Need suggestions for wood used outdoors

[Boilermaker]

My girlfriend's sister had a baby and her mother wants to make some sort of yard sign to put in their yard announcing the baby. She's gonna make a pattern of a stroller with a baby in it and wants me to cut it out for her. I'm looking to make something cheap but durable to the elements. Her other sister is having a baby in August so it has to last long enough to be re-used. What would be a good wood to use for this project? I'm thinking something that comes in a 4x8 sheet like plywood, particle board, etc. I'm not real sure how well these would hold up in the rain and elements though. This will also be painted. I'm figuring I'll tell her mom to use some type of outdoor grade paint, but is there something else I can use to seal this off after painting to help make it last even longer?

[DaveO]

MDO (medium density overlay) is often used by sign makers for outdoor signs. If you can find some, that would work great. If not I think that you could do well with exterior rate plywood. Either treated plywood or plywood with exterior rated glue. Painting either will allow it to last a very long time outdoors. You might want to pay extra attention, when painting, to the edges of the piece and apply a few extra coats there.

I have a portion of a sheet of treated plywood sitting outside my shop leaning up against a block wall. It's been there for at least two years and looks just the same as when it was bought.

Dave

[Ray Martin]

Scott,

Sounds like a fun project for you and your jigsaw. I think Dave is right... with a good coat of paint the wood will be fairly well sealed. Just make sure you get the edges well sealed. Guessing a month in front of each house, the sign probably won't really spend enough time outside to deteriorate.

Ray