Varnishing difficulties.

[BAD ORCA]

I'm trying to teach myself how to varnish. I have a lot of teak on my boat exterior i want to varnish, so thought i would start with some simple projects to get the hang of it.

I bought a liter of Le Tonkinois Original varnish a decided to start with my cockpit table. I sanded the table to 400 grit, smooth finish, cleaned it well and applied three coats so far sanding between each coating. From a couple feet away the finish looks amazing. I'm really impressed so far, however if you look at the finish at an angle in the light, there are countless little tiny what look like microbubbles evenly disbursed over the entire finish. Its not settling dust, i noticed the formation of them immediately after i 'tipped' the surface. It almost looks like micro air bubbles like you see in some epoxy coatings rising to the surface while it cures. Im using a decent synthetic brush but certainly not a great brush. Its probably a $15-20 Home Depot 'Purdy' brush. I'm working in 75degree low humidity shop, perfect conditions.
I tried taking a picture of the surface but its really hard to see what im talking about from the pics. The camera males it look more like pinholes. Is this problem common and due to using the wrong brush or technique, or is this common for this particular varnish? I have seen pics from people who use this varnish and their surface looks like glass. I dont really need a perfect glass finish, especially for a cockpit table, but i'd like to get it a little better for the exterior teak.

Thanks for any insights.

 

[Sailor Sue]

I can't really tell from the pictures, but it sounds like it might be surface contamination under the new finish. Did the table have some sort of finish before you varnished it? After you sanded it did you wipe down the surface with a solvent? Teak is very oily and should be wiped down with acetone before re-finishing or gluing.

Do a Google search on "fish-eye" or silicone contamination and finishing. Depending on how much it bothers you, your only recourse might be to sand it all off and start over.

 

[dlochner]

Like you, I have been working to improve my varnishing techniques. Some of the things I've learned are not all that obvious. More or less in order of sin.

1. Do not use the edge of the can or container to squeeze extra varnish out of the brush. Doing this introduces tiny bubbles into the varnish. The varnish dries before the bubbles have burst and the varnish flowed to fill in the bubble. Let the varnish drip from the brush or if the container is deep enough gently press the bristles against the side of container. If you see any foaming or bubbles, you are pressing too hard.
2. Radically thin the first several (2-4) coats of varnish to a 50/50 mixture of varnish to the appropriate thinner. It is best to match the thinner and the varnish from the same brand.
3. Keep the wood at a constant temperature or let it cool as the varnish dries. When wood is heated it will off gas with the gas forming bubbles that do not flow out. If wood is cooling, it will form a partial vacuum which will tend to draw the varnish into the wood. This is more important in the early coats than the later coats after the wood is well sealed.
4. Use a natural bristle brush. Better brushes will yield better results with practice, however, I've gotten decent results using a cheap chip brush.
5. Just like the old joke about how to get to Carnegie Hall, practice, practice, practice. Take your time and pay attention to what you're doing, it will take time and experience to develop technique.
6. Newer varnish formulations are easier to work with than old school varnishes. Le Tonkin's is an old school varnish loved by traditional boat builders. My current favorites are TotalBoat Lust for a finish that will build up like traditional finishes and TotalBoat Halcyon, a water based finish that is exceptionally easy to work with and clean up. Both allow recoating after about an hour without sanding between coats. Up to 5 coats a day can be applied. I've been using clear halcyon on interior surfaces. The finish looks more like a high quality furniture finish than a deeply varnished finish.
7. Always use gloss varnish. If you want a matte or semi-gloss finish, apply one or two coats of the softer finish at the end. Semi-gloss varnishes have a flattener in the mix, multiple coats of which will result in a cloudy finish.
8. Be mindful of the varnishes tint. Many varnishes have an amber tint that looks good on some woods and not others. The prior owner of my boat varnished parts of the interior with an amber tinted varnish (poorly applied) over the cherry wood work. It is is ugly.

Good luck!

 

[BarryL]

hi,

I agree that the varnish needs to be thinned. More for the first coat, less for subsequent coats. You also need to pour the varnish from the can into a jar or bowl before using it. After the varnish has dried, if it looks good do VERY LITTLE SANDING. Otherwise you are just removing nice varnish.

Note: Epiphanes is the only varnish I have used.

