sander with a dust colleting system for your health, and not creating a mess where you are working. I saw a boat owner have to assume responsibilty for cleaning up several boats around where he was bottom sanding and the dust went everywhere. Wasn't pretty. Festool system is one of the best.

[Emmalina]

I use the wife

[LouK]

Festools are nice, but pricey. Many of us use a rotary or pad sander connected to a shop vac.

[skipperpete]

I did the bottom of my boat in a yard with very strict EPA rules.... no dust, no wet sanding, all debris to be captured..... but I was reluctant to shell out $1500 for a vacuum pump and R.O sander so I did the whole bottom with a Bahco tungsten carbide scraper. I caught ALL the removed antifoul on a big plastic sheet.... hard work but really efficient with the thick layers of ancient antifoul.

[Don C L]

I used an orbital sander last time and it worked, but the vacuum filter clogs up fast and you gotta wear a full body suit and a good respirator (at least I did.) I did not take all the paint off, that seems completely unnecessary to me. The previous owner put a layer of red paint on first when he did it and subsequent layers are blue. I just took it down to where I started to see red and called it good. I am going to try skipperpete's idea of a scraper the next time, which will be soon.

[MicHughV]

For my money, rent or borrow a very good pressure washer. A good one will peel the bottom paint off right down to the fiberglass. You gotta get the tip up right close to the paint. You can fit a piece on the end of the rod looks like a small scraper for really stubborn area.
Works like a charm. Very little sanding to do afterwards.

Most yards will give your bottom a quick hose off with a pressure washer, but it does little beyond taking the slime off.

See if you can rent, borrow or use it yourself. The trick is up close work with the wand. Works like a charm.

Check with the yard that they will let you do it. Some yards have environmental catchment areas.

[dfelsent]

I’ve got an ancient porter cable 5” random orbital. From before they made variable speed units. It has taken down many boats to bare and is still running thirty years later. I’ve also used dumond peel away followed by sanding. Less dust, more ick.

[Capt Lee Shore]

Heavy material removal is done easily and quickly with a Low grit drum on a burnishing sander, the kind that has a rotating drum not a flat disc. It can make divots but no big deal on bottom jobs
https://www.cantaora.com/2022/12/Pai...y-typhoon.html

To remove bottom paint I like to use Peelaway chemical peel, left overnight on the bottom and power washed off next morning. No sanding, cost is made up for by time saved.
https://www.cantaora.com/2022/12/bot...hoon.html.html

[rslifkin]

Originally Posted by skipperpete

I did the bottom of my boat in a yard with very strict EPA rules.... no dust, no wet sanding, all debris to be captured..... but I was reluctant to shell out $1500 for a vacuum pump and R.O sander so I did the whole bottom with a Bahco tungsten carbide scraper. I caught ALL the removed antifoul on a big plastic sheet.... hard work but really efficient with the thick layers of ancient antifoul.

Even if you're going to sand, a scraper can be a good starting point if there's lots of chipping, flaking paint. A light pass over the bottom with the scraper can knock quite a bit of loose paint off, leaving less to sand off.

[bgallinger]

Hire a professional to soda blast the hull.