Epoxy coating

[raro3]

Hi all, just looking for advice on my current project. I've had the hull of my Vancouver 34 sand-blasted to remove the anti-fouling build-up. There is no trace whatsoever of osmosis, and the blasting revealed that she appears to have been copper-coated below the waterline at some stage in her life. I'm now planning to apply 2 coats of Jotun Penguard HB two-pack epoxy primer just to provide an additional barrier, followed by one coat of Jotun Vinyguard as a tie coat / primer prior to anti-fouling. All to be applied with good quality roller, and I'm assuming I don't need to sand down the entire hull prior to application - the blasting left it fairly smooth, apart from a few small areas which I've attended to.

Does this all seem reasonable, and are two coats of the Penguard sufficient, given that she already has an old copper coating? Any advice would be welcome - I don't plan to do this again, so I want to do the best job I can. Thanks, Phil

 

[oldsaltoz]

Hi all, just looking for advice on my current project. I've had the hull of my Vancouver 34 sand-blasted to remove the anti-fouling build-up. There is no trace whatsoever of osmosis, and the blasting revealed that she appears to have been copper-coated below the waterline at some stage in her life. I'm now planning to apply 2 coats of Jotun Penguard HB two-pack epoxy primer just to provide an additional barrier, followed by one coat of Jotun Vinyguard as a tie coat / primer prior to anti-fouling. All to be applied with good quality roller, and I'm assuming I don't need to sand down the entire hull prior to application - the blasting left it fairly smooth, apart from a few small areas which I've attended to.

Does this all seem reasonable, and are two coats of the Penguard sufficient, given that she already has an old copper coating? Any advice would be welcome - I don't plan to do this again, so I want to do the best job I can. Thanks, Phil

If the hull has been sand blasted below water line would you not want to apply some eopxy to prevent water ingress, then apply the high build epoxy prior to anti fouling?

Good luck and fair winds.

 

[Daydream believer]

Why not just stick another copper coating on it.
Now you have got that far it will not be dearer than your proposal

 

[raro3]

Thanks guys. I'll show my ignorance here to Oldsaltoz - when you say wouldn't I want to apply epoxy to prevent water ingress, isn't that what epoxy primer is supposed to do (e.g. Gelshield is described as an epoxy primer), or should I be looking at another product?

Thanks Daydream Believer - not a bad idea, although I don't know whether it was Copperbot, Copper Coat or some other product although it probably doesn't matter. I'll have a think about this idea....it would save on antifouling as well.
Phil

 

[oldsaltoz]

Thanks guys. I'll show my ignorance here to Oldsaltoz - when you say wouldn't I want to apply epoxy to prevent water ingress, isn't that what epoxy primer is supposed to do (e.g. Gelshield is described as an epoxy primer), or should I be looking at another product?

Thanks Daydream Believer - not a bad idea, although I don't know whether it was Copperbot, Copper Coat or some other product although it probably doesn't matter. I'll have a think about this idea....it would save on antifouling as well.
Phil

Hi Phil,

I was highlighting the fact that Epoxy will stick to almost anything, but very few products will stick to Epoxy.

So the Epoxy coat must be primed before re coating.

In your case it sounds like a lot of the original epoxy has been removed and should be replaced before applying anything else.

Good luck and fair winds.

 

[William_H]

Jotun Penguard seems to be an epoxy witha lot of filler. I understood it was also a primer for the a/f. I used it in some places last winter and it seems to have been ok for a/f attachment. What seems to have happened now is that the penguard left over wiull not harden and remains soft. I think it mst have expired. So do check a small batch to ensure it hardens before you apply it. good luck olewill

 

[oldsaltoz]

Jotun Penguard seems to be an epoxy witha lot of filler. I understood it was also a primer for the a/f. I used it in some places last winter and it seems to have been ok for a/f attachment. What seems to have happened now is that the penguard left over wiull not harden and remains soft. I think it mst have expired. So do check a small batch to ensure it hardens before you apply it. good luck olewill

Sounds like the FC version, the high build one, I assume this was used on steel?


Have you tried to stand the tin in some hot water and give it a really good stir up?

Good luck and fair winds.

 

[William_H]

Thanks Brian I will give it go again. olewill

 

[Daydream believer]

Hi Phil,



In your case it sounds like a lot of the original epoxy has been removed and should be replaced before applying anything else.

Good luck and fair winds.

You do not have to do that with copper Coat

 

[CAPTAIN FANTASTIC]

The Jotun Penguard will stick well on a clean hull, (I applied two coats on my hull this season to act as a water barrier) I did not think that you need additional primer on top of Penguard before antifouling. However, if your hull has been sand blasted and well prepared, I would consider putting copperboat antifouling, it will save you a lot of effort and money every year.

