Easiest way to sand antifoul

[2copplane]

My bottom is looking a bit rough and flakey and am looking for tips for the least energetic way to sand it smooth. For the last few years I've only lifted for a couple of days to polish and anitifoul and the lack preparation before painting is starting to show.
I've excluded slurry blasting due to cost and scraping back to bare GRP is too much effort.

Plan a is to use a orbital sander with 60grit hooked up to an industrial vacuum cleaner. Plus decent mask.

Plan b is to use the mesh sanding sheet used for drywall but use it wet. I've notice that the antifoul (micron extra) is very soft when the boat is first lifted and wondered whether it would easiest to attack it then?

Appreciate the health hazards and will wear appropriate protective masks and clothing.

Any tips gratefully received.

 

[prv]

Dry sanding antifoul is considered antisocial - you might be wearing a mask, but the people downwind of you won't be and their boats are liable to end up with a blue or red tinge as well. Obviously the vacuum helps a lot but it's probably not 100% effective.

Drywall sanding sheet on a pivoting head on the end of a pole is the way to go, along with a bucket of water to swill it in regularly to wash the sludge out, and ideally a hose to keep the hull wet and wash the sludge away from there too. I've done that part with buckets when necessary but a hose is easier.

Pete

 

[Tam Lin]

Just used the drywall sanding sheet method and was surprised how effective it was. Give it a go!

 

[Easticks28]

Just used the drywall sanding sheet method and was surprised how effective it was. Give it a go!

.... on a pole sander! Brilliant results and much easier than grovelling on your back.

 

[Tam Lin]

.... on a pole sander! Brilliant results and much easier than grovelling on your back.

Yes, you can stand up and hold the pole with two hands, giving you more control and pressure.

 

[[2574]]

Just been through this. In the end decided to pay the yard who have the right kit. Slow rotating sander with 40grit sanding pad. Took eight years of a/f off pretty quickly and left a smoothed keyed surface. Two days to do our 12m hull. Not cheap, but not bank breaking expensive either, but easy - which is one of your criteria!

 

[lw395]

Wet sand it.
You should have done it when the boat came out, it is much softer after being wet for a good while, even the 'hard' stuff.

 

[TQA]

Wet sand with 80 grit using the 'drywall' head on a pole.

Works for me.

Mind you I am not removing 20 years of crust. Just getting a babies bottom for the next load of liquid gold.

 

[westhinder]

Just used the drywall sanding sheet method and was surprised how effective it was. Give it a go!

+ another
12 m hull in a couple of hours. I used to use a wet 3M scrubbing pad (not the green kitchen variety, one meant for paint) but this is much more effective and fast.

 

[William_H]

Removing old a/f to get a smooth surface is not easy. Hence people go to balsting and scraping or similar. Using the mesh sander will get the top layers off but don't betoo dissapointed if you end up and give up long before you get all the old a/f off. Sorry that is just the way it is and the same for every body. good luck olewill

 

[cliff]

Mesh sanding disc in an air powered DA or RAS with a flow of water over where you are sanding - seconds to take the A/F back to gel coat/epoxy or what ever

 

[SandgroperWA]

I scrape. File the corners on the scraper round so they do not dig in. Do it the same day as the lift. Takes off heaps. Cheers

 

[SandgroperWA]

Sounds great. What is DA or RAS please? Can you give me the specifics of the mesh sanding disc? Cheers RnD

 

[Bobc]

The least energetic way is not to bother. Just slap some more on and chuck it back in.

You won't see it when it's in the water.

 

[Mistroma]

Just finished removing antifoul and also Primocon primer at the same time, so now back the gel coat. It took approx. 12 hours using my trusty old Bosch PSE 180E power chisel. Unfortunately, it has been discontinued by Bosch. I know this as I've just finished checking online but did find a similar looking device (out of stock though): https://andrewjamesworldwide.com/usercontrols/productIndividual.aspx?ProductID=329

A local boat repair company and another boat owner both wanted details. I've just finished sending them emails to someone in a boat further up the yard.

The professional guy said that my 42DS would take him about 7-8 days with a sander. He was amazed when I did it in around 1.5 (based on hours worked as I wandered off for beer, wine, got up late etc.). He was impressed at the lack of dust (virtually nothing on my mask) and I swept up a large bag of antifoul flakes when finished.

