2 copies same kit: yellowed vs. non-yellowed vac canopies

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2 copies same kit: yellowed vs. non-yellowed vac canopies

Joined: August 11th, 2005, 11:43 pm

March 17th, 2012, 6:04 pm #1

I know there is no way to fix a yellowed vac canopy from an older Czech-made limited-run kit, but I recently acquired another copy of the LTD 1/48 IAR-80 kit (c. 1996) and the canopies- which were rattling around loose- look great. On mine, stored in a plastic baggie, they are yellow-brown already. Now at least I have 2 good ones (YAY!)

I'm wondering if anyone has knowledge of plastics or advice on storage conditions which may help extend the life of these things. (freezer bags vice "sandwich bags" vice kit sprue bags? Wrap in tissue?) I've got 10's of kits with similar canopies and I'd hate to think it's leaching plasticizers from my own storage attempts that ruins them. I tend to doubt that they changed the grade of plastic mid-production run, but it is of course possible.

I know "yellowed canopies" is a FAQ but a quick search of that term, and "yellowed vac" turned up nothing for some reason ("Yellow" turns up thousands: popular color!). I use PETG when I vac my own and have no problems. I even have some sheets of .010" clear from 1977 that are only slightly yellowed.

TIA
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Joined: August 12th, 2004, 3:14 pm

March 17th, 2012, 6:07 pm #2

I don't think how you store it has anything to do with keeping vac canopies from yellowing or not. A big part of the problem seems to be the plastic used by some companies. It seems also that they may use what is available and not always the same plastic. I have some Rareplane kits with yellowed canopies and some from the same vintage that have not (or not as much)
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Joined: February 27th, 2005, 2:27 am

March 17th, 2012, 8:28 pm #3

Falcon/Squadron (?) canopies on models built over 15 years ago that are just as clear as the day I placed them on the model. I do wonder if:
1) Was it was the type of plastic that the manufacturer used?
2) Both canopies are coated with Future and the models have been kept in a display case out of direct sun light in a climate controlled environment.
3) The canopies before use were kept in a original boxes/ bags in a dark closet that was also climate controlled.
Environment or manufacturer's choice of plastic?
Last edited by pat9d on March 17th, 2012, 8:31 pm, edited 1 time in total.
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Joined: November 17th, 2006, 1:18 pm

March 17th, 2012, 8:37 pm #4

I know there is no way to fix a yellowed vac canopy from an older Czech-made limited-run kit, but I recently acquired another copy of the LTD 1/48 IAR-80 kit (c. 1996) and the canopies- which were rattling around loose- look great. On mine, stored in a plastic baggie, they are yellow-brown already. Now at least I have 2 good ones (YAY!)

I'm wondering if anyone has knowledge of plastics or advice on storage conditions which may help extend the life of these things. (freezer bags vice "sandwich bags" vice kit sprue bags? Wrap in tissue?) I've got 10's of kits with similar canopies and I'd hate to think it's leaching plasticizers from my own storage attempts that ruins them. I tend to doubt that they changed the grade of plastic mid-production run, but it is of course possible.

I know "yellowed canopies" is a FAQ but a quick search of that term, and "yellowed vac" turned up nothing for some reason ("Yellow" turns up thousands: popular color!). I use PETG when I vac my own and have no problems. I even have some sheets of .010" clear from 1977 that are only slightly yellowed.

TIA
suppliers.

Were the two kits bought at the same time? But even if both kits were produced at the same time, they (or their sub) just may have run out of clear sheet and bought another batch from someone else.

The Sq vacs don't yellow over time (knock wood) simply because of the brand/type of clear sheet they used.
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Joined: February 27th, 2005, 4:16 am

March 17th, 2012, 9:41 pm #5

I know there is no way to fix a yellowed vac canopy from an older Czech-made limited-run kit, but I recently acquired another copy of the LTD 1/48 IAR-80 kit (c. 1996) and the canopies- which were rattling around loose- look great. On mine, stored in a plastic baggie, they are yellow-brown already. Now at least I have 2 good ones (YAY!)

I'm wondering if anyone has knowledge of plastics or advice on storage conditions which may help extend the life of these things. (freezer bags vice "sandwich bags" vice kit sprue bags? Wrap in tissue?) I've got 10's of kits with similar canopies and I'd hate to think it's leaching plasticizers from my own storage attempts that ruins them. I tend to doubt that they changed the grade of plastic mid-production run, but it is of course possible.

I know "yellowed canopies" is a FAQ but a quick search of that term, and "yellowed vac" turned up nothing for some reason ("Yellow" turns up thousands: popular color!). I use PETG when I vac my own and have no problems. I even have some sheets of .010" clear from 1977 that are only slightly yellowed.

TIA
many, many time on this forum. It's the chemical composition of the original plastic, and Dave is correct; really doesn't matter how carefully you store 'em. The worst ones, pour moi, anyhoo, seem to be the ones outta the U.K./Czech elves (my over-a-decade-old Echelon beeg BAC Lightning now has mellowed into what is almost a medium brown). The Squadron/Falcon ones have gone decades with no yellowing.

Bondo
Last edited by bondo455 on March 17th, 2012, 9:44 pm, edited 1 time in total.
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Joined: February 27th, 2005, 7:34 pm

March 18th, 2012, 3:25 am #6

Falcon/Squadron (?) canopies on models built over 15 years ago that are just as clear as the day I placed them on the model. I do wonder if:
1) Was it was the type of plastic that the manufacturer used?
2) Both canopies are coated with Future and the models have been kept in a display case out of direct sun light in a climate controlled environment.
3) The canopies before use were kept in a original boxes/ bags in a dark closet that was also climate controlled.
Environment or manufacturer's choice of plastic?
Tore never used acetate.
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Joined: February 25th, 2007, 10:52 pm

March 18th, 2012, 3:23 pm #7

many, many time on this forum. It's the chemical composition of the original plastic, and Dave is correct; really doesn't matter how carefully you store 'em. The worst ones, pour moi, anyhoo, seem to be the ones outta the U.K./Czech elves (my over-a-decade-old Echelon beeg BAC Lightning now has mellowed into what is almost a medium brown). The Squadron/Falcon ones have gone decades with no yellowing.

Bondo
PVC plastic will yellow. A better choice for clear canopies is PETG which is a type of polyester polymer. 9" by 12" sheets in various thicknesses are available from K&S.
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