Varnish: type & amount for XL

[Brock]

My first wing is rounding the final bend and will be done soon.  I suspect the second wing will take only a fraction of time to complete.  So, my thoughts are turning to varnishing.  Reading the many search hits on the forum I see that Poly Fiber EV400 is popular.  Though most posts were a bit dated.  Is this what recent builders have used?

Also, How much varnish should I order?  I've no idea if I'll need a quart or four.

I'm planning on covering with Oratex (600 Antique).  A quick measurement of my wings and tail seems to suggest it will will require about 320 sq/ft but that does not include any fuselage covering.  I do plan to cover from just behind the seat to the firewall.  What measurements (sq/ft/meter) have others found to cover their birds?

Any other comments?

[Kamcoman77]

Water based urethane varnish is what I am using. The Oratex glue should be fine sticking to it. I buy a quart at a time and have no idea how much I will finally use. Since I buy it at Home Depot, I'm not worried about how much to buy. It comes in satin or gloss.

[Shay King]

I checked with the UK Oratex distributor, he sent me a water based product called ’Ecoprime’. It’s not the same as the other Ekoprime that Aircraft Spruce has.

[Kamcoman77]

Definitely should use the sealer that Oratex recommends.

[Brock]

Definitely should use the sealer that Oratex recommends.

So, I contacted the folks (Lars) at BetterAircraftFabric (USA Oratex dealer).  This is what he had to say...

It has to be for sure a two component wood varnish. It cannot be under any circumstances be any of those water-based single component things.
Check Marine/Maritime supply stores in your city, they should have a reasonable product. Best use one that is Epoxy based.

It's interesting that the bottle pictured in Shay's post is marked "water based".  Looks like I'll be going with the Poly Fiber EV-400.