sand old antifoul

[Rhylsailer99]

Do i really need to sand my hull to put a layer of antifoul on ? My boat was fully scraped and sanded down to gelcoat last year with 5 coats of primer and 2 coats of antifouland to be fair still looks mint on the bottom.
The thing is i don't want to risk getting the dreaded tennis elbow again after too much sanding.

 

[Jonny A]

I use a pad of scotchbrite on a pole with a swivel head, words perfectly.

 

[sarabande]

As above, a quick light rub down with either scotchbrite or 3M Abrasive mesh (plus water or suction to control harmful dust) . If the surface is reasonably smooth, no need to take it back again unless you are a racing fanatic.

If you want industrial grade Scotchbrite, try asking at a hire company for old pads from floor polishing machines. They are cheap and can be cut into required sizes, and come in varying densities.

 

[Concerto]

I use a sanding pole. Keeps you clear of any dust and accepts any roll sandpaper.
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[KREW2]

I think dry sanding antifoul is only acceptable if you can do it at home under cover. The only damage you will do is to your own lungs. I have recently just started using a well known local boat storage facility which is excellent, and I am surprised they allow dry sanding.
I have seen two people using random orbital sanders to smooth off their hulls. One used no mask, and looked like a smurf after about 3 hours. As to the white speed boat next to him words fail me, no attempt was made to wash it down.
An attempt by the government a couple of years ago, to ban owners from antifouling their own boats was thwarted.
The proposal was that you would need to pay a licensed "professional" to do it. As far as I could see the only thing the pro would do is wear suitable PPE, and not dry sand it without containment. Not beyond the bounds of any DIYer.
As has been said, I also use a pole sander with sanding mesh and plenty of water.

 

[[2574]]

I think dry sanding antifoul is only acceptable if you can do it at home under cover. The only damage you will do is to your own lungs. I have recently just started using a well known local boat storage facility which is excellent, and I am surprised they allow dry sanding.
I have seen two people using random orbital sanders to smooth off their hulls. One used no mask, and looked like a smurf after about 3 hours. As to the white speed boat next to him words fail me, no attempt was made to wash it down.
An attempt by the government a couple of years ago, to ban owners from antifouling their own boats was thwarted.
The proposal was that you would need to pay a licensed "professional" to do it. As far as I could see the only thing the pro would do is wear suitable PPE, and not dry sand it without containment. Not beyond the bounds of any DIYer.
As has been said, I also use a pole sander with sanding mesh and plenty of water.

I deployed a DeWalt dust extraction system (purchased for my workshop use) on to a DeWalt random orbital sander this year and I can report that it was very effective. I was wearing PPE as well but there was very little evidence of dust escaping the vacuum. Contrast that to my neighbour in the boatyard who was using a sander only which produced a stream of blue dust that looked like a 747 contrail downwind of his workplace, luckily I was upwind. Some people just don't care at all.

 

[Dipper]

Do i really need to sand my hull to put a layer of antifoul on ? My boat was fully scraped and sanded down to gelcoat last year with 5 coats of primer and 2 coats of antifouland to be fair still looks mint on the bottom.
The thing is i don't want to risk getting the dreaded tennis elbow again after too much sanding.

I've never sanded my previous antifouling coat. I just make sure fouling has been removed by pressure washer or wet wiping. I haven't had a problem with it in 24 years.

 

[neil_s]

Hempels A/F seems to go on fine without sanding - just pressure wash it . Sanding only needed if loose patches come off.

 

[Bandit]

For normal applications you do not need to sand down old af.

You also say you took it back to the hull last year?

Normally you scrape off old flaky af and feather the edges and perhaps put a primer on and overcoat with new af.

If the old coating is in good condition just 1 or 2 coast of af.

Sanding old AF is dangerous and should be avoided if possible or undertaken in a careful and controlled way only.