Kiln Fired Glass Enamels – Frequently Asked Questions

 

Q1. What is the difference between products referred to as “Glass paints”, “Vitreous Enamels” and those referred to simply as “Enamels”.?

Q2. What are  “Glass Enamels”?

Q3: What is “flux”?

Q4. Are glass enamels the same as ceramic glazes?.

Q5. Are glass enamels the same as ‘china paints’?.

Q6. Are glass enamels the same as metal enamels, such as used for jewelry work?

Q7: What is “Frit”? Is it the same as glass enamel?

Q8: What is “powder”, is it frit? Is it enamel?.

Q9: Can glass enamels be fired in a kitchen oven?

Q10: How are glass enamels applied to the glass?

Q11: What mediums are used with glass enamels.

Q12: Which glass enamels are the most transparent or similar to colored glass in brilliance of color?

Q13: What are these Thompson Enamels that people sift onto glass?.

Q14: Are stained glass paints the same as the glass enamels you’re describing?

Q15: How can I learn to work with Glass Enamels?.

 

Q1. What is the difference between products referred to as “Glass paints”, “Vitreous Enamels” and those referred to simply as “Enamels”.?

A: All are used interchangeably. The terms can be confusing because they can be used to describe a number of glass decorating products. Some of those products are quite different in ingredients, application and behavior. The term “Glass Enamels” is defined below in a more restrictive sense for the purposes of this document. It will be the term used in the rest of the questions.

[return to top of FAQ]

Q2. What are  “Glass Enamels”?

A.  “Glass Enamels” and “Glass Paint”  are glass surface decorating products. They are also called “Vitreous Enamels”. They are made to be melted onto the surface of the glass substrate. Their composition is based upon a framework of silica, similar to the glass substrate itself. They are applied to the surface of the glass, and then kiln-fired so as to melt and form a glass bond with the underlying glass substrate. They are typically composed of  of metallic oxides and fluxes. The fluxes provide the glass-forming component of glass enamels, while the metallic oxides primarily provide the colorant and opacity characteristics.

[return to top of FAQ]

Q3: What is “flux”?

A. Flux is any number of chemicals that are added to the pigment chemicals to provide a glass matrix and bond with the glass substrate. Flux formulations for glass enamels are likely to contain Lead Oxide and Boron Oxide. (Lead free enamels are available). Both Ferro and Reusche sell flux as a product, for use in changing the melting characteristics of their standard enamel formulations.  

[return to top of FAQ]

Q4. Are glass enamels the same as ceramic glazes?.

A. In some cases yes. Most of the commercially available glass enamels either originate-from or are sold as ceramic ‘on glaze’ or ‘over glaze’ colors for tableware and tile decoration. They may yet be a variation of those ‘on glaze’ colors modified for a specific glass temperature range by manipulation of the flux additive. Glass enamels do not contain the kayolin or clays that may be found in some ceramic glazes for stoneware or bisque pottery,.

[return to top of FAQ]

Q5. Are glass enamels the same as ‘china paints’?.

A. Yes, in a particular sense.. ‘China paints’ are the ceramic ‘on glaze’ colors mentioned above.  They’re typically sold in small vials for use in painting decorative porcelain. If the maturing temperature of those china paints are suitable for one’s intended glass painting operation, then china paints are indeed the ‘glass enamels’ appropriate for the purpose.  Most of the vendors for China Paints also sell a version or brand of paints specifically for glass, and call them 'glass paints'. These glass paints may or may not be more appropriate for your needs based on maturing temperature. The ‘glass paints’ will have a lower maturing temperature, as they are usually intended for decorating pre-made tableware, which must retain its shape through the firing. Glass fusers that work from 1350°F-1500°F will probably find the standard temperature China Paints to be more useful than the Glass Paints. They'll also likely find that buying larger quantities from companies like Ferro and Reusche will prove to be more practical than purchasing in vials as 'china paint'.

[return to top of FAQ]

Q6. Are glass enamels the same as metal enamels, such as used for jewelry work?.

A. See the Thompson Enamels question below.  

[return to top of FAQ]

Q7: What is “Frit”? Is it the same as glass enamel?

