antifoul removal

[jellylegs]

Has anybody used the scraper that attaches to a vacuum cleaner, the one I have seen has a yellow handle. Or any other suggestions that dont involve these soda blasting types. I am happy to keep chipping away by hand, slowly!
thankyou.

 

[jeanpaulcopie]

antifouling scraper

Has anybody used the scraper that attaches to a vacuum cleaner, the one I have seen has a yellow handle. Or any other suggestions that dont involve these soda blasting types. I am happy to keep chipping away by hand, slowly!
thankyou.

I've taken off most of the antifouling of my sailing boat (a "kirk" built by AMEL) with an electric scraper made by BOSCH. Very effective as long as you keep the blade to a correct angle.

 

[Seajet]

There is the gel type antifouling remover, but I've found it incredibly feeble, may be more affected ( ie less powerful ) in cold weather compared to traditional paint stripper ?

With a grp hull I'd use the 'grp safe' type of Nitromors, it usually requires newspaper to keep it on overhanging surfaces like hull bottoms.

Awful job, of course full self protection required, eyes, face, breathing, hands, everything !

There's also the point with removing antifouling using any method, one must be careful where the waste goes, it must be collected and disposed of thoughtfully, not allowed into harbours or drains.

Some boatyards have strict rules about this, and some again insist on people using their 'special' tarpaulins under boats for collection, another source of revenue...

 

[Ruffles]

I think the efficacy of the various techniques depends on the thickness of the paint and the primer used (if any). The thicker it is the easier it us to scrape off. Presumably thinner layers are easier with chemical strippers.
I used an electric scraper from Lidl and two weekends of my life.

http://www.soulbury.demon.co.uk/Ruffles/Parts/images/AFscrapingBucket.JPG

Suggest you time yourself on a section and work out how long it will take you. Have fun!

 

[VicS]

Chemical stripping is, by all accounts, a messy process and often only removes one or two layers at a time.

Strippers such as "Nitromors All Purpose Paint and Varnish Remover" and "Nitromors Master Craftsman Paint and Varnish Remover" contain methylene chloride (aka dichloromethane) making them unsuitable for use on GRP.
Nitromors AllStrip Mousse should be safe but is only avaialble AFAIK in 400ml aerosols.

Dilunett is caustic soda based and suitable for GRP
Removall 620 is suitable for GRP

The Bahco - Sandvik type scrappers have been found to be effective

See http://www.ybw.com/forums/showthread.php?t=228344

The Bosch scraper is, I believe, no longer available.

I have seen an old plane iron used effectively on a heavy build up

 

[Resolution]

Has anyone tried using a Flex Giraffe long neck sander (£560 from MTS) in conjunction with the Makita 445 wet&dry vacuum (£286 from Toolstop)? I've seen this in action in industrial decorating indoors and it was fantastic - easy to use and 99% dust free. Cost would obviously be a factor, but if it works well there would be friends to share with.

Queries for taking off old antifoul:
1. Would the rotary sanding discs clog up?
2. Surely no toxic disposal problem because the toxic bits have already leached out of the antifoul, leaving an inert paste only?

 

[rob2]

Strange how no-one has addressed the question! I don't have personal experience, although a friend used one with a removable Skarsten blade. He rounded the corners of the blade to stop it digging in and the vacuum attachment caught around half the scrapings, so he still put a trap under the work area. On the plus side, the vacuum considerably cut down on the amount of dust he was working in.

Rob.

 

[Bosun Higgs]

There is the gel type antifouling remover, but I've found it incredibly feeble, may be more affected ( ie less powerful ) in cold weather compared to traditional paint stripper ?

With a grp hull I'd use the 'grp safe' type of Nitromors, it usually requires newspaper to keep it on overhanging surfaces like hull bottoms.

Awful job, of course full self protection required, eyes, face, breathing, hands, everything !

There's also the point with removing antifouling using any method, one must be careful where the waste goes, it must be collected and disposed of thoughtfully, not allowed into harbours or drains.

Some boatyards have strict rules about this, and some again insist on people using their 'special' tarpaulins under boats for collection, another source of revenue...

One of the most worthwhile £400 I ever spent on a boat was getting the old antifoul blasted off. I'm happy to diy everything from rigging to cylinder heads via electronics but my time is worth more to me than it costs to lie under a boat in the cold getting a faceful of old antifoul and barnacles.

 

[VicS]

One of the most worthwhile £400 I ever spent on a boat was getting the old antifoul blasted off. I'm happy to diy everything from rigging to cylinder heads via electronics but my time is worth more to me than it costs to lie under a boat in the cold getting a faceful of old antifoul and barnacles.

Not all yards will allow it!

 

[Seajet]

VicS,

Nitromors do - or at least did - a stripper in normal size tins, according to the blurb printed on it it's safe for grp. I wouldn't be keen to leave a thick layer of it on grp for a long time just to prove them wrong, though.

I found Dilunet slightly less effective than breathing on the antifouling after an extra strong mint, maybe I was unlucky.

 

[Caer Urfa]

Strange how no-one has addressed the question! I don't have personal experience, although a friend used one with a removable Skarsten blade. He rounded the corners of the blade to stop it digging in and the vacuum attachment caught around half the scrapings, so he still put a trap under the work area. On the plus side, the vacuum considerably cut down on the amount of dust he was working in.

Rob.

Hi Rob
Yes just finished last weekend and it was a pain in the a---.
Removing antifoul is at best a ****ty job and you need to be flexable and use any scrapper at all angles, with a hose attached it was hopeless.

