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You are mixing metric and imperial here. 2.5 times difference

I have never been able to clean my home made powder or fine frit suitably to avoid discolouration

Sounds to me like too rapid heating on the rise. The glass may have softened at edges and strain became too much for the top layer so splitting.

The raised area in the brown looks like a bubble.
What kind of firing are you using? let us know the ramp speeds, soaks etc. to see if we can help diagnose the issue.

A superficial search of Google indicates hydrochloride will not do the same as sulphur

The kiln wash is generically referred to as a separator. The fact that it is a powdery surface gives less possibility of sticking to the glass, unless you go above 720C. I use Bullseye kiln wash that is tinted pink to give a contrast between a white mould or shelf and the separator. I coat my moulds...

Thinfire does not provide enough absorption of the silver salts to protect the shelf. You need to use 1mm or thicker fibre paper - or whiting, which is cheaper - to protect the shelf.

Suzette We really do need the firing conditions -which are more than schedule. The lay up, the glass manufacturer and styles, the kind of kiln, the separators, etc. - any of the conditions that you can think of. 788C does not sound high enough for a full fuse. What kind of glass are you using? Kiln ...

On the contrary, heating from the top provides a more even heat to the glass. Heat from the sides heats the edge of the glass first. Because glass is such a poor transmitter of heat, this difference is important. Side heat will get the edges of the glass hotter than the center, sometimes enough to c...

Peter,
I think they aim for one a month
Stephen

I suggest you contact Olympic for guidance

I have a Paragon Fire Fly kiln. It has side elements only. From my reading it appears that a side element kiln should be ramped slower than a top element kiln, is this correct? Yes This kiln is brick lined and very small so it retains a lot of heat. Is there anything about this configuration I shou...

Thyere should be a plate with manufacturer's information including voltage and wattage information. It is most likely on side or back, sometimes on the controller, if it is integral to the kiln.

I think they are worth every penny. They are quality productions with assurance the techniques have been thoroughly tested. None of the YouTube variability in quality or the self promotion.

Jan, Essentially you have no anneal cool at all. 530-438 should take about two hours for this tack fusing. 438-370 about one hr. And 370-40 about one hr. (Although it will take much longer for the kiln to cool than the hour. Others may have other ideas, but you should review Bullseye's chart on anne...

Bullseye do a nice Paragon based kiln for the 1,000 mark

I agree with Bert, and think Rosanna's advice should be followed to determine if the glasses are compatible

I understood the items to be clear, so ther is no difficulty in using polarised light filters at right angle orientations to see what stress there is. I'm not a fan of the freezer or dishwasher tests, although I understand they work. If the piece is going to be opaque, then, yes, I would make a clea...

Throughout this discussion on "how fast is safe" there has been no mention of stress testing at the end of the process. That will tell you if the annealing was sufficient. If there is significant stress, slow the annealing down.

The shelf should be below the temperature sensor. The side elements should be baffled so radiant heat does not directly affect the edges of the piece (avoiding the risk of sealing the edges too early) For this kind of lay up I would use something like (all in Celsius) 200-625, 10mins 50-675,30 mins ...