A: No, the term “frit” refers essentially to crushed glass. The term has two common usages which can be confusing. The most common usage to glass kilnworkers is in reference to a crushed-glass product made by artglass manufacturers such as Bullseye or Spectrum. It may also be homemade by crushing scrap glass. The crushed glass frit from Bullseye or Spectrum can purchased by color, and can be applied to a sheet glass substrate or cast in a mold as a primary artist medium.

 The different common usage of the term is by the enamel and glaze manufacturers. They use ingredients formed into “frits” that wouldn’t otherwise behave properly in their enamel recipes. For instance, flux compounds such as lead, borax and alumina are often ‘fritted’ before being added to an enamel mixture. Frits in this sense are usually made by specialized companies. They use large scale machinery to melt batches of the mixtures. The machinery melts the ingredients, allows it to cool or submerges it in water, and crushes the product. This crushed glass product is then used as a component in  enamel and glaze recipes.

[return to top of FAQ]

Q8: What is “powder”, is it frit? Is it enamel?.

A. The term “powder” usually refers to the smallest/finest grade of “frit” made by companies such as Bullseye and Spectrum. They sell their frit in a variety of different “mesh” categories of fineness. The mesh is a screen of a given number and size of openings per inch. A powder would be that which passes through a 200-or-smaller mesh opening. This product can be used similarly to glass enamel, that is, applied via a liquid medium, or sifted onto the substrate just as one would with the larger-mesh frit. Its behavior and final appearance will be somewhat different than the commercial glass enamels due to its composition and melting characteristics.

[return to top of FAQ]

Q9: Can glass enamels be fired in a kitchen oven?

A; No. There are paint products available from manufacturers such as Pebeo that can be cured in a kitchen oven, but they are not glass enamels. Glass enamels must reach a temperature of over 1000F to melt onto the substrate. Exact firing temperatures vary by product and effect desired.

[return to top of FAQ]

Q10: How are glass enamels applied to the glass?

A: Glass enamels can be applied to the substrate by a variety of means. Most brands of glass enamels are ground finely enough that they can be mixed into a paintable slurry. They can be applied by spray, brush, screenprint, sifting, decalomania or any number of other ways.

[return to top of FAQ]

Q11: What mediums are used with glass enamels.

A: Any glass paint that is applied wet, is wet because it is mixed with a medium. The medium consists of a liquid, or “vehicle”, and a may contain a “binder” for adhesion and other substances such as suspending or spreading agents. Together these additions can turn a powdered enamel product into a paint. The goal for a medium formula is to make the enamel applicable,  to bind the enamels to the glass before they are fired onto the glass, and also to fire-out with a minimum of ash so it disappears from sight on the fired glass.

 Mediums for applying enamels to glass come in several different classes. Most of the distributors of glass enamels sell their product in powder form, and also carry several different medium products. Some distributors will sell their enamels premixed in a medium, similar to artists oil paints. Choosing and manipulating the medium in enameling is a significant learning process in the craft.

 Talk to the distributors, read the warmglass.com archives,  take a look at “Bert Weiss” Ferro Notes” below and experiment. Below are some examples, or classes, of mediums and their characteristics. It would be an oversimplification to categorize the different mediums by application technique, so they’re simply listed in an arbitrary order. (A Gum Arabic/ water medium, for example, can be used for both spraying and for handpainting with enamels. 

Examples of mediums for glass enamels:

 

Water and Gum Arabic – Water is the vehicle, gum arabic serves as a binder. This is one of the traditional mediums used for stained glass tracing and matting. It can also be sprayed and possibly used with other application techniques. 

 

Alcohol and Water –This provides a very thin, low adhesion vehicle for applying via a “matting” process with specialized brushes, or by spray.

 

Oil-based mediums are based primarily on pine-oil derivatives, petroleum distillate products or tridecyl alcohol.  Several of the enamel distributors listed here sell “pine oil” medium for screen printing. Oil-based mediums are largely used for screening processes where a higher viscosity is needed for application and adherence. Some glass artists like to use oil-packed glass paints, such as those sold as Paradise Paints, because they approximate the application feel and handling of traditional artists oil-paints .

 

A different category of mediums based on “oils” are the aromatic oils such as lavender, clove, or anise seed oil. These are used for small scale hand painting and are particularly well suited for fine line work with a pen. Most of the pure seed oil products are very slow drying. Some of the porcelain paint suppliers sell variants of the aromatic oils that do dry more quickly.

