Van?s Aircraft does not have an ?approved? primer. We use Sherwin Williams P60 G2. This is used on the QBs and prototypes made here. The QBs primer has no pigment so it just makes the interior surfaces slightly darker and less shiny. In the US, this primer has a green tint, so the two will not match exactly. We use this primer because It is inexpensive, dries fast, and is easy to apply. Sherwin Williams will tell you that the primer needs a top coat. True, for optimum corrosion resistance, but Vans feels that this is not necessary for the way in which most owners will maintain their RVs.