Hello All Just getting things together for a solar panel install. Already got controller Panel arriving tomorrow. Ally Angle to be bought and cut tomorrow. Still need some 6mm cable and gland - probably eBay for that. Now, I'm planning on using Sikaflex 252 for sticking the ally angle down (to roof of a PVC), and am planning on prepping both surfaces by gentle scuffing and then use Sika 205 cleaner. My question is - do I need to use a primer, like sika 210- or is that overkill? When researching most people only seem to bother to clean and then straight on with the sikaflex adhesive and no mention of primer. Thanks for any help.