devitrification on bottles
- This topic has 4 replies, 3 voices, and was last updated 9 years, 10 months ago by Anonymous.
- September 12, 2011 at 9:21 pm #9668kpearmanParticipant
Some bottles I flatten have devitrification especially the blue ones. I usually heat the bottle to 1325 for 30 minutes. I have tried hotter temps for shorter periods but still get the same devitrification. I tried a borax solution but this did not help – in fact it became worse. Any good solutions?
KeithSeptember 12, 2011 at 10:53 pm #12204Stephen RichardParticipant
720C is right in the middle of the devitrification zone, so soaking for 30 minutes there is not a good idea. Try a long soak at ca. 677C or a quick one at 760C. But the main thing is to have every thing very clean. Contaminated surfaces, even if only a little, on bottles and float glass lead to devit very easily.
Stephen RichardSeptember 13, 2011 at 3:00 pm #12205kpearmanParticipant
I usually clean with isopropal alcohol. Is there something better?
KeithSeptember 13, 2011 at 10:12 pm #12206Stephen RichardParticipant
If you have water without lots of minerals in it use it. Otherwise do the final rinse with distilled water and polish dry. But you will still have a portion of the bottles devitrifying – it seems to be tne nature of bottles.
Stephen RichardSeptember 18, 2011 at 12:46 am #12207AnonymousInactive
Isopropal alcohol comes in different concentrations – typically 70% and 91%. Use the 91% (most pharmacies carry it – and it doesn’t cost a lot more). The non-alchohol portion can contain oils that don’t help.
As Richard suggests, buff your glass clean as a last step. Use a clean, cotton rag. Make sure it wasn’t dried using dryer sheets – they leave residue in the fabric that transfers to the glass.
Helios Kiln Glass Studio
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