 

Water-miscible mediums are popular for hand-painting, spraying and screen printing. The term  “Water-miscible” indicates that the product is water soluble, but it contains no water, and you do not thin it with water. They are based mainly either on ethyl  alcohols or alcohols such as methanol or ethanol.  Glycerin can be added to slow down drying, alcohol to speed drying.  There is some  soap in the mixture to reduce surface tension and prevent beading up on the glass surface.. These mediums are substituted for pine-oil or solvent based mediums as the do not require solvent clean-up, have less offensive odor, are less flammable, and are more environment friendly.

 

Carboxyl Methyl Cellulose-based mediums are another category.  CMC is a gum binder that also serves to keep solids in suspension in a liquid. KlyrFire is a commercial product that is a 3% mixture of CMC and water.  Once this mixture is dry it binds particles together and to the glass. CMC is also used in the formulation of spray mediums. Different percentages of  CMC and water are useful for various applications.

 

The commercial glass decorating industry uses a variety of other mediums for enamel application including thermoplastic mediums, ultraviolet mediums, decal mediums and others.

 

Below is link to an article about oils and mediums used by porcelain painters. In many cases the information is directly applicable to glass paints.

 

Gene Patterson’s article: ‘Oils and Mediums’ on porcelain painters.com

 

 

[return to top of FAQ]

Q12: Which glass enamels are the most transparent or similar to colored glass in brilliance of color?

A: This is a complex issue. Glass enamels, and even frits and powders, are never quite as transparent and brilliant as cathedral or antique glass. All of the enamels will allow light to pass through if applied thinly enough, but will they impart the color effect that you want if applied thinly? Some hues are naturally more transparent than others: blues and yellows seem to readily retain more transparency than browns, for example. Transparent blue-greens also seem to be plentiful. The enamels which are marketed as transparent tend to require heavy application to achieve a saturated hue. Similarly, the enamels marketed as opaque generally require heavy application to achieve complete opacity, Some colors that are transparent at 1050°F lose their coloration if taken to fusing temperatures. Transparent reds tend to be on the violet or rose-color side, and are expensive as well. Reusche and several of the other enamel suppliers sell lines listed as ‘transparent’. In each case there are limitations to the temperature the enamels can be fired-to, and the number of hues available.

[return to top of FAQ]

Q13: What are these Thompson Enamels that people sift onto glass?.

A. Thompson Enamel (see supplier list below) manufactures enamels for metal art and industrial decorative enameling processes.  They also produce an 80 mesh (rather coarse) glass enamel that many artists like to sift onto the substrate through stencils or freehand, similarly to the way Bullseye and Spectrum frits are applied to glass. Like the Bullseye and Spectrum frits, the Thompson glass enamels are a crushed or fritted glass product, rather than a mixture of unmelted fluxes and oxides.  Thompson will mill the 80 mesh product to a finer mesh for application by painting for an additional charge.

[return to top of FAQ]

Q14: Are stained glass paints the same as the glass enamels you’re describing?

A. They are similar, yes. They are enamels. They”re sold by the same distributors that sell glass enamels. The traditional stained glass colors sold by Reusche and Standard Ceramics (see supplier list below) mature at temperatures around 1250°F. The traditional stained glass paints are less vividly colored or are more opaque than the typical glass enamel. Their role in the craft of stained glass is more one of blocking out light and creating value gradation than in altering or changing color hue of the glass.

[return to top of FAQ]

Q15: How can I learn to work with Glass Enamels?.

A. There are a number of texts available that discuss painting on glass. The process of applying enamels to glass shares a lot of similarity to glazing pottery or painting porcelain. The techniques can be simple: such as sifting Thompson’s enamel onto a glass blank, or they can be tricky, such as applying a gradated value over unfired linework. Classes are available from  instructors of kilnfired glass art that include at least some instruction on glass enamels. There are stained glass painting courses available that would provide a foundation from which you could expand to the highly colored or transparent enamels.  See below for instructional texts and for sources for classroom instruction.

 

Instructional Texts

China Paint and Overglaze

Paul Lewing

ISBM: 1-57498-269-9

Excellent overview with much useful information, although not specific to glass

The Art of Painting on Glass

Albinus Elskus

ISBN 0-684-16465-5

This is the best book on the subject of traditional stained glass painting. He discusses colored glass enamels as well.

