Raku frustration

To get good copper reds in Raku, we find that it is essential that the pots still be glowing cherry red when they go into the garbage bin, and the lid must go on asap, and be sealed very well. Any delay and loss of heat and you lose the effect.

We use a small wood fired brick kiln - once it gets to temperature, it retains enough heat to do several pots at the same time - we have had some great results, all shades of red and "copper-plated" pots.

Dave

What is the glaze you are using? That is the recipe???? I have so-so results with my raku. Does anyone have a sea green glaze for raku--could be Ferguson Blue. I love it, but it was from a class I used to attend, and have never been able to duplicate it. I have since moved to the Portland area from the Bay Area where I used it in class.

Have you checked this site it might help.

My experience is the same as Dave's. You want to get it in the reduction chamber as soon as possible. When we are doing a group firing copper glazes come out of the kiln and into thier reduction chamber first, then the remaining pots are pulled. Also a little tip I was given by a seasoned potter was to use the colored Sunday funny pages instead of regular newspaper. I've tried it once since that advice and those pots were the best I have done so far.

Bert

It may not be your glaze recipe. Remember, raku is an ancient technique. They didn't have pyrometers in those days.

The raku technique I was taught never used a pyrometer. We watched for the glaze to bubble and then smooth over. At this point, the piece is pulled and put in reduction chamber. We used a sand pit as a base, placed combustible materials on the sand, and seated the chamber in the sand to minimize smoke. For the swirled reds and blues in copper glazes, we popped the chamber briefly - that is, we lifted an edge to allow air to enter. You can see the colors change and re-seat the chamber in the sand when you see what you want.

The chamber can be any non-combustible container - coffee can, metal bucket, metal garbage can, etc. There are other methods of reduction. One being a covered container in which you place your combustible material, place your hot piece within, and cover. The "pop" technique works well with this method, too. A third that I have never tried, but have seen done, is an open pit where the hot piece is placed on combustible material in an open pit and, when the desired color is achieved, quenched in water. I use the sand pit because I have asthma and it minimizes the amount of smoke. I also wear a mask (not the paper-kind, the ugly bug-looking thing). Just because I have asthma, doesn't mean I can't raku!

Years later, in our pottery, we added a pyrometer to the raku kiln as a rough guide for beginners. But the secret ingredient was always picking the right moment to pull the piece.

The kiln we used was Fiber-Frax lined hardware cloth with a similarly lined garbage can lid for a cover. Hole cut in the lid for proper circulation. The amount of air circulation wass regulated by a combination of adjusting the burner (both the air flow valve and position in the kiln) and a piece of Fiber-Frax to alter the size of the lid vent. This set-up was portable (sand pit on a wheeled dolly) as we had to do the raku firing in a parking lot. I have also used a brick kiln and a 30-gallon garbage can kiln for raku with good results. All of these were top loaders.

May the kiln gods bless your endeavors,

Jan C.

I haven't been reading here for a while. So I'm late on response. Forgive me because I have not yet tried raku but I've done a lot of reading and watching whatever show I can find on television because I have been wanting to do this for years. I'm only describing what I've read and seen. I did read that if you need more of the bright copper effect on your pots you are not getting enough reduction. One remedy was enough combustible material to cut off the oxygen or a smaller (shorter) reduction chamber. This person used a short metal tub rather than a barrel because he had small pieces. He also described the popping technique that Jan Clauson described in a previous post. If you are getting only the bright copper color with none of the blues and greens then there is to much reduction. I did read the pop technique that Jan described to be a remedy. I also saw a show on TV where the person stood the pot on top of the combustible material and grabbing it at the top with tongs moved it a little from side to side while the combustibles were flaming up around it. He then put the lid on for reduction. His pots had gorgeous color. Good luck.

we get great reduction reds & coppers when the copper based raku glaze is sprayed with water while IN the reduction container. there's some extra oxidation that occurs when lifting from the reduction can to the water dunk that seems to change the glaze. reliable results - for us - by spraying water into the can before pulling material out.

steve

southern california water - maybe there's some extra junk in our water? it does taste a little funny...

steve graber

Here's the recipe for:

Ferguson's Blue (no relation)

Frit 3110 70 Gerstley Borate 5 Flint 10 Soda Ash 10 Kaolin 5 Copper Carbonate 3

-- Gary Ferguson Raku Clay Artist Nampa, ID 83687