Hull Blasting, Epoxy and Boot-top: Advice and recommendations?

[laika]

Looking to blast many years of antifoul off my (12m) hull. I believe it's epoxied underneath it all. There was no sign of osmosis when last hauled out 2 years ago except the rudder which I (hopefully) sorted out. I've read past threads which seem to say that any method is good as long as the operator is good but I'm not really clear on what the pros+cons of each method are. I'd also very much appreciate recommendations of skilled people to do it, ideally Swanwick/Bursledon area but Brighton or Plymouth also possible if that's where the best people hang out. Additionally...

I'm *probably* discounting coppercoat as the balance of opinion seems to say it likes a bit of abrasion quite frequently. I only haul out every other year. I also don't have a problem with antifouling as it's one practical task I can actually do.

Previous threads seem to suggest no need to re-epoxy as blasting won't touch that. True?

Lastly...what's the deal with "boot tops"? I think my boat once had one but it's all antifouled to above the waterline now. Stripping the antifoul will reveal a scraggy boot top but what are they for, why *wouldn't* you have antifoul up to just over the waterline and how best to restore a scruffy boot top?

Any info appreciated

 

[Tranona]

www.symblast.com for blasting. Not sure that abrading is an issue for coppercoat. I am having my new boat done and I only intend to lift once a year for a wash. Would be more concerned about applying it DIY in the open. Best done in a shed. The blasting gives a good surface for application.

Boot topping is mainly aesthetic as it visually breaks the AF from the topsides. Usually 50mm wide parallel to and above the LWL. Trilux is commonly used as it will withstand being out of the water most of the time but will reduce weed growth on the waterline.

 

[Twister_Ken]

I used Symblast, almost 10 years back, on the Twister. There was some (not much) damage to the gel coat so I wouldn't be confident that epoxy won't be damaged.

New boat was Coppercoated from new. The annual 'abrade' is nonsense, apparently put about in the early days by a/f manufacturers. Coppercoat doesn't suggest it, and after five years I've never done it but the c/c is still working just fine.

 

[Tranona]

Good to hear that, Ken. Osmotec start apply the Coppercoat on my new boat today. Hope it does as well as yours - give me time to recover from the cost!

 

[RichardS]

We had our first cruise this month since I had the Coppercoat applied last October.

The boat had no growth along the waterline at all but both hulls were coated with slime and some short whiskers of weed a cm or two long. I had to have the boat lifted in slings because of rudder problems and tried rubbing the hull with my hand. The slime and weed fell off and it looked like the original copper underneath although the waterline stuff is a mottled blue / green. The guy gave it a quick blast in one spot with the power washer and it came clean instantly. I asked the guy not to power wash it as it was so easy to remove that I would brush it with a hand-brush once back in the water.

I scrubbed both hulls wearing my mask (water at 28C in Rab/Croatia this year!) and it looks lovely .... smooth and coppery!

I will probably do this once a year because the boat is not used very often but I think with a regularly used boat the Coppercoat might be self-cleaning.

Richard

 

[rob2]

I did a DIY blasting using a Kaarcher with sand blasting attachment. It was very slow as it has little power compared with a commercial rig and the weather just wouldn't play ball - you can't blast with wet sand. The advantage, apart from cost, of this DIY approach was that I wasn't at risk of breaking into the epoxy layer beneath the antifoul. Once the colour of the a/f has gone, a couple of seconds opens the surface of the epoxy to an eggshell texture which gives excellent adhesion of subsequent coatings.

Like you, I always had a line of fouling both on and above the boot top, so when applying Coppercoat we extened to where the top of the boot top had been and then added a scrubbable boot top above that. Got to be a bit pragmatic, eh?

Rob.

 

[Caer Urfa]

Looking to blast many years of antifoul off my (12m) hull. I believe it's epoxied underneath it all. There was no sign of osmosis when last hauled out 2 years ago except the rudder which I (hopefully) sorted out. I've read past threads which seem to say that any method is good as long as the operator is good but I'm not really clear on what the pros+cons of each method are. I'd also very much appreciate recommendations of skilled people to do it, ideally Swanwick/Bursledon area but Brighton or Plymouth also possible if that's where the best people hang out. Additionally...

I'm *probably* discounting coppercoat as the balance of opinion seems to say it likes a bit of abrasion quite frequently. I only haul out every other year. I also don't have a problem with antifouling as it's one practical task I can actually do.

Previous threads seem to suggest no need to re-epoxy as blasting won't touch that. True?

Lastly...what's the deal with "boot tops"? I think my boat once had one but it's all antifouled to above the waterline now. Stripping the antifoul will reveal a scraggy boot top but what are they for, why *wouldn't* you have antifoul up to just over the waterline and how best to restore a scruffy boot top?

Any info appreciated

If you are having the hull sandblasted then for peace of mind and a good job I would at least give it a few coats of International Gelshield 200 to protect your nice clean hull.

Then apply a primer like Primocon

I changed over to using Jotun antifoul a few years ago as I also only lift out every 2 years so I apply 2 coats and very happy with it.

Like many rivers I have to clean muck from the waterline and have found a 4" boot topping is fine and I use International Toplac which is scrub able

Hope this might help

View attachment 52850

 

[jerrytug]

I used Toplac for my boot topping, and it has a huge amount of growth after a few weeks, hard to scrape off and very annoying. Next time out I will put blue antifouling for the boot topping, instead of Toplac which looks pretty but attracts weed.
No growth at all on the main antifouling, Cruiser Uno.

