Finishing with Spar Varnish


Like the epoxy, marine spar varnish provides protection from the elements and adds to the finish. Unlike epoxy it goes on thinner but provides a great amount of UV protection which will prevent the dye from fading and the epoxy from becoming cloudy, hiding the beautiful grain from the wood.

I used a high end Pettit Z-Spar 2015 Flagship marine spar varnish.


Before I was ready to varnish I had to sand down the epoxy, knocking down and bumps and providing a good surface for the varnish to adhere to.


After sanding I wiped the surface with a rag and some mineral spirits. Like epoxy dust is bad and will ruin your finish, I cannot stress this enough.


The process of application is similar to epoxy. With the varnish however I applied it and tipped it off with a natural bristle brush.

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First coat done, two more to go. You need to let the varnish dry 24 hours between coats.


Another round of sanding. This one is done more lightly as the surface is becoming more smooth with each successive coat.

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Two down, one to go.

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The final product after 3 coats or epoxy and 3 coats of varnish. After a year or two I will need to sand and apply more coats to repair any micro scratches and to replenish the UV protection.


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  • Glenn

    Has anyone modify this design for a 5 x 8 ?


    • Most people I have seen stay with a 5′ X 8′, however I think I have seen a custom trailer instead of the Northern Tool. With that said I see no reason why you couldn’t modify it for a different size trailer as long as you plan your cuts accordingly.

  • Jeff

    Hi Ryan,

    About the varnish, I’m wondering how long you waited for the epoxy to cure before applying. Also how long did you let the varnish cure before adding the doors and windows?


    • I let the epoxy cure overnight and that seemed to work fine, you may wish to wait a full 24 hours but that isn’t really necessary. The epoxy will be solid with no tackiness to it. When that happens its ready to sand.