Final Primer Sanding Part 1 (panels)

The Mini shell and panels had been sitting under some old bedsheets with its first coat of high build primer for two winters and upon close inspection showed only a few areas of surface rust showing through the paint. Luckily they were only on some panel edges which were easily sanded and re-primed. 

Once that was sorted, the bonnet, doors and bootlid exteriors were guide coated and block sanded with 180grit. I found a one of the doors needed a really thin skim of filler over two larger areas from when I did some panel beating to correct the door-to-body alignment. 

After the 180grit sanding, the panels were again guide-coated and block sanded with 240, 320 and 400grit. 400 grit was either on a DA sander (with interface pad) on large flat areas, or hand pads / sanding sponge for detailed areas. With everything sanded to 400grit, "super-fine" (500-600 grit) foam hand sanding pads were used for the final sand over everything.

Rubbing through the epoxy primer (to expose bare metal) was an annoying issue faced with rinvuts that sit proud of panels as it was hard to sand around the every rivnut edge. My solution was to fit a bolt and small washer so I could use a hand sanding pad and not touch the rivnut.

In terms of finding and removing fine scratches I used some bright LED worklights to illuminate each of the larger panels to help highlight any small scratches. For detailed panel shapes I used a handheld inspection light up against the panels to help highlight fine scratches that required further sanding. 

One problem I found was finding a small crack in the primer the front corner of the bonnet (where the factory sheet metal is usually brazed). It's hard to see here but a fatigue crack was visible in the top of the bend once I stripped the primer back to bare metal.

Some TIG welding later had the corner fixed and strengthened.

For the bootlid, doors and bonnet I put around 200 hours of sanding, primer touch-ups, multiple cycles of sanding and more primer touch-ups to get down to the super-fine grit level. There were plenty of areas where I had sanded through the white high build primer to the grey epoxy primer so it all looks quite patchy however a white primer/sealer coat will be painted over everything prior to the base coat colour.

With all the panels completed and ready for paint, I made a storage rack using timber from a neighbours old patio and added some small castor wheels to move it around the workshop. 

To prevent anything from getting scratched or scuffed, I cut strips from an old foam yoga mat and glued the pieces to the frame. 

With a footprint of just 1m2, I now have a relatively compact rack for the panel storage, instead of having everything just leaning up against random shelves & walls in the workshop.