Practicing with wine bottles - devit problem

[CCVICKERS]

Hello all,

I'm very new to fusing. (Brad's awesome intro class, his book and this great forum are the bulk of my "experience") I've been practicing with my new, first, kiln by melting wine bottles with different schedules, forms, and shelf release (paper, fluid and cloth). I'm starting to get a bit of understanding with scheduling. I DO understand that bottle glass is "unknown" therefore unpredictable. My expectations are not for perfection... but better than 50% to reproduce an out come.

My "projects" were all going well, then all of a sudden I began to get devit on the bottle closest to the front of my Fusion 16 kiln. The bottles are spotless. I'm using Spartan glass cleaner as my final cleaning. I'm using dedicated, smooth contain bar towels. I'm using Primo kiln wash. My molds are very thick (Love them! bought them on etsy) I wear white cotton cloves to load the kiln. My molds are dry. I've been using Primo kin wash. My schedule is as the mold maker directed:

500/180/30
500/950/0
275/1365/5
AFAP/1020/45
150/700/off

I don't open the kiln until <200. I've been using the same shelf that I kiln washed when I first got the kiln. I haven't applied kiln wash since. My kiln has bead doors in the front that are closed. I don't have a vent hole.

Is there something I should be doing or doing better? Could there be something that's contaminated the kiln and causing the glass closest to the from to devitrify? I can put 2 bottles in the kiln, parallel with the front of the kiln and the front one has been devitrified for 4 runs in a row.

Any help would be appreciated. I would like to move on to real fusible glass, but I'm afraid to ruin it.

Thank you, Carla

[Kevin Midgley]

my only suggestion when working with bottles is to ......
buy fusible bullseye glass and you will have more consistent results.

[Bert Weiss]

Placing glass too close to an element or the edge of the kiln, can create problems. If your problems are consistent, look at what else is consistent in the cleaning protocol, shelf prep, and placement.

[Brad Walker]

Some things to try:

Rotate your shelf so you can determine if the problem is the shelf or the placement of the bottles in the kiln.

Lower your top temperature in the firing. (that's a strange schedule, by the way, strange stops on the way up)

Check to see if the kiln heats evenly. You might have a hot spot in the front.

Do you reapply the Primo Primer every time? What kiln of shelf primer is on the shelf?

Has anything else changed? How you use the bead doors, for instance? The type of bottle?

One more thing -- while using bottles will help you learn the mechanics of your kiln and get you started, you'll find that firing using fusible glass is a very different animal.

[JestersBaubles]

Try some devit spray -- either commercially purchased or mix up your own from 20 Mule Team Borax (google and you'll find a recipe).

Dana W.

[CCVICKERS]

Thank you every one for you kind advice. Some followup...

I clean these bottles with oxy clean and dawn, followed by goo-be-gone, followed by dawn and a scrubbing pad, dry them then wash and dry with Spartan glass cleaner and a dedicated white cotton towel that have never been washed with fabric softener. The bottle colors are green, antique green, light antique green, and clear. I slump 2 "like" bottles each time to keep a constant, as I log data and results for each run.

I've rotated my shelf each time for 3 firings. Ive rotated the molds in the kiln for one firing. I don't see the devit follow. IOW, if i rotate the bottles the devit should go across both bottles that is closest to the front of the kiln... it didn't do that. I paid attention to rotate the shelf and the molds so they would be perpendicular to their original placement.

The schedule was supplied by the mold designer. The 500/180/30 is to dry the molds according to the instructions. These molds are very thick and heavy, not the thin, hollow walled molds. Maybe that is the difference for the atypical schedule.

I never use the bead doors. I only had them installed because my mother-in-law wants to try bead making someday. I don't even open them to peek at the glass during firing. I have a window. I have no side elements. My top elements are new and lay evenly in their tracks.

I still don't really have a frame of reference when I'm told to lower the temperature. How much of a temp reduction is enough? From 1365 do I go to 1350? 1300? I did one run with a lower temp at 1350 for 5 min. and still got devit. I do think my kiln runs on the hot side.

I haven't primed the shelf itself since the original "getting ready for first use". I've always use either shelf paper or Refrisal cloth (so far) if firing directly on the shelf. (I didn't get devit any time I used those two products, with any bottle glass).

During all my experimentation the only thing that's changed is the shelf primer. When I first started slumping bottles I'd used the kiln wash that came with my Paragon kiln. I didn't experience any devit. When I ran out I bought Primo. I'd been reapplying the kiln wash each firing, then I tried one firing with out reapplying, it worked, so I've been using it for 2 firings. I always move the mold that is on it's second firing to the back of the kiln and place the mold with a fresh application of kiln wash in the front, or to the right if I rotate the molds. The bottles with the fresh primer are the bottles I'm getting the devit on 90% of the time. Sometimes I'll get a little bit of devit on the bottle adjacent to the freshly primed mold, on the edge closest to the freshly primed mold, as well. When this first started I'd had a feeling it could be the Primo, but couldn't find a single forum, blog or internet article where anyone else reported having a similar experience. I set the thought aside and worked more on cleaning. I don't scrub off any of the old primer since it's very smooth and in tact. I add a single coat of new primer over the old. Could that be what i'm doing wrong?

As Dana suggested, I fired one with devit spray. It turned out very nice and shiny. Kiln wash stuck tot he back... I think I may have over sprayed. I'll take care to wipe off the back next time.

Thank you all for your help!

[Valerie Adams]

Carla, is your plan at some point to work with fusible glass? Sounds like you're just practicing with bottles? If so, then for all the time, attention, and detail you're putting in to your efforts, I'd suggest you take Kevin's advice and just jump in and begin working with materials that are more suitable (and predictable!).

If however, your goal is to work with bottles (I have a strict 'no bottle' policy in my studio ), then it sounds like your newly washed molds may be contributing to the problem. How about firing them first without the bottle? Sounds like some kind of off-gassing from the new wash is adding scum to the bottles.

Remember too that all bottles are different so it's probably more due to the quality of the glass than your cleaning practices, which sound quite sufficient.

[Bert Weiss]

People have all sort of glass cleaning rituals. Mine is extremely simple. I use only Glass Plus from the grocery store, and Bounty (identical) paper towels. It works. You have to train your eye to see the dirt.