Go ahead and read below to hear about the experiments (and the comments, some great info there too!), but here is a summary of some of the lessons learned with the various techniques.  What you choose depends on your desired results, and also what you have decorated your shrinkies with:

• Spray Acrylic – As we learned in our previous experiments, this can cause permanant markers to lighten and/or run together.  So use cautiously, or include these ‘bugs’ as features in your design!
• Embossing powder – although several people swear by this, our tester did not have much success.  If you use it anyway for other crafts, and have it on hand, give it a try.
• Polyurethane – my trials with this are documented below.  It is a good option for some projects, but be conscious of the possibility of cracking issues for small items like jewelry that have holes in them.
• Diamond Glaze (or Triple Thick Glaze or Crystal Effects) – Diamond Glaze has consistently good results from testers, and is recommended.  Cons are that it may be hard to find, but I’ve included Amazon Links at the bottom of this post (support Dabbled!).
• Mod Podge: Recommended by a couple of readers, but this was not tested as part of the lab.
• Nail Polish: Apparently works really well, but note that it can yellow over time.
• Spray Poly:  Able to apply a thinner coat than by dipping or brushing, so this might work really well without having some of the downsides of the paint on kind.

Do you have a sealing story to share? Leave it in the comments!

See all 5 installments in this 4 part series! If you’re starting with this one, go read the first several to get to this point.

Also: an Instructable on the original doodle earrings, including some of the lessons learned.

So, I thought I had it all figured out. After some web research, and checking what supplies were in my basement, I figured I’d seal the shrinkies with a jar of Polyurethane.. There are other methods (embossing powder, nail polish, and other stuff–ValGalArt mentioned in the comments that Shrinky Dinks makes something to seal them with) but this seemed like a good bet.

I took two charms (colored front & back), and dipped one (the red one) and painted the coating on the other (green). I then hung the green one to dry thoroughly (the poly needs to cure overnight. This actually worked well, no smearing, colors stayed true. However when I started to take pictures, I noticed that both of them had a tiny hairline crack in the plastic itself, by the hole. I’m not sure if the poly stressed the plastic or what. It seems to be structurally sound (i don’t think it’s going to break at the crack or anything), but still not perfect. So read on..

I figured that the culprit was either hanging them to dry (stressing the plastic more around the hole) or that the top was just too narrow. So I did a few more experiments. “Star” was done as a rounded rectangle, and dipped and hung. No cracking. “Andrea” was done by painting on the poly and letting it dry flat. No cracking. However the yellow “Dominic” was done the same way, and it cracked after I coated one side. So my guess is it’s somewhat hit or miss. The narrow tops of “Andrea” and “Dominic” are just more prone to cracking. But perhaps I didn’t stress the plastic too much when i hole punched “Andrea”. From this I’d guess that the wider rectangle is just less prone to cracking. But it doesn’t seem to matter if you hang them or lay them flat.

So, I appeal to you, my readers, to let me know your results if you try this method, and if you try anything else. Take before and after pics and send them to me and I’ll post them here @ dabbled as a follow-up. I particularly want to see how embossing powder works (it was recommended several places), but I don’t have an embossing gun so I’ll need a volunteer to do that option.

8/8/08 Edit:
Heather Sitarzewski did some sealing research for us! The results:
Better late than never… I tried coating the shrinkies with embossing powder and I ended up with a bubbly, melted mess. So I decided to try a clear embellishing accent called “Crystal Effects” from Stampin’ Up (you can also get something called Glossy Accents from Archiver’s, Hobby Lobby etc.) it worked brilliantly!!! Although I lost the one I did that to… so I’ll have to make more! Will try to post as soon as I have the next batch completed!

Edit: From the commenters:
meggiecat said…
I love shrinky. JudiKins Diamond Glaze in the squeeze bottle works beautifully as a sealer and a glue for multipiece objects.
Lucky Squirrel has a chart about sealers for their PolyShrink product.http://www.luckysquirrel.com/info_sealers.html
Aimee said…
..I’ve used embossing powder on shrinkies before, and it works really well, I think it would be hard to coat both sides though.

I hope you’ve enjoyed this Shrinkies Experiment series! I’ve had a lot of fun trying all this stuff and hopefully you’re now inspired to create some fun stuff from things you would normally throw away.

Oh yeah, and remember, i need validation that I didn’t write all this up for it never to be seen by human eyes… so don’t forget that posting a comment on one of the posts in this series enters you in the drawing to win some of the output of the experiments!

See all 5 installments in this 4 part series!

Not on Amazon: Crystal Effects from Stampin’ Up