Coppercoat: is sanding before launching necessary?

[MapisM]

Half way there with CC - see below. The rest will follow tomorrow, and I'll report about the results in due course.

But I'm actually posting for a different reason now.
I heard contrasting views about the light sanding which in theory should be necessary before launching the boat, to "activate" the a/f protection.
I mean, nobody argue that this is what CC suggest, but according to some folks this isn't strictly necessary, unless the boat right after launch is going to sit in a marina for a longish period.
In my case, in a matter of a few days after launch we will hopefully leave for the delivery trip, so also the CC surface should have a proper shakedown PDQ.
So, I was wondering if the sanding could be skipped altogether...

Wadduthink, folks?

 

[sailorman]

The resin will after application "encapsulate" the CC therefore the copper will n ot be in contact with water & will not work

 

[MapisM]

Yup, I understand the principle, but the point is, isn't regular (practically daily) cruising enough to expose the copper in a reasonable time anyway?

 

[sailorman]

Yup, I understand the principle, but the point is, isn't regular (practically daily) cruising enough to expose the copper in a reasonable time anyway?

Once the epxoy surface, is worn away to reveal the copper particles

 

[rafiki_]

Rafiki did not need any activation before launch. You could see that the CC was active.

 

[MapisM]

Interesting, P. Did that require any peculiar launch procedure, by chance?
I mean, my understanding is that the resin should be allowed to polymerize completely before launching the boat, i.e. min 72 hrs.
And by doing so, it's also intuitive that what sailorman said (copper powder remaining "trapped" inside the resin) is bound to happen.
My doubt was only for how long, assuming that the boat keeps moving frequently.
If what you are saying is that in your boat CC was effective right away with no sanding, that's somewhat surprising...

 

[vas]

You could see that the CC was active.

odd,

P, how could you see that CC was active???
wasn't turning green on the hard?

 

[rafiki_]

Yep the CC was completed 72 hrs before launch. It wasn’t green, but you could see it was active. Just a little activation required on the patches that were completed last when she was reblocked. No special launch procedure.

 

[Tranona]

Mine was launched about 5 days after completion without any sanding and worked except for the patches finished last under the pads which did not activate as quickly. Still not sanded though, just had a different colour. Has been in the water almost continually since then (August 2015) and has still not needed any sanding.

 

[vas]

It wasn’t green, but you could see it was active.

Paul,

HOW can you see it's active on the hard?
rather confused!

V.

 

[MapisM]

Hear, hear...
I wasn't expecting a Coppercoated hull to need re-sanding at any time during CC lifespan.
A powerwash whenever lifted is bound to be useful I suppose, but it's very logical that once the copper micro-grains are exposed/oxidized, there's no way they can get fully re-encapsulated into the epoxy resin anymore.
What I don't get is how the a/f effect can work right away upon launch of a newly CC-ed hull with no sanding.
I mean, I'm glad to hear that obviously, but... Just can't get my head around it.
There's even a pic with a sanding sample on the web, showing how a properly prepared hull should look like before launch, according to CC themselves.
I'm not posting it as an embedded image because it's pretty large and would screw the thread view, but just click here to see it.
Now, what do you guys mean exactly, when you say that you could see it was working even if unsanded (or not so much under the patches)?

 

[Elessar]

Hear, hear...
I wasn't expecting a Coppercoated hull to need re-sanding at any time during CC lifespan.
A powerwash whenever lifted is bound to be useful I suppose, but it's very logical that once the copper micro-grains are exposed/oxidized, there's no way they can get fully re-encapsulated into the epoxy resin anymore.
What I don't get is how the a/f effect can work right away upon launch of a newly CC-ed hull with no sanding.
I mean, I'm glad to hear that obviously, but... Just can't get my head around it.
There's even a pic with a sanding sample on the web, showing how a properly prepared hull should look like before launch, according to CC themselves.
I'm not posting it as an embedded image because it's pretty large and would screw the thread view, but just click here to see it.
Now, what do you guys mean exactly, when you say that you could see it was working even if unsanded (or not so much under the patches)?

just take the shine off it with scotchbrite. It will expose the copper. Rafiki got away with it because the water is colder. If the slime builds before the corrosion starts it doesn't go green and you have to haul and sand to kick start it. Sailorman was dead right is his replies.

Sometimes it needs a light sand after 5 years or so, if it starts becoming less effective.

 

[Hurricane]

We are in the boatyard right now - waiting for a relaunch.

