I would merely rough it up with medium grit (120) sandpaper, then spray it with KILZ primer. The primer will adhere to the tube, and fill in the spirals at the same time. The KILZ primer will also sand very easily...
I guess I should ask if you can even get KILZ primer across "the big pond"
Roughing the glassine finish should be enough to get a good start on a finish.
I'm not sure we can get that over here , I'm used to using 'Plastikote' or 'Halfords' primers & paints. I'll sand the tubes down & get some white primer to see if that will do the trick of filling the spirals. But on these tubes , the spirals are only faint?
lol yep , clear coat this time and not epoxy (doh) hahaha!! Well I did use Plastikote Enamel Pewter and Plastikote Enamel White primer yesterday , and boy did they not like each other ! Yeah I like that Halfords Matt yellow primer , it's more 'powdery' than normal spray paint , and gets EVERYWHERE!