What tool to sand the bottom?

[geoleo]

Originally Posted by thomm225

I used a 6" Porter Cable Orbital sander the last two bottom jobs to sand the bottom, and I also sanded off all the painted topside paint down to the original 43 years old gel coat

https://www.homedepot.com/p/Porter-C...E&gclsrc=aw.ds

The yard I was in required you to lay tarps to collect the dust

That Porter cable is a great machine -but a little heavey

[paralog]

Originally Posted by Cap Bill Des

I have to sand off 6 years of Micron 66 (what's left of it) from the bottom of my 33-ft sailboat. We have returned from 6 years in the Caribbean to the fresh water of Lake Ontario. Interlux tells me I must sand off the Micron 66 before I can put on a paint suitable for fresh water ( or cold northerly salt water) like Micron Extra.

What tool to use? One person said rotary sander. Another said angle grinder with sanding disc. The boat is outdoors so I don't need to tent the boat and the boatyard said they don't care (!?) about sanding dust. Underneath the the bottom paint is several coats of epoxy barrier coat, which I think is in fine shape and I do not want to disturb or have to redo.

Looking for advice on what tool to use for the sanding. Thanks.
( I'm planning on doing the sanding now in the cold weather so that the whole bunny suit and respirator outfit is not uncomfortably hot...)

I bet the other boat owners in the Yard would not be very happy when their boats are covered in your antifouling dust. I have had my boat covered with someone elses sanding and I was not happy.
Tarp underneath, make some cheap plastic curtains to go around the boat. Most boat yards here in Canada now make that mandatory.

[SVTatia]

Originally Posted by maine50

I share with a fellow boater a Porter Cable 9 in motorized drywall sander with vacuum attachment built in. They go about $450 new but frequently they can be had used for 200 to 250 on Craigs list. Reduces the sanding effort by 75 to 90%. It has about a 5' pole attached.

That is something I never tried.... These use sanding disks right? Do they clog or you have change often?
I believe you use it to sand prior to painting, but are they agressive? How well would they work if you use it to remove the paint?

[billknny]

Well, there are lots and lots of yards in the world I would never put my boat in. And clouds of sanding dust from toxic bottom paint is one damn good flag to a place anybody who values their boat needs to avoid. I don’t want that stuff all over my boat, inside and out! A good boat yard is a clean, neat place. Like any good workshop.

If you are sanding next to my boat and I end up with your sanding dust all over MY deck, you‘ ARE.going to clean it. It has happened to me twice in thirty years. In both cases the yards charged the offender for cleanup. And for one repeat offender they picked his boat up within the hour and put it in the water and sent him packing—half sanded and unpainted. As they should.

I don’t care what gear you use, but it has to work. There are sanding systems that leak almost nothing if used properly and maintained well.

[Topspin]

I dont know how you feel, but working with a quite heavy power tool for a significant time is very tiring and it feels as my arms are falling of after some time (yes, I should workout more.....).

Some time ago I tried a very lightweight tool which was used at the boat next to me. It is an air sander and it felt very good especially for overhead work. The only problem is, it needs a compressor, but you easily can attach more than one tool to this compressor. They are also made with a self-vacuum function.
A compressor may be available for rent at the boatyard....

Example here:


https://www.amazon.com/FivePears-Ran.../dp/B074CWLW89


https://www.youtube.com/watch?time_c...ature=emb_logo


Regards,


-Richard

[Simi 60]

Some real gluttons for punishment here.

[Cap Bill Des]

Hi, this is Bill, the OP. Thanks for all the suggestions!

My plan is to try a variable speed sander/polisher with a soft 7" backing pad and 80 grit paper. I'll tape poly sheeting from the waterline and put down plastic. I'm going to wear a full respirator, face shield, and tyvek suit with gloves.

Next week we should have a couple of days above 35F and I'll give this a try. Given the tyvek suit, I'd like to make progress in cool weather rather than trying to do this all in the Spring. I'll give an update on progress...

