Swirls and sanding...I don't want to miss a step

Hi there,

 So I've now applied what I hope will be the last coat of epoxy.  This is after sanding and sanding down to 120 the previous coats of epoxy.  I re-applied a very thin coat and now will sand with 220 grit to get rid of all the final little bumps and be ready for paint/varnish.


I just read this however in one of the website help topics:

"Remember, any wooden surfaces that are to be displayed under varnish must be sanded up to 220 grit prior to applying epoxy and fiberglass to eliminate the swirls caused by the sander."


I can't remember, because it was years ago when I was working with the bare wood (literally years)...but I DOUBT seriously that I sanded the wood with 220.  I probably sanded it with 120 grit.  I just can't remember.  


My question is, have I screwed myself on this one?  Will any varnish end up showing a huge number of swirls and craziness?  It doesn't look swirly when wet...nor does the epoxy show that many swirls (because of the last coat).  

I suppose there is no going back at this point so what is done is done, but it will have some bearing on whether I paint the hull or have a bright finish for the whole thing.


Last question for now:  After I've epoxied and sanded the hull and combing down to 220, is it time to paint/varnish?  Or am I forgetting some kind of step in between.  I assume the deck fittings are put on after the paint/varnish, as will be the seat/knee braces/carry toggles/bungie/etc.  I guess maybe I'm just so amazed that I might be nearly done with sanding and epoxying I can't believe I'm ready to move on to finishing.  What am I forgetting to do?





12 replies:

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RE: Swirls and sanding...I don't want to miss a step


I've done it both ways and not gotten a swirly. I think that warning applies to bad sanding technique.

If you're happy with your sanding job, you're ready to go with the varnish. The one thing you might want to do is to take it out for a quick spin to make sure that there's nothing that needs to be changed. After all the work of getting a a nice varnish finish, think of how much it would hurt to have to cut through it or sand part of it off to glue something on.Better to find things that need changing before the varnish goes on.



RE: Swirls and sanding...I don't want to miss a step

I, too, have been confused by seeming conflicting info about epoxy and sanding issues.  The Kaholo manual warns that the final sanding before glassing should be with 220 grit to avoid a scratched cloudy finish but the article "Don't oversand" in the Shop Tips says that a too smooth surface will not bond well with the fiberglass.  On page 52 of the manual we are told that no more than two costs of epoxy are required to fill the weave latter on page 61 the manual says it takes a total of three coats to fill the weave.  It is not clear if the earlier 2 coats means 2 coats after the initial wetting down or two coats in total.  The manual goes on to describe the proceedure for the skim coat.  Is this one of the three requrired to fill the weave or an additional coat ?


p.s. It would be helpful if the manual would be a little more specific about how much epoxy to mix for each stage (what is a "sizable batch" p 47 ?).   

RE: Swirls and sanding...I don't want to miss a step

Hey Rabbit,

As much as I respect Nick Schade for his boat designs and amazing workmanship, he's out to lunch with his warning about the bonding. Don't get me wrong - his sanding advice will give you a superb boat and eliminate unnecessary labor, so by all means do follow it. However, when it comes to epoxy and raw wood bonding, there's no problem with a #220 finish. The fact is that raw wood has open pores that suck in the epoxy and yield a lot of surface area for bonding, even after having been sanded to #220. In addition, epoxy bonds chemically to the lignin in wood.His bonding advice is more in line for a non-porous plastic, like PVC pipe. But based on what his completed boats look like, you can't go wrong following his advice anyway.

As far as the number of coats go, that depends on how thick the coat is. I routinely use 5 coats to fill the weave, but that's because I apply very thin coats. The thinner coats save epoxy, prevent runs and minimize the required sanding. So instead of worrying about the exact number of coats, concentrate on the results and use what is necessary.

The sizable batch also depends on the individual builder. Depending on the skill level, the exact type of work, the hardener speed and, most importantly, the temperature, a sizable batch can be from 3 to 12 ounces. After a bit of experience you'll know what you need.




RE: Swirls and sanding...I don't want to miss a step


    How do you apply the epoxy in such thin coats, I used a roller wich put on a rather thin application but left a very rough surface? At this point Im looking for hints for a second boat as Im varnishing my first. Shoul be done in about a week.


RE: Swirls and sanding...I don't want to miss a step

I use the yellow thin nap roller covers sold by CLC to apply the epoxy. After I've rolled on a few square feet (exactly how many depends on the temperature), I tip it out with a disposable foam brush to get rid of the bubbles. This is for the fill coats, not when wetting out.

For a 16LT, I typically used 3 oz of epoxy to coat the entire hull exterior. It took about 4 for the WD12. It's impossible to get runs with that little epoxy. It also looks as if nothing is happening, but be patient. By the 4th coat it's ready for the first sanding with #220. With coats that thin I don't sand with coarser paper, but without the drips, I don't need the coarser paper. The sanding knocks down the weave and and bubbles that the tipping may have missed.

If there are any glossy pits left, then the boat gets another coat of epoxy (2 if the pits are deep) and another sanding. This is repeated until the pits are gone and the boat is a uniform smooth dull finish.

At the risk of sounding like a shill for CLC, I've found that their rollers and brushes work better than the ones from the Home Despot.


RE: Swirls and sanding...I don't want to miss a step


 3-4 oz's of epoxy for an entire hull exterior? Am I reading that right or is that for the "few square feet" you refer to?

I'm getting ready to 'glass my MC16.5 and am a bit shocked at that number/amount. I like the benefit of the reduced "runs" however.

Correct me if I'm wrong please,

These thin coats are AFTER the 'glass has been wetted out with epoxy and a squeege?



The Ranger


RE: Swirls and sanding...I don't want to miss a step

Hey Ranger,

That's for the entire hull, exterior only, deck not included, after the glass has been wetted out. Told you they were thin coats :-)



RE: Swirls and sanding...I don't want to miss a step

As you may have figured out Laszlo is an artist with epoxy.  My kayak is covered with drips and runs and varnished right over.  I wanted to get on the water, to H with the finish.  So, I do not have much to add about making it light and beautiful but I will say this.  If you wet the surface and everything looks good chances are it will look just as good or beter under varnish.  Besides, its to late now so why sweat it.  Its a boat, its going to get scratched.  The important thing is to get you in it and the water on the other side. 

 Happy paddling.


RE: Swirls and sanding...I don't want to miss a step


Not an artist, just good with thin coats. The artist is the guy who win the awards, which isn't me. As far as paddle rather than sand, I'm right there with you. This last O-fest was the first one where I showed up with varnished boats. The rest of the times it was bare epoxy, some with drips and bumps. There's a lot to be said for wet paddling instead of wet sanding. And you're dead on about the scratches. Any boat that doesn't need to be refinished at the end of a season is unloved :-)

See you on the water,



RE: Swirls and sanding...I don't want to miss a step

DAMN!!!  If that is the case Laszlo, then my yaks are truely loved, they dont make a whole season. LOL


RE: Swirls and sanding...I don't want to miss a step

They are called beauty marks by some!

I spread fill coats with a chip brush and squeegie.

Foam rollers and epoxy are harder to master and no matter how slow I rolled still had to tip off.

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