Capturing dust while sanding bottom

[IH82BL8]

Using a RO 5" DeWalt with a 10-gallon vac, but the dust goes everywhere. Tried a bigger vacuum, same result. Today I bought a variable speed RO sander thinking I could run it at a slower speed giving the vac time to collect more dust.

Am I on the right track? I haven't unpackaged the new sander yet; thought it best to ask here first.

Note: the bottom paint is not ablative. Could that be the reason, maybe it's coming off in a finer dust?

Thanks.

 

[syjos]

I use a Bosch dual mode sander (pic 4) with vacuum for fast and large sanding. For smaller areas I use a smaller Bosch sander (3) hooked to vacuum. The Bosch Sanders have a good dust pick up system. Fein and Festool also make great dust capturing sanders and vacuums but I find the Bosch easier on the hands for sanding a lot or large areas.

The dual mode can switch from random orbit to direct drive eccentric orbit mode which will sand 3X faster. It's sands almost as fast as a grinder but with dust collection!

For a vacuum, I use a Porter Cable vacuum designed for collecting sheet rock dust. It is dual stage, separate fan for sucking and another for cooling motor. The vacuumed dust does not travel through the motor cooling fan. The vacuum turns on when sander is turned on and off when sander is turned off. It has an extra fine filter and a special collection bag. I use a large hose to connect the sander to vacuum.

The sander and vacuum probably picks up 90% of the fine dust. I wear a full face dust mask. Especially sanding overhead.

Keeping the sanding pad flat to the surface should capture more dust through the holes in the sanding discs.

 

[Lepke]

I use a Mirka and have almost zero dust in any sanding operation. I routinely sand the hull over the water without any apparent dust on the water's surface.

 

[Frosty]

This might be a silly question, but are you using a sander with the specific vacuum holes in the pad, and a "spout" to attach the vacuum to? And if so, are you using sandpaper with the corresponding holes? Also, is the little "skirt" intact around the sanding disc area?

I've sanded with both my smaller RO Porter Cable, and a bigger 6" one (more grinder shaped), and they both do a pretty good job catching dust when I tape a vacuum hose onto the "spout." I wasn't sanding bottom paint, but gelcoat makes pretty fine dust.

I never seem to have the correct fitting vacuum hose (or if I do I still want to connect another vacuum hose), so I make the joint with tape, which seems to work fine.

 

[FoxtrotCharlie]

What Frosty said - just make sure some of the holes in the sanding pad line up - only need two or three. and tape those vac hose joints. Worked for me.

 

[Antares]

The last time I strpped our boats bottom I used the yards set up. Through experimentation they detrmined the best results were a combination of a Festool sander and a Fein vacuum. The thing that really seemed to make acdifference was a cyclone dust separator mounted on a five gallon bucket between the sander and the vacuum. Although it wasn't absolutely dust free it captured enough that they were able to allow diy sanding. This was all on a cart so it was easy to move as needed. I still had to tent off the bottom and clean the area every day. The set up picked up over 10 gallons of residue in the bucket and the finest ended up bagged in the vacuum.

All said the next time I'm going to let my check book do the sanding. These power boats are more work than our previous sail boats. I don't know if its because of being closer to the ground, the work of doing chines or just getting older. No one has said I'm getting smarter so that can't be the reason.

 

[syjos]

Most of the sander manufacturers sell special adapters to connect to vacuume hose. If not, Rockler or Woodcraft sell a variety of hose adapters.

The Bosch dual mode connects to a regular hose without adapters. The smaller Bosch require an adapter to convert the square dust port to a round port.

Klingspor sells sanding discs for most sanders with holes matching exactly.

Also make sure the vacuum is powerful enough and you start with new filter and bag. Clogged filters/bags can reduce suction by a significant amount.

 

[wkearney99]

Festool sander and vacuum would be my choice, but I already have those. An upstream cyclone separator helps avoid the cost of multiple bags and filters. I've got an Oneida designed to sit atop the Festool vac, but one over a trashcan/bucket would be just as effective (and likely cheaper).