 

[oldbilbo]

'Just looking for advice'....?

Why not ask Jotun's Yachting Business Development Manager, Jim Brickwood, who has been visible at recent boat shows AND most helpful in exactly the circumstances you detail? He has several decades' experience and the tech resources of perhaps the world's largest protective coatings business.... james.brickwood@jotun.co.uk

 

[Cloven]

when you say wouldn't I want to apply epoxy to prevent water ingress, isn't that what epoxy primer is supposed to do (e.g. Gelshield is described as an epoxy primer)
Phil

Gelshield recommend 6 coats for barrier protection. You can then either anti foul directly over that final coat whist it is still slightly tacky but if fully cured, then you will need a anti foul primer.

 

[Elessar]

Hi Phil,

I was highlighting the fact that Epoxy will stick to almost anything, but very few products will stick to Epoxy.

So the Epoxy coat must be primed before re coating.

In your case it sounds like a lot of the original epoxy has been removed and should be replaced before applying anything else.

Good luck and fair winds.

Solvented epoxy dries Matt, has an infinite overcoating window and does not need to be sanded.
Solvent free epoxy dries shiny so needs to be over coated within 24 hrs OR thoroughly sanded.
Primer before Antifoul is recommended, not neccessary before Coppercoat.
I'm not sure I get your "sticking to epoxy" thing.

 

[longjohnsilver]

Solvented epoxy dries Matt, has an infinite overcoating window and does not need to be sanded.
Solvent free epoxy dries shiny so needs to be over coated within 24 hrs OR thoroughly sanded.
Primer before Antifoul is recommended, not neccessary before Coppercoat.
I'm not sure I get your "sticking to epoxy" thing.

Just to be clear, effectively what you're saying is that after applying Gelshield 200, there's no time limit before applying coppercoat? That's certainly what the International website implies.

 

[oldsaltoz]

Solvented epoxy dries Matt, has an infinite over coating window and does not need to be sanded.
Solvent free epoxy dries shiny so needs to be over coated within 24 hrs OR thoroughly sanded.
Primer before Antifoul is recommended, not necessary before Coppercoat.
I'm not sure I get your "sticking to epoxy" thing.

Are you sure you got that the right way round?

Every time I have ever used the West system epoxy resin ( and I have used a truck load) I had a very high gloss finish, rolled on and tipped with a brush to reduce sanding after 4 or 5 coats?

Good luck and fair winds.

 

[Elessar]

Just to be clear, effectively what you're saying is that after applying Gelshield 200, there's no time limit before applying coppercoat? That's certainly what the International website implies.

Correct - but what is critical with a solvented epoxy like gelshield 200 is that all the solvent has evaporated prior to Coppercoating, or you will get micro bubbling.
So you must leave a minimum of a week. But there is, as you say, no maximum.

 

[Elessar]

Are you sure you got that the right way round?

Every time I have ever used the West system epoxy resin ( and I have used a truck load) I had a very high gloss finish, rolled on and tipped with a brush to reduce sanding after 4 or 5 coats?

Good luck and fair winds.

Yes. West system is solvent free I think, or may have just a small amount.

The solvented epoxies such as gelshield are just 45% solids, ie a 100 micron wet film thickness will shrink back to just 45 microns. West system doesn't shrink like that thus my assumption it is solvent free or nearly free.

 

[Jim@sea]

Gelshield recommend 6 coats for barrier protection.

On my boat (23'6") I am now up to 7 coats of 2 pack epoxy and will go for more. It had been Gelshielded previously but when I had it sandblasted I think it took some of it off. Mind you the sandblasted surface gave a really good surface for applying the epoxy. I can do a full coat with 1 litre of epoxy. I always use a brush as I think you can get more on, and as epoxy dries so quickly you can overlap a bit. Although they say epoxy will stick to anything if I leave it for a few days I just run over the surface with an orbital sander to give a bit of a key.

 

[longjohnsilver]

Correct - but what is critical with a solvented epoxy like gelshield 200 is that all the solvent has evaporated prior to Coppercoating, or you will get micro bubbling.
So you must leave a minimum of a week. But there is, as you say, no maximum.

Thanks, wasn't aware of the micro bubble issue. Very useful.

How long after copper coating do you leave it before re launching?

 

[Elessar]

Thanks, wasn't aware of the micro bubble issue. Very useful.

How long after copper coating do you leave it before re launching?

5 days. Maybe 4 in summer.