Ch 10 - Canard - Part 8

Trailing edge peel-ply removal (1.7 hrs)

Before securing the canard to the table once again (right side up this time), I decided to take care of a few operations on the trailing edge, while I could still slide it around the table for better reach.

The main objectives were to remove the foam “fishtail”, and the embedded trailing edge peel-ply right below it, then sand the trailing edge to a smooth transition.

I used a small saw to cutoff the bulk of the fishtail.

Removing the fishtail

Next, I dug the foam out until I got to the pure epoxy crusty layer covering the embedded peel-ply/staples layer.

One of the staples ripped out of the peel-ply

Clearing this much epoxy crust took nearly one hour. This was some slow going!

I’m sure someone else must have already figured this out 30 years ago, but not knowing about it, it had to be rediscovered all over again. So, acting on my friend Ary’s suggestion, I didn’t apply any micro-slurry over the peel-ply (before fiberglassing). 

Back in time to show you that no micro was applied above or below the peel-ply before fiberglassing

As a result of this decision, and with the canard sitting right side up now, there was nothing but pure epoxy between the peel-ply and the fiberglassed bottom below it. Ary’s theory was that this should make the peel-ply removal much easier than if it had had micro-slurry.

Because some of my friends took up to three days to clean up this area, I was willing to try anything that had even the remotest chance of making progress easier.

Skipping the micro turned out to be a great suggestion after all, and ripping peel-ply and foam became nearly a pleasure.

While the first inch took nearly one hour of chipping hard epoxy, the next 4" took only seconds.

Perhaps I should show the video I made to give you a better sense of the lack of effort involved using Ary’s idea.

Insert peel-ply video

With the peel-ply out of the picture, I marked where the fishtail had merged into the airfoil with a marker, and gently sanded the foam aft of the black line smoothly into the trailing edge.

Long black mark is where the fishtail began

Sanding until the black line starts to disappear

One additional benefit of not using micro-slurry was that no additional sanding of the fiberglass trailing edge was necessary, due to the textured surface left by the peel-ply, and the absence of micro.