Copppercoat patch in

[TwoCan]

Just pulled the old girl out for annual bottom scrub, we are copper bottomed. Just around the bow thruster, the fibre glass has started to peel away. Not a big patch but needs seeing to. Happy to fibre glass the area but any ideas on how to then patch in the copper coat.? Some one has suggested mix coppper powder with marine epoxy. Don’t really want buy a complete tin of copper as we are not due to be renewed for another 7 years

TIA

 

[Canopy Locked]

worth giving Copper coat a call - found them very helpful when I was doing my 2nd boat with CC. The copper material should last quite a while if it's kept properly and the resin is not so expensive to ditch once finished. Worth remembering that you'll need to rub back more than just the patch that's coming away so that you get a good repair.

 

[AllanG]

Coppercoat can supply a small tin, think it’s 1 litre, for touching up repairs.

 

[Hurricane]

We are re-Coppercoating this week.

Just get yourself some fresh Coppercoat.

First - do your F/G repairs.
Rub down the area concerned to provide a key.

Coppercoat comes as a "two pack" - you just mix the two pack and add the Copper that also comes with it.
Mix enough for one coat.

Then after mixing - get someone to keep mixing it.
Then apply with a roller - wait for it to go slightly drier than "tacky" and add another coat
Keep going for 4 coats.

Don't worry about overcoating the old Coppercoat - just make sure that it was rubbed down to crete a key before re-Coppercoating.

Well, thats what we are doing now.
And we did the waterline exactly like that last year which looked fab when we lifted earlier today.

 

[Bandit]

I am not sure what your boat is, but have good look around the bow thruster tube on the inside of the hull for movement and stress, you may have more of a repair than you expect.

Basically you take a well laid up hull cut two large holes in it near the keel line and it allows the boat to flex in that area with the only hard point where the BT tube is glassed and pasted in.

Many bow thrusters are poorly fitted and inadequately laid up inside and outside the hull. There should be a reasonable “Blister” on the outside to allow enough glass and mat to make a good connection. Some you see the outside of the hull is flush with little if any blister.

 

[FenderPhil]

we have a hardy seawings 355. thank you - we have had it expertly checked and there does not seem to be any movement. just a patch about 4inches long around the top . I will get some images and post them later

 

[Elessar]

We are re-Coppercoating this week.

Just get yourself some fresh Coppercoat.

First - do your F/G repairs.
Rub down the area concerned to provide a key.

Coppercoat comes as a "two pack" - you just mix the two pack and add the Copper that also comes with it.
Mix enough for one coat.

Then after mixing - get someone to keep mixing it.
Then apply with a roller - wait for it to go slightly drier than "tacky" and add another coat
Keep going for 4 coats.

Don't worry about overcoating the old Coppercoat - just make sure that it was rubbed down to crete a key before re-Coppercoating.

Well, thats what we are doing now.
And we did the waterline exactly like that last year which looked fab when we lifted earlier today.

All agreed!

I would add: use 80-100 grit to sand thoroughly to provide a good key.
If using a mini roller do 5 coats.
If you must use a brush in a corner then stipple don’t brush (brushing sends all the copper to the bottom and it doesn’t t work)
If you’re not in Spain use a hairdryer to speed drying so you can get the coats on before it goes off I’m the pot.
And don’t forget to leave lots of time before launch. At least 5 days in the uk. Prob 3 for you Mike.

Also.....
You can get 1/2 litre pots and it keeps if frost free.
If it goes off the white pot splits like month old milk and it’s obvious.

 

[MapisM]

Thanks Hurricane & Elessar, interesting reading.

Btw, since I had the boat CC-ed last year, you might be surprised by my interest in patching the hull.
But as it happens, upon lift I found a few marks on one side of the bow, where the CC layer detached from the hull, showing the gelcoat underneath.
The largest one is around the size of a 1 Eur coin, with a dozen of others much smaller - like a finger nail, or even less.
They are all below the static w/line, just about in the position where the hull cuts the water while planing, and concentrated in a small area.
So, my guess is that those marks are due to some floating object, solid enough to chip the CC layer but luckily not enough to damage the hull surface.

Have you ever seen that happening, by chance?
And most importantly, your suggestions above are valid also for small patching like these, I suppose?

