My favorite primer for wood doors is Bins Bullseye, pigmented shellac. This primer bonds well, hides wood grain well and gives a very smooth surface for top coats. If you prefer to stay with a latex product, then Kilz premium is good too.
Remember prep is of the utmost importance for a good finish. Sand everything and clean it well before applying primer. On a new piece, I like to lightly sand the first coat of primer. You will feel the difference, trust me. I like to use two coats of primer, then sand it again very lightly to make it super smooth: 220 grit used lightly is fine. Clean it well with a tact cloth or very slightly water dampened rag.
Now for the top coat. Use a premium quality 100% acrylic exterior trim paint. Usually a gloss or semi gloss looks great, but that's a personal preference. Don't skimp on the brush: get a good Purdy Glide, poly/nylon 2½" angled, soft chisel tip. Apply nice smooth, thin coats, and expect to do three coats for a good solid fill. Start in the panels and work your way out to the rails and stiles. If you can take the time to remove the door after it is installed, (never remove door from frame before installation!!!!) lay it flat to paint. Laying it flat will really help avoid drips and runs. Pay special attention to the panel corners and details for drips and puddles a few minutes after you apply the paint. Use long smooth strokes to finish each panel, rail and stile.
BTW, a really good latex 100% acrylic is every bit as durable as an oil based product. Oil based paints are going away and have been compromised greatly in recent years due to VOC laws. I stopped using oil paint several years ago. The only oil based product I use now is urethane.
Thanks for everyone that asked questions. There were a few things I had to change to finally get it working. I had just bought the house and I assumed that the previous owner had the door's rollers fitted properly, basically I had to:
- Use the old wheels and brackets as the ones i purchased were not sticking out the same length
- The wheels were put on the wrong side of one of the doors
- The bottom guides were not screwed in the correct spot
- The wheels had to be adjusted as they were not the same height
Once all of these factors were fixed the door finally worked!
Best Answer
You're probably going to get a few opinions on this based on individual experience. Is there a reason you excluded aluminum? I have installed composite, vinyl and aluminum sliding doors and all of them have preformed well to the best of my knowledge (no complaints). They all require little maintenance. I've replaced the rollers on my aluminum doors after 30 years and really appreciated the strength and durability of the aluminum doors. I've also noticed the track for aluminum doors are narrower than for the other types as are the frames so there's more glass to look out (and clean,lol). Because of the strength of aluminum, it can support a larger area so you can get by with fewer doors.