The repair looks good but I dont know composites that well. The finished surface looks wavy- like too much epoxy or air bubbles? If it needed to be perfect like surrounding areas would you sand smooth? Is there any way to assure that surface is perfectly level and coplanar rather than what is there in the video?
You are correct that the outer layer is not perfect. This is an outer (non-structural) glass layer that we tried to apply within the same process cycle as the (structural) carbon plies. The carbon plies were all prepreg plies whereas the glass layer was a dry fabric ply. Unfortunately we did not have any prepreg glass material (with a compatible resin) available at the time, so we tried to impregnate the glass layer with resin/adhesive within the same cycle. As you noticed correctly this resulted in quite some voids, but only in the outer non-structural glass layer. In a later stage we modified our process and decided not apply this glass layer anymore. For an actual on-aircraft repair you usually do need to restore non-structural items like copper wire mesh for lightning protection, an outer protective glass layer, and paint. If you need to do that I would recommend this to be done in a separate processing cycle after the structural repair has been finished and inspected. For more info, please visit: www.nlr.org/capabilities/composite-repair/
BEAUTIFUL work. Truly impressive.
Very good job!
Very Precise.
Are these Repairs applicable on A350?
The repair looks good but I dont know composites that well. The finished surface looks wavy- like too much epoxy or air bubbles? If it needed to be perfect like surrounding areas would you sand smooth? Is there any way to assure that surface is perfectly level and coplanar rather than what is there in the video?
You are correct that the outer layer is not perfect. This is an outer (non-structural) glass layer that we tried to apply within the same process cycle as the (structural) carbon plies.
The carbon plies were all prepreg plies whereas the glass layer was a dry fabric ply. Unfortunately we did not have any prepreg glass material (with a compatible resin) available at the time, so we tried to impregnate the glass layer with resin/adhesive within the same cycle. As you noticed correctly this resulted in quite some voids, but only in the outer non-structural glass layer. In a later stage we modified our process and decided not apply this glass layer anymore.
For an actual on-aircraft repair you usually do need to restore non-structural items like copper wire mesh for lightning protection, an outer protective glass layer, and paint.
If you need to do that I would recommend this to be done in a separate processing cycle after the structural repair has been finished and inspected.
For more info, please visit: www.nlr.org/capabilities/composite-repair/
Are those pre-peg patches?
Yes
what tools are using for scarf/step milling
For scarf and step milling we used a depth-adjustable router with diamond coated tip.
Nice work
Why your not wearing gloves in this process?... this materials are very sensitive to be contaminated by the bare hands
Good job
Wicked good job!!
Gazza B waz ere 2K13