Fri. Jun 14th, 2024


Varnish applied by brush. Amazing results are possible if you follow certain rules.

Please note, this article applies to single part, oil based yacht varnish systems only, two part varnishes are very different.

After more than 20 years of varnishing no end of yachts I am now well placed to share with you the elusive secrets of varnishing. I will teach you how to achieve varnish that not only protects your woodwork but also looks fantastic, flat and glossy as good varnish should.

Most people think they can varnish and it is true that most people can follow the instructions on the tin and produce average varnish but without a good understanding you are likely to be disappointed in the finish, or how long your once fine varnish has degraded so quickly.

First some facts: Good varnish takes a long time to achieve. If someone is claiming that their varnish will solve all your problems with just a few simple coats then they are misleading you. The only way you can get good protection for your woodwork is to ensure that the varnish you put on is thick enough to withstand the harsh environment it finds itself in.

When a boat or any other wooden product for that matter is sold, the manufacturers put the absolute minimum of varnish on mainly to keep it looking good for long enough to sell it. They do not have the time to do the job properly and most people would be horrified at the cost if they did.

On a yacht or any exterior woodwork you must have at least 8 coats and be prepared to add more coats periodically to keep the varnish looking its best. 8 coats! I hear you say. Yes, 8 coats. That is because the first few coats are applied thinned, that is to say mixed with thinners to make them thinner so those first coats can better soak into the wood and ensure that latter coats stay put. So when you further consider that you will be sanding each coat of varnish you can see that in fact perhaps you only have about 4 proper coats for every 8 you put on.

Here’s the best advice I can offer you. If you see that your varnish has begun to die, (you can see this demonstrated by tiny cracks in the surface), then put on another coat as soon as possible. It is a lot easier to put one coat on than it is to strip all the varnish and start again! You would be amazed how often this excellent advice is ignored by my clients. I spend weeks making their boats look fantastic and I always explain that they will need to keep on top of it, yet sure enough I see that they have not taken my advice and the varnish is failing. I shouldn’t complain since I get the job of redoing it again but it is so unnecessary!

For some reason everyone thinks that varnish is a one time effort and that it will last for years. This is a myth. Varnish lasts only months. It depends where you are in the world and how much care you take of your varnish but if you want nice varnish you will have to be prepared to keep it up. The sunshine is what kills varnish the fastest but damp conditions can cause moisture to get under the varnish and lift it too. It doesn’t really matter where you are varnish will still need regular attention.

Varnish degrades slowly so you will have plenty of time to catch it before it’s too late. Modern oil based varnishes all contain UV inhibitors which stop the effects of sunlight from destroying the varnish but they only work for a short while. This is why you need to apply further coats regularly.

Protecting varnished surfaces.

OK, no more lecturing. I hope by now you have understood that good varnish is not a quick thing to do or maintain. Let’s talk about how best to maintain your varnish once it’s done. As I said the weather will quickly wear down the varnish so anything you can do to keep it out of the elements is a good idea. Covers are the best thing you can provide. They might cost you money but in the long term they are a great investment especially if you are short on time as most people are these days. Wouldn’t you rather be sailing? Get covers.

If you don’t want to spend the money on covers but you want to protect your varnish during the winter when you are not using your boat then here’s a cheap trick that will help. Apply cheap masking tape to all your varnish. After some months it will start to lose its stickiness and will start to come unstuck, not so much that it will blow away in the wind but enough that when the sailing season comes around again, you’ll be able to remove most of it easily enough. Those areas that are stubborn can be persuaded to come off with some gentle heat from a hot air gun. Afterwards use lighter fluid or petrol to clean off the dried on glue from the tape. Of course there is an expensive product designed especially for this which is called polywrap. Basically it is the stuff that is put on new cars to protect them in transit.

Surface Preparation

Let’s move on to surface preparation. Let’s assume that the wood is already covered with an old varnish and it must be removed. The fastest and most efficient way is to use a hot air gun and a scraper. Bahco make an excellent range of scrapers on comfortable handles. They have replaceable blades which are not cheap but they work so well that it is money well spent. Put the hot air gun on the low heat and be careful not to leave the heat on any one area, get into the habit of moving the gun around so as to ensure an even heat.

