sandblasting old anti-foul

Nick_H

Nick_H

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www.ybw-boatsforsale.com
Can anyone reccommend a company to sand blast a hull to remove old antifoul in Lymington? I've heard some bad experiences where the gel coat has been damaged, so i'm ideally looking for someone who has used a company with good results, rather than just knows of someone.
 
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 shiny gel coat 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 over polished 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 ?
 
I recall a 36 foot yacht having this done a couple of years ago using the farrow system. I was quite impressed, all done & dusted in a day. Understand it's kind to gel coat.

Eddie
 
There is new technology out there with much higher precision and less waste for that matter.

A friend of mine used it over the week, I was there checking it out incase I would need to remove paint one day.
They use dry ice or frozen carbon dioxide and "shoot" it at whatever needs removing at very high speeds/pressure.

There was no visible damage to the gelcoat.

I google'd dry ice and found this "http://www.dryiceinfo.com/cleaning.htm" which hopefully can get you started finding someone who could help.
 
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I love the testimonial on the web site, it's by their own MD /forums/images/graemlins/laugh.gif

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I think it's more of a statement than a testimonial...
 
Slurry Blast? Forcing water at high pressure into a hull while trying to remove coatings I was under the impression it was better to keep your hull dry rather than injecting it with water??
 
[ QUOTE ]
Slurry Blast? Forcing water at high pressure into a hull while trying to remove coatings I was under the impression it was better to keep your hull dry rather than injecting it with water??

[/ QUOTE ]

Well if your gelcoat lets in water I'd be worried if I were you, and my hull is wet for 10 months of the year. Yours?
 
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