An easy method to apply tissue over a mylar film finish using Eze Dope.
Eze Dope is a durable and water based finish and can be applied indoors as there are no fumes like with traditional cellulose dope finishes.
Mylar film used was 10 micon and was applied beforehand using balsaloc on the perimeter of the framework and the edges of the ribs and then heat shrunk in the usual way.
Tissue used was Esaki Liteflite which works really well with this method. Its vital that the tissue posseses 'Wet strength' or it will likely disintegrate with manipulation when wet.
The main benefit of using this combination of materials is you get the structural stiffness of a traditional doped tissue finish but with the durability of a plastic finish in that you wont be easily poking holes in it!
As the wing is already air proof with the mylar underneath it only needs the one coat of Eze Dope but subsequent coats may be wiped on if you want to acheive a glossier finish.
UPDATE
Since making this video I've updated my method following some advice received in the comments and now I put the tissue on with just plain water initially and do all the teasing and wrinkle removal, then wipe down with the tissue to remove as much water as possible and any bubbles etc. Then when happy with the fit and finish I give it a liberal coating with the ezedope mixture and let that soak in a little and then finally wipe to a finish with the tissue again.
I find this even easier still as you have unlimited time to fettle any wrinles and can rewet it with water if necessary. It's a lot less messy too and more ecomomical with the Ezedope.
Mylar is a brand name for Polyester films manufactured by Dupont Tejjin Films. There are many manufacturers of Polyester film and as far as I can tell for our purposes they're all quite similar and its only really the thickness that concerns us.
I get my mylar film from Mike Woodhouse at Freeflight supplies: https://www.freeflightsupplies.co.uk/
Another source I've recently found is here:
https://www.preservationequipment.com...
You can get a 12 Micron Polyester Roll 1524mm x 100M (!) for £35+vat and postage. Fantastic value and probably a lifetime supply .
If Mylar (Polyester film) isn't readily available where you are it's also possible to use the lighter grades of document laminating films which are available in large rolls quite cheaply. These are generally either Polyester(PET) or Polypropylene (OPP) based and have a heat activated adhesive on the back like regular covering film. While heavier than the Mylar, due to the adhesive, they're fine for models 36" span and upwards.