Hi,

I'm about to start building a couple of interior doors that will be roughly 28 X 80. These will be paint grade doors so probably looking to use mdf panels. The design will be fairly simple because my wife likes the mission style design. I have a few questions that I hope you guys can help with.

1. What thickness do you typically use for the panel for a non-raised panel interior door? I was thinking 1/4" but should it be larger?

2. Given that this is a simple mission style door, would you use tongue and groove or groove for the panel and loose tenon joints for the styles and rails (or cope and stick?)? I have a shaper and slot mortiser. If the answer is tongue and groove type joinery, would I have to increase the width of the panel in order to have a thick enough tenon on the rails and what is the minimum length of the tenon? If loose tenon is the answer, how big should I make the tenons (length and width)? One thing I'm really confused about loose tenons is how to make the grooves for panels without grooving the entire length of the stile....or do you?

Thanks in advance for your help.

Cheers!!
Mickey