The wrapping (and unwrapping) of KELLI GIRL
Larry started an outstanding thread here about HOW to wrap, and was pretty specific about not wanting to hear about vinyl wrap's pros and cons. Out of respect, I didn't post my experience until I got to talk to him personally about KELLI GIRL's wrap, particularly about the vinyl's performance as a VFR, then hard IFR, aircraft. He urged me to tell the story here, and I hope it provides good food for thought.
In a nutshell: My fully wrapped RV-7A did great for the first 2 years in VMC-only conditions. Then, in IFR and rain, it really took a beating. After flying the wrap for 8 years and 1700+ Hobbs hours, I have now stripped the vinyl: She goes into the paint barn next week.
BACKGROUND
Here's KELLI GIRL's wrap saga from 2015:
https://vansairforce.net/community/showthread.php?t=132000
In 2017 I upgraded KELLI GIRL and me to IFR, and haven't been shy about flying through rain. However, the rain drops' impact on the vinyl's leading edge blasts away the outer pigmented layers, showing the inner cushion and lower adhesive layers. Case in point:
Look at the white invasion stripes on the wing's lower leading edge. You can see the ugly gray blotches. That's the damaged vinyl where the rain drops impact-blasted the white surface. That damage appeared on most of the forward-facing surfaces like the cowling, vertical stab, etc. After 8 years of continuing degradation, I was ready for something more durable...like paint.
VINYL REMOVAL
Starting in 1 November, took just over a week for me to remove all control surfaces, panels, and fiberglass from the aircraft, and then remove the vinyl from those parts and the aircraft itself. I removed all the vinyl using a Wagner heat gun set to low. No scraping involved, and no solvents. I used a small blunt plastic scraping blade and concentrated heat just to raise a corner of the vinyl so I could gain purchase. After that, I developed the technique (ie, 'got the hang') of the right amount of heat (only about 2 or 3 seconds), wait a second, then pull UPWARD on the vinyl with force perpendicular to the part's surface. Don't pull forward on the sheet parallel with the metal surface: It'll rip. Pull 90 out. I started at the tail and worked my way forward. After about 8 days I got it all off. BTW, the thicker nitrile-dipped work gloves work great for this job (sufficient tactile contact but thick enough to last).
VINYL REMOVED, BUT RESIDUE REMAINS
Mark King at GLO Custom paint emphasized the need to get any residual vinyl sheet adhesive OFF of the aircraft. This need became apparent as I discovered just how well the original wrappers treated the surface edges and seams. Because I had placed such emphasis on zero water intrusion in 2015, the wrappers ran a strip of surface adhesive along the skin edges and skin seams:
Here you can see that "glue" strip along the wingtip edge.
MEK AND SCOTCHBRITE
To address this, I donned the butyl gloves, carbon mask, and eye protection, and tackled the entire airplane with MEK and red Scotchbrite, including all the metal parts I had already removed (turkey feathers, panels, etc.). That strip of residue came right up with MEK, with a reasonable amount of scrubbing. I MEK-scrubbed the entire airplane. I then sprayed more MEK on the areas and removed all the
residual residue with blue shop paper towels. It took time and patience, but it worked fine. I didn't work the fiberglass parts because they'll get surface-sanded, but I really worked over the aluminum.
I did not externally prime KELLI GIRL when I built her, so I was happy to find no corrosion other than VERY minor surface blemishes here or there. GLO will follow my MEK scrub with another thorough surface acid scrub, then Alodine.
I'm sticking with the same color scheme for KELLI GIRL, although the blue and silver metal flake I chose is going to POP in the sun.
8-12 weeks and she'll be back ready to fly.
TAKEAWAYs:
- Vinyl wrap is just fine for VFR-only aircraft.
- Vinyl wrap is NOT good if you plan to fly through rain often.
- Vinyl wrap is easier to damage than paint. Paint is more durable.
- Vinyl wrap is easier to repair than paint, but the repair is apparent.
- My decision to wrap over un-primed skin was just fine, but you can expect to have some
minor spots of surface corrosion that can be cleaned/buffed whenever the wrap is removed.
- Vinyl on the belly loses adhesion when exposed to engine oil and smoke oil.
- Wrap removal took some work and patience, but it WILL come off.
Would I do it again?
Probably not. It looked great until it didn't. Next time, I'll just go ahead and paint.
