Pin holes (again)

We nuke about an ounce of epoxy in the shop microwave until it is almost too hot to hold, then quickly squeegee it across the pinholed surface so it forms a meniscus that fills in the square corners of each pinhole. An ounce covers like 10-20 square feet. We generally do that twice, and then sand the remaining epoxy off and fill the remaining weak depressions with Duratec.

I use the soft squeegee and polyprimer to good effect. Something else that helps is to get the wing hot and then prime it. Allow to cool. The cooling seems to suck the primer down into the microvoids as the air in them cools and thus decreases its volume, creating a slight vacuum.

Fidel, actually pulled a slight (2-3"hg) on my wings. Then spread thinned out epoxy on the surface over the multitude of pinholes. Cured it and then tested it with 3-4 ft of head pressure with water worked great and the completed the refinish😀 No leaks so far that was about 8 years ago?

On Wednesday, April 5, 2017 at 7:19:17 AM UTC-7, wrote:
Fidel, actually pulled a slight (2-3"hg) on my wings...

I'm going to remember that trick; it sounds like a great way to address the leaky bondlines that I've heard of on early LAK-17. But I imagine that if your vacuum regulator slipped you could make a mess of a wing in a real hurry.

--Bob K.