Because of illness and other issues this past year I let the varnish go somewhat. Poor varnish makes the boat look terrible and a cracked and flaking finish allows water to get to the underlying wood where it will turn black and further add to, what I call, "the handrail of shame."
Because I retired from BoatU.S. at the end of last year I'm hoping that I have more time to spend not just using the boat but catching up with some much needed maintenance. The engine and mechanical systems are all well cared for but some of the external surfaces could do with a freshening up, hence the varnishing job.
Ideally, it's a good idea to add a refresher coat mid-season to build up the surface finish that is lost to UV degradation. But for the reason outlined above plus the restrictions imposed by the Covid-19 crisis, that did not happen, so I now find myself with a rather large job on my hands. Initially I had thought that I would be able to get away with taking the bad sections down to bare wood and recoating the other parts but no sooner had I made a start I realized that this was not going to cut it – all the existing varnish has to be removed and taken to bare wood so I can make a fresh start.
Removing varnish is best achieved with a scraper. My prefered tools are those by Sandvik, they have carbide blades and remove many layers of varnish swiftly without damaging the underlying wood. If you are doing this job yourself don't be tempted to think you can sand off the finish, it takes too long, uses tons of abrasive paper, creates clouds of dust which will annoy your boat neighbors in the ajoining slips, and is liable to damage the wood. Please invest in some scrapers, it will be both cheaper and way faster in the long run.
I removed all the varnish from the handrails (75 linear feet in all) in an afternoon and as you can see in the picture this comes off as a satisfying shaving rather than clouds of dust.
So, you may ask. Once I have got all the old coating off what do I do next?
Varnish, simply put, is paint without the pigment. It protects wood from sun, sea, wear and tear and if it makes the wood look good in the process, that’s a bonus. My first attempts at varnishing were embarrassing but they did the job of protecting the wood and each application gave me the opportunity to do it better than last time.
Varnish is a mix of resins, oils and solvents, although newer varnishes often have synthetic materials blended in to improve flow characteristics. Choose one type of varnish and stick with it. Don’t dismiss a varnish too quickly just because you’re not getting the finish you desire; it could be down to temperature, high humidity or dust.
Tools For The Job
The one essential tool is a decent brush. While modern varnishes are forgiving in terms of technique, they’re very unforgiving of the wrong brush. Never use an inexpensive synthetic brush for varnishing: the bristles will come out and it’s unlikely to have sufficient body to hold enough varnish. Many professionals use high-quality badger- hair brushes; these have excellent flow characteristics and can produce spectacular results. However, I’ve become a big fan of foam brushes and I know some pros who use them almost exclusively. They don’t shed hairs to mar the finish, and they seem to hold just the right amount of varnish. Most beginners lay on varnish too thickly, and in warm weather, this leads to 'alligatoring', when wrinkles appear in the varnish and make the results look like alligator hide. Foam brushes tend to prevent this. Avoid cheap foam brushes because the shanks often break. The biggest advantage of foam brushes is that you can just toss them at the end of the job. Pure bristle brushes require meticulous cleaning, before and after use and should be wrapped in foil to keep the bristles straight.
You’ll need plenty of clean, lint-free rags for wiping down the woodwork and cleaning up. A vacuum cleaner with a brush attachment is perfect for sucking up sanding dust.
You’ll also need abrasive paper. Lots! Cheap sandpaper is a waste of money: the grit falls off as soon as you look at it, and it wears out very quickly. I favour an aluminum oxide paper that cuts fast, lasts a long time, and comes in all grits. Buy 80 grit for sanding bare wood, 120 for sanding the initial thinned coats and 320 grit for sanding between full-strength coats.
Tack rags are valuable for picking up those last bits that get missed by the vacuum cleaner and solvent wipe. Keep them in a resealable bag to prevent them from drying out and getting dirty.
Preparation
It’s easy to feel overwhelmed by the amount of work that lies ahead. If you break the job into manageable tasks, it's less daunting. You might varnish the toerails one day, then move on to the handrails the next.
Working outdoors is often not the best place to do brightwork, especially if the guy next door is pressure washing. If you can, remove parts from the boat so that you can varnish under cover in a controlled environment, such as a garage or workshop. Hatch covers, washboards and cockpit tables can all be worked on indoors when
the weather is less than ideal. Try to varnish on a warm day with little wind and plan to have few interruptions.
