karenkstudio Posted June 17, 2018 Report Share Posted June 17, 2018 The results for raku firing always very, and I've heard that humidity effects results. During my last 2 firings I noted the humidity % and noticed a difference with the copper glaze results. At 80% humidity my pieces were an iridescent green with a little copper color. At 50% humidity they were copper with a few other iridescent colors. Has anyone else noticed this specific anomaly? Link to comment Share on other sites More sharing options...
JohnnyK Posted June 17, 2018 Report Share Posted June 17, 2018 As you've noted, Karen, Raku firing results ALWAYS vary...in your case I would have to assume that everything was exactly the same for each firing except the humidity. You pulled your pieces, which were glazed exactly the same, at the same temp each time and reduced them in the same combustible material each time for the same amount of time and used the same method of cooling before quenching... and you've done this more than twice... My experience has been that just a different placement in the reducing bucket, the amount of combustibles below and above the piece, how long the bucket stays open before covering by even a few seconds...ALL can have a different effect on how your pieces turn out. With the heat levels that you are dealing with, I find it difficult to accept that the level of ambient humidity, for the amount of time between the kiln and the reducing bucket, would have that great of an effect on the performance of the glaze between one firing and another. I would suggest that you do a number of further firings with the EXACT same conditions before you draw any specific conclusions. in the photo, the 2 top pieces of the fountain were glazed the same, and fired at the same time and reduced in the same bucket, but came out looking very different...results do vary! JohnnyK Link to comment Share on other sites More sharing options...
neilestrick Posted June 18, 2018 Report Share Posted June 18, 2018 I don't see how humidity would have any effect on raku results. I think that's just a convenient place to put the blame for variations in the results. Link to comment Share on other sites More sharing options...
karenkstudio Posted June 18, 2018 Author Report Share Posted June 18, 2018 Johnny, My system for raku firing is the same each time. Can and materials are the same each time for reduction. I've used this system 50+ times, of course with varying results when using the copper glaze, and plan to check humidity % during summer months when firing. I enjoy Raku because of the many surprises the process creates. If I don't like the results I just reglaze. Link to comment Share on other sites More sharing options...
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