I'm with you on paying someone else to do the job, ugh, I used a buffer ONCE to do our old boat. The next day it felt like I'd been hung by my thumbs.

Rockler hoses are crap, they're heavy compared to others.

 

[SoWhat]

There is going to be dust no matter what you do. Heavy duty vac might catch a lot of the dust via the holes in the disc, but a of debris will spin off the edge of the disc. Belt sanders are even worse.

I covered the ground in blue tarps and vacuumed them at the end of each day. I believe I trapped most of it. I also wore a full face mask but a tyvek suit was intolerable. Wife refused to let me wash my work clothes in the washing machine.

 

[syjos]

Forgot to ask. Sanding all the bottom paint off or just roughing up for recoat?

If removing all the paint to gel coat, a carbide scraper is faster and more pleasant to use than sanding.

If recoating, pressure washing and sanding the waterline is all you need to do. I've taken shortcuts to avoid sanding the waterline by using Liquid Sandpiper to wipe down the waterline with good results. Even an acetone wipe would prep the waterline.

 

[ghost]

Fein 6” orbital and fein vac. I usually don’t even wear a mask and my clothes stay clean. Big difference in outcomes. I stopped using the yards vac as they often need a new bag or hepa filter because they are expensive. So they shed a little dust. New bag and filter is like 99% recovery on bottom paint. It really does work.

I really hate it when a guy shows up with his Home Depot gear and starts sanding before the yard shuts him down. He’ll have enough time to send his dust all over my boat and luck says it will rain before I can blow it all off and it turns my gel green for a month before I bleach it off not waiting for the sun to slowly work it away.

Use the yards gear or buy your own, but the cheap stuff unfortunately doesn’t really work. Buy once, cry once. Both fein and festool are rediculously expensive, but the stuff lasts, especially fein. I’ve got a festool finish sander my fein can’t come close to the swirl free finish, but the fein will survive the next apocalypse.

 

[magna 6882]

This is what i use. I have lung concerns so need to use caution. Not dust with is combination. I use a cpap hose for the transition for flexibility. The air goes thru the sander with such force it keeps the sander turning when the power switch is turned off.

 

[Comodave]

I have done bottom sanding in the past but last time we paid to have it soda blasted. They charged $35 per foot and I thought it was a great deal. I had about an hours sanding in a few spots and it was ready to paint.

 

[motion30]

I found the standard filter in the vacuum was not effective. It was much better when I installed a bag in the back

 

[psneeld]

my experience suggests sanders made for dust collection are way superior to home handyman models that will accept a vac attachment.

 

[motion30]

I 100% agree with that. But they are also very expensive

 

[psneeld]

true...but after washing more than 30 boats one week ( some boats multiple times) because my dust stained other boats.... a $1000 a sander would have been worth it....

 

[syjos]

I 100% agree with that. But they are also very expensive

I sand a lot. I'll buy a sander and vacuum at any price if they reduce time, effort, discomfort and dust while sanding.

Fine Woodworking and Fine Homebuilding magazines review and test sandes and other tools frequently. I always buy their recommendation.

Buying a sander is only the beginning. Sanding discs can add up. High quality discs can cost $30 to $40 per box of 50 depending on size, type of abrasive and grit. Changing discs frequently is the key to speedy material removal.

 

[IH82BL8]

Thanks all. I appreciate the help.

 

[Lepke]

The better sanders use a grid that looks like a screen instead of sandpaper with holes. So the dust never gets a chance to leave the disk.

 

[sbman]

I am using a Bosch dual mode 6" with mesh sanding discs. (about a $300 sander, had to order it online, no one stocked it in stores) A rigid brand vacuum which I fit with both a dust bag and a hepa filter (all vacuum stuff from Home Depot). I bought the upgraded hose for the rigid as well which makes it a lot nicer to work with. No dust escapes the process. This only works on fairly flat surfaces though, on a highly curved area some dust escapes since the sander surface isn't sealed very well on the work.

