etching question

[JimWoo50]

In the vans construction manual, 9-12, the section dealing with the fiberglass work around the canopy, etching with phosphoric acid is mentioned. Has anyone done this and what strength did you use? How do you tell when the aluminum is sufficiently etched?

[rwtrwtau]

Jim,

I've not done this but I think Alumiprep 33 would do the job for you here. Just follow the directions supplied.

Richard