Infrared stripper like the speedheater cobra would be a good buy. Even if you use it to strip the door and sell it on. One big advantage of infrared on exterior woodwork like front doors is getting the sap out of knots, it just boils out and that helps avoid bubbling later on.
One downside to stripping entirely is you might get movement in the panels once they're painted, expansion or contraction. If they contract you get unsightly unpainted lines.
I've got one of the knockoff ebay ones which I successfully used for our doorstep - and like you say it boiled the sap out. Unfortunately in that case I used a paint that only lasted a year, so I need to do that again too!
Infrared stripper like the speedheater cobra would be a good buy. Even if you use it to strip the door and sell it on. One big advantage of infrared on exterior woodwork like front doors is getting the sap out of knots, it just boils out and that helps avoid bubbling later on.
One downside to stripping entirely is you might get movement in the panels once they're painted, expansion or contraction. If they contract you get unsightly unpainted lines.