 

[grandbanksbayfield]

Precipitator first.

We are using a Makita 5-inch RO sander attached o a Rocker precipitator which is ten attached to the 12-gallon shop vac. Not sure if ten or twelve, but pretty large. Using 80 grip hook and loop paper, the red stuff for Home Depot, sanding is miraculously clean. Rockler tube system with a stand that holds up the hose for you and it is very helpful. Hardly any sanding dust gets to the shop vac. It may sound silly to buy a thing that looks like a five-gallon bucket for about $100, but it works great and has obviously been engineered so the dust settles and does not move on. Good luck.

 

[PNW Drifter]

When I sanded the bottom of my boat this spring, I used a 3M Random Orbital Sander - Elite Series 28561, Air-Powered, Central Vacuum, 5 Inch, 3/8" Orbit and a Dyson DC37 for sucking up the dust.

Work very well - pretty much zero dust, but the Dyson filter needed frequent cleaning. You also need a good sized air compressor to run the sander.

 

[Dcbeach]

My experience is with the Festool system

I really am not a fan of the mesh discs it seems they clog up faster than the discs with the holes.
I’d try a few with holes and see where it goes from there

Chris

 

[Chrisjs]

The only time I sanded the bottom of my 50ft boat I used a vacuum sander provided by the boat yard. Sort of worked but after sanding the bottom for a day, I was as blue as the bottom of the boat. Covered in dust. Not sure my basic mask provided much protection. So, I figured there was no way I would ever do that again!

Apart from paying somebody else to do the job - undoubtedly the best option -I found it was much easier and perfectly fine to avoid sanding completely. That assumes that you are using an ablative paint, not a hard bottom paint.

The approach I adopted for several years after was to simply scrub the ablative paint with a wet coarse "scrungy" scrubbing pad mounted to a holder. Yes, you get dripped on when under the boat but so much easier, faster and NO DUST.
Never had a paint adhesion problem. Worked great.

 

[cabinetman1955]

Sanding

I have used my 3200 psi pressure washer with the sand blast attachment to clean a number of boats the water eliminates the dust. You can use different grades of sand or medium to remove,clean or actually polish if it is done correctly. I have cleaned aluminum fiberglass and wood hulls without problems.

Using a RO 5" DeWalt with a 10-gallon vac, but the dust goes everywhere. Tried a bigger vacuum, same result. Today I bought a variable speed RO sander thinking I could run it at a slower speed giving the vac time to collect more dust.

Am I on the right track? I haven't unpackaged the new sander yet; thought it best to ask here first.

Note: the bottom paint is not ablative. Could that be the reason, maybe it's coming off in a finer dust?

Thanks.

 

[Chrisjs]

Has anybody experimented with just how much sanding is really needed for hard bottom paint? I realize that some sailboat racers need a "polished" bottom to achieve an extra knot or so, but what about regular guys? Is it really necessary to sand every year or can get away with scrubbing as for ablatives?
I also realize that hard paints tend to build up on the hull over time, but that really calls for soda blasting or similar once in a while, not every year before repainting.

 

[ghost]

Has anybody experimented with just how much sanding is really needed for hard bottom paint? I realize that some sailboat racers need a "polished" bottom to achieve an extra knot or so, but what about regular guys? Is it really necessary to sand every year or can get away with scrubbing as for ablatives?

I also realize that hard paints tend to build up on the hull over time, but that really calls for soda blasting or similar once in a while, not every year before repainting.

I cant speak for others, but I’m sanding hard paint for reliable adhesion. Keeps the build up from getting out of hand and prevents paint blisters, flaking and rashes.

I used to use a drywall screen or scotch brite, but that isn’t good enough now that I try to prep to go 4-5 years between hauls.

If I was hauling every year, I’d do less and just fix while she was out.