What is the best masking material to use for curved lines. Is there a rubber beside Mask-Al.

I use Silly Putty. You can also use firm therapy putty. The therapy putty is less expensive and can be found on Amazon.

I like Silly Putty too (it's only $.79 at my local drug store). But recently I've begun to use the thinnest Tamiya vinyl tape-- its great also, and confirms to any curve easily. I've recently done a couple of compound curves, and think it'll be my "go-to" tape for curves now.
VR, Russ

I have been looking at the Tamiya tape also. Think I will give it a try. Thanks

I recommend the thinnest Tamiya tape-- I think it's about 1.5mm wide. That goes around the corners and curves the best, then I backfill it with regular washi or Tamiya tape (you can buy washi tape at Hobby Lobby or Michael's here in the states-- stay away from 3M brand washi tape-- it has poor sticking qualities). I've tried the wider Tamiya Vinyl tape too-- but find it's too wide to really bend well around curves, but it has it's uses.
VR, Russ