Sun damage to gear

[fasted3 0]

Suppose that after a cutaway the main and freebag could not be located immediately, but were later found having been fully exposed to strong sunlight. When would the damage become severe enough to be considered dangerous to use? I have heard that just a few days would be too much. Is this true, and are there ways to tell?

But what do I know?

[2cmyzx 0]

I was at lost prairie boogie in 05 and a guy had a cutaway that floated into the foothills of the mountains to the south. Sabre 170, we looked for a couple of days by foot and Fred took the 182 up to look for it but with no luck. This was end of July and was told that TY spotted it in sept or oct and it was found. Far as I know he is still jumping it.

[GLIDEANGLE 1]

You have asked an interesting question. I don't know the answer.

I wonder if most riggers would consider the rig airworthy if it passed multiple thumb tests or multiple pull tests (per PIA TS 108).

While the pull test might answer the question about the canopy fabric, how would one test the lines and risers?

The choices we make have consequences, for us & for others!

[riggerrob 643]

PIA TS 108 is the most precise way to test canopy fabric tensile strength.
Reserve fabric should pass a 30 pound (Performance Designs) or 40 pound (round reserves) tensile test.
Reserves must be in "near new" condition when they are repacked.

Remember that strength standards are lower for main canopies. If the worst faded part of the main canopy (usually center, top tail) passes a 20 pound test, I will return it to service.

[bjornufknu 0]

Quoting BrianM from another thread http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3194520;

Quote

Glass filters out some UV, but not all.

Poynter Volume 1, 9.3.8.15 has information about UV damage, including this table:

Percent breaking strength in pounds lost for Tybe 1 Fabric exposed to the summer sun. First column is without glass, second column is with glass.

1 week 52% 40%
2 weeks 71% 61%
3 weeks 94% 85%

d.d.s.

[fasted3 0]

Thank you for your response. It was very useful by leading me to this link:
http://books.google.com/books?id=2PopFBjLZV8C&pg=RA1-PA364&lpg=RA1-PA364&dq=Poynter+ultraviolet&source=web&ots=lcnWz9vW8Z&sig=nMOVHdHDyNmIroIR9OT1ffB8IDA&hl=en&sa=X&oi=book_result&resnum=5&ct=result#PRA1-PA364,M1
I now have much more respect for the damage that can be caused by sunlight, and am particularly surprised by how little protection glass affords. The post above, where a canopy was exposed for weeks or months and then put back in service, seems almost foolhardy in light of this article.
I will note that the information seems at odds with other sources, and will look for further debate on this, hopefully from those with scientific knowledge on the subject.

But what do I know?

[novacaine 0]

**WARNING NEWBIE HERE**

In a case like this, would it be best to have the main shipped back to the manufactor for an 'offical' test and report?
Oh is this something that manufactors don't (I understand that they will charge you, being IF they perform such a thing)?

[hackish 8]

novacaine, I think any rigger is sufficiently equipped to test it as we must test many reserves before repacking.

-Michael

[fasted3 0]

I am still confused.
One post:
Percent breaking strength in pounds lost for Tybe 1 Fabric exposed to the summer sun. First column is without glass, second column is with glass.

1 week 52% 40%
2 weeks 71% 61%
3 weeks 94% 85%
Another post:
This was end of July and was told that TY spotted it in sept or oct and it was found. Far as I know he is still jumping it.

It appears from the Poynter Manual that after that much time had elapsed, the canopy would be so weakened that it would come apart just by picking it up, yet it was still usable. Also, the sources I've found say that glass blocks a lot more than 10% of u/v rays. Is Poynter wrong, or am I missing something?

But what do I know?