{"id":107,"date":"2009-05-08T10:00:23","date_gmt":"2009-05-08T14:00:23","guid":{"rendered":"http:\/\/nanrothwellpottery.com\/wordpressblog\/?page_id=107"},"modified":"2009-05-10T14:34:02","modified_gmt":"2009-05-10T18:34:02","slug":"firing","status":"publish","type":"page","link":"https:\/\/nanrothwellpottery.com\/?page_id=107","title":{"rendered":"Firing"},"content":{"rendered":"

Notes on Firing Cycles<\/h2>\n

Salt Kiln Firing Cycle<\/strong><\/h3>\n

Turn on VERY LOW in the evening and fire on low overnight.\u00a0 (This is necessary because I\u2019m firing raw work. When I fire only bisqued work, the first fourteen hours of the firing can be compressed into about five.)<\/p>\n

Gradually turn up the heat until on full in the early morning. (I usually turn it up in three small increments at around 1:00, 3:00 and 5:00 AM.)<\/p>\n

My current salt kiln tends to fire in a neutral to slightly reducing atmosphere, so I only intentionally put it into reduction during two brief 45 minute periods at cone 06, and at cone 4-5. (Reduction by adjusting the passive dampers in the chimney.)<\/p>\n

After the second reduction at around cone 5, I reoxidize until about cone 6-7.\u00a0 At that point, I start introducing salt and continue until it is all in, trying to have it done before cone 10 starts to bend. That process usually takes about three hours.<\/p>\n

Salting is followed by a late firing soak, trying to keep it firing for quite a while without getting any further cone movement — ideally, I want cone 10 over but not flat and cone 11 up. My current kiln is still uneven front to back, so it actually fires with two cone spread.<\/p>\n

I put in about 6 kilos of salt suspended in water and sprayed into the firebox area, not directly onto the pots.\u00a0 My salt kiln has four stacks of 12’x24″ shelves.\u00a0 It is a hardbrick car kiln, built by Donovan Palmquist of Master Kiln Builders<\/a>.<\/p>\n

Cone Ten Reduction Firing Cycle<\/h3>\n

Start on low heat for about two hours (longer if the pots are very recently glazed)<\/p>\n

Turn up in two increments for a steady rise until cone 010<\/p>\n

60-90 minutes of heavy reduction \u2013 I reduce the oxygen by adjusting active and passive dampers, and making the gas\/air mixture richer<\/p>\n

<\/strong>Keep the kiln in light reduction until end of firing — ideally I want cone 9 flat, 10 going over and 11 still up.<\/p>\n

Carbon Trap Shino Firing Cycle<\/h3>\n

Low heat for about two hours (longer if the pots are very recently glazed)<\/p>\n

Turn up for a steady rise until cone 018-016<\/p>\n

90 – 120 minutes of VERY heavy reduction \u2013 I reduce the oxygen by adjusting active and passive dampers, and making the gas\/air mixture richer.<\/p>\n

Keep the kiln in medium reduction until end of firing — ideally I want cone 10 flat, and 11 half over.<\/p>\n

Further notes on Firing<\/h3>\n

When I set up my first studio in Virginia in 1973, I built a salt kiln. During most of my time as a potter I worked exclusively in salt. About seven years ago, I had to convert my old salt kiln to reduction. (The bricks were deteriorating and I made that switch to prolong the kiln\u2019s life.) After working just in stoneware for a while, I built a second kiln for salt, so now I have the option of both. That combination, plus the chance to put pots into my friend Kevin Crowe\u2019s<\/a> anagama\/noborigama wood kiln, means that in pottery terms, I live in the best of all possible worlds. I\u2019ve enjoyed finding and developing reduction glazes \u2013 the expanded color range, the chance to learn new ways of decorating. But if I could only work in one firing, it would still be salt. It doesn\u2019t make economic or business sense, but I love the warmth and texture of salt glazed pots!<\/p>\n","protected":false},"excerpt":{"rendered":"

Notes on Firing Cycles Salt Kiln Firing Cycle Turn on VERY LOW in the evening and fire on low overnight.\u00a0 (This is necessary because I\u2019m firing raw work. When I fire only bisqued work, the first fourteen hours of the … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":9,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-107","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=\/wp\/v2\/pages\/107","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=107"}],"version-history":[{"count":11,"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=\/wp\/v2\/pages\/107\/revisions"}],"predecessor-version":[{"id":140,"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=\/wp\/v2\/pages\/107\/revisions\/140"}],"wp:attachment":[{"href":"https:\/\/nanrothwellpottery.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=107"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}