|Overview|||||Glazing|||||Kiln & Firing|||||Slip Casting|
Raku Kiln Firing
The first step in the raku kiln firing process is to set up the kiln. There are many ways of making and firing a Raku kiln. What follows is the approach that I have developed that works for the type of raku ware I produce.
I prefer a soft brick kiln to fiber; mine is made of k-23’s. I believe fiber kilns reflect the heat in a more radical way than soft for hard brick; this can cause uneven melt and boiling of the glaze. I am sure people will differ with this point, and I accept the possibility of being wrong on this. I fire updraft; the kiln is a converted Scutt electric. I find that positioning the burner underneath the kiln shooting straight up to a target brick works well.
The bottom shelf is about a foot up from the burner ports with lots of hard brick baffles to break up the flame. This seems to reduce hot spots and facilitate a good recovery time. It normally takes 4 hours at 4 water column inchs to get first load out then 30 minutes at 5 WC” recovery after that. This may seem slow, but faster firings will encourage glazes to boil, resulting in an uneven melt. I find firing on the reduction side of neutral also gives a “fat” look to the glaze. My main focus has been to achieve a smooth and even melt, not a quick temperature rise in oxidation, and then reducing to smooth out the glaze.