 

[Elessar]

Thanks Hurricane & Elessar, interesting reading.

Btw, since I had the boat CC-ed last year, you might be surprised by my interest in patching the hull.
But as it happens, upon lift I found a few marks on one side of the bow, where the CC layer detached from the hull, showing the gelcoat underneath.
The largest one is around the size of a 1 Eur coin, with a dozen of others much smaller - like a finger nail, or even less.
They are all below the static w/line, just about in the position where the hull cuts the water while planing, and concentrated in a small area.
So, my guess is that those marks are due to some floating object, solid enough to chip the CC layer but luckily not enough to damage the hull surface.

Have you ever seen that happening, by chance?
And most importantly, your suggestions above are valid also for small patching like these, I suppose?

Look at the back of the bit that flakes off. Is it copper coloured or gel oat coloured. The answer to that changes the reply.....

 

[MapisM]

Look at the back of the bit that flakes off. Is it copper coloured or gel oat coloured. The answer to that changes the reply.....

I perfectly understand the logic behind your question, but I'm afraid I can't give you a definitive answer.
I fact, I only noticed the chipped bits after the boat was lifted and powerwashed, and I didn't think of looking around to see if the bits that flaked off had possibly been removed by the powerwash, or if they were older.
Fwiw, around the chipped parts, the CC layer still appeared strongly attached to the gelcoat.
But at the same time, the gelcoat under the flaked off CC didn't look damaged at all...
And sorry, I also didn't think of taking pics!

 

[Elessar]

I perfectly understand the logic behind your question, but I'm afraid I can't give you a definitive answer.
I fact, I only noticed the chipped bits after the boat was lifted and powerwashed, and I didn't think of looking around to see if the bits that flaked off had possibly been removed by the powerwash, or if they were older.
Fwiw, around the chipped parts, the CC layer still appeared strongly attached to the gelcoat.
But at the same time, the gelcoat under the flaked off CC didn't look damaged at all...
And sorry, I also didn't think of taking pics!

Ok the reasons the cc might fall off the gelcoat are contamination eg from grease, insufficient abrasion during prep or solvent entrapment if putting it over solvented epoxy or over a repair.

In all those cases wash with hot soapy water and abrade well then do as Mike said.

If the gelcoat itself failed it could be an air bubble in the layup or osmosis. Poke the hole with a spike. If it’s solid just do as above. With a bit of filler if needed. Allow time for the solvent to come out of the filler (days).

If it’s soft it could be very localised failure. Dig it out, fill and do as above.

If there is any smell of vinegar, different rules apply.

 

[Hurricane]

Just for the record.
We don't actually need to recoat but for another reason that I might post sometime, JW has to be out of the water for about a month.
Her Coppercoat will probably need doing in a couple of years so we though now would be a good time to get it done.
That way, it will have lots of time ti cure before relaunching.

We are doing the job ourselves.
Bought some cheap orbital sanders.
I've been sanding all day today.
I'm knackered.
The paid hand that I commissioned is still at it.
Sun setting now.
Should be doing the CC next week.

 

[MapisM]

Ok the reasons the cc might fall off the gelcoat are contamination eg from grease, insufficient abrasion during prep or solvent entrapment if putting it over solvented epoxy or over a repair.

In all those cases wash with hot soapy water and abrade well then do as Mike said.

I will re-check better before patching, but in all the very small bits where CC flaked off, the gelcoat underneath looked perfect and solid.
So, if you think that hitting a floating object is not a possibility (which was my guess just based on the localized area, and the distribution of the chipping, which has a sort of longitudinal pattern), I suppose it's bound to be a bad hull preparation in those particular spots, for any of the reasons which you mention.
Thanks again!

 

[Elessar]

I will re-check better before patching, but in all the very small bits where CC flaked off, the gelcoat underneath looked perfect and solid.
So, if you think that hitting a floating object is not a possibility (which was my guess just based on the localized area, and the distribution of the chipping, which has a sort of longitudinal pattern), I suppose it's bound to be a bad hull preparation in those particular spots, for any of the reasons which you mention.
Thanks again!

Very possible. I forgot mechanical damage as a reason!