Totem’s Coppercoat application

Coppercoating Totem’s hull was a thrilling prospect, but pressure to do the application correctly gave me more anxiety any boat project in memory. The product features are substantial: a strong environmental case (nothing toxic ends up in the water, as with conventional antifouling paints), and solid financial value (the epoxy bottom should last for many years, a significant savings). But long term success relies on nailing the application. We did NOT want to screw this up.

Totem started from bare fiberglass bottom (no gelcoat) because a prior owner peeled it, presumably to resolve a blister problem. A clean gelcoat surface is best, ahh… if only! Our process to prep the hull, detailed here, took 18 steps. It also took a lot of ibuprofen! Honestly? This was the hardest part of the entire transition, because Coppercoat cannot be applied over existing bottom paint (every last bit of old antifouling must be removed) and the surface must be smooth. To understand why a smooth bottom is important, you must first understand a little more about Coppercoat.

The British Navy first used copper sheathing in the 18th century to mitigate marine growth. It was a miracle. Skipping ahead from wooden warships to fiberglass recreational boats, copper is still an effective method of deterring marine growth. That sheet form nailed to the bottom is a little problematic, though, so clever people worked out you can mix it into paints instead. Unfortunately, still problematic – the paint sheds, by design, which adds all kinds of nastiness into the water while losing effectiveness. Enter Coppercoat: pure, fine copper powder suspended in water-based epoxy.

Once applied and cured, the final step is to sand the surface to expose copper from within the epoxy. When done applying, sand the surface to expose copper from within epoxy. If the surface wasn’t smooth before Coppercoat, the final sanding will yield inconsistent copper exposure. Totem’s bare fiberglass bottom took much more work than a Coppercoat-over-gelcoat application.

Starting the second coat: not pretty yet. Not at all.

Although applying Coppercoat isn’t complicated, each step needs attention. Getting the application right is key to product success, and we felt that mixed reviews we read online stemmed from improper applications. Coppercoat provides a lot of information to help you get it right, from the UK company’s directions to Coppercoat USA‘s retailer’s six-page list of “do’s and don’ts” with additional tips and tricks. Phone support from the Coppercoat team in the UK helped us to get it right and mellowed my nerves.

Coppercoat epoxy kits consist of three parts: a container of resin, another of catalyst, and a bag of fine copper powder. Coppercoat UK directed us to also add isopropyl alcohol (must be 90% or greater) to add, thinning the mixture.

  1. Mix resin and hardener parts thoroughly
  2. Add isopropyl alcohol (four or five capfuls for the first two coats, five or six in later coats)
  3. Add the copper powder and stir until evenly blended

The mixing was easy: one kit at a time. It took three kits for coats one and two, four kits for coats three and four.

Application is a multi-person job for all but the smallest boats. On Totem, it required three: one person to mix and two people to roll it on. The mixer must monitor while rollers are busy applying, to ensure copper is not settling to the bottom of the container. With Mairen and Siobhan helping, we had four people; that gave one person a chance to rotate out for a spell, or freed someone to get drinks or sandwiches.  We did the work in early December at Cabrales Boatyard in Puerto Peñasco, where Totem rested for months to dry out wet fiberglass.

Application morning

We’ve never done this, never seen it done, and really didn’t want to screw up. Cabrales Boatyard’s manager, Salvador, has been there / done that with Coppercoat. He provided great support, helping us get rolling (sorry…) on application day. In reality it’s quite simple, but his presence and advice took the pressure off us Coppercoat newbies.

Humidity is highest at sunrise, so even in arid Puerto Peñasco (hello, Sonora desert) we waited for the sun to lower overnight dampness, warm our bones and warm the boat. A perfect time to clean the hull in final prep, right? We initially planned to do a wipe-down with isopropyl alcohol. Jamie had just wet the first rag and was wiping it at the bow when I had a chat with the Coppercoat folks in the UK who said – stop! They directed us to just do the dry wipe instead, and said that ideally, we’d have washed the boat with plain water and allowed it time to dry. We were out of time for that, but a dry wipe was sufficient.

Salvador Cabrales helped us mix to ensure that we were doing it right.

Rolling proceeded steadily. Each subsequent coat was applied over the last before it dries, “hot coating” to provide a chemical bond. At that point, the surface is tacky: that is, it’s still sticky, but no material comes off when touched. If any material comes off, it’s still too wet! With two people rolling full time, we completed one coat on the hull at just the right time to start a second coat. That’s great, although a break might have been nice…

The product mixer’s role – Mairen owned this! – included topping up the trays used by those rolling it on, and watching their timing in working through the product. If we had to wait for the next kit to kick, we risked falling behind and having product on the hull dry too much for hot coating.

Sisters working together: touching up around exterior fixtures

We’re lucky it wasn’t hotter weather in Puerto Peñasco, as that could have caused the epoxy to kick faster and made our task more complicated if we couldn’t keep up. If a coat dries, you default to physical instead of chemical bonding on the next coat: the first must cure, then get roughed up, then the application process can resume.