 

[Caer Urfa]

I used Toplac for my boot topping, and it has a huge amount of growth after a few weeks, hard to scrape off and very annoying. Next time out I will put blue antifouling for the boot topping, instead of Toplac which looks pretty but attracts weed.
No growth at all on the main antifouling, Cruiser Uno.

I think it depends on the water conditions where your boat is kept, I have never had any growth on the waterline, mind I do use the boat min 10 days a month offshore!

 

[Rivers & creeks]

I did a DIY blasting using a Kaarcher with sand blasting attachment. It was very slow as it has little power compared with a commercial rig and the weather just wouldn't play ball - you can't blast with wet sand. The advantage, apart from cost, of this DIY approach was that I wasn't at risk of breaking into the epoxy layer beneath the antifoul. Once the colour of the a/f has gone, a couple of seconds opens the surface of the epoxy to an eggshell texture which gives excellent adhesion of subsequent coatings.

Like you, I always had a line of fouling both on and above the boot top, so when applying Coppercoat we extened to where the top of the boot top had been and then added a scrubbable boot top above that. Got to be a bit pragmatic, eh?

Rob.

For God's sake anyone reading this beware that full positive air supply breathing apparatus must be used and the boat shrouded to protect other yards users. Silicosis is debilitating and often fatal.

 

[laika]

I think I made the fatal mistake of asking too many questions at once.

Anyone care to refer me to a source outlining pros and cons of various types of blasting (soda/sand/co2, although I've read a thread on co2 on here before...)?

Keep the recommendations (/cautions) for people to talk to coming

...and I'm still not really sure about this "boot top" malarkey and what it's really all about. I always just paint treble thickness antifoul at the water line. Seems I might have been doing it wrong all along...

 

[RichardS]

I think I made the fatal mistake of asking too many questions at once.

Anyone care to refer me to a source outlining pros and cons of various types of blasting (soda/sand/co2, although I've read a thread on co2 on here before...)?

Keep the recommendations (/cautions) for people to talk to coming

...and I'm still not really sure about this "boot top" malarkey and what it's really all about. I always just paint treble thickness antifoul at the water line. Seems I might have been doing it wrong all along...

The boatyard at my marina recommended Red Garnet blasting medium as the best one for removing old anti-foul in preparation for CopperCoating.

In the end the job was done by electric scraper as the old antifoul layer was thinner than expected.

Richard

 

[Tranona]

I think I made the fatal mistake of asking too many questions at once.

Anyone care to refer me to a source outlining pros and cons of various types of blasting (soda/sand/co2, although I've read a thread on co2 on here before...)?

Keep the recommendations (/cautions) for people to talk to coming

...and I'm still not really sure about this "boot top" malarkey and what it's really all about. I always just paint treble thickness antifoul at the water line. Seems I might have been doing it wrong all along...

As ever you will find advocates for all blasting media. The firm I suggested has been doing it for years and regularly prepares hulls for copper coating and will apply the coating. An experienced operator will know what to do to get the best surface for your chosen coating.

Nothing magic about boot topping. Waterlines can be a real problem - particularly on a swinging mooring so antifouling to above the waterline is necessary. All the boot top in a different colour does is make it look more attractive than plain AF. Some people get away with ordinary paint - I have used that in the past - but if you do get fouling or weed growth it is a pain to remove, so best to use a special boot topping or Trilux which can cope with not being permanently immersed.

 

[laika]

Nothing magic about boot topping. Waterlines can be a real problem - particularly on a swinging mooring so antifouling to above the waterline is necessary. All the boot top in a different colour does is make it look more attractive than plain AF. Some people get away with ordinary paint - I have used that in the past - but if you do get fouling or weed growth it is a pain to remove, so best to use a special boot topping or Trilux which can cope with not being permanently immersed.

What you say about not being immersed makes complete sense, although in practice I've not had a problem with my micron extra.

To display my complete ignorance though....What you and others seem to be describing is a strip of paint directly above the uppermost extent of the anti-foul (which presumably makes applying masking tape 3 times as long as using only anti-foul?). What I'd previously heard it applied to was a strip which I'd thought was mainly decorative, separated by bare grp from the anti-foul below. Presumably that was incorrect usage?

 

[Tranona]

What I'd previously heard it applied to was a strip which I'd thought was mainly decorative, separated by bare grp from the anti-foul below. Presumably that was incorrect usage?

That is also common. My old Bavaria had that but as soon as I loaded it up for living aboard it got fouled and is a pain to clean, so I painted it in Trilux. My new Bavaria has two black stripes - a narrow one presumably on the waterline and a wider one above. The Coppercoat will go up to the bottom of the first stripe (I think, will find out on Monday). These are "style" and help reduce the visual height of the topsides as does another black stripe just below the gunwhale. If I get fouling on the lowest stripe I will Trilux it.

As to masking off, not a big deal. On my old wooden boat the white boot topping between red AF and blue topsides and white above is visually very attractive. I mask the topsides, paint the boot topping, mask the waterline and then antifoul the underside. Peeling that last run of tape off is always satisfying.

 

[Twister_Ken]

I suspect actual boot topping is rather passé on new boats. Nowadays there's often a stripe (or stripes) of contrasting gel coat a smidge above the waterline, and the a/f just comes out of the water and up to the bottom of the stripe.

 

[duncan99210]

Can't offer any help on the blasting methods but we've just reapplied Coppercoat on to the fifteen year old coat. The orginal was getting thin in places (under sink drains for example) and had been abraded once by us to restore effectiveness about two years ago. The new stuff is working so well that theres nothing to scrub at even on then water line.