I'm almost finished stripping multiple layers of paint and varnish off my front door. It's revealed some really nice detailing that was previously hidden by paint. I'd like to stain and seal the door now, but each of the 4 panels on the lower part of the door have substantial cracks in them. Right now, those cracks are filled with paint. What can I use to fill the cracks? Sorry for the blurry picture of the door]2
Word of advice, do not sand the door anymore than what has occured already. You can see how there are a few lighter areas where some dings are that the "patina" has been removed by something. Sanding will ruin the patina, making the door look blotchy as well.
On old furniture and doors where the cracks are not structural, burn in sticks are what I use. They are made of lacquer, and if you finish your door in a water based or poly finish, this will fill the cracks nicely. Burn in sticks can be bought on Ebay, its where I got mine, they come in a wide variety of colors, and the color you see is the color you get, they don't change color once applied.
Once the door is sealed, NOT finish coated you get yourself handy a heat gun. Use that to melt the stick of the color you want where it starts to flow down the stick, careful. Then move it onto the door with out dripping and push it into the crack. On small cracks, I use a putty knife heated and set the stick on it to melt it a little and use the knife to apply it. When the crack or hole is sufficiently filled, I take the heated putty knike and flatten it out, removing the excess. This will leave a small skim over the surface, which will then clean up with a little lacquer thinner on a clean rag. Do not get the rag to wet, it may try to dissolve the sealer too.
Apply the finish coats over the repairs as you normally would.
Use this only in cracks, not joints, wood needs to move and if it is placed in a joint you will hinder the movement, doing more harm than good.
Nice door - good work on the restoration! First I'd try to remove as much of the paint as possible. A putty knife and razor blade will probably help. Then the best filler would be a medium-brown tinted epoxy that matches the color of the stain you'll be applying. If that's not available, a stainable wood filler should be used.
The cracks look pretty straight, so I would try to cut a thin sliver of wood, glue and wedge it in. A table saw is the easiest approach to this task. You are cutting a very thin piece that may tend to fly off the table, so be sure to wear safety glasses and stand slightly to the side, away from the strip about to be freed.
The wood looks like oak. If there is some old oak around the house, that would be my first choice. If not, I would buy some new, cut some strips, stain them to about the color of the door before trying to insert them.
To put them in, I would work from both sides, using strips that are less than 1/2 the thickness of the door. After putting in the strip from one side, you could use a bit of exterior grade wood filler in the middle before inserting the strip for the other side, but probably not necessary.
I would try not to get glue on the face of the repair (wipe it off while still wet if you do), because it might interfere with any stain you apply ti the door after repair.