Just Antifouled - tiny bits brushing off?

Richard10002

Richard10002

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Hi,

Antifouled with Cruiser Uno yesterday, over original Cruiser Uno. Intend to put a second coat on on Saturday.

Before the job, I scraped all flaky bits off, and sanded these areas and areas where it was down to the gelcoat. Then I primered with primocon all the sanded bits, including the white bits.

About 7 hours after finishing, I brushed against the rudder, and a small patch of the paint rubbed off down to the gelcoat.

I'm thinking that I should sand and prime the area before the second coat - any ideas or suggestions?

Many Thanks

Richard
 
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Sounds odd.

About 7 minutes after application A/F is usually pretty firmly stuck. Was the consistency OK when you put it on?

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I think so... used 2 and a bit tins, and stirred all of them loads, and am sure I got all of the thick stuff from the bottom to a consistent mix. Also, nowhere did it seem runny when put on. In most places where I've touched/rubbed it, it seemed well stuck.

Given that the 1st coat is on, I'm really wondering how to deal with the few iffy bits... sand and prime, or something else?

many Thanks
 
could be dust from the sanding preventing the paint sticking.did you wash it off thoroughly?
 
I've had a similar problem; thinking that I had done all the necessary preparation, scraping back and priming the obviously loose areas, only to find that areas which had looked fine flake off on the roller right back to the gelcoat.
I think that if you let the paint thickness build up too far over the years it eventually starts flaking off. I'm two thirds of the way through a three-winter programme to scrape off all the old antifouling back to the gelcoat. In areas which have been scraped back I don't get any trouble with paint flaking off.
The bare gelcoat was all lightly sanded and degreased before re-painting so another explanation could be that the hull wasn't properly cleaned when it came out of the mould.
 
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Given that the 1st coat is on, I'm really wondering how to deal with the few iffy bits... sand and prime, or something else?

[/ QUOTE ]Richard, I think you've answered your own question...parts are iffy and if you don't take them back to gelcoat and do them again, they are liable to come away. The problem is one of adhesion and if there was no difference in the paint or technique then there must have been a difference in the surface. Grease is the obvious target.
 
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Richard, I think you've answered your own question...

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<g> Seems like it from the various responses, (Thanks to all). I guess it's just reassuring to get it confirmed.

Anyway.. just got back to the boat, and have given the "iffy" areas a rub wit a dry rag. Seems to have solidified, but I'm going to sand it back and prime it tomorrow, (today?), just to be on the safe side.

For info, I used B & Q premium blue masking tape on Wednesday and, having peeled a bit off tonight, it releases fine... so we know it is good for at least 3.5 days, (It says it's good for 28 days on the pack).

Richard
 
It is possible for AF to go "off" with long term storage .....

I had a large tin of Jotun Professional stuff years ago ... Bought it from a stall at a Boat Jumble at knock down price.

When used - it literally flaked and in some places produced onion skin like areas ....

I spoke to an International Paint Inspector when he visited a ship we had dry-docked .... explained the matter and he reckoned that AF has a shelf-life and solvents, stabilizers etc. that help it flow / adhere are the reason that mine did it.

Probably not what your problem is - but though it worth mentioning - as I know many people do keep a pot or two at back of garage !!
 
Bought from mailspeed marine a week before applying.

Of course, we never know how long they have had it in stock.

I think it's going to be OK with a sand and prime.

Thanks.
 
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