Spectrum 850 Series Sample Pack 4oz jars
Quick Overview

Contains: 851 White, 852 Turquoise, 854 Celadon, 861 Metallic, 862 Galaxy, 863 Nebula, 864 Sunspot, 866 Deep Space, 868 Gator, 870 Starry Night, 873 Red, 874 Metallic Lime

Raku glazes were developed for firing in either electric or gas kilns.  The firing process is described below.  All are lead free except the discontinued colors which are marked.

Some are AP Non-Toxic.  852, 853, 855, 860, 861, 863, 864, 865, 866, 868, 870, 879 are Caution Label which means these particular colors contain some colorant such as cobalt, copper, or cadmium which pass tests for release when fired to temperature, but are not safe to "drink" in liquid form.  Here at, we like to say: Please don't drink any glaze! :-) 

Raku temperatures are low and not predictable, so Raku is typically not used in dinnerware.  However Spectrum does consider these dinnerware safe.

The liquid glazes are set up for brushing application.  They can also be poured or dipped, although they should probably be thinned with a little water for this type of application.  The dry glazes are set up for dipping application.  Due to the many variables involved in Raku firing, particularly during the reduction phase, our color charts should be used only as approximate guidelines.  Your results may vary greatly.  

Rakuing Process: Raku glazes should be fired up to cone 06 (1850 F) in either an electric or gas kiln.  They they should be allowed to cool in the kiln to 1400 F.  While still red hot they should be transferred as quickly as possible into a reduction bin (typically a metal garbage can or small metal container with a lid that has been lined with organic material such as newspaper and/or sawdust, etc.) 

As soon as the pieces are in the bin the lid should be put on to keep oxygen from entering the container, in order to develop the reduction atmosphere.  The pieces should be allowed to cool in the bin for at least 20 minutes.  

When the red hot pieces go into the bin, the organic material ignites producing flames and smoke so this part of the firing should be done outside.  

Firing tips: 

Try to size the reduction bin to the size of the piece being fired. Position the organic material and the piece so that the flames can get all around the piece. Different organic materials can produce very different results, so for example a glaze reduced in newspaper could be a beautiful blue color and the same glaze reduced in sawdust could have a metallic copper appearance. Pieces should be cleaned immediately with water and a hard bristle brush. (Note from Cindi - Ajax and Windex also work great for this.) After cleaning, warm the pieces in the kiln to evaporate any water from the piece.  This helps to set the colors more permanently. 

Note:  Small tiles are electric kiln fired (oxidation) to 1600F.  Large tiles are electric kiln fired to 1600F then reduced in newspaper.

Pint sizes are stocked in all colors.  Gallon and 10# sizes are special order, except for some popular colors.  We don't mind special orders at all.  However, we order about once a month so your order could take up to a month to arrive.  If you prefer to drop ship your special order items, Spectrum charges a $10 drop ship fee.  Spectrum only ships once a week, so this may be faster than waiting for our next order, but not as fast as we usually ship.  Please check a box below, OR indicate in your comments when you check out if you wish to pay the fee to get your glazes sooner.  (Note: If you purchase $150 in Spectrum glazes, we will pay the drop ship fee for you!)  To speed up your order, please click one of these boxes if you have special order items.

Cone Low Fire Raku Process
Dinnerware Yes*
Lead No, except discontinued colors
Safety label Some AP Some CL
Volume Gallon
Shipping Group Parcel
For Schools Order using a PO & other useful information.


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