Mesh and Net 125mm (5") sanding disk?

[Ian_Edwards]

I'm about to sand the CopperCoat on my boat, it's been on since 2011, and has been patched and sanded over the years.
It's well worn and the boat had a lot of mussels on it at haul out this year, after just 6 months in the water.
I have a Ryobi random orbit sander, which I'll use in combination the a Henry vacuum cleaner, I've used this before and it really keeps the dust down.
I plan to use 80 grit Mesh and Net disks, with interface pad.
In the past I've used 3M disks, but they are a lot more expensive than many others on the market.
Are the 3M versions worth the extra?
It's a 14m boat with a 4.25m beam, so there's a lot of sanding, and probably a lot of sanding disks to buy.

 

[KevinV]

In my experience almost anything made by 3m is worth the extra money - they prove time and time again that you can't make such high quality for less, everyone who tries fails.

 

[Geoff Wode]

Try Smirdex ceramic disks. Quality product.

 

[CrikeyChris]

I recently sanded my old coppercoat in preparation of a few coats of Gelsheild 200 and then reapplying coppercoat. I used Mirka Autonet/Abranet/Abranet Ace (in order of cost) but a finer grit - mostly 180. At that grit using a interface pad would result in minimal sanding so I reserved using it to sharp edges etc. Like you I hooked up to a Henry vacuum. Im sure you will use the proper numatic Hepa-Flow bags but I once used cheap generic bags and found they had much poorer filtration.
I also like 3m products but almost always buy them on ebay, but the best deals are normally on auction listings and with limited amounts so might not be convenient to you.
As you said it is a big job on a big boat so I would go for a product that you have confidence in.
You have not asked about the health aspects of exposure to copper dust but it is considered a toxin. In my experience you will need a good mask (3M do a good FFP3 mask-Aura 9332+)and goggles as the dust irritates eyes.
The price of the 3M mask I mentioned varies hugely but I bought mine on ebay at a very good price.

 

[CrikeyChris]

Sorry just read your title - you are using a 125mm sander - I used a 150mm machine. I would recommend the larger size for such a large boat. The downside is they are heavier. Professional grade sanders of that size are about £260 but cheaper ones must be available.

 

[Ian_Edwards]

Thanks for the input, I've looked at the reviews of 3M's new Xtract Cubitron II net disks, and the disks don't seem to impress, not as good as the Abranet I've been using. The Smirdex ceramic disks look a better bet.
I'll start using the 125mm Ryobi sander, partly because I have one with lots of batteries for it, some time ago I standardised on Ryobi, and have quite a few Ryobi power tools. I also think a light weight sander will be easier to use, the boat is a Southerly, the rig is out and she's in big shed. She has the keel up and she is sitting 2 sets old railway sleepers, effectively about 4 sleepers high off the concrete floor. This means that most of the hull is only accessable by lying on by back, working above my head.
It's not going to be easy, I want to minimize the weight of the sander, and may even buy a mains powered one, if the weight of the battery Ryobi is to much, and I can find a lighter mains unit.
I already have both full and half face masks and a supply of P2 and P3 filters.
I plan to start work on it yearly in the new year, at the moment I'm trying to think it through, and get all the stuff I'll need organized, the boat is 160 miles away, so it not easy to return home if I've forgotten anything critical.

 

[dankilb]

+1 for Mirka Autonet (the finer/more expensive abranet isn’t required until you get to finishing grits - this was a tip from a local pro paint/body shop).

Also +1 for investing in a 6” sander.

We did our entire 42’ awb for barrier coat and fairing (after blasting) with a single box each of 80 grit Abronet 125mm and 150mm.