Restoring yellowed decals?

[Miko]

I've read putting yellowed decals in a plastic bag and leave them in strong sunlight restores them to their former glory, Is this a real thing?
If so, how long does it take?

Miko (it would be good if it worked on yellowed vacformed canopies!)

[Tim Marlow]

I’ve read about it in several places, but not tried it. I’ve always assumed the decal undergoes some sort of UV bleaching. I would think the plastic bag is counterproductive though, cutting down the UV reaching the decal. From what I’ve read you tape the decal sheet, image side outermost, to the inside of a Sunny window and leave it there for a few days.

[Dave Ward]

I can confirm that this does work to a certain level - It can restore to useable, but don't expect it to be pristine! I used an old photo frame - the glass keeping things flat. I actually left them in the window for a few weeks ( OK, I forgot I put them there! ) . I don't think you'd have much success with all white decals, but what have got to lose?
Dave

[Guest]

the inside of a Sunny window

Safety tip: Do not do this on a window that might get condensation on it. Any double-glazed window should be safe, of course.

[Ian M]

What's a bright, sunny day?

[Miko]

I’ve read about it in several places, but not tried it. I’ve always assumed the decal undergoes some sort of UV bleaching. I would think the plastic bag is counterproductive though, cutting down the UV reaching the decal. From what I’ve read you tape the decal sheet, image side outermost, to the inside of a Sunny window and leave it there for a few days.

I assumed the plastic bag was to stop dehydrating the decal sheet which would lead to cracking, maybe?

I can confirm that this does work to a certain level - It can restore to useable, but don't expect it to be pristine! I used an old photo frame - the glass keeping things flat. I actually left them in the window for a few weeks ( OK, I forgot I put them there! ) . I don't think you'd have much success with all white decals, but what have got to lose?
Dave

Photo frame! Genius! Thanks!

Safety tip: Do not do this on a window that might get condensation on it. Any double-glazed window should be safe, of course.

Yep, good thought!

What's alright sunny day?

Erm?

Miko (the stash stock-take continues)

[Andy T]

I've recently had partial success with that method, after picking the correct window! Some of our newer ones have a UV reflective coating and obviously didn't work...

[davecov]

I suggest you buy a UV lamp that is used for drying nails to cure yellowing decals.

This is a simple unit I bought 13 years ago:


The decals before "treatment"


After 24 hours (continual use)


After 44 hours (continual use)


I kept the unit on continuously for 44 hours and as you can see, the results are very good.

I have since replaced the unit with a bigger one with two lamps and a timer and it works even better.


Dave

[Miko]

I've recently had partial success with that method, after picking the correct window! Some of our newer ones have a UV reflective coating and obviously didn't work...

So it is the UV in the light that does whatever it does?

I suggest you buy a UV lamp that is used for drying nails to cure yellowing decals.


I have since replaced the unit with a bigger one with two lamps and a timer and it works even better.


Dave

Good to know! That's quite a commitment to deyellowification of decals! Are there other modelling related applications for such a device?

Maybe we could just send you our decals to be de-yellowed for a small fee! Ha!

Miko (obeying the laws of physics)

[davecov]

Miko, you can also use the UV lamp to cure UV Resin.

Dave

[Ian M]

I assumed the plastic bag was to stop dehydrating the decal sheet which would lead to cracking, maybe?



Photo frame! Genius! Thanks!


Yep, good thought!

Erm?

Miko (the stash stock-take continues)

A bright sunny day ...auto correct it fun when you have it set to Danish but write in English lol.

[Miko]

A bright sunny day ...auto correct it fun when you have it set to Danish but write in English lol.

Det var det, jeg troede, du mente (that's what I thought you meant)

Miko (isn't Google translate just brilliant)

[Ian M]

Det var det, jeg troede, du mente (that's what I thought you meant)

Miko (isn't Google translate just brilliant)

Don't use it that much. Fluent in Danish and English, (And all the common varieties of it.

[Tim Marlow]

Don't use it that much. Fluent in Danish and English, (And all the common varieties of it.

I’m fluent in Wiltshire and Somerset, but unfortunately Google translate doesn’t do those…..