If you are stuck on PPG products like me, mainly because my friendly local paint supplier is exclusive to PPG, the DPLF is a non sanding product. Due to my inexperience, I have sanded it anyway. Problem is, its not a very nice product to use with sandpaper. Much easier to just use K36 Urethane high build over the top. The K36 is very sanding friendly and comes out very smooth. If you have lots of rust pitting in your project, the high build will correct that if you do it right. No experience at all with SPI.
