Last Updated: Jul 19, 2016     Views: 30

It is beyond the scope of our museum library to answer technical questions in detail (our library focuses more on the art and history of glass, with some technical information). Also, without seeing your molds and getting more information about your tecniques, it is very difficult to diagnose the problem.

It will take continuing experimentation to resolve your mold problem. For example, try adjusting the heat cycles (it may be too high? too long?); try different mold compositions -- is there enough silica in the mold batch to be compatible with your glass? There may be ways to coat the inside of the mold to decrease porosity.

Contact the "Warm Glass" website -- their exchange of information can be very useful:

Try commercial glasses and mold materials. Companies like Bullseye Glass -- the Warm Glass site lists many such companies -- offer compatible glass and mold making materials.

I am sending a bibliography for molds and mold making. Many of the books and articles give plaster/silica recipes.

I added a kilnworking bibliography -- experiment with the annealing charts you find in these books. Lucartha Kohler's book, Glass: An Artist's Medium" includes an article and chart by Frank Woolley that is a good overview.

The following book is difficult to find, but very useful:

Stone, Graham. Firing Schedules for Glass: the Kiln Companion. St. Highett, Vic, Australia: the author, 2000. 225 pp.

We have many other bibliographies for these topics (one specifically for plaster molds; another for annealing). Please let me know if they would be useful to you.

If you wish to obtain copies of any of the items in our bibliographies, please contact your local library. The Rakow Research Library is a member of the Online Computer Library Center (OCLC); your library can contact us through OCLC or they may mail an Interlibrary Loan form to us. You may request up to five items at a time. We send photocopies of articles and microfiche copies of our books (if they have been microfilmed) through Interlibrary Loan for four weeks use.

The Scholes Library at Alfred University, New York State College of Ceramics is another resource for technical questions. They have a substantial collection of technical information about glass. Pat Lacourse answers technical reference questions ( Their reference desk number is: 607-871-2951. Their library catalog is available for searching on the web:

Please let me know if we can help you again.

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