We are making slooooooooooooow painful progress stripping the original built-in cabinet. Progress is extremely slow even with the Speedheater. We learned during the process that the entire cabinet and all of the surrounding trim on the wall had been completely sanded down to raw wood. We guesstimate this happened sometime in the 50s or 60s based on the nature of the oil based paint layers. The extremely strong oil based paints made a VERY STRONG bond to the wood grain making it next to impossible to remove the paint.
Throughout this process we have been using the Speedheater to remove as much paint as possible without damaging the wood. When we scrape with too much pressure we gouge the wood, which we've done in a number of places. That will lead to more sanding and difficulty during the finishing process. We have resorted to using chemical stripper to remove the final layers of oil paint that have adhered to the raw wood. We are using Multi-Strip Advanced, which I have used in the past. It is less toxic, but still pretty strong stuff. The trick has been to leave the stripping paste on the surface for at least 10 hours before the final scrape. It leaves quite a bit of paint residue, but we expect to be able to sand most of it out during the final finishing stage.
The good news is that we did a test run on the box beams and surrounding trim in the dining room and the original finish was not sanded off. The Speedheater penetrates through the paint layers, softens the shellac layer, and the paint slides off like butter. We are hoping that this cabinet and surrounding trim is the last of the sanded wood work. Why would anyone bother to sand all of this and then cover it all up with paint? Not sure we'll ever understand exactly what happened here. The mysteries of an old house!