Removing old antifouling ?????

[mpprh]

Hi

My boat co-proprietor has drawn my attention to an advert in a French yachting magazine.

Apparently, there is a Co who can remove old anti fouling using liquid carbon dioxide. They have an attached vacuum cleaner, and the old AF crumbles into dust leaving clean gelcoat after a quick wipe with a duster.

Sounds too good to be true ?

They have a website here : http://www.supratec.fr/index.htm
but I can't find any mention of this apparent miracle .

Has anyone else heard about this ?

Peter
http://tlp.netfirms.com









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[Jools_of_Top_Cat]

carbon dioxide does not have a liquid state, remember chemistry 'o' level.

<hr width=100% size=1>Julian

<A target="_blank" HREF=http://www.topcatsail.co.uk/TC_minicruise_2003_01.html>Cardigan Bay Cruise</A>

 

[Twister_Ken]

O\'level chemistry

I remember O'level chemistry, but I seem to recall that all gases liquify if subjected to enough pressure.

I also recall that liquid gases cool when allowed to exapnd back into a gaseous state, so if this works, does it do so because it freezes the antifouling off of the substrate? In which case, what does it do to the substrate (your hull)?

<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>

 

[BrendanS]

Re: O\'level chemistry

Jools is right, insofar as that CO2 at room temperature and atmospheric pressure sublimates directly from solid to gaseous forms, without becoming a liquid.

CO2 however can exist as a liquid under pressure as you've stated. I'm not sure what the cleaning process is (though liquid CO2 is a very very good solvent,I doubt that this would have any effect, as the liquid would be turning in to a gas instantly as it exited under pressure). The cooling effect of any liquid/gas of this sort tends to be extremely localised and is unlikely to harm the hull if used with common sense. Probably a freezing and pressure blasting effect on the antifoul, breaking it into little freeze dried pieces.

<hr width=100% size=1>Err, let me know if Depsol enters the forum, I'll go and hide

 

[ecudc]

Re: O\'level chemistry

Isn't that what they use on stage for romantic misty effects (dry ice)

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[Twister_Ken]

Re: O\'level chemistry

Yes, but that goes straight from solid to gaseous without any measurable liquid stage (although it must exist as a liquid momentarily).

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[mpprh]

Re: O\'level chemistry

Hi

My partner may have been wrong about CO2 ......... could have been another gas.

The advert had an illustration showing an insulated container with electrical connections and a spray wand. Similar to the kit used by skin doctors to remove small skin blemishes etc. ?

If it does all it says, its a miracle !

Peter





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[Twister_Ken]

Nitrogen?

I think docs use liquid nitrogen to freeze off warts, etc.

And it's not a greengouse gas, either.

<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>

 

[Mirelle]

Water?

There is a system, not in full scale production yet, for removing AF from ships which uses water at very very high pressure and leaves the steel as if it had been grit blasted to Swedish visual standard 2.5.

The water and bits are captured and the water is recycled leaving the nasties in a container for reprocessing.

Perhaps a rather lower pressure would work for yachts?

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[Jacket]

Re: Nitrogen?

Liquid CO2 is obtained by cooling down air, so you can hardly complain that its use is adding to greenhouse gasses- you're simply putting back something that was removed earlier.

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[ccscott49]

Re: Water?

Ultra High pressure water blasting has been in use offshore, for years, also used for runway/tunnel cleaning and other high strength cleaning jobs. We even use it under water, with a minute amount of abrasive, for cutting off old steel structures, cuts through them like butter. The system for cleaning hulss sounds a good one, especially as it filters out all the crap, instead of it going into the ground or water.

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[Sybarite]

Here's Supratec's
response to my query :

Cher Monsieur,

Nous vous remercions pour cette information. Il est possible de contacter le fabricant au 00 45 76 56 15 00 ou de visiter le www.icetech.dk.

Pour la France, n'hésitez pas à nous joindre au 01.69.11.81.81.

Cordialement,
R. LEFEBVRE
SUPRATEC

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