6 years into CC now and it was showing signs wear.
I want it to last about 10 years so we decided to be more aggressive with it than previous years.
A yachtie friend has been doing his so he helped.
We sanded the vertical face next to the water line and reapplied 4 coats of CC
We have also sanded most of the underside back to the brown CC but not recoated.
The BIG thing for me is that the hull is very sound and I think that is mainly due to the CC (epoxy layer protection.)
Hard work but we have very aggressive marine growth here in SC
That was 5 days ago.
Yesterday, we lightly sanded the new CC to activate it.
I am told that this it IS important to sand new CC just before launch.
I will post some pics later when I can find the time to upload them.

MapisM
I would definitely give the new CC a light sand.
IIRC, we sanded by hand 6 years ago but yesterday, we used a small orbital sander and 80 grit disks - very lightly.
I'll take a close up pic for you and post with the others.

Good luck

 

[Hurricane]

Got some time right now - waiting for the travel hoist.

This pic showed the lift out

And this shows what we have done this season

The idea is to heavily activate the CC so that it is effective for the next 3 or 4 years.
After which, we will then re-coat the lot.

The white bits are not the gelcoat showing through - just dust left from the barnacle deposit (worm casts this year).

Only spent a couple of hours on polishing the props this year - we had lots of other stuff to do - I'll post later.

@MapisM
Here are a couple of close ups of the sanding of the new CC

Hope that helps
M

 

[Eren]

Hi Hurricane,

I see that the rudders, props and shafts also came out to be very clean. What had you applied to them?

 

[Elessar]

We are in the boatyard right now - waiting for a relaunch.

6 years into CC now and it was showing signs wear.
I want it to last about 10 years so we decided to be more aggressive with it than previous years.
A yachtie friend has been doing his so he helped.
We sanded the vertical face next to the water line and reapplied 4 coats of CC
We have also sanded most of the underside back to the brown CC but not recoated.
The BIG thing for me is that the hull is very sound and I think that is mainly due to the CC (epoxy layer protection.)
Hard work but we have very aggressive marine growth here in SC
That was 5 days ago.
Yesterday, we lightly sanded the new CC to activate it.
I am told that this it IS important to sand new CC just before launch.
I will post some pics later when I can find the time to upload them.

MapisM
I would definitely give the new CC a light sand.
IIRC, we sanded by hand 6 years ago but yesterday, we used a small orbital sander and 80 grit disks - very lightly.
I'll take a close up pic for you and post with the others.

Good luck

Mike, 80 grit is good for over coating however - too late now - it is too course to be ideal for a pre-launch abrade. Scotchbrite is better. A juvenile barnacle is about the size of a grain of pollen and 80 grit gives them a nest.

 

[rafiki_]

Mike, 80 grit is good for over coating however - too late now - it is too course to be ideal for a pre-launch abrade. Scotchbrite is better. A juvenile barnacle is about the size of a grain of pollen and 80 grit gives them a nest.

Yep, scotchbrite used on Rafiki.

 

[MapisM]

Yep, scotchbrite used on Rafiki.

Oi, I understood your post #5 differently - i.e. nothing done at all...

 

[MapisM]

just take the shine off it with scotchbrite. It will expose the copper. Rafiki got away with it because the water is colder. If the slime builds before the corrosion starts it doesn't go green and you have to haul and sand to kick start it. Sailorman was dead right is his replies.

Sometimes it needs a light sand after 5 years or so, if it starts becoming less effective.

Thanks M, light sanding it is, then.
I'm just unsure of what you mean exactly by scotchbrite, because there are different products branded as such (well, down here at least), like some sort of kitchen sponges for cleaning pots, erasers, abrading disks...

 

[MapisM]

@MapisM
Here are a couple of close ups of the sanding of the new CC

Thanks M, a very interesting update indeed.
I'd subscribe to achieving a result comparable to yours - time will tell...

Just one Q, you seem to NOT have CC-ed non-fiberglass bits, any reason for that?
Based on my researches and suggestions received, I had CC applied on just about everything u/w: flaps and their cylinders (piston rods aside, obviously), rudders, P bracket, external part of seacocks.
Essentially, only for the props and their shafts I'm going to use a "normal" a/f (International Trilux, based on yard suggestion).
I'm not holding my breath anyway, but after speaking with someone who is at his third CC-ed boat, he told me that he gave up trying to have CC sticking to props for any meaningful amount of time, so I thought it was pointless to try...