Inset letters : Spar urethane outdoor signs

How To Finishing
1

Can I get any recommendations for finishing techniques for these two slabs? Both are going outdoors and I’m wanting to put on spar urethane.

Any experienced people want to give me an insight on how to apply it successfully? I see online some dilute with paint thinner and wipe on? Result like that better? Don’t mind spending extra time on more layers while learning.

My concern is the inset letters (3-4mm) and the “brothers” sign is right off the sawmill and not smooth. How am I going to avoid drips?

Any input appreciated!

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3 Likes
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Nice project, not sure what you mean when you say you’re worried about drips and the letters? I have not mixed or thinned spar urethane but assume it would be applied as other urethanes? I the wood is not planned then you may need to thin the urethane out more so it will penetrate rough finish vs just wiping on a smooth surface.

I’m sure others will chime in.

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Seal it with dewaxed shellac before coloring the letters to contain the color.
It stops bleeding along the fibers outside the letters.

Let it fully dry ( 24hrs + )

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4

Whenever I’ve used spar urethane, I’ve gone with Varathane spray.
Apply it in light coats and build gradually until you achieve the finish you’re aiming for.

The link is just for reference—you can typically find it at any big box store.

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It won’t have bubbles? Just bought the can - will practice both on a different piece. Thanks all for recommends!

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You’ll likely run into some bubbles and dust nibs after each coat.

The can suggests sanding between coats with 220 grit, but I find that a bit too aggressive.

I’ve been lightly going over it with 400–600 grit instead—it’s gentler and still evens things out without cutting too deep into the finish.

Definitely worth practicing on scrap first—helps dial things in before committing to the real piece.

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