Project Wrap Up

Once your project is fused, you can slump it any way you would like!

When slumping iridized projects, keep in mind these two important facts from the beginning of this tutorial:

  • An iridized surface on glass doesn’t stretch. If you slump an iridized piece of glass into a deep mold, the irid will likely take on a crackled appearance.
  • Iridized glass reflects heat differently from non-iridized glass. This can make iridized projects more likely to thermal-shock. Conservative firing schedules for iridized projects heat and cool more slowly below 1000° F (538°).

Here’s a close-up photo of the finished glass:

Irid-on-Irid technique

And here’s the completed project:

Irid-on-Irid technique



This is a Fantastic and well illustrated document explaining the characteristics of fusing irid-to-irid glass.  I can't wait to share this with my students.

Thank you,


Sylvanye "Sam" Roh,
Warmglass Artist & Instructor
Designs by Sylvanye Glass Studio
Studio#: 615-397-6406 (TN)

irid-on-irid question

Marvelous explanation of the process of building new techniques for beautiful irids.  I just wondered if you could use etching cream as a substitute for the sandblasting?  Would the cream be strong enough to create the patterns.  Unfortunately, I don't have ready access to a sandblaster.

irid on irid

YES! Etching cream works great. Must be cream, not the liquid. I have done some fantastic pieces with layering not only irid, but dichroic as well. Etching cream works great on dichroic too. Contact paper, if burnished well, is fantastic. Etch resist is great...Use punches to punch out leaves, trees, hearts, or cut your own design. Use the cut out and keep the negative for use in another project. Let's say you punched out a leaf.....on your contact paper. Now you have a sheet of paper with the leaf punched out. This is your negative. Now peel the wax paper and burnish it well. Etch....Next take your little leaf that you punched out (this is your positive) peel the wax paper and burnish it well on your irid or dichro (black backed is best) and etch. You now have 2 pieces of glass: one with a positive leaf, one with a negative leaf. Stack these two, and full fuse. You will have a crisp dichro leaf with a shadow.....and depth. the design possibilities are endless this way, and no sandblaster needed.

shelf primer

I just took a Bullseye class on working w iridized glass; it would have been helpful to read your article beforehand! This occurred to me afterward - I use Boron Nitrate (MR-97) for my mold release; can this product be used as a shelf primer?


Thank you for the great tutorial! I've been learning about irrids for a barter-commission for a friend, and your very clear explanations have helped me integrate information from various sources. Lightbulb moment! And the manufacturing-process video is a nice inclusion.

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