I recently found out about a terrific masking material called Parafilm-M which can be found at lab equipment suppliers. A lot of scale model kit hobbyists use it. Stretches real nice, does not leave a residue and is economical. A 2" wide x 250' length roll retails for about $19 to $20. Also comes in a 4" wide roll, but the 2" width is easier to work with. Just thought I'd throw this out there.