Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

It's here.  For my 1st wooden boat build (Chesapeake17LT), I have completed 5th coat on deck & hull.  Instead of fanfare & confetti I have a dilemma.

Varnish has been satisfying, because of the result I have been seeing up until the deck 5th coat last night.  Almost from the beginning of applying this coat, I noticed streaks.  These "pitted streaks" are mostly parallel to the length of the boat (which I'm guessing come from my "dry to wet (horizontal) strokes" from applying the varnish).  

Photos:  It's not clear to me how to post photos here, so here will be my first attempt at trying using the "IMAGE" button in this interface (if this works I'll try to post more):

  • Deck streaks (wide shot)  <----this is a wide shot of the deck w/ some of the streaks
  • If my photo attempt above fails, here is a link which has varnish photos I just took:  Photo Link 

I had not seen this in all the other coats I applied (I would see air bubbles, but they would go away after a few seconds).  Since I saw these "pitted streaks", from near the beginning (just behind the bow), I thought maybe my unused foam brush had particles stuck in it and they were causing these pitted streaks.  I switched to a new brush, but still saw the same effect.  I decided to just push through...I was hoping gravity would help fill these streaks, but no luck there.

So now here I am the next morning.  I'm wondering, "now what?!"

  • I can leave it as is.  I have 5-coats on.  This won't affect performance, or
  • I wet sand (400grit) again and apply a 6th coat. But I wonder:  will I just see these streaks again?

Not really sure what is different with this 5th deck coating.  I've been wet sanding with 400grit sandpaper in between every varnish coat and wiping clean with water (was thinner for the first 3 coats).  Before this deck's 5th coat, I perhaps sanded a little aggressively to remove some runs (drips along the edge which came from the hull coats), but those were fairly localized & only a few spots...these pitted streaks are fairly uniform on the whole deck.  

What To Do??  Any wisdom is much appreciated!! 

11 replies:

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RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

Since my photo attachment attempt didn't work above,  are there instructions for how to post/embed photos in posts?  I've not been able to find anything other than under in the "Forum Guidelines" which say:   

"If you include images in your post, you'll want to use the "Dimensions" field to keep the width down to about 500 pixels.  Anything too wide for the frame will be chopped off at the right."

I have photos on my computer, but the Image button asks for a link/URL, so I uploaded photos to my google drive & then got a link to a photo from there & tried using that. 

RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

Ewwwww .... Sure, you can leave it. But you haven't spent all that time sanding with 400-grit, mopping the floor, etc. to have it end up looking like that

Your 5th coat didn't want to wet the surface very well. That points to some kind of widespread surface contamination on the 4th coat. Almost like your water rinse wasn't completely dry before you started varnishing. Other suspects to check would be your sandpaper, your rags, and anything (or anyone) else that touched the boat.

The only cure I've heard of is to sand it off and try again. This probably isn't going to be a 400-grit sanding to make the surface cloudy and give the next layer some grip. You need to sand the surface smooth, getting rid of those streaks, otherwise the streaks will just print through the varnish layers you put on top of them. I'd try 200 and see if that does it. If not, go coarser as needed and work your way back up to 200. Then you'll need a couple of varnish coats to get back to high gloss.

After sanding, I suggest you go back to cleaning the surface with what worked for you before - thinner. You know how to make that work.

(ps: Sorry, I don't know how to do pictures here either. Your pictures didn't show but the link worked for me.)

RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

   @Chenier:  Yeah, I don't mind doing anything to try and salvage it. And yeah, another coat, as is, sounds like not the thing since I definitely don't want those streaks to print through.  

OK, so for sanding:

  • Starting with 200 sounds good (moving up in grit if needed)
  • Would this be wet sanding?
  • Try by hand, sanding block?

And then yeah, fine with moving back to thinner and better with cleanliness.  

Thank you!!

RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

Try this link for posting pictures:

May be this is still th right way to go.


RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

( RE:  photos---->@ruud:  Ha....there you go.  The links I used didn't end in .jpg (i.e. Google Drive).  Actually it is hard for me to find photo sites I use which have links which end with .jpg.  So I'll need to look into that...but thank you for sharing!  This was exactly the type of info I was looking for!)

RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

>> Starting with 200 sounds good (moving up in grit if needed) / Would this be wet sanding? / Try by hand, sanding block? <<

The point of wet sanding is to wash the sanding dust out of the sandpaper as you go along to defer as long as possible your need to replace the paper. Fresh varnish is fairly soft and will clog up paper real fast. It takes about a week for it to get hard. So, yes, I'd start with wet sanding.

What you want to do here is find the gentlest means possible to get a smooth surface. You don't want to eat into the good varnish already on the boat any more than necessary. And these layers are really thin (or had better be!) On the continuum of hand sanding - sanding block - random orbital sander, hand sanding is going to be gentlest. Increase the intensity as needed. Don't kill yourself with hand sanding if it isn't getting you anywhere.

RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

@Chenier:  Thanks!   
I've learned my lesson with sanding...the pre-varnish sanding w/ orbital had me take a few spots down to the fiberglass.  :( 

So yeah, will definitely try to be gentle. Just went through sanding with 220grit in a sanding block on the entire deck (this is wet and with same paper the whole time).  Still see the streaks.  :(

On to a 120grit wet sandblock to the deck and we'll see how that goes.  Thanks for the guidance & wish me luck!  

OH:  I'm guessing I want to sand to completely remove the streaks (vs taking material off but still seeing the streaks....and hoping varnish fills/eliminates the streaks).

Additionally, I hadn't said how the weather is.  I'm in the garage and the temperature is around 95degF (learned epoxy work is HARD when it's hot).  Ha.


RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

   UPDATE:  After wet-sanding w/ 120grit, still saw some streaks (but also removed some).  Since I was afraid of going down to 80 grit, I opted to do another pass with the 120.  After this I wetsanded the deck with 220 & finally 400.  

It was ultimately hard to see the streaks (but it was cloudy and had marks from sanding).  

I just finished apply varnish.  I was very particular about stroke technique and was mindful of how it went after completing every section.  It was stressful!  Ha.  

Overall it does look much better (but it is easier to apply varnish with the cloudy surface.  I plan to do atleast another varnish coat.

Side Note:  Unfortunately, during the sanding I did today I had my garage door open (because it was in the mid-90s & hot.  So I need some air to cool things off.  But I am now seeing that this brought in the bugs. I just went out to check the boat and counted about 5 bugs who met their demise in my varnish.  I was hesitant to try and remove them.  I ended up grabbing some forceps and tried to remove as much from them as I can.  I guess I'll have some more sanding to do to remove the bugs.  
@Chenier:  Thanks for the help with this!

RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

Or you can just consider the bugs to be future fossils and leave them to help future archeologists date exactly when that neat boat they found in the mud under the old river was built. Between the bugs and pollen, they'll be able to even figure out the day of the week that you varnished it.

BTW, varnishing on a hot summer night in the garage with the door shut not only attracts mosquitoes who probably interpret the wet varnish as stagnant water to lay their eggs in, but when you start closing the overhead door it dumps a load of dust into the varnish. Guess how I know this.

Sometimes you have to remind yourself that after 2 trips to the river, the varnish will no longer be perfect anyway, and from 5 feet no one will be able to tell and that people will be so impressed with a real wooden boat instead of one of those clorox bottle jobs that it all won't matter.


RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

Yeah, mercy, what Laszlo said.  It's a boat, not a Martin guitar, for pity's sake!  <;-)


RE: Varnish: Another Coat Or Leave It? Seeing "Pitted Streaks"!

@Laszlo:  Ha ha ha!  Love it!  That is totally true!  I happened to watch '93 Jurassic Park last night & those bugs in my varnish look like mosquitoes in amber! ;)  And yeah, I have kept my garage the cleanest it's ever been in this varnishing epoch...except for yesterday when I was melting from sanding all day in the heat.  Anyway, totally right about not dwelling so much on certain things---it's been a total learning experience! 
@Gramps:  It does look like a guitar though!  But Laszlo's right, it'll be different once I get it out there & give it some "character"!  

Anyway--while I wait for the coat from last night to cure/dry, I'm getting all decking & cockpit jobs prepped/staged.  Hoping to complete by tomorrow---now I just need to get a paddle & find some water (destination in mind already).   

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