Heat the area in front of the area that you want to strip and use the scraper and the gun at the same time. As you strip one area you will be softening up the area to come and the job will go very quickly. I prefer to use the small triangular scraper that bahco make since the blade is small and strangely enough it is quicker to use a small blade than a big one (unless the surface is a large one) Work always with the grain. This applies to every thing you do to wood, eg: sanding, varnishing etc. Be careful not to scratch the wood with the edge of the blade. You do not need to use much force as the softened varnish will come off easily. If you are struggling try heating the varnish more before you strip it.

After you have stripped the old varnish or paint you will need to sand the wood to remove all traces of old varnish or paint. This is where most people make mistakes. It is easy enough to sand a piece of wood and get it clean enough for varnish but what everyone fails to understand is that the sanding must be done with a block right from the start. The flatter you can get the wood, the better your varnish will look at the end and not only that it will be considerably easier to sand between coats. The extra effort spent getting the surface flat in the beginning will be repaid tenfold.

Let’s look at how to get the surface flat. Wood is an amazing material and as nice as it would be to have a full understanding of it there is no time here for that kind of detail. What you need to know is depending on how the tree was cut will determine the grain pattern on the wood you have. If you can, take a look at the end grain on the wood you are sanding. If the grain is vertical you will find this more forgiving than grain that is horizontal. This grain is in fact made up from summer and winter growths. The tree does not grow much in the winter and this can be seen by the thinner, harder and darker parts of the grain. In the summer the tree grows much faster and this can be seen by the lighter, softer and thicker areas between the winter growths. The summer growth is always softer as it has grown so much faster. The problem for you when you sand the wood is that the summer growth will sand down much faster than the winter growth. If you do not use a block with your sandpaper you will sand the softer areas more than the harder ones. This will leave you with dips in the wood. Perhaps you won’t be able to see this with your eye when the wood is bare but it will become more noticeable as your varnish gets shinier and shinier.

A block can be anything relatively hard and flat. You can buy special rubber blocks which are designed to hold sandpaper firmly while you work. The longer the block the better. The hard backing to the sandpaper means that both the soft and hard areas of the wood remain at the same level.

Depending on the wood, the amount of damage (if any) and the level of finish you want use 80 grit sandpaper and a block to clean up the wood after you have stripped it. Always sand with the grain. In those difficult corner pieces you will still have to sand with the grain and this is very hard. A way to do this is to use a cabinet scraper or a sharp chisel, always remembering that your aim is to keep the surface flat.

Always look at your work, get your eye as low as possible and look across the surface, this will help you to see if the surface is flat. More than just looking, get into the habit of using your hands and fingers to ‘feel’ the surface. With practice you will quickly learn to feel when there is a high or low spot.

I cannot emphasise enough the importance of getting the surface flat. The final quality of the job relies on this fact. 90% of the skill of good varnish is in the preparation.

When you have sanded the area with 80 grit sandpaper, it is time to move on to a finer grade of sandpaper. Now use 120 grit and go over the surface again. The reason you are using 120 grit is so that you can remove the sanding marks made by the 80 grit. Again sand with the grain and either use a vacuum cleaner to suck up the dust or a brush so that you can clearly see what you are doing.

A word on sandpaper. Sandpaper comes in many forms. It is made for different tasks and for machine or hand use. Unless you have a completely flat surface, with no curves I do not recommend using power tools for any aspect of your varnishing. Buy only high quality sandpaper, preferably made by 3M. There is no substitute. You might think you can save some money but cheap paper clogs faster and wears down faster, the worst case scenario is a paper which loses the sand as this can cause problems further down the line when you come to varnish.

For the 80 and 120 grit paper buy the red 3M paper on a roll.

Now that you have sanded your wood it is time to consider the first coat of varnish but before that you need to have a good clean up. Consider not just the area where you are working but also the surrounding areas. When the area is clean you must mask up the work so that when you varnish you make sure you only put the varnish where you want it.

It is possible to varnish without masking everything up but it takes longer and as you will see later one of the secrets of good varnish is a speedy application. If you have to slow down to cut in you will compromise the finish.

Masking tape comes in many shapes and forms but again 3M is the master in this department. I can only recommend the Blue masking tape that 3M make. It is hideously expensive but it can be left on for a couple of weeks and its extra cost will even out in the long term.