I have just removed all the old antifoul on my CW boat back to the gel coat which on a 24' boat has taken roughly 80 man hrs using a Baco 650 2" scrapper for the difficult parts and ended up using £63's worth of Bosch 40 grade grit abrasive disc's on my orbital sander ( the white sanding disc's are the best).

I then went over everything with 180 grit sand paper, jet washed off and cleaned with thinners No 7.

Job done, just waiting for weather to get up to 8 Deg C so I can start putting on the 4 x Gelshield 200, 1 x Primocon, 2 x Micron Extra coatings.

Hope this helps
Mike

 

[VicS]

VicS,

Nitromors do - or at least did - a stripper in normal size tins, according to the blurb printed on it it's safe for grp. I wouldn't be keen to leave a thick layer of it on grp for a long time just to prove them wrong, though.

I found Dilunet slightly less effective than breathing on the antifouling after an extra strong mint, maybe I was unlucky.

The three I mentioned are the only ones I can find now. Two contain dichloromethane but I also vaguely remember there being one that was said to be suitable for GRP but it does not seem to be about now.

Very variable reports on Dilunett and Removall. I've no experience of either so no comment!

Next owner can have the pleasure of removing 30 odd years worth from mine!

 

[yerffoeg]

About 4 years ago I removed 20 years worth of antifoul using Dilunette (in very large quantities). It does work, but you need warm conditions, and it needs to be left on for several days before scraping. I tried a Bosch scraper, but found it difficult to control and it easily gouges the gelcoat.

 

[salinia]

On the subject of removing anti-fouling does a smooth hull travel faster than one with an uneven surface? I read somewhere that a golf ball (with its undulations) travels faster and further than a smooth one. Thats my excuse for just painting over the old anti - fouling anway

 

[LittleShip]

Has anybody used the scraper that attaches to a vacuum cleaner, the one I have seen has a yellow handle. Or any other suggestions that dont involve these soda blasting types. I am happy to keep chipping away by hand, slowly!
thankyou.

www.gelplane.co.uk/proscraper/product.asp

This is what yout looking for, works very well although it's still hard work Stripped my boat down to wood in a weekend.

Tom

PS round the corners off before using.

 

[Seajet]

Salinia,

You're into a subject close to my heart !

In aircraft flight testing - and broadly speaking, high speed in air is equivalent to low speeds in water - there is the 'boundary layer' over aircraft surfaces, interest being especially focussed on wings for obvious reasons.

As an aircraft gets vaguely even near supersonic, the airflow tends to separate from the wing, increasing drag and reducing lift, leading to at best a fall-off in performance, at worst loss of control leading to structural failure.

The P51 Mustang fighter was among the first to try a 'laminar flow' wing, kept ultra-smooth with no protruding domed rivet heads etc, indeed polished.

This worked in delaying airflow separation but was a pain to maintain.

There was a famous experiment when British engineers considered using a laminar flow wing, and glued on shelled peas to simulate the use of much easier and potentially stronger dome-head rivets; the result with the 'dome heads' was about 5mph slower, so the obvious answer was " forget all the sodding about and polishing, it's a warplane so we'll happily give away 5mph ! "

Later trials centred on ways of keeping the flow onto the wing, with 'vortex generators' ( the tiny triangular fins you'll see on fighter wings, see Harrier photo below) and 'fences' to try to prevent the airflow from sliding the easy route off the end of the wing rther than going over it and producing lift - 'wing' keels and shaped ballast bulbs on yachts do the same job.

In the late 1980's America's Cup races, the U.S. team had multi-million $ backing from the then aerospace giant McDonnel; who produced a skin covering for the U.S. boat of 'riblets', a sort of shark-skin finish.

The shark being another example of boundary layer control, rather tan ultra-smooth as one might expect they have evolved their own 'riblet' surface.

So yes, the good news is a rough surface is potentially faster than a smooth polished one.

The bad news is it has to be very precise, and not like a badly antifouled boat, ie mine !

Below, Harrier GR7; the dots along the wings are triangular vortex generators to keep flow attached as with dimples on golfballs or shark skin, the 'cuff' plates seen end-on halfway along the wings are fences to act much the same as racing boat keel bulbs, the protrusions at the outer ends of the wings ( I can say it now, countermeasures system ) work in the same way, as do the weapons carriage pylons beneath the wing.

 

[jellylegs]

Thanks, totally put off now. I will find a nicer, cleaner healthier job to do, in the warm.

 

[jeanpaulcopie]

Chemical stripping is, by all accounts, a messy process and often only removes one or two layers at a time.

Strippers such as "Nitromors All Purpose Paint and Varnish Remover" and "Nitromors Master Craftsman Paint and Varnish Remover" contain methylene chloride (aka dichloromethane) making them unsuitable for use on GRP.
Nitromors AllStrip Mousse should be safe but is only avaialble AFAIK in 400ml aerosols.

Dilunett is caustic soda based and suitable for GRP
Removall 620 is suitable for GRP

The Bahco - Sandvik type scrappers have been found to be effective

See http://www.ybw.com/forums/showthread.php?t=228344

The Bosch scraper is, I believe, no longer available.

I have seen an old plane iron used effectively on a heavy build up

Hello, I think you can still find the BOSCH scraper, in France anyway...

www.idealo.fr/liste/1424745/grattoir-electrique.html

 

[emandvee44]

Anti-fouling removal

And 400 euros later.........
Hand scraped 8 years worth, and none of that environmental nonsense.
I found a Bosch scraper in a local shop, but the price was double that in the UK. As far as I know the scraper is now out of production.
I have used a Sandvik two-handled type in the past to great effect, but I had more energy then.

The next question.....coppercoat?


Michael.