Refinish gone yellow?

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I recently looked at a glider that had been refinished by Dave Nelson in 2001/2002. It has been in it's trailer, and hangar for the last 2 years and not flown. It is located in Texas. In the dim hangar lights, the finish seemed a very faint yellow. Could of been all the dust... It was glass smooth, with no cracks or crazing, but when I used a flashlight, in the dim light, it "seemed" slightly yellow. I live in AZ, and have been told that once I moved it to a hot dry climate, it would "perk" up and whiten up.. Any further thoughts on this?

Thanks

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On Monday, January 5, 2015 2:16:45 PM UTC-5, wrote:
> I recently looked at a glider that had been refinished by Dave Nelson in 2001/2002. It has been in it's trailer, and hangar for the last 2 years and not flown. It is located in Texas. In the dim hangar lights, the finish seemed a very faint yellow. Could of been all the dust... It was glass smooth, with no cracks or crazing, but when I used a flashlight, in the dim light, it "seemed" slightly yellow. I live in AZ, and have been told that once I moved it to a hot dry climate, it would "perk" up and whiten up.. Any further thoughts on this?
>
> Thanks

Any 13 year old polyester finish can be expected to be a bit more yellow than when fresh. With some luck it will come more white when lightly sanded and polished.
Also note that some of these materials are a bit more "creamy" and not as pure white as others,
It won't bleach white in the sun.
Get it out in good light and look at it.
How perfect did you expect it to be 13 years later?
Good Luck
UH

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No expectations at all. Just wanting to get other opinions.. Just as long as nothing structural was wrong with it I guess is the ultimate goal.

I don't need luck, I've got the winning lottery numbers..8-)

[Charlie M. (UH & 002 owner/pilot)]

On Monday, January 5, 2015 2:16:45 PM UTC-5, wrote:
> I recently looked at a glider that had been refinished by Dave Nelson in 2001/2002. It has been in it's trailer, and hangar for the last 2 years and not flown. It is located in Texas. In the dim hangar lights, the finish seemed a very faint yellow. Could of been all the dust... It was glass smooth, with no cracks or crazing, but when I used a flashlight, in the dim light, it "seemed" slightly yellow. I live in AZ, and have been told that once I moved it to a hot dry climate, it would "perk" up and whiten up.. Any further thoughts on this?
>
> Thanks

As mentioned, it may come up with a good polish, I've seen "brownish" finishes come up nicely with a good machine polish.
If it's not crazed, it's likely fine. Remember, "the air doesn't see the finish color......"

Incandescent lights tend to cast a yellowish light, seeing it in sunlight will show any real flaws, or show better finishes.

[Iain Baker]

I understand that the catalyst for Schwabbellack contained styrene and
that if a finish or repair was not thoroughly post-cured, then the
slightly lower crosslinking density allowed the styrene to migrate to the
surface over time...and styrene is yellow.
Post-curing through localized external heating or cycling the whole
structure to progressively higher temperatures increases the cross-
linking density. (Done properly on a major repair or new-build, this
can substantially eliminate polyester gel shrinkage over time and
largely avoid the need for refinishing. Provided it's not finished in T35
which is not UV-tolerant.)
With Schwabbellack the post-curing 'locked' the styrene and prevented
discoloration.
A chemist would be able to explain better and more authoritatively. Or
Wikipedia !
It's cosmetic only though. I had a new-build LS6 (one of the very last
from Schneider) that had yellow patches where lots of gel had been
used. Went like a dream.
Akso-Noble stopped producing Schwabbellack some years ago but
other polyester finishes are likely to have the same chemicals.
It can be really difficult to see how discolored a finish is - need
daylight but not sunlight and a reference colored surface.

[Diederick]

Op maandag 5 januari 2015 20:16:45 UTC+1 schreef :
> I recently looked at a glider that had been refinished by Dave Nelson in 2001/2002. It has been in it's trailer, and hangar for the last 2 years and not flown. It is located in Texas. In the dim hangar lights, the finish seemed a very faint yellow. Could of been all the dust... It was glass smooth, with no cracks or crazing, but when I used a flashlight, in the dim light, it "seemed" slightly yellow. I live in AZ, and have been told that once I moved it to a hot dry climate, it would "perk" up and whiten up.. Any further thoughts on this?
>
> Thanks

My gliding club owns an LS6 that was acquired after 10+(!) years of indoors storage (inside trailer). Initially it was very yellow in color. I have no background in chemistry, but I like to think there might be a chance that the original coat of solid wax was what had discolored. Now, two years later, it looks quite nice and the white color has brightened. Machine polishing sure does help.

Best regards,

Diederick
(NL)