I saw a arbor made with old shutters. Can I use louver closet doors

With proper preparation for outdoor weather conditions anything can be used. Exterior paint and exterior varnish

Hi Captain, You'll want to waterproof them first. Here's a link that should help: https://www.todayshomeowner.com/how-to-finish-wood-furniture-for-use-outdoors/

Have fun!

I wouldn't think they would be much different other than the size. Just make sure you use something like Marine poly on it to make it more water resistant.

Yes once painted with a preserver, but they won't last as long as the shutters because the shutters were meant to be outside.............

Those would work well. Be sure to sand to the bare wood before applying primer and painting them. The key to protect them from the weather is to apply the appropriate sealant. Click on the link below to view the different options:

https://www.homedepot.com/c/concrete_sealer_driveway_sealer_wood_sealer_deck_sealer_exterior_sealer_buying_guide_HT_BG_PA

Plastic shutters/doors hold up like a dream. Wood ones will last for a while, but are manufactured with water soluable glue and woods that aren't particularly made for outside weather. You'll get 3-5 years out of them even with exterior paint/dealers/varnish. On a porch or brought in for rain season they will last longer.

They can be a fun accent, so why not? Just don't expect it to last as a perminent structur.