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BrianM

Reserve with smoke canister residue/damage

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Attached is a photo of a reserve canopy that came in contact with a smoke canister after landing. The nylon does not appear to be melted or burned, but it has gone right through the fabric and looks almost the same on the other side.

As I don't know what chemicals are involved or what effect they may have on nylon, I don't want to pack this as is. I'm hoping it is possible to clean this off. Any suggestions on how? I tried a damp cloth, it had no effect at all. I'm wondering if naptha would be effective.

The area in the photo is a stabilizer. There are a couple much more minor spots on the top skin as well.
"It's amazing what you can learn while you're not talking." - Skydivesg

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Don't quite understand what we're seeing. If ash from an out and cold smoke I wouldn't have expected it to go through. If it was hot I'd call it damage that needs repair. Even if it was cold I'd expect the residue to be caustic. I'd give up on the idea cleaning is enough.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Hi Terry,

councilman24

Don't quite understand what we're seeing. If ash from an out and cold smoke I wouldn't have expected it to go through. If it was hot I'd call it damage that needs repair. Even if it was cold I'd expect the residue to be caustic. I'd give up on the idea cleaning is enough.



Those are pretty much the same thoughts I had. I don't know how hot the canister was, though I'm pretty sure it was out. Probably not completely cold. I'll see how much I can find out from the owner, but I'm guessing he won't know.

Is it possible for heat to blacken nylon like that without melting it? I wouldn't think so, which is why I was thinking it's probably a residue deposit and not a burn.

The residue being caustic or acidic is my concern as well. If I am able to clean it off well and the fabric doesn't appear to have heat damage, would you consider it airworthy, or still be concerned about it?

I'm hoping to avoid patching this. There are several small spots close enough to that circle that they'd need to be included in the same patch, so the patch would be bigger than just the area in the photo. The same is true of some of the other areas. I'm looking at one stabilizer, at least two areas on the top skin, and at least one area on the bottom skin. [:/] I'll have to look closer to see how if any seams are involved. This is on a 90's MR-135 that's otherwise in really nice condition.
"It's amazing what you can learn while you're not talking." - Skydivesg

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Ok, the owner says the canister was not hot, it had burned out. Yes, I know those two are not necessarily the same thing! I saw the malfunction video, smoke was ignited in the plane and trailing out the door for a bit, so the smoke would have burnt out well before landing.

I had another look at it last night, and I'm not sure it has actually gone through to both sides. A damp cloth on one side picks up a bit of the black stuff, on the other side it doesn't. I think I might just be seeing it through the fabric.
"It's amazing what you can learn while you're not talking." - Skydivesg

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Continue patting it with a damp cloth.
The next step involves dipping it in warm water and a mild detergent like Woolite.
Washing should neutralize most nasty chemicals, then closely inspect the threads for changes in cross-section, melting, etc. if inspection under a magnifying glass reveals no structural damage, then you may return it to service.
OTOH Replacing damaged fabric (with F-111) patches is a fussy process, best done by a master rigger. Remember that you are allowed a maximum of 5 or 6 patches per certified (reserve) canopy. The largest patch can only be half the size of a panel.
Bottom line, gentle washing can prevent difficult patching.

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Neither Woolite nor naphtha have had any visible effect on this.

riggerrob

Washing should neutralize most nasty chemicals



"Neutralize" and "remove" aren't the same thing. If I wash it and it looks the same, would you consider it neutralized and therefore serviceable? I don't know of any way to determine if what is left is an ugly but harmless stain, or if it's going to compromise the fabric strength.
"It's amazing what you can learn while you're not talking." - Skydivesg

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If you worry about tensile strength, there are two testing methods. The old-school method uses "calibrated thumbs."

The scientific method uses (rubber jawed) Vice-Grips and a calibrated fish scale. Tensile-test was popular during the acid-mesh era (late 1980s) and Performance Designs encouraged it until recently. Tensile-testing tools are available from Para-Gear.

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After looking at the canopy, I concluded that there was no "melting" damage to fabric. It looks like cold dust pressed into the fabric.
I could not smell any residue on the part that you washed with Woolite.
However, the unwashed part tastes "BLAEIOUYK!" and needs to be washed and rinsed thoroughly.
Washing should reduce any caustic chemical residues.

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Oddly enough I just had this exact thing happen to my main canopy after a smoke landing... Except my canister not only stained the fabric but also put two penny size holes in the fabric. I'm currently researching whether or not I can get away with a wash & some stick-on ZP or if I need to cut out and patch this area on the canopy.

I'll try to also post my findings.
Woot Woot!

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