Bought some West Systems resin and filler to make a start on finishing, or at least getting my head around it.
West 105 epoxy batch L2016507 West 206 (slow) hardener batch L2016511 West 410 microlight filler.
I packed as much 410 and micro as I could fit in a test pot and compared the weight, then added West 105/206 to a dry mixture and compared the finish weight. Finish volume looked about the same. I was astounded at the difference, just looking at the powdery 410 I thought it would be heavier:
410 - dry = 0.7g - with resin = 7.0g Micro - dry = 1.5g - with resin = 10.0g
In accordance with a conversation I had with somebody I forget I mixed up another test pot of micro, and mixed them together. Result is creamy and easy to spread, and a lot cheaper than straight 410. A mix of 1/3 410 & 2/3 micro will hereafter be called 410/micro.
I drooled some West epoxy on the port aileron bottom, and squeegeed it to a thin smear, then wiped off whatever would come off with a paper towel. Then I skimmed a thin even coat of 410/micro over the surface.