Masking tape is pressure sensitive, that means it needs to be pressed into place to ensure it is well stuck. When you have applied the tape it is wise to run a rag over it to ensure that the tape is stuck down right to the edges. If you do not do this you may find that varnish will get under the tape and stick where you do not want it to stick.

When you have a slight curve you should be able to persuade the tape to stick down in one piece but if the curve is tight, such as going around a cleat, then you will have to do it in many pieces. Start in one place and keep adding smaller pieces on top of the piece before it, each time changing the angle very slightly so that you create a clean curve. The advantage of doing it like this is that when you come to remove the tape you only need to pick up one side and it will come off in one piece.

Often it is quicker to remove the fittings before you varnish. It seems like a lot of work but it has many advantages. You will find the initial sanding considerably easier and consequently the quality of your work will be better. If you do not have to slow down to varnish around things you can move at a better pace and again your varnish will be better. Also it is a very good idea to make sure that there is varnish under fittings such as cleats and stanchions since it stops water getting under the fittings. Later when you come to do a follow up coat, you can mask up the fittings happy in the knowledge that they are well varnished underneath.

Once you have masked and the surface is dry and clean you can wipe the surface with alcohol to make sure that any oils which may have risen from the wood will be removed. Any quality yacht varnish will produce good results but there is a clear (no pun intended!) leader and that is Epifanes Gloss Varnish. It is expensive, but no more so than any other quality varnish. It is made in Holland and is the most commonly used varnish in the classic and mega yacht world.

There are many other additives that yacht varnishers like to add to the varnish but I am not a fan of these. In my opinion they thin the varnish too much and lose the shine more quickly than a well applied correctly thinned varnish. The reason people use these additives is to make up for a lack of understanding or error in their varnishing.

There are some products that work well as thinners. For example I love pure turpentine. if you cannot get pure turps, then Stopani make a very good ‘expander’ which is actually for paint but I have found it works extremely well with varnish. It is called 678. Also International make 333 which is similar and works well.

The additive that many people use is Owatrol, by Rustol. It is basically a thin, clear liquid that is used to stop metal rusting. I have also seen it used as a quick fix to cheer up faded gelcoat. However, like most quick fixes it is not wise as months later it will look worse than before as the Owatrol clouds up. If you must use this try a few drips at a time. It does help the varnish to remain workable for a while longer but as I will show you later, you do not need this extra time to work the varnish.

In areas where the day is short and cold you can add an accelerator to the mix to speed up the drying process.

Brushes and technique

It is amazing how good varnish can be even using a cheap brush. If your preparation is good you can get away with a lot. But there’s no denying that a quality brush will do a better job and if you are searching for perfection it is essential.

One of the secrets of varnishing is using the biggest brush you can. That sounds obvious but a bigger brush can hold more varnish in its bristles and putting as much varnish down as possible is very important. Obviously you don’t want sags or runs but you want to put as much varnish as possible on the surface. A larger brush allows a more even layer of varnish to go down.

I can only recommend two brushes for varnishing. One is made from Badger hair and the other is made from OX hair. Visit for the Ox hair and try for the badger hair brushes. These are the best. As I said before you can achieve surprisingly good varnish with lesser brushes, just make sure you buy a pure bristle brush of quality.

A good varnish brush is only expensive if you don’t take care of it and have to buy another. You must get in the habit of cleaning your brushes regularly and well. One reason for dusty varnish is a dirty brush. Varnish is sticky and obviously dust will stick to it. Never leave a brush in a jar of spirits as you may forget about it and the bristles will get damaged. You can buy a clever box, called a Brush Mate. It contains a special impregnated sponge which gives off fumes and stops the varnish from hardening on the brush. These are excellent for the early coats of varnish when cleanliness is not so paramount but it is always worth washing your brush well before attempting the final coats.

When cleaning a brush, use white spirit, fill a jar or container so that it is about as deep in varnish as the length of the bristles on your brush and push the brush down and up a few times to rid the brush of the varnish. Do this for about one minute, then pour the spirits away. Make sure you collect the old spirits for correct disposal later. Do not pour white spirits or any other thinner or brush cleaner down the drains or into the sea as it is very bad for aquatic life.

