Protecting irridized surfaces

[crocusmartis]

Is there a way to protect irridized surfaces exposed on the surface while fusing? The glass I am using is spruce pine with kugler / reichenbach / gaffer - then sprayed with stannous - annealed - then used for a fusing project.

[Brock]

I'm not getting this. Protect it from what?

[crocusmartis]

The irridized surface likes to burn away slightly. It is very vibrant on the blown pieces that I create but loses its punch when fused. I realize that the fumed surface is extremely thin and also flows / stretches / etc. when it is being taken up to high temperatures. Compared to working the fumed glass in the glory hole, the kiln is way cooler yet the higher temperature doesn't diminish the color. Will a product like Super Spray Over glaze protect a stannous irridized surface and keep it looking more vibrant?

Here is how the glass typically looks to start with:

Here is a typical fused result - piece was full fused and slumped. The blue pieces in the fuse originally looked just like the prior image.

[Brock]

No, overspray won't work. Try a gather of clear, after you've sprayed the stannous.

[Judd]

Are these flat sheets of glass? If so, I fire iridized side down. After full fuse, the slumping isn't hot enough to destroy the coating.

[williamslaybaugh]

In my experience spruce pine is not a good kiln working glass, it easily devitrifies and becomes cloudy. I think it might be the glass its on that's causing your irridized surface to loose its shine. Have you tried fusing any without the irridized coating to see how the glass reacts on its own.

[crocusmartis]

I have fused SP many times without the stannous fuming and have had good results so I am not thinking the base glass is an issue. The pieces I am fusing with are sometimes moderately flat or can have a slight bend to them- determinately not like flat sheets. I started down this path of madness because I wanted to salvage some pretty blown pieces that ended up being floor models.

Here is my process for making the fumed glass:
SP clear - coated with silver bearing colored glass frit - reduced in the GH - sprayed with stannous chloride (reagent grade anhydrous stannous mixed with distilled H2O) - exposed to reduction atmosphere again in the GH (mattes the finish out)- then annealed.

[Tom Fuhrman]

you'd be better off putting the pieces in a warm oven and then picking up and use as decoration on other blown or solid pieces comingout of the furnace. holding at fullfuse temps changes the surface on those pieces. BTW: stannous works a lot better on glasses that have bit of metal in them as opposed to Spruce Pine. another hint, did you add a little muriatic acid to your stannous solution?