When decals go Bad? (I mean Yellowing not the TV show :)

The textbook solution is to tape them facing out on the inside of a window pane that gets a lot of sun so the yellow bleachs out. It takes some time. Don't risk doing it in any window that has ever had any condensation form on the inside.

Is there any other way to bleach decals, than by using sunlight? I only ask this as England is rather grey and wet at this time of year, and sunlight is not so common!

You could try a sun lamp or any lamp with a high UV output.

Regards, Rick

Thanks Rick! I'll try that out sometime

Thanks for the tips

However has anyone used a very slightly yellowed decal on a grey paint scheme? How much did it stick out? Does the Micro Sol (or other solutions) help?

Coincidentally, I've just started the ol' bleaching-in-the-sun routine on an old, yellowed decal sheet from a 60's vintage Revell "Jet Commando" B-52. I've had it in about five days worth of good sunlight, but I can detect no difference at all so far.
How long are we talking about here before any results become apparent?

Hate to be a downer, but both times I've tried "window bleaching" old decals, the sunlight took care of the yellow just fine, but once on the models, they yellowed again within about two months. And that was with Future underneath and on top, plus MM flat as a finish coat.
Maybe my experience was uncharacteristic.
Greg

I never had them yellow after sun bleaching. But then again I use a laquer based sealer instead of future. Perhaps that makes a difference.

I've avoided yellowed decals so far but kept the sun bleach fix in mind for when I eventually have to. After reading that the yellow comes back and lacquer overcoat might keep it from happening, my plan is to spray the bleached decals while still on the sheet with something like Krylon, which is an acrylic (lacquer?) clear coat. That also reduces the tendancy of old decals to crack. After overcoating, you'll have to trim around the decals if you want to minimize the extent of resulting clear film but you might as well do that anyway to minimize the original clear area if the bleaching isn't permanent - you don't have to cut through the paper, just score through the film with a very sharp (read new) blade before dipping it in water and then remove the excess clear edge before you slide off the decal itself. Otherwise, you risk having bits of that edge underneath or on top of the decal when it is in place on the model.

do u have to put it in a ziplock bag and tape it to the window?

There was another thread on yellow decals that wisely recommended the ziplock bag to avoid any chance of condensation on the window ruining the decal.

i wouldn't tape it to the window - too risky with regards to condensation especially in a temparate country in the winter. just put it someplace sunny and be patient.

Brian - in the tropics it still took me 3 weeks to get only slightly yellowed decals white again. so i would guess up in osaka in the winter it will take alot longer. patience, just tape it up somewhere where condensation wont be a problem, then go back to check on it now and then.

QUOTE: Originally posted by reggiethedorf [Brian - in the tropics it still took me 3 weeks to get only slightly yellowed decals white again. so i would guess up in osaka in the winter it will take alot longer. patience, just tape it up somewhere where condensation wont be a problem, then go back to check on it now and then.

Thanks, Reggie!
Yeah, it's been almost two weeks, and nuthin'!

Sometimes you have to be veeeeeerrrry patient with them.

So Far so Good ....
I have some old F-16 Decals from a Hasegawa kit they had just started to show some yellowing (very minor) & with only 2 Very Sunny Colorado days they have started to bleach back.
Now for the test... some older Hasegawa A-4 decals that have some morerate yellowing (at least in my limited exp
To get a good consistent pics I have decied to scan them (so not to have problems with lighting & detail of the pics). So for this experiment I plan to do a scan every day or 2 until the start to bleach to document the progress I will post them later if everything works out ;)
Thanks

Well I am quite happy with the results
After just over 1 day a the yellowing is almost totally gone !
Below are the starting scan (2pm Tue) and the scan I did today (5pm Wed ).
(Start


I think my results may be slightly better then other because of my location in Denver. Higher altitude means more rays get through and we have had some very good sunny days the last 2 days here.

Wow!!! I wished I would have known this before .Man!!!!!!! trashed away so many yellow decals .. But the zip lock bags idea is great...! thanks for info. guys. JJ

Wow, Iron Chef! Great results! In only 1 day?!?!?!?!
I tried mine for a sold month, with no change whatsoever.
I guess this Osakan sun just doesn't pack much of a UV whallop!!

I am currently bleacing some old revell decals with this method, in a zip lock bag, and it is working very well. I think being in the higher elevations speeds things up, I'm in Albuquerque, NM.

Kyle