Read the instructions on the can, which will give important safety information and tell you which solvent to use. Don’t use any old paint thinner; use only the solvent recommended by the manufacturer. Never use varnish straight from the can. Decant the amount you’ll use in about 15 minutes into a clean container, pouring it through a fine-mesh paint strainer.
A deep gloss finish is achieved by filling the pores of the wood, so the initial coats need to penetrate and seal the wood. The recommended method is to thin the first coat to a 50/50 ratio with thinner. Add thinner to your decanted varnish and stir very gently with a clean stick. Allow the varnish
to rest for any bubbles to disperse. Dip your brush about one third of the way into the varnish, then tap it lightly on the inside of the container to knock off the excess before brushing onto the wood. Keep the brush moving, and don’t overbrush the varnish, a mistake known as 'worrying'. Three or four stokes should be all that’s needed before you move onto the next section. Make sure the wood is coated fully but not dripping wet; the extra solvent you added will ensure that it’s absorbed into the wood. Leave it overnight. The next day, sand the surface lightly with 120 grit paper, then repeat the varnishing procedure but this time, thin the varnish by 25%; it will be noticeably thicker, and less will soak into the wood.
Leave these two initial coats to sit at least 48 hours before laying on the first full-strength coat. This gives time for the solvents to evaporate and the varnish to harden. You can apply additional coats without sanding, but I don’t recommend it; imperfections will be magnified by each subsequent coat.
Sanding knocks off any rough spots, smooths raised grain, and allows the third coat to go on without a hitch. Sand lightly with 120-grit paper. Don’t rub too hard or you’ll go right back to bare wood. If the varnish rolls up into a gummy mess, it needs longer to harden.
After sanding, it’s essential to remove all the sanding dust. Use a vacuum cleaner with a brush attachment on the work and adjacent areas to remove as much dirt as possible, then wipe down everything with a rag lightly dampened with solvent. Turn the rag often to avoid spreading dirt from one area to the next. Decant some fresh varnish into a clean pot through a strainer but before starting to apply the varnish, lightly wipe the surface with a tack rag to remove the last remaining specks. Wipe an area just ahead of where you’ll be varnishing. For example, I’ll wipe about 3' (1m) of toerail, then leave my tack rag at the point that I stopped wiping. Working toward the tack rag, it’s easy to pick it up and give the next length a quick wipe as I progress along the boat.
Good quality foam brushes are an excellent choice and I like them. You simply toss them out at the end of the job.
Brush Technique
Think of laying on the varnish rather than brushing it on. We’re not painting a fence here: we’re on a journey to a smooth, mirror-like gloss. Varnish should be applied with a slow, deliberate stroke. Grip the brush like a pen and draw it across the wood, laying down a uniform coat. If needed, you can use two or three extra sweeps of the brush to distribute the varnish. Finish by drawing the brush from the wet area to the dry along the grain. Reload the brush and apply varnish to the next section of wood, 'landing' the brush just into the end of the wet edge. Repeat the process until you reach the end of whatever you’re varnishing. Occasionally sight along the work with your head almost touching the surface. If you spot areas you’ve missed or you see runs, make a note of them for touch-up with the next coat. Don’t try to fix things now, because varnish starts to skin up remarkably quickly; trying to touch up at this stage will only make things worse. Five or six full-strength coats is the minimum to provide UV and wear protection, though eight or nine is better for that deep, luxurious gloss.
I use 320 grit paper for inter-coat sanding.
Sanding And More Sanding
For the perfect finish, you must sand between each coat to improve the glossiness; omit the sanding and each coat gets progressively rougher in both look and feel. Sand between coats with 320-grit paper backed with a cork sanding block for large flat surfaces, changing the paper as soon as it starts to lose its cut or become clogged. After sanding, remember to dust, wipe with solvent and then go over with the tack rag before applying the next coat.
The results after 8 coats of varnish using the techniques described. (Click on the image to make it larger)
Thank you for this helpful post. I will keep reading your post.
Posted by: Oliver Jane | March 11, 2021 at 06:40 AM