That next years job for me ,I'm interested as well I know Bubble777 did his and has a you tube vid trying to get it off worst job hes had on the boat he told me
Some soda blast first but that $2000 you will spend for a start

I had Morning Bird soda blasted a few years ago and one of the best things I have done. Perfectly clean and smooth, we were able to inspect the glass and recoat her properly. Not a trace of osmosis and much improved performance afterwards. Highly recommended. It cost me $4500 in 2011, I combined it with a due anti foul.

Existing antifouling Altex no. 5

I use Altex No5 as well. usually comes up dead smooth after a good going over with a really good high pressure cleaner.

In your case I would flat board the surface with a coarse wet and dry, touch up any bits were you get down to the gelcoat or old primer with Primicon or Jotuns version of grey primer. Recoat with Altex.

Find a couple of energetic youths and pay them to do the hard part of sanding if you are so inclined. Probably a couple of hours work there.

MorningBird said..
I had Morning Bird soda blasted a few years ago and one of the best things I have done. Perfectly clean and smooth, we were able to inspect the glass and recoat her properly. Not a trace of osmosis and much improved performance afterwards. Highly recommended. It cost me $4500 in 2011, I combined it with a due anti foul.

Was the cost for the completed paint job Morning bird? hope its not just for the soda blast as thats what Ive been thinking after Bubbles job hes said it was dam hard work and took a while to find the right method or tool to use.

DrRog said..
Here's the link to the previous thread with Bubbles video: www.seabreeze.com.au/forums/Sailing/General/another-bottom-paint-question-should-i-remove-it/

I'm going to have to strip back next year - mine is also 30 years old. I was just up on the hard but I couldn't face doing it this year in addition to what we had on. I think that the primer's coming away underneath so after the recent antifoul there are already chunks that have fallen away.

I'm contemplating going further north - perhaps Port Stephens as someone suggested earlier - to go up on the hard. Somewhere cheaper than $150 a day! Somewhere I can take my time; scrape back with a power tool like Bubbles used or some hired labour, leave the hull to dry a bit, repair, paint. Saw a video today in which they pulled the rudder off so they could get in between and do it thoroughly; seemed like a good idea (except for the principle I saw on someone's boat blog, 'If it's 30 years old and you pull it apart, it's broken'!).

Your still going DR Rog and the boat you own maybe younger

Keensailor,
West Systems have a pretty good handbook available on osmosis prevention and treatment. It has info on barrier coating and using their products to do this with a step by step guide. I bought a hard copy of the manual but you may be able to download it online for free?? I have chosen West systems 105 epoxies and barrier additive 422 to coat below the waterline on my boat. I may need in total 8 to 10 coats because most of the gelcoat has been removed. I believe that the gelcoat blisters on my hull have come about from too much gelcoat being removed over the years during haul outs and antifouling, too much scrubbing and sanding, then a botched attempt to fix up a manifesting problem, bog and flog as they say. I would recommend that you clean back a few small areas of antifoul and assess the gelcoat, then decide a method of attack. If it is soda blasting you choose, soda blasting can get a fantastic results and the job over quickly but if you have years of anti foul build up , I would scrape the hull first then soda blast, A day spent with a scraper or similar tool may save you 4-5 hours with the soda blaster guy at $180 to $200 per/h. If you are real keen scrape and sand , you may be happy with what you find and a barrier coat unnecessary

HG02, it is now a few years since it was done and the bottom is still excellent. It is important not to over antifoul, I do mine when the previous coat is wearing through and then wet rub nearly all of it off before redoing.

Libran said..

keensailor said..
Boat is a 30 year old NS 27 which has some of its original coats of antifouling in some patches.
Hull is in good condition other than the antifouling build up. Would like some suggestions on the best methods to;
1. clean the old anti-fouling off (without taking off un-necessary Gelcoat)
2. check hull moisture levels, what level ?
3. coat with some type of epoxy etc have heard good things about West System ? how many coats
thanks

I use Bote Cote rather than West because it is Australian, and supposedly does not have a problem with amine blush between coats. I have used it for the last 5 to 6 years without any problem and have never sanded or cleaned between coats.

Ive use boat cote as well and works for me. The local distributor if I ring him will wait for me before he closes at 5 pm usally I make it just on 5 very helpful guys

Some great advice gents, thanks.

Will probably go the soda blasting option. But just need to make sure she is dry enough before using barrier coat.

What you can use to remove old anti foul and base paint is a power planer.

You need to be careful using it and have the cut depth set to the minimum. An Ozito from Bunnings will cost less than $100.

Another method is with a mini grinder. Save all your blunt 36 grit discs. With a pair of tin snips cut 50mm straight bits off the circumference so that you end up with corner points all around the disc. Use the grinder as normal [not flat]. The crap really flies off. Wear a good mask!

Last easter I sanded my anti foul off and forget to use a mask a mate dropped by and said you better wash your face went to wash it off gees I had more anti foul on my face than was left on the hull . Not a good practice wont be doing that again

Gel planes are really just an intensely modified wood powerplane. The drum is about all they have left in common, I looked into modifying one for the job of removing gelcoat but decided against the plane method simply because they rely on the existing surface to control the cutting depth. If the hull is uneven or gelcoat is thinner (patchy) in places, you still cut to the full depth following the guiding surface. Some of the power type paint peelers (like an angle grinder) that use a disk with a single tooth cutter also use the existing surface to control the depth and are difficult to use on a concave surface unlike a planer style drum. I bought a belt sander( maktec) to do the concave down to the keel. It had to be a sander that had the front roller protruding from the frame of the machine like a gel plane, allot of them aren't built that way.

Yes but obviously no good for concave areas DrRog.