Hi all, I mostly make things for indoor use. I recently made this outdoor signage for a friend and within a day or two the water got in and is ruining it. This is in the PNW and I want it to be able to survive the moisture here for as long as possible. I put 4 layers of Spar Urethane on it, with a brush and sanding in between. This doesn’t seem to have worked the way I expected. I am using 1/8in maple sheets from craft closet, they are the veneer mdf center ones. My first thought is maybe those products just aren’t up to the task at hand, and I’ll need to use solid wood instead.
I’m looking for any advice from the community, and happy to share more info as needed.
Edit to add, I might not be able to reply to comments right away, im heading out for a bit today. Thanks in advance for any help!
I’ve never had any luck with cheap plywood that’s exposed directly to water, although both MDF and MDF-core ply hold up fine outdoors if sheltered from direct contact.
I’ve got one piece in particular - a vented box for a weather sensor - that hangs just about a foot from the edge of a gutter, made from untreated MDF. It was one of the first practical projects I made when I first got my GF - I was one of the “founders” so it’s been out there for several years in Atlanta humidity, storms, snow, etc.
A sign I made from proofgrade ply, however, was able to get wet from blowing rain, and it didn’t last the summer.
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By law (in Baltic countries), Baltic Birch has to have minimal standards (like not coming apart when wet), so I would still cover them with urathane varnish at the least, and last, but they should hold up well outside.
I purchased some regular birch that was not Baltic Birch and it was the worst stuff I have ever used.
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Awesome, thank you for the replies here! I think ill try some baltic birch and see how that works, do you think 1/8in would be fine or should I go for 1/4in for something a bit more sturdy?
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If you have an Aura, then 1/8 is thick, and 1/16 is not terrible. If you are using the bigger machines, it could still be 1/8 unless the customer wants 1/4.
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I have a pro, and I really just want would work best. I need to make 2 complete projects of this, so maybe ill try one with 1/8 and one with 1/4 to see how they work. Thanks again!
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