Barry

 

[dlochner]

@BarryL reminds me, do not pour the varnish from the can. Ladle it into a small clean container. Pouring makes a mess of the can and can introduce bubbles into the varnish. I use a ¼ cup measuring cup or a 1Tbsp measuring spoon for smaller jobs. Ladling reduces bubbles and makes thinning to a percentage much easier. Finally do not put any left over varnish back in the can! With practice you'll get good at estimating how much varnish to ladle out for any job.

 

[jssailem]

Varnish work is tricky. Success comes from:

• Choice of chemistry (varnish)
• Starting surface
• Application techniques
• Conditions during application
• Acceptance of imperfections
• Time allotted to the project

I can see the tiny bubbles you describe. They appear to me to be solvent evaporation. The previous surface was not cured before you applied the next coat. I’ve not used the varnish you describe. I would examine the manufacturer’s requirement for cure before applying next coat. Your cleaning solvent may not have completely evaporated before you started to apply the next coat

I watched a worker at the Mystic Seaport Museum Shipyard applying varnish in the open dock area to the bright work of a boat being restored. Conditions were open to environmental contamination, 83 degrees,
full sunlight. Application tool a cheap foam brush. He stated he wished he had a quality brush. Varnish was Awlgrip. He said the shop applies the product hot (surface is dry to touch, not tacky) so no sanding required between coats. 2-3 coats per day.
Standing 2 feet apart at the gunnels of his boat the bright work looked great. No bubbles of contaminates were evident. I was a bit surprised as the work place was exposed to the environment.

To address your project first assuming the bubbles are unacceptable, you need to strip the table back to bare wood. You might explore another varnish product. I have been getting good results using Total Boat varnishes. Follow the instructions regarding application, cure time for each coat, sanding between coats, cleaning of sanded surfaces, use recommended cleaning chemicals, allow dry time after cleaning so that all solvent is evaporated.

Best of luck with your project.

 

[BarryL]

Hey,

Here's how I learned to varnish.

I am not an expert and I hate varnishing but it does look nice.

Before

After

 

[RitSim]

A between coat tip. After the varnish has dried, you can wet sand the flat surfaces with 400 or higher grit. This keeps the sandpaper from blinding and gives an excellent starting point for subsequent coats. Be sure to wipe carefully/correctly to remove sanding residue and remaining thinner. Let dry and wipe again.

 

[dlochner]

Varnish work is tricky. Success comes from:

• Choice of chemistry (varnish)
• Starting surface
• Application techniques
• Conditions during application
• Acceptance of imperfections
• Time allotted to the project

I can see the tiny bubbles you describe. They appear to me to be solvent evaporation. The previous surface was not cured before you applied the next coat. I’ve not used the varnish you describe. I would examine the manufacturer’s requirement for cure before applying next coat. Your cleaning solvent may not have completely evaporated before you started to apply the next coat

I watched a worker at the Mystic Seaport Museum Shipyard applying varnish in the open dock area to the bright work of a boat being restored. Conditions were open to environmental contamination, 83 degrees,
full sunlight. Application tool a cheap foam brush. He stated he wished he had a quality brush. Varnish was Awlgrip. He said the shop applies the product hot (surface is dry to touch, not tacky) so no sanding required between coats. 2-3 coats per day.
Standing 2 feet apart at the gunnels of his boat the bright work looked great. No bubbles of contaminates were evident. I was a bit surprised as the work place was exposed to the environment.

To address your project first assuming the bubbles are unacceptable, you need to strip the table back to bare wood. You might explore another varnish product. I have been getting good results using Total Boat varnishes. Follow the instructions regarding application, cure time for each coat, sanding between coats, cleaning of sanded surfaces, use recommended cleaning chemicals, allow dry time after cleaning so that all solvent is evaporated.

Best of luck with your project.

Just to be clear about the wood's temperature. The absolute temperature is less important that the change in temperature. A rising temp will cause the wood to off gas, a falling temp will create a partial vacuum that draws the varnish and gasses back in. This is the same dynamic that causes varnish to lift off wood exposed to the sun. Drying time can be adjusted by increasing the amount of thinner added to the varnish, in hot temps, more thinner is needed to prevent the varnish from drying prematurely.

The finish on the table looks fine as a substrate. There does not appear to be any lifting or cracking, thus it is not necessary to remove all the finish. Do sand out the bubbles with some 220 grit paper and remove all the dust.

