John Deere Buff Primer

Is Deeres Buff Primer sandable? Is there another type of primer to use with Deeres Classic Green? Or should i switch to PPG and other brand?

There's really only one reason to require a sandable primer and that is if you plan on sanding it, which would mean that you are using it to fill in surface imperfections. That being said , what you need is specifically a "primer/surfacer" which has high solids and a high film build and is meant to be block sanded to level the surface for paint. Because of this high film build you will also want a two component (catylized) primer surfacer because it will cure uniformly and completely so no shrinkage later on. A simple sandable primer will skin over from the top down and if you apply enough coats to fill very much, it will take forever for the bottom mils to dry. If you sand and paint over this uncured layer of primer then the top coat will react with the soft stuff and project it through to the top shiney coat and later on when the bottom finally drys, it will shrink and show through the top coat. If you have perfect sheetmetal and nothing to "fill" then use the buff primer. yes you can sand it. You can sand any primer once dry. The ones like epoxy which say non-sanding are to save you the time / effort of sanding and will accept/adhere to the top coat without the sandpaper marks for bite. Primer has two jobs , one is to provide adhesion/corrosion resistance which would be an epoxy and/or self etching primer,usually non-sanding. The other would be primer/surfacer or "build primer" which should be used over the first primer and after block sanding is what makes or breaks a paint job by making everything smooth. Your end result priorities are what decides whether you need any of these. Primer can be a tool for perfection or it can just be a flat coat of product that will disguise all the flaws/sand marks/pits to fool one into thinking it is ready for paint. The shiney paint is what will tell you if it was a "wooops" or not.