Repeat the action with fresh spirits and again push the brush up and down for one minute. Repeat this until the spirits remain totally clear in the pot. Now you must remove the spirits. You can buy a special tool that you clamp the handle of the brush in and it spins thus ejecting the last of the spirits. When you have done this start to wash the brush with washing up liquid and water.

Use warm water if possible and rinse and repeat for a good five minutes. Use your fingers to work the soap into the brush. When you are sure your brush is devoid of thinners you can use your spinning tool to eject the water. If you do not have the tool, remove the water by swinging the brush quickly. If the handle is round you can spin it by placing it between your hands and moving them back and forth.

Work the bristles until they are tidy and there are no bits sticking out. Then hang the brush up to dry (that is what the hole in the handle is for!) somewhere clean and dust free.

To be absolutely sure the brush is dust free when you come to use it next you can use a vacuum cleaner.

Many people use foam pads for applying varnish but nothing beats a brush. It is impossible to apply the varnish with a good thickness with a foam pad. Also they cannot be cleaned and must be disposed of which is a terrible waste. A good varnish brush might last you a lifetime if correctly looked after.

If for some reason you have ignored my advice and your brush is as stiff as a board you may be able to rescue it by using a brush restorer. But make sure you use soap and water afterwards to ensure that it is properly clean.


There is no need to go into great detail for the first few coats but you must follow these instructions.

Thin the first coat 50% and allow 24 hours to dry before applying the second coat. Sand very gently the first coat. Thin the second coat with 25% thinners and allow 24 hours to dry. Before I discuss sanding techniques I am going to jump ahead a bit to varnishing techniques since the more evenly and accurately you can apply the varnish after the first couple of thinned coats, the easier you will find to sand the varnish between coats. It is only the first two coats that are thinned like this. After this you want to apply the varnish as thickly as possible using the least amount of thinners. This is the hardest aspect to explain in writing since there are so many variables, the temperature of the varnish, the weather, the age and make of the varnish etc. All I can say is that you should treat your earlier coats as experiments. Try to thin the varnish at 5% and see how you get on. If you find the varnish is too thick and you are spending too long spreading it about, try thinning it a bit more on the next coat. Experience counts here and I cannot share the 20 years of varnishing experience I have with you here. What is important is that you only add the absolute minimum of thinners so that you can apply the varnish easily without the brush dragging.

Obviously the weather will play a huge part if you are varnishing out doors. Your location will have a say in the matter too. In a hot country you might have to start very early in the morning since varnishing in the hot sun dries the varnish too quickly and it is almost impossible to keep a wet edge. In colder climes, you may not be able to start early because everything is covered in dew. The answer here is to use a chamois leather and wipe off the worst of the water and wait until the day has warmed up a bit.

Never use varnish straight from the pot, asides from the possibility of introducing dust to the varnish, it will also allow the thinners in the pot to evaporate and that will make the varnish thicker which means that you will have to thin it more next time you use it. It is wise to use the absolute minimum of thinners once you have done the first few coats. If you thin varnish too much you cannot get a good thickness of varnish on the surface and it will quickly lose its shine.

If you are varnishing a vertical surface start at the top and work down. Work from left to right. Do not try to cover to large an area, the most important thing is to keep a ‘wet edge’ that is to say that if you leave varnish too long, the edge will start to dry and if you want good results you cannot let this happen. So for this reason I recommend doing relatively small areas. For example, let’s say you are varnishing a panelled vertical door on a yacht. It is about 3 feet high and 1 foot across. It has two panels.

The first thing you would do is the inside top edge of the panel, this is because edges always get more varnish and there will probably be sags but don’t worry about that now. Varnish the horizontal beam at the top next, then start on working down. Varnish about 4 inches down on the left side beam, then move to the right and do the first few inches of the panel right across to the right hand side. As you varnish the panel you will catch any sags that may have begun. Quickly go back to the left side and do another 4 inches on the beam, then the panel next to it, and so on. Always varnish the tricky bits or corners a little while before you arrive there so that you can catch the inevitable sags.

A good technique for large vertical surfaces is to apply the varnish with a roller and ‘tip off’ with a brush. Using a roller allows the varnish to be applied very quickly. This enables a wet edge to be maintained.

