Hopefully this will restore the original integrity of the door by maximizing the glue surface of the joints as originally intended and perhaps they will last another 70 years.
Restoring hardwood door rail.
Remove the three hinge pins from the door by placing the flat.
Once stripped the door should be lightly sanded with a 120 grit sandpaper to remove any remaining traces of paint and paint stripping product.
If you leave it too long in one spot you ll damage the wood.
Rot is often caused by water collecting at the bottom of panels in rail and mullion grooves.
Keep the palm sander moving.
Priming end grain areas before reassembly is a good idea especially for exterior doors.
This gives you a good key for the new coats of primer plus your chosen exterior paint for wood in whatever colour you fancy.
Coat both the mortise and tenon sides with a good wood glue to and tightly clamp the doors back together.
As with any diy project preparation is key.
On this weekend workbench segment blake sloane of the rebuilding exchange helps ryan restore a sad old door without sanding stripping or any hard chemical.
Other rot prone areas are the exposed ends of door components since end grain cuts absorb water more quickly than surfaces parallel to the grain.