OK, shoot me down if you like but I am rolling 2k onto my bodywork. The epoxy primer went on lovely , nice and smooth and thick, however months later . Using the same make paint 2K semi gloss rolled on, all is well, nice and smooth until just as it is hardening off tiny bubbles appear ruining the finish. I am mixing with the correct quantities etc. but using an aluminium stirrer in the electric drill . I'm sure i read years ago I think that this is not a good idea as it causes some kind of reaction? though I can't find the reference any more. Any ideas please?