Varnishing vertical surfaces are notoriously hard to do. If it is possible you could remove the doors and lay them horizontally. It is possible to apply a much thicker coat of varnish to a horizontal surface.

Varnishing a capping rail is a task since you cannot stop! If you want nice varnish you must keep going, using that wet edge the whole time. You can start at the bow, normally the capping is split here by an anchor. If the capping is continuous all around then you have a small problem. Is there a join in the capping perhaps that has a bead of sealant in it to allow for movement? You can stop here. If there are no joins and all the woodwork has been scarfed then you will simply have to decide where to start and stop and accept the fact that there will be a slightly raised edge to the varnish at the place where the beginning and the end join. If possible make the join somewhere where it won’t be seen. If the rest of the varnish looks fantastic no one will notice your neat join.

As I mentioned earlier use the biggest brush you feel comfortable with. Pre soak the brush by plunging it into the varnish, leave the brush for a moment or two for the varnish to penetrate the bristles. Then wipe both sides of the brush on the edge of your pot.

When varnishing dip the brush about 1 inch into the varnish then wipe only one side on the pot, this will force the varnish into the bristles and will ensure that you do not put too much varnish on the brush. Now apply the varnish.

What you are aiming for is an even spread of varnish. Here is the other secret of varnish. This is information you will not find anywhere else! If you apply enough varnish, the weight of the varnish will ‘pull’ the brush lines clean out and your varnish will look sprayed on. It’s as simple as that. That my friends, is pretty much the secret of varnishing! With a good well charged brush you can apply a good amount of varnish but evenly. I’m sure you can imagine that if your varnish is not even and you have heavy areas, they will sag and if you have light areas they will not be protected, nor will they be shiny. A good brush puts down an even coat with very little effort.

The other big secret which follows on from the one above is that it does not pay to work the varnish. What I mean by that is, how many times have you seen someone varnishing, frantically moving the varnish up and down, backwards and forwards, from side to side. You will NEVER achieve good varnish like this. If you can apply a good amount of varnish evenly the first time you do not need, nor is it helpful to work the varnish. While you are doing this the varnish has started to dry and there will be no weight in the varnish left to pull out the brush lines.

If you are right handed you will probably prefer to work from the left to the right. It is important to ‘Lay Off’ the varnish as you go. This is where you join the area you have just varnished with the last area you varnished. You must try to blend the areas. Run the brush from right to left so that the two areas join up. As you cross the line from old to new reduce the pressure on the brush as you go so that as you pass the line the brush is just barely touching the surface and try to lift off as smoothly as possible. You have already applied the varnish, what you want to do here is simply join the areas with a gentle swipe with the brush.

The first time I varnished with the Ox hair brush I was horrified at the lines in the varnish left by the brush. One thing you learn with varnish is that once you have begun you are committed. However if you make a mistake it’s not such a bad thing since if you have to put another better coat on afterwards you simply have more protection so don’t worry about it. What was amazing with the Ox hair was that by the time I had gone full circle I was pleased and delighted to see that my varnish had no lines at all and was as perfect as one could wish.

Do not try to varnish too large an area, it is far better to make more trips to the pot and work along a few inches at a time. When you have gained experience you can do more but as a rough guide, assuming you are working on a 3 inch wide rounded capping, do no more than 6 inches at a time.

The amount you thin the varnish has a huge bearing on the outcome. As I mentioned earlier, the quality of the thinners is important. It seems crazy to me to spend £20 on a tin of quality varnish, only to dilute it with cheap spirits. One thing I have learnt about varnish is that if you do your best with every tiny aspect of the job you will always end up with very nice varnish. But no matter how hard you try you will never get perfect varnish, at least not if you are working outdoors but the more you pay attention to these details the more chance you have of overcoming any problems that do occur.

Now you can apply your first coat. In the early stages of applying varnish you do not have to worry too much about the finish or any dust that may be around. As you progress though, you will have to take more and more care.

Leave the first coat for 24 hours.

Now use some 280 grit 3M Trimite sandpaper. Again I cannot recommend any other brand of sandpaper, this is quality stuff and will save you time and money and will ensure the best possible job. Quality paper clogs less often and the sand on the paper is very even.