[Cadence]

I don't envy you needing to hold the tool over your head so to speak.

[wingless]

Originally Posted by Cap Bill Des

My plan is to try a variable speed sander/polisher with a soft 7" backing pad and 80 grit paper.

Expect the paper to clog at an unacceptably rapid pace.

When I vacuum sand my bottom I get zero clogging and complete the job w/ zero mess, using about 10 sheets of paper for my 38' boat.

Being trapped under a tarp w/ bottom paint dust is going to get old really fast. It is also really bad for your health, even w/ a bunny suit, mask and goggles.

[SVTatia]

Originally Posted by Cap Bill Des

Hi, this is Bill, the OP. Thanks for all the suggestions!

My plan is to try a variable speed sander/polisher with a soft 7" backing pad and 80 grit paper.......

I would use 40 or 60 grit at the most, it will clog less and would be easier on you, as more agressive paper requires less pressure on the sander. Once you start seeing the barrier coat its time to back off and move on.

[RossD]

I just did mine, a 29' Bayfield. It had multiple coats of unknown types of paint, so I took it down to bare glass, cleaned, finished up with clear epoxy resin primer to seal her up.

During the tedious and dirty process I wore tyvek suits (new each session), half face respirator, clear safety visor and glasses and used an old shop vac to suck the dust away from me. You can build a dust trap from a plastic bucket to save your vacuum, look online for details. I began the job with a scraper. From there, a Porter Cable orbital sander, but that unit is a bit heavy. So I ordered a $29 pneumatic orbital sander online which was lighter and faster. Even though my pancake compressor would handle it, the thing ran constantly, so I supplemented with my upright (just had to run 100' of hose). Buy disks online, they are cheap 60-80 grit depending upon where you are in the process. I suggest no more than 80 as you near the barrier coat.

Sorry re the picture, not sure why it's sideways.

[jdecris]

Originally Posted by chowdan

Doubt the yard cares if they are in the USA.

Use a vacuum sander of any type. I'd also recommend saving yourself the effort and have it soda blasted.

I don't know what USA your'e referring to, but every yard I've been in from Massachusetts to Maryland has very strict rules about bottom cleaning, scraping, sanding, etc.

[Tusitala]

Captain Bill, it depends on the sander/polisher - one that is strictly a random orbital will take forever. One I know works well is a Bosch 1250DEVS, and you can connect it to a standard shop vac. Shop Amazon or some tool specialty sites. I have several Porter Cables, one similar to the links and slightly different model that aren't as efficient. Festool is a decent system, but very $$$ for what you get. Some yards actually have dustless sanding equipment available for rent.

If you find you're clogging the shop vac filter too often get an extra length of hose and add a 5 gallon Home Depot bucket with some plumbing fittings in the middle. I'm sure there's threads in the forum somewhere detailing how to do this. My standard working grit is 80, you could start with 50 for faster removal. Porter Cable 9 in motorized drywall sander with vacuum attachment. FWIW yes, I do a lot of this type of work both professionally and privately and I've used all of the above listed tools.

Pat

[skenn_ie]

Flap-wheel, or industrial Scotchbrite disk

[JWJClarke]

Lots of good advice here...

Definitely contain the dust. It is carcinogenic and harmful to plant, animal, and aquatic species, not to mention yourself as well.

Don’t use synthetic products for sanding such as 3M products, as you’re just introducing micro plastics to the disposal mess. Stick with scraper, sandpaper discs on a rotary sander, and power sprayer (make sure you don’t power sprayer near seacocks, fittings, etc., as it will destroy any proper seals you have).

Lastly, look at vinyl wrap as a much more ecologically safe and very effective anti-fouling hull protection. No more carcinogenic dust during maintenance schedules, no more carcinogenic paint entering the waters off the hull, no more plastic sheeting to prevent dust when removing previous applications, and the list goes on.

Seriously, look into it. The ocean and the yard neighbours will thank you - and so will your skin and lungs.