Before any wooden door is stripped there is one question to be asked: Is it worth it? If the wood is of bad quality or in a sad state of affairs one may consider looking at reclaimed doors (although often hard to match with the original door and architrave). A new door is another option. A joiner could make a door to your exact requirements. However, it will look brand new, which may not be the look you are after.
If the door is to be stripped consider a firm who will dip-strip the whole door in a bath to remove all traces of paint from the wood. This process is intense and the dip-stripping can leave the joints and mouldings loose…and the door may warp. If the door is to be re-painted the mouldings will have to be made sound and the holes filled.
To avoid the problems of dip-stripping a slower process is required. Layers of paint may have to removed from the panels and moulding. A hot-air gun and scraper can remove heavily built up areas of paint quickly. You need to concentrate on the job as it is easy to strip back the paint to wood but equally simple to start burning the wood leaving the circular nozzle shape of the hot-air gun all over the wood. You often see this on badly stripped doors.
A paint stripper should now be used. The stripping agent will give off fumes so make sure the area you are working in is well ventilated. With an old brush apply the paint stripper to the door and leave for approximately two minutes. This is a messy job…move any objects out of the working area as the paint stripper will burn almost anything. The paint should have reacted with the stripper and begun to bubble and blister.
Wearing disposable rubber gloves, begin to carefully scrape the paint off the wood. The stripper may have only penetrated the paint so far and hence continue this process until you have removed as much paint as possible. When you have completed this process start to work on the mouldings and any stubborn areas of paint still remaining. Re-apply paint stripper sparingly to these areas and remove with wire wool. If you are leaving the door in a natural wood state you will have to dig out paint and filler that has sunk into cracks and holes. If the door is to be re-painted apply a two-part wood filler to any holes. The wood filler will dry in about five minutes and will require a rub down. Repeat this process until all holes are flush.
Finally, rub down the whole door, with extra attention given to the mouldings. Start the sanding (a palm sander is a great help) with a 120 grade paper and work up to a 180 grade paper to ensure a high finish to the door. The sanded door should now be in the happy position to be re-hung or re-painted.