Antifoul removal and hull preparation

nondikass

nondikass

Member
Joined
18 Dec 2005
Messages
30
Location
UK south coast
Visit site
Just about to scrape the hull by hand to remove about 10 years of International Cruiser Uno ant-fouling . Having removed the antifoul I plan to use a random orbital sander with vacuum cleaner attachment to clean up and smooth off.
Looking for advice on what grade of sanding sheet to use as I will need to order a sizeable quantity.
I plan to apply 2 coats of Primacon before antifouling again with Cruiser Uno.
The hull has had a gelshield coating on construction.
 
Last edited:
flinesse said:
Just about to scrape the hull by hand to remove about 10 years of International Cruiser Uno ant-fouling . Having removed the antifoul I plan to use a random orbital sander with vacuum cleaner attachment to clean up and smooth off.
Looking for advice on what grade of sanding sheet to use as I will need to order a sizeable quantity.
I plan to apply 2 coats of Primacon before antifouling again with Cruiser Uno.
The hull has had a gelshield coating on construction.
Click to expand...

100 or 120 grit.

Wear a mask and goggles even with your vac!

(ps a lot of the boats we do are partially scraped before the owner gives up :) )
 
Last edited:
I've never done this before, but I would use a Fein Multimaster with the appropriate scraper blade as they make light work of such tasks. Has anyone tried using one of these?
 
You do not say what size your boat is!

Tried a sander with a vacuum attached and a pain in the A---s.

I have just finished removing all the old antifoul on my Colvic Watson 23'-6" and it has taken me 82 hrs with a Bahco scrapper AND using 40 grade sanding discs on an orbital sander the 100 or 120 grade would not look at it!

The black you see left on the hull below is the 'original' VC Tar Epoxy and it will remain, I photographed everything and sent them to Internationa Paints.
I have been in discussions with the excellant technical department who advised the above and to finally clean down with No 7thinners, fresh water off then 4 x Gelshield 200, 1 x primocon, 2 x Micron Extra.

The above re-coating of coarse will be done WHEN we get warmer weather!

To remove your old antifoul and then just recoat with 2 x primocon to me would be a waist of time, you will never just leave all the original Gelshield 'intact', my recommendation is do the job properly and re-coat with 4 x Gelshield 200 then the primocon then the antifoul.

It's one of those jobs you wish you never started, but with all the hard work the final results will be in the preparation!
Good luck
Mike

5lefttoremove19-12-2010.jpg

DSCN3667.jpg

DSCN3666.jpg
 
Last edited:
I have scraped A Sigma 33 and a Sigma 38 twice each, using a Bahco pull scraper and about 4 blades each time. They had both been epoxied and it was possible to get all the antifouling off without marking the Hullgard coating. It takes several sessions as it is tiring to keep going all day and the thicker the antifouling the easier it is, that is why every five years or so is often enough. To begin it is worth taking the corners off the first blade with a file but after that you get the feel off it and do not scratch. I am doing only the rear third of our Finngulf this winter after 4 seasons because the antifoul is beginning to flake a bit above the propellor wash and I will fair the edges off with wet and dry. I have tried strippers but it is slower and a lot more messy than the Bahco, it always seems to leave a residue that needs sanding while the blade leaves it clean and smooth. Finishing off all over with wet and dry is very tedious with water getting down to your armpits and worth avoiding if possible unless you are a very keen racer.
 
I am in the process of doing this same job, and the same way. I did about a sq mtr the other day in about 30 minutes, i think I will get it done in about 2 days work. I plan to sand with about 120 grit sandader, lightly, with an electric sander, then follow your plan with primocon and 2 coats of trilux antifoul.
I find that pushing with a scraper, as opposed to dragging one of these fancy things much quicker. Be sure to grind the edges off. But gel coat seems tough. any chips, 2 so far, I will fill.
I dont have epoxy layer to worry about damaging, though.

Cheapest option, and its working well.
mask and goggles important, as is a boiler suit, with a scarf to keep bits out.
 
Please think of your neighbours

Its ok putting ppe on yourself - but what happens when the wind blows the stuff around the yard?

Just a thought


John
 
Caer Urfa said:
I have just finished removing all the old antifoul on my Colvic Watson 23'-6" and it has taken me 82 hrs with a Bahco scrapper AND using 40 grade sanding discs on an orbital sander the 100 or 120 grade would not look at it!
Click to expand...

Well I hope you finished off with 100 or 120 grit. This is the right grade to use if it has been scraped well. His question was what grade to use after scraping.

40 grit is fine for rapid removal if it is poorly scraped, but you are going to eat your gelcoat with it.

You need to sand with 100-120 after the 40 for best keying, 40 is too coarse. Whats more if you are needing 40 grit because youve left so much on with he scraper, youll be covering everyone elses boat with antifoul dust

Best scrape well and use 100-120 in the first place.

(if you must scrape that is :))
 
For a cruising boat I'm not sure why antifouling should be removed.
Surely I need as much as I can get on there, and so removing un-used stuff from previous years, that means more to apply this winter?
For racing, yes, I can see that smoother bottom means a little more speed.
For hull repairs, I can see that getting to base material is required.

Otherwise, Why strip?
 
Why strip...

I was trying to understand the why strip theory when I brought the boat last year. I assumed the a/fouling had some sort of magical property that meant to provide eternal protection however long it was on there.

Having won the worse fouled boat award this year and seen the patches where the jet was took of section/sheets of a/f my view has changed somewhat.

I think different products applied/slapped on over 40 years could result in the requirement to strip back at some point in the boats life. Now thinking of a good strip/clean/prime next year and maybe even looking at the "C" coating word. :eek:
 
MM5AHO said:
For a cruising boat I'm not sure why antifouling should be removed.
Surely I need as much as I can get on there, and so removing un-used stuff from previous years, that means more to apply this winter?
For racing, yes, I can see that smoother bottom means a little more speed.
For hull repairs, I can see that getting to base material is required.

Otherwise, Why strip?
Click to expand...

Because:
1) the thicker the old A/F gets, the flakier it gets, with the result that eventually you don't have a solid surface to repaint.
2) Old A/F doesn't retain A/F properties (that's why you get a hanging garden if you leave the boat in too long) so it's not doing any good
3) Once you've got a few years of A/f on, some flaked, some scraped, some as was, your hull is beginning to look like the craters of the moon, and you'll go slower - slow enough to notice even for a relaxed cruiser.
 
Malo 39 - hand scraping and finishing, repairing the dings you will undoubtedly make??? When do you want to go sailing?? It will take you weeks....pay up and get it done professionally - it will be a better finish as well !!
 
In 2004 I did up my Evasion over the winter. the boat next door sanded off his antifoul. He is now in a wheelchair because the toxins in the residues have given him disease similar to asbestosis, and he has major breathing difficulties.
I strongly urge all removing antifoul, to use scrapers with full masks and overalls. Under no circumstances sand it. Do not breathe the dust, and ensure that the overalls are washed immediately after . This stuff is as dangerous as organophosphorus compounds
 
You must log in or register to reply here.

Share this page

Top