A Book for the Curious Painter

Gene Patterson and Ricki Wiersema

This is an indispensable reference targeted toward china painters, but much of the information is applicable to glass as well. This is self-published.

ppio.com/genepatterson.html

SGAA Reference & Technical Manual

The Stained Glass Association of America

ISB: 0-9619640-1-4

A collection of articles, some of which concern glass painting

Painting China and Porcelain

Sheila Southwell

ISBN:0 7153 0283 3

Painting porcelain is similar to painting glass. Much useful information can be learned from porcelain painters.

The Technique of Decorative Stained Glass

Paul San Casciani

ISBN 0-486-26157-3

Information primarily about staining and painting for stained glass

Contemporary Warm Glass

Brad Walker

ISBN 0-97009334-9

An excellent introduction to kilnworking with glass. Includes brief discussions of glass paints.

Thompson Enamel Workbook

Tom Ellis ed.

A forty-one page book about enamels and their use.

Available from Thompson Enamel Co.

Advanced Fusing Techniques

Glass Fusing Book Two

Boyce Lundstrom

ISBN: 0-9612282-1-0

This book has a chapter devoted to glass enamels.

Glass Enameling

Kay Bain Weiner

ISBN 09625663-7-3

A step by step glass enameling introduction. Includes a pattern for a clown face project.

Glazes and Glass Coatings

Richard R. Eppler

And Douglas R. Eppler

ISBN 1-57498-054-8

A technical reference with much background information on enamels. Not a how-to book.

Silver Stain – An Artist’s Guide

By J. Kenneth Leap

Eventually any glass painter will run into a colorant called ‘Silver Stain’.  This is the book to learn about that product.

 

 

 

Sources for Glass Enamels

 

Ferro Corporation,
Glass Decoration

251 West Wylie Avenue,
Washington, PA 15301
Tel. +1 724 223 5900;   Fax +1 724 228 3170

 

Ferro Enamels are available from

http://www.warmglass.org/Sunshine.htm

Per Brad:

Ferro has made it more difficult to order directly from them unless you're a previous
customer or you order 5 kilos at a time.  To make it easier for folks to
get them, we stock the full line of Sunshine Enamels at warmglass.org,
and sell them in 2 ounce containers.

 

 

Reusche & co.

A division of Trans World Supplies Inc.

1299 H Street, Greeley Colorado 80631 USA

(970) 246 8577

Fax (970) 346 8575

Email: info@reuscheco.com

 

Reusche is a venerable supplier and manufacturer of glass and porcelain colors. They offer eight different categories of glass colors distinguished by their maturing temperature and suitability for specific glass types. Reusche is the leading supplier of traditional stained glass pigments for American studios as well. Reusche carries a number of different manufacturers colors (e.g. Ferro, Drackenfeld) that are sold as non-brand identified Reusche color lines. They will sell retail but have a $50.00 minimum charge and they sell by the pound or half-pound. Their products are available from some of the retailers listed below in small or large quantities,

 

Retailers for Reusche Products:

 

S.A. Bendheim Co. (wholesale only, but they sell Reusche products by the ounce)

61 Willette Street

Passaic, New Jersey 07005

800-221-7379

Outside USA 973-471-1733

Fax 973-471-1640

Email: info@bendheim.com

 

S.A Bendheim West

3675 Alameda Avene

Oakland CA 94601

800-900-3499

Outside USA 510-535-6600

Fax 510-535-6615

 

 

Standard Ceramic

http://www.standardceramic.com/glassenamels.html

 

Mailing Address: P.O. Box 4435, Pittsburgh, PA  15205

Office Phone: 412-276-6333

Fax: 412-276-7124

E-mail: standardceramic@msn.com

Office Hours: 8:30 a.m. to 4:30 p.m., Mon. thru Fri.

Location: 9 Sansbury St., Carnegie, PA  15106

 

Standard Ceramic is a wholesale-only distributor of ceramic products. They carry a line of glass enamels and a line of stained glass tracing paints.

 

Distributors of Standard Ceramic products can be found on their website.

