An article by Lionel Kong. Thanks Lionel!
For more advanced/experienced customisers, there is a viable option of adding a water-based gloss clearcoat over the sticker sheets before application.
A layer of gloss topcoat or clearcoat is essentially a varnish layer, fusing with the top layer of the sticker paper, and improving its resistance to moisture. Art supply and hobby stores typically have a selection of them as spray cans in stock, but you must choose the correct type. Use only a water-based clearcoat, and those that are designed for clearcoating artworks. A lot of other mass market and automotive-type applications use a very ‘hot’ solvent that may cause the sticker inks to run.
Don’t get fooled into buying satin or matte finish clearcoats, they have their uses, but for stickers on toys, gloss provides the best toughness.
If in doubt, test the whole process on a printed part of the sticker sheet that you will not use, cut off together with the backing paper and separated from the main sheet. Optional stickers that you don’t plan on using make good test mules. You need to check for two things: 1. The spray does not cause the ink to bleed/run. 2. The clearcoat is flexible, will fuse and bend with the paper, and not crack.
You only need to spray 2 fine layers, with about 15 minutes in between. You want the sticker sheets just covered enough to be wet but not totally saturated. The first layer typically soaks into the paper, and the second one levels off nicely.
If you’re new to spray painting anything, practice on something else first until you get the hang of how to move your arm and how long to hold the button down for. Follow the instructions on the spray can, as different brands have their own dry times and optimal application temperatures.
Because the stickers have already been pre-cut, they will still come off the backing paper cleanly as the clearcoat doesn’t seal up the seams between the sticker.. Leave it to dry on the sheet for 8 hours and it should be good to go. Apply like regular stickers.
From my (Lionel’s) experience, I know that these sprays will work, but they may not be available in your country:
A big disclaimer applies: Do this at your own risk and do not expect a free replacement sticker set if you somehow muck up your sticker sheet! The clearcoating option is a suggestion, but the choice, execution, and responsibility to do it properly is entirely yours.
A note from Phil – my stickers should last at the very least as long as the originals if properly applied and cared for without the above treatment and I have not tried Lionel’s suggestions so I cannot directly endorse them – but in the spirit of our fabulous MASK community I am pleased to include his suggestions here on my website, and am very grateful that he has taken the time to submit this article. As noted above though please understand I take zero responsibility for messed-up sticker sheets caused by following – or trying to follow – Lionel’s suggestions!