What tool to sand the bottom?

[wingless]

My Festool RO150FEQ ROTEX sander with my Festool dust extraction tools have been a workhorse for well over a decade.

These tools are perfect for bottom sanding.

There is almost zero dust plus the abrasives last a looong time, with very few sheets to do my 38' boat.

[skipperpete]

This is a good alternative when you get tired of clogged discs. I did the bottom of my boat in 2 days back to gelcoat. Hard work but good exercise and I'm still on the original tungsten carbide blade.
I definitely like the idea of soda blasting but its very expensive

[wingless]

Originally Posted by wingless

My Festool RO150FEQ ROTEX sander with my Festool dust extraction tools have been a workhorse for well over a decade.

These tools are perfect for bottom sanding.

There is almost zero dust plus the abrasives last a looong time, with very few sheets to do my 38' boat.

Here is that Festool RO150FEQ in-action on my bottom and the boat ready for fresh bottom paint.

[thinwater]

Originally Posted by a64pilot

And yet everywhere I’ve even been, they haul the boat and as soon as it’s out of the water and still on the ramp, they pressure wash it good and blow all kinds of bottom paint off and of course it goes right into the water.

Around here, at least, the water all goes into a treatment tank, not into the water. If allowed to go into the water that almost certainly violates clean water regulations. If you see them doing that, say something. Most likely they simply have not been caught yet.

[Shrew]

Any of the US yards I've been to in the last handful of years now require dust collection if you're sanding, and don't allow wet sanding of bottom paint without a runoff collection system. (this includes simple pressure washing).

Everywhere I've been in the last few years if you wanted to sand it required ground tarps, and the hull have plastic 'curtains' taped up. The sander had to have a dust collection system and you have to clean and dispose of the debris properly.

If doing it by hand, a long handled scraper works very well, then a sanding to clean things up.

The amount of labor as compared to cost, hire someone to media blast it (soda or walnut shells) for you. About half way through this job, you will gladly break out the checkbook and pay someone to finish.

[Wulf]

If you’re going to power sand with a vacuum to collect the dust consider adding a Dust Deputy cyclone between the tool and vacuum inlet. We used one with a cheap Home Depot vacuum while recoring,, glassing and fairing the deck of our Union 36. Very little found it’s way to the vacuum, the Dust Deputy caught virtually all of the fine and coarse debris. I blew the vacuum filter out 5 times over the whole job. No connection to the product except as a user thoroughly impressed with the “magic”. I’m going to install one in our house vacuum system and will likely never (Almost) have to buy another filter for it.
Link below.

https://www.oneida-air.com/dust-depu...lone-separator

[clockwork orange]

Originally Posted by skipperpete

This is a good alternative when you get tired of clogged discs. I did the bottom of my boat in 2 days back to gelcoat. Hard work but good exercise and I'm still on the original tungsten carbide blade.
I definitely like the idea of soda blasting but its very expensiveAttachment 203825

I have a similar carbide scraper made by the gelplane company which has a hollow handle and hooks up to a vacuum cleaner. I used it to strip the bottom of a Gemini cat back to the gelcoat, no need to suit up or mask as you are not making any dust and it collects everything. Only really suitable when you have so much paint on that it is brittle and falling off but then, majic. Don't use a belt sander or disc sander fcs unless you have a lot of prior experience with these tools. I have a Makita sander/polisher with 8" 3m soft pad with a home built fiberglass dust shroud that hooks up to vacuum that is pretty much the standard at any boatyard(sans the dust collection) but a lot of bottom paints will juat clog up too much paper to be practical. I would leave the paint you have and see how it fares in fresh water, maybe it will be fine. Naturally they want to sell you more paint.

[fatherchronica]

I also recommend a Porter Cable orbital sander. I am a retired framing contractor and still have a lot of tools. My 6" Porter Cable sander is about 25 years old and has done 2 blister repair sanding jobs on 36 foot boats. I have had to replace 2 hook and loop pads on it in that time, but still runs like a champ.

[rbk]

Originally Posted by Wulf

If you’re going to power sand with a vacuum to collect the dust consider adding a Dust Deputy cyclone between the tool and vacuum inlet. We used one with a cheap Home Depot vacuum while recoring,, glassing and fairing the deck of our Union 36. Very little found it’s way to the vacuum, the Dust Deputy caught virtually all of the fine and coarse debris. I blew the vacuum filter out 5 times over the whole job. No connection to the product except as a user thoroughly impressed with the “magic”. I’m going to install one in our house vacuum system and will likely never (Almost) have to buy another filter for it.
Link below.

https://www.oneida-air.com/dust-depu...lone-separator

You have to purchase and install proper dust collection bags in your shop vac in order to catch fine dust. You can also buy hepa rated bags which catch a lot, never used hepa on a bottom job and I’d be worried it would clog too quickly. The fine dust rates bags catch virtually everything.

[wfetter]

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 just finished removing VC17 from our 43' getting ready to go to salt water. I used a random orbital with 120 grit but you could go as low as 100 or 80 if you're careful. My orbital has a hepa reservoir for dust.

[Door Sail]

Fein tool sander with dust collection using Mirka mesh sanding discs.

[SVTatia]

Originally Posted by flyingfin

Sounds like too much work for bottom job. Just ruff up the Micron, wipe down with MEK and slap on the new bottom paint. Check after a year to see how well it held. You are not painting a Ferrari

The above is a terrible advice and the poster does not understand bottom pain compatibility - a recipe for having to do this horrible job again.

You'll have to remove all of the Micron 66 down to the barrier coat before applying the new paint. Be smart and find a paint that is compatible with any future paints you may use if/when you return to salt water.

I am doing the same, but only removing the top layer of the current bottom paint (Bottomkote XXX) and applying PPG ABC 3.

Using a 5" Porter Cable RO with a cyclone + vacuum.

[SteveSadler]

9" softpad disc sander variable speed with 60 grit floor sandpaper if you have to remove it. It takes some skill but 10x faster than a random orbital. Personally I'd leave the paint on until it wears off on it's own. It's overkill for cold fresh water but will keep your bottom clean.

[Cadence]

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...)

If you think the barrier cost is fine, which it probably is, stay away from a rotary sander or an angle grinder. I would be temped to look into having it blasted. Or work your ass off with an orbital sander and a medium grit paper..

[Michael Pope]

For yourself and your conscience at the very least lay down old tarpaulins to catch the discs and dust. 2) rent or buy a hose fed air mask with the fan at least 50 ft away up wind. Do the sanding with a light 7" two speed or variable speed disc sander and mount on it an 8" soft foam disc with a stick -on face
a couple of boxes of 60 0r 80 grit open coat sanding discs and a dozen 40 grit.
Makita makes an excellent 7 inch grinder that is at least two pounds lighter than the popular 8 Inch ones and has less tendency to scar up your bottom . Unless you are superman plan your life so that you sand for no more than FOUR HOURS a day or you may permanently damage yyour shoulders --- and back but shoulders go first.
When you come to smoothing out the crescent scars you left on your first day make a Mini long board 4" wide 18" to 24" long of 1/4" ply Drill and counter sink a couple of holes in each end to mount handles of your choice so the screw heads do not make a lump in the sand paper you are going to stick over them. Cut and spray glue the 100 --120 grit sand paper covering the edges or if you are lucky to find a roll of self adhesive sand paper of right grit and width buy it. Wear your mask when painting . Launch the boat and take a vacation with therapy------- therapy lifting many times a day a small weight about as heavy as a double Gin and Tonic ( kills the shoulder pains)
You may learn it is cheaper to hire some guy to do it for you!! Mike Pope