Lumber and Siding - Luan Plywood...

hi all,
rather than scraping, sanding and repainting the ceiling of the outdoor porch on my colonial home, i purchased some luan plywood and installed it over the existing chipping ceiling. i used liquid nails and screws to attach it.
now, my question is, how do i correctly cover up the screws and seams on the luan??? the porch is about 20 feet long so there are several pieces. is there some sort of outdoors-grade compound that can be placed???
any help would be greatly appreciated.

I'd use Famowood. FW Wood Fillers 050307 (http://www.biosafe-inc.com/famowoodfillers.htm)

thanks furd...
is it available at HD/hardware stores???

Famowood may be available from your local hardware store, I don't think I have ever seen it at a big box homecenter but I have never specifically looked either. It should be available from the bigger lumberyards and especially any yard that caters to the cabinetmaking industry. You might try a yard that supplies to the wooden boat builders as this is where I first came into contact with Famowood.

I would not use the product that has the initials PW. In my opinion it is far inferior to Famowood.