The Glaze Committee’s mission is to keep the glazes and decorating materials in good shape and ample supply and to make sure that club members and students who use these materials are kept informed of all developments.
Welcome to the committee and thank you for your participation.
- Read at least first 3 pages of the booklet called "Glaze Safety"
- Wipe down glazing table, glaze dollies, glaze shelving, and outside of glaze buckets as needed.
- Straighten up glazing area as needed and keep the underglazes, slips, overglazes, and commercial glazes in their designated areas.
- Members should note when an ingredient is getting low and write it down on the list in the glaze room.
- Keep an ample supply of bisqued test tiles on hand for use by the committee. Please make some test tiles if they run low.
- Test tiles should be replaced each time a new glaze is made and the glaze is put out. Old test tiles should be placed in the trash or put on the bucket of old glaze.
- The person who makes a glaze should monitor the new bucket and combine the glaze from the old bucket into the new when there is room. The old glaze bucket needs to be scrapped down mixed and then sieved into the new bucket.
- Be sure that labels on glaze buckets are legible and indicate any problems with running and possible health concerns. When a new glaze is made please label with the date made. Labels should be made for both and lid and the side of the bucket.
- Look for new glaze recipes.
- Periodically stir the glazes, especially those that are infrequently used.
How to Mix a Glaze
- Find recipe in blue glaze recipe book. See if the ingredients are available. If they are not – contact glaze chairperson.
- Find 2 clean 5 gallon buckets and a clean lid. There are various size buckets so make sure that 5 gallon buckets are used. Plug the scale in, turn it on and tare with container on top. You are ready to weigh ingredients. A blue container may be used for quantities greater than 1000 grams.
- Before opening or handling any ingredients, put on a mask and gloves. Do not put your health at risk.
- Get the needed ingredients. The glaze materials are in the sink room, roughly in alphabetical order. Flint and Silica are considered the same (Silica is 325 mest). Colorants (oxides, stains, etc.) are on the top shelves. If there is not enough glaze material or you can’t find it, check the northwest wall of the basement. If you have time to make the glaze all at one time, put 1 1/2 green pitchers of warm water, measuring to the line into a bucket. Measure the ingredients and add them to the bucket. Record the amount measured on a pad. Brush out the scale tray with a brush into the bucket after each ingredient. If you put the ingredients into a dry bucket, whisk the ingredients together.
- This is a good stopping point if you do not have enough time to finish the glaze. Use the drill to mix it thoroughly otherwise.
- Sieve the new glaze through an 80 mesh screen into the second clean bucket. Using the remainder of the water in the green pitcher, rinse the initial bucket and sieve apparatus. Again sieve this glaze through the 80 mesh screen into the first bucket. Fill the pitcher a third time and use small quantities of water to rinse materials out of second bucket. There is a spatula kept with the sieve for scrapping out the glaze. Note: It is easy to add too much water. After two screenings the glaze should have the consistency of light cream. Keep the remainder of the third pitcher of water to add to the glaze as needed later.
- Place lid on bucket and label both lid and bucket with the name and number of the glaze. Put "testing" and date the glaze was made on the lid label.
- Leave glaze to meld in the sink room and come back in a day.
- Be sure and clean the drill bit, extra bucket etc. in the waste water bucket, then rinse in the sink, and put materials and equipment back where they belong.
- A day later, stir glaze and check consistency. The glaze level is usually 2/3 to 3/4 of the 5 gallon bucket. Water frequently needs to added at this point because the glaze becomes thicker when left to sit overnight after the initial making of it. Use the left over water from the third pitcher and write down how much was used. Most glazes take 2 3/4 to 3 pitchers of water. Label a red clay test tile and a white clay test tile with the number of the glaze made plus the date (2/17/10) with the underglaze pencil (hanging cabinet). Dip both tiles to within a quarter of the bottom, hold for 4 seconds. Let dry, and then dip half the tile again for 4 seconds.
Put them in the cabinet to be fired.
- Place the bucket in the corner by the door. It will stay there until you check the fired test tile.
Check the outcome of the test tile firing. If the glaze looks as it should, replace the old bucket with the new putting the old brush in the new glaze. Discard the old test tiles and replace them with the new ones. Keep an eye on the new glaze quantity. When it is low enough to combine old glaze do so by scrapping down the sides and lid of the old glaze bucket and sieving the glaze into the new glaze bucket. Wash the now empty bucket and put it away.
If the test tile does not look right, check your recipe sheet with the original in the book. Check with the Firing Committee for any misfires and consult with other members of the committee. You may need to remove water if the glaze is too thin, or add water if the glaze is too thick.