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Be Creative Delphi Glass Blog

Denise Christmas-Gibson

Studio News: Tips for Using Frit Molds

by Denise Christmas-Gibson on February 14, 2012 in How-To (3) comments
Studio News: Tips for Using Frit Molds

Frit Molds are becoming increasingly more popular, especially with all the new styles of jewelry molds coming out.  Getting a beautiful finished project can be tricky at times. 
Issue #1:  Glass tends to stick;  and create sharp ‘daggers’ on the sides of the glass project.  This can happen when the glass ‘separator’ is getting thin or worn away.
Boron Nitride MR-97 is the answer.   It is a versatile product that can also be used on stainless steel molds as well.  Think of it like ‘teflon’ on your frying pan.   It will not allow the glass to stick to the mold.  Projects pop right out and are ready to wear.  You do have to follow the instructions and reapply as directed.  
Watch a video on how to use Boron Nitride MR-97.
However if you do get ‘spurs’ on the sides of your project, simply use a wet hand sanding pad to clean up the edges.
Issue#2:  The frit is trapping a lot of air bubbles that you can see in the finished project.
That’s frit for you.  Air bubbles will happen, however if you change the ‘soak’ or hold time based on the size frit you used, you may have better luck.  For example, if the mold calls for a 10-minute hold for fine frit, then it might be 25-30 minutes for medium frit and 30-35 minutes for course frit.  I don’t normally recommend coarse frit for casting molds.
For best results, follow instructions for the frit ‘weight’ you should add.  After filling the mold, brush it slightly away from the edges.  Use an underglaze pencil to write the ‘weight’ requirements on the side of each mold when you get them.
Some other helpful tips when using frit molds:
•    Never fire your mold more than 500 degrees per hour; and never over 1450 degrees. 
•    Mix your color frit (1 part) with 5 parts clear or water clear frit.  Then add a couple drops of water, so that you get a better sense of what the color will turn out like. 
Check out these hot new jewelry molds...
Pictured top left: Necklace made with new NEW Nano Beads Mold. Read this project sheet from Colour de Verre on How to use the Nano Bead Molds.
Pictured middle right: Heart Trio Earring & Pendant Jewelry Mold.
Pictured lower right: Pillow Pendants Mold. Read this project sheet from Colour de Verre on How to Use the Pillow Pendant Mold with Dichroic Glass.



1 Post
Thursday, October 30, 2014
I purchased 3 jewelry molds from Delphi. I have tried two different places to fire them and none have turned out. How to I find out what the exact fire process is for my molds.
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147 Posts
Top Contributor Gallery Artist
Chandra Agostini
Wednesday, February 6, 2013
@JackiS Yes, you can certainly use the MR-97 on molds that have previously been treated with a primo-primer (or the like). It is recommended that you remove as much of that previously applied product as you can before spraying on the boron nitride spray so that all of the raw mold can be exposed to the spray. Just remember that once you apply the boron nitride spray it will not take the other kind of release anymore, but popular opinion boasts that it is well worth the switch.
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3 Posts
Monday, January 28, 2013
I just ordered MR-97. I understand about using it to prime new molds for easy glass release, but is it possible to begin using it now on already- used glass molds which have previously been primed with a powdered release agent/kiln wash (the kind you mix with water and brush on, then fire)?
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