Initial coats go in more thinly; later coats were thicker, as the tacky layers beneath softened the application layer and grabbed more paint. These later coats used substantially more paint than the first. It was exciting to see Totem go from looking like a boat with a bad rash to a glittering metallic hull.

Application complete! This was one very long day. It was hardest on Jamie, who rolled for the duration. Although all four coats were applied to Totem in a single day, the project took a week in total. Three days were needed to cure before Totem could be lifted to move keel supports and jackstands to coat previously uncoated areas. Then, those areas need to cure before final sanding and launch.

Jamie supervises while Siobhan applies coppercoat under areas covered by jackstands.

Nearly four months in, we’re really happy with the bottom. It’s performing as hoped, and I wish the water here was clear enough to show it off better.

Next: what it costs, why it’s a good value vs. antifouling paint, DIY vs. professional, and how the bottom looks after several months in a high-growth area.

Preparing Totem for Coppercoat

Two girls talk next to a sailboat on a hardstand.

 

Coppercoat’s advantages in durability (=savings!) and environmental friendliness (=how we live!) have made me more excited about antifouling than I believed possible. As if to complete the picture, Totem’s shiny new metallic hull is dazzling in the Sonoran sun. Once sanded to activate the copper the hull will oxidize to rich shade of verdigris, but for now it is stunning. Applying Coppercoat was an intense day of work, and an even bigger effort to prep. Researching our options confirmed how critical good prep is for this unique antifouling to be effective: here’s what we did, and why.

Two men scrape paint off the bottom of a sailboat
Jamie and Rudolpho tackling the bottom in June

  

Prepping for Coppercoat: two people examine the hull of a boat on a hardstand.

1. Stripped. Bottom paint and barrier coat were stripped to bare fiberglass last June, shortly after getting hauled in Puerto Peñasco. Totem didn’t have gelcoat left, the surprise that greeted us after blasting decades of accumulated bottom paint in Grenada. We painted on paint stripper, and scraped it off; not a perfect job of paint removal, with some visible bits in the valleys of Totem’s not-very-smooth hull, but sufficient for the summer. Boats with different substrates (e.g., gelcoat, metal hulls, etc.) get different prep.

2. Dried. From June until November, Totem’s wet hull dried out on the hard in the Sonora, Mexico. That’s Sonora, as in The Sonora Desert, where heat and low humidity provided an ideal climate to dry out during the summer months. Elsewhere (like the US east coast, or mainland Mexico, or further south) would have taken many months longer or required additional equipment (e.g. heating pads) or both.

Hull moisture meter readings were around 25% when we left. Eight blue-tape boxes were masked off to ensure repeat readings were in the same location; during our five months away, Cabrales Boatyard manager, Salvador Cabrales, would take periodic readings. He’d write the new measurement on the blue tape, then send a photo of it for us to see. Great peace of mind on progress while we were remote! The readings were at 6% to 7% at the end. During the drying period, the boatyard pressure washed the bottom to remove glycol, the sticky byproduct of a Polyester / Vinylester resin and a wet hull, that migrates to the surface as the hull dries.

 

A man writes on blue tape affixed to the hull of a boat.
Salvador updating measurement on the blue-tape reading area
Excel chart showing hull moisture readings declining over time
Homeschool bonus: charting the readings over time
Moisture meter showing reading.
Lower every time!

3. Stripped again. Totem’s bare hull was a rough surface, with flecks of paint remaining in the crevices. Brushing on paint stripper (we used Aquastrip) softened the remaining paint, which came off completely with a pressure washer.

Man brushes paint stripper on a boat.

 

Man powerwashes the bottom of a sailboat.

 

4. Sanded. The entire hull was sanded with 80 grit. After a full day of holding a vibrating sander mostly at or above shoulder height, Jamie hired a couple of guys from the yard crew to speed the job along and save his back.

Man in tyvek suit and face protection sanding a sailboat hull.
These guys helped a lot, but Jamie’s basically been in pain at night for a few weeks. 

  

5. Epoxied. If you’re at bare fiberglass, like Totem, the substrate (fiberglass) is porous and rough. After was wash and acetone wipe down, one coat of West system epoxy went on. When it was tacky, a second coat of West System with 410 micro-balloon filler to thicken the mix to work towards a smoother surface. Adding another layer of epoxy on top of a tacky prior coat is called hot coating: this creates a chemical bond between layers. The alternative is curing between coats and replying on roughing up the surface for a physical bond.

Three people measuring up epoxy to roll on a boat.
Mairen and Siobhan help mix up epoxy

 

6 – 9. Cured, sanded, washed, then wiped with Acetone. Epoxy was given a few days curing time before sanding. Sanding the thickened epoxy coat greatly improved substrate smoothness. Washing the hull got rid of the dust, and wiping with Acetone prepped for the next layers of epoxy.

 

Two people wipe rags on a sailboat hull while wearing heavy gloves
Wiping on acetone. Every once in a while need to demonstrate that I am not just behind the camera! 

 

10. Epoxied again. Several times actually: three coats of West System (two with 422 barrier coat additive) were applied to Totem’s hull bringing the total to five layers of epoxy, minus the 80 grit sanding.

