Linnea Sailing - Epoxy and Coppercoat

April 7, 2021
5:22 pm
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Applying Coppercoat!

In this post we will cover our tips and tricks for actually applying the Coppercoat. Coppercoat is applied to the hull all layers in one day. So we gathered friends and family willing to help (thank you, you are heros!), bought a lot of snacks, and spent a whole day painting. Preparing the barrier coat, with all the sanding, new thru hulls, and painting the final patches, took about two weeks, and once all the preparations were done, it was just a matter of finding a weather window that promised good and non-rainy weather for at least 48 hours. Before starting we had made sure to paint and sand the barrier coat of the entire hull, except for two patches under the keel (which she was standing on). Once the Coppercoat was painted we had the crane guy helping us move Linnea a bit so that the keel was supported on two new spots. These two spots were then painted with barrier coat, sanded, and painted with Coppercoat together with the other remaining spots.

Update Nov 13, 2021:
The epoxi treatment we did in 2020 failed due to a series of unknown events and had to be redone in 2021. This post about how we applied the Coppercoat still applies and contains some good tips if you are to do this yourself. If you are doing an epoxi treatment, or just have a general curiosity for boat stuff, we really recommend that you read our summary about the epoxi failure and what we learned, described here. Since we now have applied Coppercoat twice, this post has been updated to add some additional tips (italic notes).

The waiting time and time frames described in this post correspond to the instructions given for the specific barrier coat we painted with the first time. When we did the Coppercoat the second time, over the new epoxi which works in a different way, the time frames changes. If you are about to apply Coppercoat to your own boat, talk to Coppercoat directly! They are great and will help you get your the right waiting times and time frames for your project.

Enjoy 🙂

Why do you need good weather?

As strange as it may seem, the Coppercoat is actually water-soluble until it has cured. This is a good thing in one way, because you can wash all the brushes, trays and rollers in freshwater once you are done. But when doing the Coppercoat application outdoors this means that you really need to find a good stable weather window, where it is just warm enough (too warm will cure it faster than you can paint), just damp enough, and definitely no rain! We were pretty lucky with the weather and didn’t have to wait too long for a good window. For extra safety it is recommended that you make a “skirt” of tape once the painting is done, in case any moisture or water starts running from the deck or hull, to prevent it from reaching the Coppercoat. We had long since stoped using the water aboard so that we wouldn’t by misstake wash greasy hands and have greasy water running down the hull for instance. So Swedish summer night dew was the only potential water we needed to care about when we did the first painting session. Other was it when we did the keel and the stands. Swedish summer weather is not always to be trusted and on the same evening as we had made the second painting we actually got a real squall passing by. We protected the newly painted areas with extra tape skirts and lids from storage boxes, and luckily everything turned out ok.

Painting

Coppercoat is applied by painting several coats wet on tacky. How much Coppercoat that is needed is calculated depending on hull shape, width and length of the boat and draft. Depending on how thick you make each layer the paint will be enough for 4-6 coats. For our 40 foot we ordered 11 liters of Coppercoat and saved one of them for the rudder, under the keel and the 4 patches under the stands (which were painted later).

The plan was to have 4 people painting at the same time so that’s what we ordered rollers and roller shafts for. In the end that was not really how we best did it, so we changed and ended up being 2 people painting with the normal size rollers (20 cm) and 2 people holding the trays and alternating painting with a smaller roller (10 cm) in the tight and tricky places. This last part is not something that is described in any of the guides we found but something we really think made it easier. Having someone holding the trays and stirring the paint in it from time to time made the application less stressful and more even. Also, buying a few smaller rollers that could reach the tricky parts (like inside the bow thruster tunnel, around the keel and thru hulls) made the application in these spots a lot easier. We also used a painting brush to push some paint into and around the thru hulls.