Sand lightly the first coat. You do not need to use a block as you only sand very gently this time. The purpose of sanding is to ‘key’ up the surface. This means you scratch the surface of the varnish with sandpaper to create a rough finish for the next coat to stick to. If you did not sand between coats the next coat of varnish may not stick well to the shiny surface.

There are now many varnishes that do not need to be sanded between coats but if you want a good job I do not recommend using them as the finish is never as good as real varnish.

For the next coat thin the varnish about 25% and apply as before.

This time sand a little more thoroughly with 280 grit sandpaper and a block. Do not overdo it. Remember, there is very little varnish on the surface because it was thinned.

Apply the next and succeeding coats thinned as little as possible. Allow 24 hours to dry between coats and sand each coat with 280 grit sand paper and a block.

If you have any sags, do not try and sand them out, instead use a scraper and remove them, then you can sand them after a while when the edges have dried.

After about 4 or 5 good coats you will start to find that the sanding is taking a lot longer each time. This is because each time you sand with a block you are making the surface flatter so you have to sand a greater area.

Eventually you will find that the entire surface of the varnish is being sanded. This is a good sign because it means that the varnish is now even all over and the following coats have the potential to look fantastic. Until you get to this stage you cannot expect perfect varnish. Depending on the wood and your varnishing techniques it may take as many as 8 coats to get to this stage but normally after 6 coats you should be starting to get a great finish.

When you are ready to do the last coat

For that final coat extra special care needs to be taken. The most obvious is the weather. In a hot country start varnishing as early as possible since the sun will spoil your chances of a good finish. Also the wind will probably have got up a bit later too.

There are three things that will really spoil your chances of a good finish, the sun, the wind and dampness. You must choose a day when the weather is good and settled. As an outdoor varnisher I have got very good at knowing what the weather is going to do but you can always check the weather forecast. A good trick is to study the weather up to the day that you plan to do the final coat. Often there is a pattern which you might be able to work around.

You must make sure that your surface and surroundings are clean. The day before the final coat you should remove all the old masking tape and then wash the entire area thoroughly. It’s not enough just to get the hose out. You must wash the whole area with a sponge and soapy water. Then rinse well and chamois dry.

Before you can varnish you must mask up again. If you can do this the day before all the better but if you can’t don’t forget to allow some time to re mask the whole area.

Make sure your brush is very clean. You will always get a much better finish if your last coat is from a freshly opened tin of varnish. Old varnish needs more thinning, so the resulting coat will be thinner, offer considerably less protection and will show up your brush lines. If possible, wait for a week or two before sanding and attempting the last coat. This will allow the coats underneath time to fully harden.

Wipe the surface with a tack rag, these are special sticky cloths that collect any dust that has settled. These are essential. After you have wiped all around you can begin to varnish. By now you will have a clear idea of where to start and where to finish.

Dust settles very quickly on horizontal surfaces so it is wise to keep your tack rag with you and wipe a section just before you varnish and if you get any insects landing in your varnish just leave them until the varnish has dried and wipe them off. You’ll hardly be able to see their little legs that will be stuck in the varnish forever!

When you are done, don’t move about and if possible get away from the area and hope that the wind doesn’t pick up or it starts raining! You have done the best you can.

Some hours later you can carefully remove the masking tape and start to enjoy the comments from your jealous neighbours. Do not leave the tape on too long as it needs to be removed while the varnish is still soft.

Some dos and don’ts

Always sand along the direction of the grain.

Always varnish along the direction of the grain,

Use a block with sandpaper where ever possible,

For the last coat always use a new tin,

Use only a quality brush, make sure it is clean.

Never use varnish straight from the tin. Decant into another container,

Always buy 3M sandpaper. You will save time and money,

Always wait 24 hours between each coat,

Always sand between coats,

Start varnishing as early as possible,

Always use a tack rag.

Avoid windy days,

By admin

2 thoughts on “Varnishing for the best results”
  1. Some good tips here. We are stripping out caprails presently and we have several cases where blistering occurred along the joins where the original varnish was thinner. After stripping and sanding with 80 grit, the wood is still discolored in these areas. How do you go about getting these “brighter”areas to blend with the rest of the capping rail?

    Any advice you have will be greatly appreciated!

    Thank you in advance.


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