DIY Slurry/Soda/Sand blasting

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NigelChattin

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Hi all,

Has anyone any DIY experience with slurry or soda or sand blasting to remove antifouling? I need to remove several layers of antifouling this winter however the cost of having this done professionally is prohibitive.

Can anyone help advice how I can do this myself?

Thanks,
Nigel
 
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 ?
 
I agree with DAKA. Blasting is a v aggressive procedure. Would it not be better to use an antifoul removal paint like THIS ?
 
Hi Kev,
I know your boat had a great job done, but it is much newer.

I think we are talking about a 1986 Princess 37 ???????????

That is a similar age to my mates Corniche and whats worst is the poster is from my area and more likely to get the same toss pots my mate got /forums/images/graemlins/shocked.gif

still a good idea to put the link in for Southerners with new boats /forums/images/graemlins/smile.gif

cheers
Pete
 
I wouldn't DIY it. As reported it can be very aggressive. Get a pro to do it (around £500 on my F33 but cost depends entirely on how quick it comes off). Needed some filling in some places around chines afterwards. AF remover wouldn't touch mine - anybody want to buy 20 litres of Removall 620?
 
Went into this a few years ago.
Simblast or equivalent cheaper and more effective than anything you could do yourself (£480 for 37 ft)
Major consideration is what you apply afterwards. I went for copperbot, easily applied myself, and have so far not regretted it.
 
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