removal of old antifoul....???

[Firefly625]

Our Hardy is now 10 years young. Last couple of lay ups I wet sanded just to key up old antifoul for fresh coat, but just toying with the idea when the boat is lifted in December of doing a rather more substantial rub down to get the build up of a decade of antifoul layers down to a thinner layer....

Complete waste of time? or a worth while job....

(BTW, Skint at the moment so would not pay for any kind of blasting procedure! it will just be me and my black & decker sander, and a bad back..)

 

[kashurst]

don't sand it without breathing gear as the dust is poisonous (I believe) and it will take ages. try an electric chisel - I've used one a few times and its quick and relatively easy. the antifoul comes off in little chips instead of dust and is easy to collect etc. Any reluctant patches left you can either leave as it is well bonded or remove with a suitable chemical stripper.(not nitromors though that will dissolve your boat too)

 

[Firefly625]

don't sand it without breathing gear as the dust is poisonous (I believe) and it will take ages. try an electric chisel - I've used one a few times and its quick and relatively easy. the antifoul comes off in little chips instead of dust and is easy to collect etc. Any reluctant patches left you can either leave as it is well bonded or remove with a suitable chemical stripper.(not nitromors though that will dissolve your boat too)

Indeed antifoul dust is not good at all! so I do use very good breathing apparatus and I wet the patch of hull I am sanding. The idea of an electric chisel makes me nervous... but perhaps they are not as severe as they sound??

 

[Ripster]

I have seen a lot of peops using scrapers hand and power versions to take the AF off. Not tried it yet myself. Just make sure you don't go breathing any dust! I always use a wet paper if I am sanding any areas of AF. Is blasting really that costly?

 

[Fantasie 19]

Our Hardy is now 10 years young. Last couple of lay ups I wet sanded just to key up old antifoul for fresh coat, but just toying with the idea when the boat is lifted in December of doing a rather more substantial rub down to get the build up of a decade of antifoul layers down to a thinner layer....

Complete waste of time? or a worth while job....

(BTW, Skint at the moment so would not pay for any kind of blasting procedure! it will just be me and my black & decker sander, and a bad back..)

Well purely my view, but I would say waste of time... your post above implies only two coats on there - it wears off through the season to an extent anyway, you then sanded it to get a key which takes more off, unless she's a racing beast I'd do the same again and worry about taking it back to gelcoat in a few years time....

 

[maby]

Indeed antifoul dust is not good at all! so I do use very good breathing apparatus and I wet the patch of hull I am sanding. The idea of an electric chisel makes me nervous... but perhaps they are not as severe as they sound??

The "electric chisel" works fine, but some of the blades are vicious sharp! Get a blunt blade - or blunt it yourself on a grind stone. Round off the corners of the blade so there's nothing to dig in...

 

[Poignard]

Regardless of whether you are happy to risk inhaling the toxic dust please consider other people in the vicinity before you go dry sanding anti-fouling. If your activities result in someone being harmed you would find yourself in deep doo-doo!

I once laid my boat up in a boatyard shed on Hayling Island and an imbecile employed by the yard started dry-sanding the boat next to me. He had made sure he was fully kitted out in protective clothing but my boat got covered in a/f dust. He seemed puzzled when invited to stop doing it - couldn't understand what I was "on abaht".

 

[LittleShip]

Complete waste of time? or a worth while job...

Forget sanders get one of these.

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

Connects to Vacumm and therefore less danger to you and others.

Tom

 

[Poignard]

Forget sanders get one of these.

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

Connects to Vacumm and therefore less danger to you and others.

Tom

Looks like a good idea. Best price I can find is from Gaelforce Marine

http://www.gaelforcemarine.co.uk/37955/Gelplane-The-Pro-Scraper-Hull-Scraper.html

 

[Firefly625]

Regardless of whether you are happy to risk inhaling the toxic dust please consider other people in the vicinity before you go dry sanding anti-fouling. .

indeed, hence why my initial post contained the sentence...

Last couple of lay ups I wet sanded just to key up old antifoul for fresh coat

 

[Firefly625]

Well purely my view, but I would say waste of time... your post above implies only two coats on there - it wears off through the season to an extent anyway, you then sanded it to get a key which takes more off, unless she's a racing beast I'd do the same again and worry about taking it back to gelcoat in a few years time....

Thanks Fantasie19, I wouldn't call my little tug a racing beast and do like the sound of your advice... But there is still a desire to scrape all the old stuff off... not sure why, perhaps between now and when the boat is actually lifted out I will come to my senses and just do the same as always!!

 

[Firefly625]

Looks like a good idea. Best price I can find is from Gaelforce Marine

http://www.gaelforcemarine.co.uk/37955/Gelplane-The-Pro-Scraper-Hull-Scraper.html

thanks for this, looks a useful bit of kit and just the job (if I can't persuade myself its a lot of work for no reason)

I wonder if just one blade would do my boat? I see they sell just the blades but they seem expensive compared to the whole thing, but always very irritating running out of something when doing a job....

 

[exfinnsailor]

I watched a guy on the hard at Ipswich using a chisel to remove the old anti-foul. I wandered over to see how he was getting on and was surprised to see that he had managed to remove the GELCOAT from an area round the bows. You could actually see the strands of glass. I wandered off and left him to it.

