The Long EZ Build: Outside strut layup

The main landing gear strut is made from 'S' glass in a mold purchased prefab. It would be great if it was ready to be mounted onto the plane - but since we don't live in a "trouble-free-everything-comes-easy" world, a lot of work is required before we can do that.

The strut must be sanded completely dull and then receives an 8-ply torsional stiffness layup as follows (note that I'm not planning on adding the 1 ply BID that hides the brake line at the trailing edge until AFTER the strut has been installed on the airplane. Also, this layup is split into two - left half of the strut and right half - so you have a total of 16 plies):

First, I cut all my UND cloth. This consists of 16 strips of UND at 30 degree bias. Each strip is at least 9" wide as stated in the plans.

All 16 strips rolled up and ready to go!

I sanded the entire strut dull using 60 grit sand paper. I cheated a bit and used an electric hand held sander. In hindsight, I would sand the strut tips flat (the last 3" of the strut where the axles will mount later) so that they have a nice flat surface to mount onto; else, you will have to sand most of the fiberglass off at the tips in order to achieve a flat surface. A slight toe-in angle is required, but this is taken care of later when the axles are mounted (see my later post about mounting the axles).

I outlined the strut on my bench, and drove three 3.5" drywall screws into my bench (making sure they were all at 2.5" above the surface). I mixed up 5-minute epoxy with some micro... dabbed a good amount onto the screw heads and positioned the strut on top - trailing edge up.

I let the 5-minute epoxy cure and I started to prepreg. The layup schedule is simple - 4 layers on the left half and 4 layers on the right half. Here I am prepregging the first 4 layers (remember to alternate from +30/-30 for each layer!)

Here is one end of the 4-ply prepreg - showing the alternating layers between +30 and -30.

I cut the other end straight - since this end will be in the center of the strut.

I then proceeded to paint the right half of the strut with plain epoxy - this is to assure a good bond between the prepreg and the strut - and of course, to keep those annoying air bubbles away.

Right side ready to receive the prepreg...

I then took the prepreg... gently placed it on top... and peeled the plastic away. Notice how I aligned it starting with the straight edge on the center of the strut.

Close up...

I then removed the plastic off and began to smooth everything out.. making sure the 4-ply layup was conforming to the shape of the strut and carefully removing all the air bubbles away. This was done by hand. I made sure my gloves were always wet with epoxy. I then trimmed the tip allowing a 2" overhang.

I then repeated this for the left side... another 4 plies (alternating between +30/-30)...

The next day, I knocked the strut off of the screw heads...

Using the vibrating multi-tool, I trimmed the overhang that dripped past the trailing edge.

Close up showing the roughly trimmed trailing edge of the strut.

I then used 60-grit sand paper to sand everything smooth and prepped it for the final two layups of the torsional layup on the flip side.

Sooooooo smooooooooth... couldn't even tell where the torsional stiffness layup ended and where the 'S' glass of the leading edge strut began...

I then remounted the strut onto the screw heads (this time trailing edge down) and followed the same process. Four plies on one half of the strut...

And four plies on the other half of the strut. The plans specifically state to not overlap the two halves, but rather butt them as close to each other as possible. I peel-plied this gap just because.