The majority of boats at Mystic are not being finished to yacht quality, like you might find at a Hinckley shop. At least the ones in the yard now, Virginia, Armistad and the other large boats being maintained or restored are work boats if they pass the 10' test that's good enough. A few flaws in the finish and no one will complain. Now at Hinckley, that would be another story.

Mystic Seaport Museum is an outstanding organization. Last month I spent 4 nights in the museum and was able to spend time with the Chief Shipwright in the yard. Especially in the morning and evening, one really gets the feeling of living in an 18th and 19th century sea port. Next year they are opening a 60,000 square foot exhibit of more contemporary boats. Currently some of those boat are scattered across the museums grounds. If you are in the area, spend some time there.

On our way out, we passed by Groton and came face to face with this guy. Guess who blinked?

 

[BAD ORCA]

I can't really tell from the pictures, but it sounds like it might be surface contamination under the new finish. Did the table have some sort of finish before you varnished it? After you sanded it did you wipe down the surface with a solvent? Teak is very oily and should be wiped down with acetone before re-finishing or gluing.

Do a Google search on "fish-eye" or silicone contamination and finishing. Depending on how much it bothers you, your only recourse might be to sand it all off and start over.

It had Cetol previously. I scraped the cetol off with metal scrapers, sanded the teak with #120, #220 and #400 sandpaper then cleaned a couple times with alcohol before coating. The first coating i did did not have this problem.

 

[BAD ORCA]

Like you, I have been working to improve my varnishing techniques. Some of the things I've learned are not all that obvious. More or less in order of sin.

1. Do not use the edge of the can or container to squeeze extra varnish out of the brush. Doing this introduces tiny bubbles into the varnish. The varnish dries before the bubbles have burst and the varnish flowed to fill in the bubble. Let the varnish drip from the brush or if the container is deep enough gently press the bristles against the side of container. If you see any foaming or bubbles, you are pressing too hard.

Good luck!

Thanks Dave. Good stuff. I was wiping the brush several times after dipping against the side of can. I read this in another forum last night and think this may be part of the problem. I will try again today NOT doing this and see if it makes a difference. Might also switch to a natural brush. Have a few lying around.

My table has this amazing slight cherry red color. The picture i posted looks brown, but its not really that color. If i can get the rest of the teak that redish color i would be very happy. Its what i imagine teaks perfect varnished color before ii even began. fingers crossed.

 

[BAD ORCA]

Varnish work is tricky. Success comes from:

• Choice of chemistry (varnish)
• Starting surface
• Application techniques
• Conditions during application
• Acceptance of imperfections
• Time allotted to the project

I can see the tiny bubbles you describe. They appear to me to be solvent evaporation. The previous surface was not cured before you applied the next coat. I’ve not used the varnish you describe. I would examine the manufacturer’s requirement for cure before applying next coat. Your cleaning solvent may not have completely evaporated before you started to apply the next coat

I watched a worker at the Mystic Seaport Museum Shipyard applying varnish in the open dock area to the bright work of a boat being restored. Conditions were open to environmental contamination, 83 degrees,
full sunlight. Application tool a cheap foam brush. He stated he wished he had a quality brush. Varnish was Awlgrip. He said the shop applies the product hot (surface is dry to touch, not tacky) so no sanding required between coats. 2-3 coats per day.
Standing 2 feet apart at the gunnels of his boat the bright work looked great. No bubbles of contaminates were evident. I was a bit surprised as the work place was exposed to the environment.

To address your project first assuming the bubbles are unacceptable, you need to strip the table back to bare wood. You might explore another varnish product. I have been getting good results using Total Boat varnishes. Follow the instructions regarding application, cure time for each coat, sanding between coats, cleaning of sanded surfaces, use recommended cleaning chemicals, allow dry time after cleaning so that all solvent is evaporated.

Best of luck with your project.

I realized after reading this that i did sand and wipe the surface with isopropyl alcohol to get the sanding dust off and did varnish it fairly quickly after that. I wonder if the alcohol seeped into the previous surface a bit and was evaporating? I figured alcohol would be the most mild solvent to clean it with but maybe not. I will try today without wiping with alcohol. Le Tonkinois recoat is 24 hours and the surface is very hard so i think my recoat time is ok.

 

[BAD ORCA]

Hey,

Here's how I learned to varnish.