I thought that 12 hours to completely strip a 13m boat back to the gel coat wasn't bad and not particularly hard work (even for an oldie). I made a short video to show speed of antifoul removal but can't upload it at the moment. That didn't include the keel as I did that last year (took approx. 3 hours to completely strip the keel).

 

[aquaholic]

Why not use a caustic soda mix to strip the AF? I used it on the boot top due to the thickness of the AF and was impressed with the results, I found it much better to wash off with a high pressure jet wash.
Low cost and effective, Caustic Soda costs around £2 a bottle (500gr) 250gr to a litre of water, add some wallpaper paste to thicken and bobs your uncle, best left on for at least 12 hours if not longer.
I have stripped a hull with a hand scraper and vowed never to do it again, always thought I would bite the bullet and pay for blasting until I tried this method.
there's a video of the mixing here https://youtu.be/LrUd6dBbQiM
Just take the normal safety precautions as with any chemical stripping, you do not want the stuff anywhere near your skin or eyes.

 

[cliff]

Sounds great. What is DA or RAS please? Can you give me the specifics of the mesh sanding disc? Cheers RnD

Duel Action or RAndom (orbital) Sander
80 mesh is good
produces an antifoul slurry so a little water is needed to keep the mesh clean and wash away the abraded AF Hence the use of Pneumatic (Air powered) tools

 

[Gordonmc]

Just finished removing antifoul and also Primocon primer at the same time, so now back the gel coat. It took approx. 12 hours using my trusty old Bosch PSE 180E power chisel. Unfortunately, it has been discontinued by Bosch. I know this as I've just finished checking online but did find a similar looking device (out of stock though): https://andrewjamesworldwide.com/usercontrols/productIndividual.aspx?ProductID=329

.

I started removing AF from my boat three weeks ago with a power scraper from Lidl (Parkside) which worked extremely well until a rather enthusiastic helper began using it like a hammer. It died. I bought the tool about two years previously and had used it for various jobs.
Lidl Customer Services told me if their scraper is not in the shops there is no other way of buying one.
Drat.
So I tracked down a second hand Bosch PSE 180E on Ebay. It was doing a fine job until it died half an hour in.
Field windings have gone... no continuity.
So, back to the hand-scraper to finish the job.
The Bosch cost me £60 second-hand. The Lidl scraper was under £20 new.
If Lidl do restock their scraper I will get two or more.
BTW, the Bosch and Parkside blades are inter-changeable.

 

[Topcat47]

Interesting but I bought the Lidl tools when they were last in, about a month ago, and they most emphatically DO NOT fit my Bosch 180E. The Fein tools do though (from personal experience, their metal saws are so much hardier than those from Bosch.) The holes in the Parkside tools are too small to fit over the "studs" on the Bosch.

 

[Mistroma]

I started removing AF from my boat three weeks ago with a power scraper from Lidl (Parkside) which worked extremely well until a rather enthusiastic helper began using it like a hammer. It died. I bought the tool about two years previously and had used it for various jobs.
Lidl Customer Services told me if their scraper is not in the shops there is no other way of buying one.
Drat.
So I tracked down a second hand Bosch PSE 180E on Ebay. It was doing a fine job until it died half an hour in.
Field windings have gone... no continuity.
So, back to the hand-scraper to finish the job.
The Bosch cost me £60 second-hand. The Lidl scraper was under £20 new.
If Lidl do restock their scraper I will get two or more.
BTW, the Bosch and Parkside blades are inter-changeable.

Sorry to hear your 2nd hand Bosch gave up so quickly. Mine must be 15-20 years old, has been used by quite a few people over the years and is still going strong. The Andrew James tool looks fairly similar but may not last either (it's only £27). https://andrewjamesworldwide.com/use...?ProductID=329

I don't the Bosch chisel often but every time I do 2-3 people ask what it is and where to get one. I usually end up lending it to at least one person. I make certain that they know the blade goes in upside down as correct chisel orientation would dig holes in the hull. I also blunted the blade slightly on a grinding wheel before using it for the first time and it is pretty kind to the gel coat.

It is great on brittle antifoul but does nothing on softer types. Cruiser UNO and similar types are fine and just shatter and land on the ground in bits.