Centaur hull sand blasted, advice for next steps please.

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BeccaW
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Centaur hull sand blasted, advice for next steps please.

Post by BeccaW »

Hello All,
Just bought my first boat - a Centaur, very excited but need to do a few jobs before she goes in the water. The big one is the hull. It was covered in little blisters (less than 1cm diameter). The surveyor popped some and did a test with litmus paper and says they're not osmotic. The boatyard had a go at scraping it but there were still some blisters below the surface so they've now sand blasted. Some of it is now smoothish, majority has a lots of little craters (see attached pictures). They're going to jetwash it for me and put primer on the bits of bare metal on the keels. Having trawled through forums and magazine articles and youtube videos I think my plan of attack is now:
1. Wipe down with white spirits on lint free rag to get rid of any dust
2. Thin coat of epoxy primer to seal it all (with a roller)
3. Fill in blister holes with epoxy filler and let dry
4. Sand
(Repeat 3 and 4 as necessary to get nice smooth finish or until I lose the will)
5. A few coats of epoxy primer
6. Antifoul
7. On the metal keels just primer and then antifoul
8. Scrape out the old mastic in the keel joint and put in new
My questions are...
1. Is this right?
2. Am I realistic in hoping to do steps 1-5 over a four day weekend? (I have an orbital sander and a massive pile of sanding pads)
3. I'm using EU45 antifoul - does it matter what epoxy primer and filler I use beneath this?
4. How many coats of epoxy do I need and how long should I leave it between coats - also if it takes me too long to get all over the hull will I then have to sand back before the next coat to get it to stick properly? In which case should I do one side at a time?
Happy to receive any advice or knowledge from you more experienced folk. Thanks in advance! Becca
Attachments
before and after scraping
before and after scraping
tiitikki hull scrape.jpg (3.06 MiB) Viewed 2005 times
sand blasted
sand blasted
tuutikki hull 3.jpg (42.89 KiB) Viewed 2005 times
sand blasted
sand blasted
tuutikki hull 2.jpg (52.2 KiB) Viewed 2005 times
sand blasted
sand blasted
Tuutikki hull 1.jpg (58.62 KiB) Viewed 2005 times
Jolly Roger
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Re: Centaur hull sand blasted, advice for next steps please.

Post by Jolly Roger »

Becca

Welcome to the WOA Forum and Westerly ownership. If you have not already joined the Westerly Owners Association then I highly recommend it. For £15.00 per year, it is a bargain. On joining you will get a book on the history of Westerly, which is interesting as it includes every model built. There are 2 magazines a year, a year book including a list of members boats and their contact details. The extra bonus is access on the web site to the technical articles previously published in past issues of the magazine. Other bonuses are discounts from suppliers, the best of them is the insurance scheme that has extra cover built in over their standard policy and the discount is greater than the WOA fee.

Regarding your hull, the blisters are small air bubbles in the gel coat due to poor brushing out of the gel coat in the mould to remove them. My Fulmar has the same problem, so you are not alone. Westerly always applied a double coat of gel coat, so you may get some bubbles from the second coat. As the hull has been blasted clean you should have no further problems in the future from blisters. Personally I would fill the holes before applying any epoxy as any sanding will destroy the integrity of the first coat of epoxy.

I used Plastic Padding Gel Coat Filler to fill the holes, but products like International Watertite (https://international-yachtpaint.com/en ... /watertite) should be considered. Filling the holes may take more than one application, this is from experience. International suggest using their Super Cleaner (https://international-yachtpaint.com/en ... er-cleaner) to wash down with before painting. With the day time temperatures at present, you should be able to apply 2 coats of Gelshield 200 in one day. The recommended number of epoxy coats is 5, but my surveyor suggested only 3 as the potential of further problems in the future would render the extra coats as an expensive mistake. Sanding between coats is unnecessary. Going from memory you should apply the first coat of antifouling before the epoxy goes hard for better adhesion.

Hope this is of help.
Roger
Concerto Fulmar FR38
Photos at http://s1294.photobucket.com/user/Conce ... 2/library/
BeccaW
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Re: Centaur hull sand blasted, advice for next steps please.

Post by BeccaW »

Thanks Roger - very useful!
I have indeed joined the WOA, but have yet to read the book, perhaps this weekend between coats of paint.
I'll update with some pictures of how it went and time taken, costs etc when I'm done for future forum trawlers.
Becca
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