Painting Givi Motorcycle Luggage - part 1

This will be a multi-post saga documenting my journey in painting Givi Luggage for my Bandit 1200S.

Intro:

For the past couple of years, I've been searching for a good way to mount a set of Givi sidecases and a top case on my 2002 Suzuki Bandit 1200S. Unfortunately, Givi discontinued the only strong rack I had liked - the Wingrack 2 - for this bike. The newer tubular style racks are just not soild enough to make me comfortable mounting them.

A couple of weeks ago, I finally found a used Wingrack 2 for my bike. The seller would not sell it to me alone, and insisted on me purchasing his luggage set with it, so I ended up with my beloved Wingrack 2, two E36 side cases, and a V46 top case.

While the top case is in a really good shape, the side cases are not. There are some scratches, some UV damage, and a corner that took a hit, leaving a deep gauge.

I almost pulled the plug on ordering a set of new E41, which I had on my previous Bandit 1200S, but then I looked at the shape of the E36 cases, and actually liked their squareness. The black, however, makes them look bulkier than they really are, especially against my white bike.

So, the decision was made to paint the cases a matching color.

Problems:

I ordered some matching paint, an adhesion promoter, and catalyzed clear to get the job done. The plan was to proceed the same way I painted many other plastic pieces in the past - clean, scuff, paint.

But alas, it is not to be this easy. The lid on the V46 is ABS plastic, so that one is easy, however, looking inside the E36 cases, I found the plastic recycling code - Polypropylene.

Crap. For those not familiar with Polypropylene, it is one of the group of plastics known for Low Surface Energy. In other words, like the nonstick Teflon coating in your kitchen pots, nothing sticks to it. Well, not really nothing, it is just much harder to achieve good adhesion.

Polypropylene cannot be wetted, which really means that water, adhesives, and paints bead up on the surface. Not exactly a quality one looks for when painting these things. Nevertheless, thanks to science, I should be able to overcome this problem.

And this is where the cost vs benefit ratio leaves the realm of reason, and my stubbornness takes over.

The plan:

Test various adhesion promoters to see which one works. Spray with high build primer, sand smooth, shoot with base color, and finish with 2k clear.

So far, I wetsanded the cases with 400 grit paper using Dawn dish liquid to degrease the plastic. That did nothing except to make my tub dirty. The UV damaged layer came off nicely, but the beading continued. I tried some Prep-All, and some Lacquer Thinner to degrease the parts, but again with no success.

So, I wetsanded the cases with 220 grit, removing a little more plastic, and leveling the surface. It worked wonders on the ABS lid, but the Polypropylene is so resilient that it does not seem to be affected much.

My next step is to go to the store and buy some SEM Scuff and Clean product to see if it makes any difference.