 

[Firefly625]

I watched a guy on the hard at Ipswich using a chisel to remove the old anti-foul. I wandered over to see how he was getting on and was surprised to see that he had managed to remove the GELCOAT from an area round the bows. You could actually see the strands of glass. I wandered off and left him to it.

this is what I would be afraid of, although surely most people would know when enough was enough!!

 

[maby]

The electric chisels are a lot more gentle - they vibrate a sharp blade very quickly rather than relying on brute force. You do not apply much pressure - the action is much more like shaving with a manual razor - so I think the risk of significant damage to the surface should be small.

We recently redecorated a house that we rent out. The previous tenant had (against the rules) glued name plates to the doors of the children's rooms. With my electric chisel I was able to remove the name plate without damaging the wood at all - actually it didn't even remove the paint below the glue - it simply sliced through the glue...

 

[DAKA]

The electric chisels are a lot more gentle -

Another vote for electric chisels

My personal view is I would never have a grit/soda blast or paint stripper anywhere near my gel coat.

A few years ago at lift out a friend had his 1987 Fairline corniche at the side of my 1988 corniche.
He wanted me to join him for a slurry blast of 'gentle soda'.
I wasn't keen even when offered a two for one deal and declined.
My mate went ahead and I saw the damage the following weekend

Whole hull was riddled with small holes in the gel coat.
The whole boat had to be filled and epoxy coated.
At some stage a section of 1 ft by 2 ft on my bow had also been blasted.
It is unclear if
they started on the wrong boat.
they hit it by accident
they wanted to see if my hull would also be wrecked
they thought it was such a good job I would want mine done


My 'test' section was also covered with pin prick holes that I needed to fill.
I was pleased a small section had been tested as it confirmed to me that GRP shouldn't be grit blasted unless it needs an osmosis treatment.
A friend was then kind enough to clean my hull with an electric chisel, the old antifoul came off and left beautiful white shinny gelcoat with no visible signs of weakness.
It is clear that older boats have naturally occurring bubble holes deep within the gel coat that are created during the mixing. These bubbles are fine and will not cause a problem unless the Gel coat is overpolished with compound, over sanded or slurry/grit blasted.

The slurry blast had not made the holes but it had exposed voids that had been water tight for 15 years (moisture reading were very good).

The grass under the treated boat has still not grown back and turned into a bog for a while.

From my experience I would only have a slurry blast on a modern boat that had used a vacuum technique to mix the gel coat and so reduce the amount of bubbles.

If you read the professional sites they warn about this in a round about way " leaves a nice key finish ready for filling and epoxy coating " shouldnt the surface be ready for AF Primer ?

 

[Poignard]

indeed, hence why my initial post contained the sentence...

Sorry

 

[Firefly625]

Sorry

no problemo whatsoever... you are spot on being strict about antifoul dust... it is nasty stuff...

 

[Elessar]

Another vote for electric chisels

My personal view is I would never have a grit/soda blast or paint stripper anywhere near my gel coat.

A few years ago at lift out a friend had his 1987 Fairline corniche at the side of my 1988 corniche.
He wanted me to join him for a slurry blast of 'gentle soda'.
I wasn't keen even when offered a two for one deal and declined.
My mate went ahead and I saw the damage the following weekend

Whole hull was riddled with small holes in the gel coat.
The whole boat had to be filled and epoxy coated.
At some stage a section of 1 ft by 2 ft on my bow had also been blasted.
It is unclear if
they started on the wrong boat.
they hit it by accident
they wanted to see if my hull would also be wrecked
they thought it was such a good job I would want mine done


My 'test' section was also covered with pin prick holes that I needed to fill.
I was pleased a small section had been tested as it confirmed to me that GRP shouldn't be grit blasted unless it needs an osmosis treatment.
A friend was then kind enough to clean my hull with an electric chisel, the old antifoul came off and left beautiful white shinny gelcoat with no visible signs of weakness.
It is clear that older boats have naturally occurring bubble holes deep within the gel coat that are created during the mixing. These bubbles are fine and will not cause a problem unless the Gel coat is overpolished with compound, over sanded or slurry/grit blasted.

The slurry blast had not made the holes but it had exposed voids that had been water tight for 15 years (moisture reading were very good).

The grass under the treated boat has still not grown back and turned into a bog for a while.

From my experience I would only have a slurry blast on a modern boat that had used a vacuum technique to mix the gel coat and so reduce the amount of bubbles.

If you read the professional sites they warn about this in a round about way " leaves a nice key finish ready for filling and epoxy coating " shouldnt the surface be ready for AF Primer ?

Glad to see you have slightly updated this old record DAKA.

 

[Firefly625]

Another vote for electric chisels

My personal view is I would never have a grit/soda blast or paint stripper anywhere near my gel coat.
.......

Hi daka, I think you are famed for that view... It is one I share, it really is a very brutal treatment, if its the first step to getting rid of osmosis... then fine... otherwise wouldn't ever want it done on my boat.

I am warming to the chisel idea though... like the idea of nice shiny gelcoat.