Man in respirator with sander working on hull.
Looking pretty shiny after all the West Systems was applied! Fashion by Goodwill of Phoenix.

 

Siobhan uses a sharpie to mark rough spots that need more sanding; evening guard, Federico, looks on.

 

11 – 14. Cured, sanded, washed, and wiped with Acetone…again. Very intimate with the surface area of Totem’s hull at this point.

Drying the hull after a last rinse before the barrier coat went on.

  

15. Barrier Coat. Three coats of Interlux Interprotect 2000 were applied over the West Systems. Interlux recommends five coats, but with five prior coats of West System (including two with barrier protection additive) we feel confident that the combined eight coats will serve.

Three people work together to apply Interlux barrier coat to a sailboat hull.
Barrier coating as a family affair: Mairen stirs, Jamie and Siobhan roll on.

  

16 – 18. For the third time: cured, sanded (lighter, much lighter), and wiped down– but this time, no acetone! The hull was dusted with rags instead to remove debris from sanding, and leave a surface primed for Coppercoat. For future Coppercoaters, we have done even better to gently pressure wash one or two days in advance.

Consumables list – I’m probably forgetting something:

  • gloves – decimated a box of 150, plus a half dozen heavy-duty pairs for paint stripper
  • 80 grit disks – 175
  • 320 grit disks – TBD
  • paint brushes – 4
  • 3/8″ roller covers – 10 (Interlux Interprotect 2000)
  • 1/8″ roller covers – 6 (West System epoxy)
  • Acetone – 3 gallons
  • blue tape – 1 big roll
  • rags – large bag of clean, lint-free rags
  • mixing sticks – 20
  • spreaders – 10
  • Aquastrip  – 5 gallons
  • West System – 4 gallons for 5 coats, plus 410 filler and 422 additive
  • Interprotect 2000 – 7 gallons for 3 coats

A note on safety equipment:

Toxic stuff is all over this project. One of the reasons we’re excited about Coppercoat is how environmentally friendly it is, compared to alternatives, but getting to that point is not – really, a lot of boat work is pretty nasty, and this prep is no exception. Take care of skin, eyes, and lungs!

My friend Kate Laird (Check out her expedition sails and homeschool expertise!) called out safety kit shortcomings in some pictures posted, and she’s right. We should be better about how we’re protecting ourselves, and I also seemed good at capturing moments when we weren’t! Here’s an equipment list to help with planning ahead, with products we like.

Kate Laird from Seal expedition sail sanding paint on her boat's hull.
Kate- or is that Hamish? Or one of their teenage daughters? Working on the hull of their expedition vessel, Seal.

Respirator: Jamie and Kate both like this 3M 6200 half-mask. Bad luck was the straps on Jamie’s broke just before we started. You can get replacement straps and other parts – it’s one of the nice things about the respirator.

These reusable respirators have filters for particular matter (these pink ones) and VOC fumes (white ones here). Hot tip from Kate: keep the VOC filters in a ziploc bag to extend their useful life. They actually keep filtering away in there!

Jamie decided to try these disposable Moldex-Metric respirators this time. They were easy to source, lighter weight, and relatively comfortable. However, they’re really for “nuisance levels” organic vapors vs. fumes of OSHA PEL standards.

Skin protection: Tyvek jumpsuits are the standard, and they did get modeled around Totem, but the Goodwill in Phoenix turned out to be a good place for quick, affordable cover-up (50% off on Saturdays, and help from the Jollydogs crew picking things up for us!). We needed a few warm layers, anyway: we were NOT PREPARED for cool weather here in the late fall, and didn’t have clothes for it. Jamie’s happy: he hasn’t had a single day of gritty itchy boatyard yuck.

Eye protection: Jamie wears glasses but adds goggles over them when he’s worried about exposure. We picked up inexpensive eye protection in a hardware shop in Peñasco that worked fine for the girls. For more souped-up protection, this full-face respirator (3M 6700) Kate recommended is gold standard: big, single lens for easy viewing.

Further note on toxic junk, and being outside the US: I don’t know if there are any standards for the toxic waste produced in boatyards but the practices here mean we’re doing work that wouldn’t be handled the same way in the USA. Some things can be addressed by individual boaters, with some planning ahead. A shopvac using HVAC filters to capture and dispose of dust off sanders (Jamie’s got a bag on his that he’d empty regularly, and dispose – amazing how much of that stuff comes off – but no special filtering). You couldn’t just paint on stripper and pressure wash it off on a hardstand spot like we are, but set up for catchment and hazardous waste dispo…no, actually, you probably couldn’t because there’s probably not a hazardous waste facility. In the US, you’d stage the boat for this at a place where runoff is captured. For the most part, our lives are an incredibly light footprint environmentally: every once in a while, they’re really not.

Totem has 12 coats of epoxy right now. TWELVE. OK, so some got sanded off in the process, but even if we lost a couple of coats – it’s a long way from the bare fiberglass that peeked out when we blasted at Grenada Marine last year.

Coppercoat application: next post.