I am not an expert and I hate varnishing but it does look nice.

Before
View attachment 228159

After
View attachment 228160

That looks great! I'll give that video a watch after work.

 

[BAD ORCA]

Just to be clear about the wood's temperature. The absolute temperature is less important that the change in temperature. A rising temp will cause the wood to off gas, a falling temp will create a partial vacuum that draws the varnish and gasses back in. This is the same dynamic that causes varnish to lift off wood exposed to the sun. Drying time can be adjusted by increasing the amount of thinner added to the varnish, in hot temps, more thinner is needed to prevent the varnish from drying prematurely.

I have been doing my coatings early in the day and they sit all day in rising temperature. Its 70 in the morning and 85 by afternoon so could be a factor also. I might wait today until later in the afternoon.

My step Dad worked on the Navy base in New London on Tridents when i was teenager. Mom used to take me down to the sub docks to look at all of them. Pretty cool stuff. I moved to west coast but really miss that part of the New England coast.

 

[JoeWhite]

I am not an expert, but I watched YouTube showing that the bubbles are caused by the air trapped in the brush bristles. Must expell the air by dipping the brush in the thinning agent and flexing it multiple times until no bubbles are seen coming out of the brush. I, too, was not able to completely eliminate the bubbles.

 

[Joe]

Even though I abandoned the path of varnishing enlightenment years ago, I brought many of its techniques to my current preference (Helmsman Spar Urethane) Therefore, my experience reflects what the others have said, so I'll just add that I always use a "tack cloth" for final wipe down just before applying each new coat. Also, I second Dave's comments, especially: "It is best to match the thinner and the varnish from the same brand". In other words, don' t be cheap when you purchase your thinning solution and other additives.

 

[BAD ORCA]

Even though I abandoned the path of varnishing enlightenment years ago, I brought many of its techniques to my current preference (Helmsman Spar Urethane) Therefore, my experience reflects what the others have said, so I'll just add that I always use a "tack cloth" for final wipe down just before applying each new coat. Also, I second Dave's comments, especially: "It is best to match the thinner and the varnish from the same brand". In other words, don' t be cheap when you purchase your thinning solution and other additives.

Thanks. I have not been thinning it yet. Le Tonkinois apparently does not need to be thinned according to their website because it has a lot of natural oils in it. I may order some anyways just to give it a try if i cant figure out whats causing my problems.

 

[jssailem]

I figured alcohol would be the most mild solvent to clean it

The Total Boat HALCYON WATER-BASED MARINE VARNISH. I would use Denatured alcohol (only on bare wood, or after 24 hours). Being water based it is compatible with alcohol.

For oil based varnishes you need a different solvent.

• synthetic resins dissolved in petroleum solvents similar to mineral spirits. Mineral spirits for cleaning and thinning if needed.
• acrylic resins are used in water based varnishes. Denatured alcohol to wipe bare wood. Clean up with water and soap.

 

[capta]

Of course, all the info is important, but from my experience, it's about preparing the wood.
Any old varnish must be completely removed and the surfaced and sanded smooth, around 400 grit. Then a teak cleaner, I like "Snappy Teak-Nu Two Step Teak Cleaning Kit" best, but be careful, the stuff is dangerous. Wear safety glasses, gloves, and protect painted and metal surfaces from teak cleaner.
After cleaning the teak, the grain will have risen again, and it needs to be sanded to around 400 grit a couple of times, then repeating with 600 grit until it is very smooth. As above, use a tack cloth after every sanding. You do not want to varnish over sanding dust!
At this point I put a couple of coats of clear wood sealer on, thinned on the first coat. Sand to at least 600 after the clear wood sealer has dried. Now your wood is sealed from the elements, and you have something to varnish to.
Now is the time to thin the varnish (I prefer Pettit Z-Spar Captain's Varnish 1015) at least 50/50 or even more.
See above posts from here, just remember to sand between each coat, using a finer grit each coat after you are at the working strength. Sometimes full strength varnish just isn't possible, so don't feel any instructions on thinning are binding.
Below is varnish done aboard Skipping Stone at anchor. The before & after on a dorade and the helm seat, which was just too complicated to do well, in the time we had.

 

[jssailem]

I like your thoughts, @capta. I have a dorade resembling the "dorade old box 1" image.
Maybe I can get it to look more like the reflection image in time.