Vac-form canopies going yellow

JayBee · January 07, 2019, 11:42:35 AM

As the title says, I have some vac-form canopies that have started to go yellow.
Does anybody out there know of a way to reverse this.
They are from the Special Hobby F2G Corsair in 1/72.
Could it be the material that has been used to create them?
I have several sheets of Falcon canopies that are far older which are clear as anything!

I would be most grateful for any helpful suggestions.

Jim

Lord_Voyager · January 07, 2019, 12:49:56 PM

It's the UV in the air from non-incandescent light bulbs... I have the same issue with vacuformed ABS and plastic. There are commercial brand cleaners but I find that the methods here:

http://www.howtocleanstuff.net/how-to-whiten-yellowed-plastic/

this should help you out.

The Wooksta! · January 07, 2019, 01:31:28 PM

It's unfixable.

JayBee · January 07, 2019, 01:50:44 PM

Quote from: The Wooksta! on January 07, 2019, 01:31:28 PM
It's unfixable.

Oh F*^$ !

The Wooksta! · January 07, 2019, 02:46:58 PM

Once the chemical reaction starts, that's it. All you can do is get a replacement.

It's not a UV issue. I've several MPM/Special Hobby kits where the contents haven't been out of the packet, just stored in a box well out of sunlight and the canopies are now a nice deep gold. I mean, you could get away with it for the TSR2 (gold in the canopy glass) but not a Ju 388K.

zenrat · January 08, 2019, 03:22:02 AM

Do they get brittle as well?

NARSES2 · January 08, 2019, 06:10:19 AM

Strange enough I was looking at a CMR kit this morning and the canopies had started to turn, whilst a couple of far older ones were as clear as the day they were formed. I've never found rhyme or reason for the process ? $:-\$ and yes I've not found a way to fix it.

zenrat · January 09, 2019, 03:07:04 AM

I've seen it on old toy packaging which I presume uses the same material, albeit thinner, for the "window".

The Wooksta! · January 09, 2019, 03:40:58 AM

I've seen it happen with Lego too. Late 70s onwards. White, yellow and blue are always the worst affected.

jcf · January 12, 2019, 01:52:16 PM

Quote from: NARSES2 on January 08, 2019, 06:10:19 AM
Strange enough I was looking at a CMR kit this morning and the canopies had started to turn, whilst a couple of far older ones were as clear as the day they were formed. I've never found rhyme or reason for the process ? $:-\$ and yes I've not found a way to fix it.

Different types of plastic used for the particular canopies, nothing to do with the age of the kit.

NARSES2 · January 13, 2019, 04:20:37 AM

Logical Jon

Rather naively I just assumed that they'd have used the same type of plastic, but then to me plastic is plastic. Now try getting me on the subject of different types of "steel"

PR19_Kit · January 13, 2019, 08:36:21 AM

Quote from: NARSES2 on January 13, 2019, 04:20:37 AM

Now try getting me on the subject of different types of "steel"

It's all metal 'innit?

Gondor · January 17, 2019, 01:39:04 PM

Quote from: PR19_Kit on January 13, 2019, 08:36:21 AM
Quote from: NARSES2 on January 13, 2019, 04:20:37 AM

Now try getting me on the subject of different types of "steel"

It's all metal 'innit?

Depends on the PSI you want to put through it I would guess

Gondor

zenrat · January 18, 2019, 03:38:19 AM

Quote from: Gondor on January 17, 2019, 01:39:04 PM
Quote from: PR19_Kit on January 13, 2019, 08:36:21 AM
Quote from: NARSES2 on January 13, 2019, 04:20:37 AM

Now try getting me on the subject of different types of "steel"

It's all metal 'innit?

Depends on the PSI you want to put through it I would guess

Gondor

Is that irony?

kitnut617 · January 18, 2019, 06:08:27 AM

Going through my stash over the weekend and found I have a M&E Models Jetranger conversion (can't remember when I got it) which is vacuformed in clear. And it's going yellow now too. But the RarePlanes clear vacuform one I also have is clear as clear (they're packed together in the same box)