Update Nov 13, 2021:
In 2021, when we did the application again, we could not get hold of the same rollers as used the first time. Instead we got a tip to use thin, but long, ultra fine mohair rollers (15 cm) for the entire application which we think actually worked out much better. First of all, they were not as heavy to paint with, and secondly there was less waste product left in each roller when throwing them away. Even though it is pretty hard to say, it also felt like it resulted in a smoother surface.

Around the rudder tube we spared 5 cm that were not painted so not to risk galvanic corrosion on the rudder shaft. We also decided not to bother with the smaller stuff like strainers and the bow thruster (drive and prop) and just save these for the second painting together with the remaining patches and spots. Being outside meant that we did not have the same condition on both sides. We had quite a sunny day and that meant that one side was warmer than the other and cured faster. It was also a difference depending on who painted, so we made sure to rotate who painted which part with each coat. All in all, we managed to cover the hull with 5 coats of paint and at least it looked like it got even all over.

Sanding

There are a lot of dfferent instructions on how the Coppercoat should be sanded. As we understand it, the instructions differ depending on what area (and hence what kind of water) the Coppercoat is sold and used in. Sanding the Coppercoat was one of the hardest jobs we did this summer, and it probably took about 40 hours to finish the job. It was hard to know when the surface was sanded enough but we found a pretty good image at Coppercoat US’ website with example patches. Based on that information, the image to the right shows the 3 “stages” in the sanding process, non-sanded, almost there, and done. We used 320 and 400 grit sanding pads. We started by using the more coarse pads and then got the final finish using the finer ones. This was the only way for us not to run through millions of sanding pads. The Ace HD kind we used before is not developed with this grade of grit, which meant that we needed to use sanding pads not suited for such a tough surface and the copper would eat up the sanding pads really quick. It is supposed to get harder the longer the time is between the Coppercoat curing and sanding, but since we were outdoors it was hard to decide when we could sand or not. Maybe it would have been easier if we could do it earlier. Update Nov 13, 2021: It actually was easier to sand when doing it in the “5-days-window”. The second time we sanded on day 5 and 6 and could really tell a difference on how long you could get before each sanding pad was dead. This time we also got the tip to use Scotch-brite pads on the orbital sander and sand it with a spray of water. This speeds up the process since you activate more copper while removing less material. This way, the surface does not end up as smooth as when it is sanded, and therefore we used 400 grit sanding pads to run the hull over with as a complement before using the Scotch-brite pads. For the small and tricky parts, like the bow thruster drive and prop, the thru hulls, under the keel, and the sharp angels on the rudder, we used a Scotch-brite to rough up the surface. If needed we finished off with some of the finer grit sanding pads. The rudder and under the keel was the last part to be painted and sanded and once done we were ready to relaunch! Our biggest summer project was finally done, it took a lot more time than we had anticipated, but hopefully we have painted and sanded the hull enough for at least the coming 10 years. In May we will hull out again to check on the result and to see if any part needs some touch up. Update Nov 13, 2021: It feels like such a punch in the face to read the above paragraph now that we know that we had to do it once again, spending another summer up on the hard. But it must really be noted that the issue was not with the Coppercoat! Unfortunately there was no way of saving the Coppercoat since the issue was in the epoxi underneath to which the Coppercoat had bonded really well. When we hauled out, there was not a single barnacle, and all we had to do was to wash it clean with water.

Why did we choose Coppercoat?

The main reason that we decided to go with Coppercoat is the low maintenance and the long durability. Yes, it is very expensive to buy and it took a ridiculous amount of time to get done… BUT, if we only need to do this every 10-15 years it will be a lower cost per year than traditional anti-fouling. In fact, in 5 years the cost will already break even and that is excluding the cost of hauling out every year to repaint. We also believe that there is an environmental benefit in not having to haul out every year to sand and repaint, which otherwise would have been the case here. All we are supposed to have to do with the Coppercoat is to wipe it down with a Scotch-brite once in a while. Fingers crossed this will work out great!

Applying Coppercoat