Fusion Headquarters

15500 NE Kincaid Rd.
Newberg, OR  97132
Tel 503-538-5281 · Fax 503-538-6527
 Email glaswiz@aol.com.

http://www.fusionheadquarters.com/index.html

 

Fusion Headquarters carries a line of European enamels they brand as “Fusemaster”. There are transparent, opaque, and opaque lead-free lines. Sample sets of prefired enamel on glass are available.

 

The Fusemaster line is also carried by

 

S.A. Bendheim wholesalers (See listing under the Reusche information above)

 

Delphi

3380 E. Jolly rd.

Lansing MI 48910

1-800-322-3336

FAX 1-800-748-0374

www.delphiglass.com

wholesale@delphiglass.com

 

Stained Glass Warehouse

97 Underwood Rd.

Asheville, NC 28732

888-616-7792

FAX 828-684-8861

 

Thompson Enamel

650 Colfax Avenue  Bellevue, KY  41073  USA
P.O. Box 310  Newport, KY  41072  USA

Phone  (859) 291-3800
Fax (859) 291-1849

To place Visa, MasterCard and Discover orders
(Recorded 24 hours a day)
1-800-545-2776

 

Thompson Enamel is best known for their artist enamels for metal work and jewelry. The carry two lines of enamels suitable for glass:

 

·        Medium Temperature- Low Expansion Enamels for Window glass & 400 series Stainless Steel

 

·        High Temperature – Medium expansion enamels for Stained Glass and Hot glass blowing. There is evidence that this line of enamels is better suited for glass rated at 96 COE than for glass rated at 90 COE.

 

Thompson enamel is processed at 80 mesh unless a special request is made for a fine mesh. At 80 mesh the most practical means of application is sifting. Sifting tends to produce a heavier layer of enamel than painting or other liquid application. Care must be taken to not apply too thickly, to avoid compatibility problems with common brands of fusing glass. 

 

Thompson sells retail direct, but there are many distributors worldwide who sell Thompson enamels as well. Distributors can be located from the Thompson website.

 

Schlaifer’s Enameling Supplies carries a large inventory of Thompson enamels.

 

Schlaifer’s Enameling Supplies

http://www.enameling.com

1441 HUNTINGTON DRIVE #1700

SOUTH PASADENA, CA 91030 USA

(626) 441-1127 (800) 525-5959

Our FAX numbers are the same as above (Wait for the beep and press *51)

 

Kathy Peterson’s “The Good Stuff”

http://www.thegoodstuff.com/

 Kathy Peterson’s carries an extensive line of porcelain painting, glass enamel and glass decorating products.

 

sales@goodstuff.com  Sales Information

support@goodstuff.com  Customer Support

feedback@goodstuff.com Feedback

 

Kathy Peterson’s "the good stuff"®
4919 E. 38th Avenue
Denver, Colorado 80207-1007

 

Ph. (303) 377-0762
Orders (888) 590-6628
Fax (303) 377-0954
Toll Free Fax (800) 377-6009

 

 

Paradise Paints

Paradise paints are sold by a company in California. Their website presence is a little disconcerting if one expects to find a glass art supply company, but nonetheless many glass artists use Paradise Paints successfully. They are sold either pre-mixed in a pine-oil medium, or in powdered form.

PARADISE & CO. 2902 NEAL RD. PARADISE CA 95969

fax 530-872-5052, ph.530-872-5020
paradise@sunset.net

http://www.paradise-co.com/paints/pricing.html

 

Note:  Paradise paints are no longer available according to the website. It suggests contacting Ferro, which itself may not be productive (see Ferro entry above).

 

Potterycrafts

Potterycrafts is a UK retailer with several locations and a web presence as well. They sell a low-fire and a high-fire line of glass paints.

http://potterycrafts.co.uk/

Crest Molds Inc. Unique Glass Paints
411 Magnolia Street
PO Drawer 20
Logansport, LA 71049

Monday thru Friday
7:00AM - 4:30PM

Voice (318) 697-4401
          (318) 697-2611
  Fax  (318) 697-2409

Unique Glass Paints are sold by the Crest Mold Inc, a ceramic mold manufacturer.  They are sold in liquid form eady to apply to glass. Their recommended firing temperature is higher than many of the other brands of glass enamels (>1500ºF). They offer a lead free line of paints as well as an older line that contains lead.

Rynne China Company

Rynne China carries a line of German enamels as well as lusters and tools suitable for glass painting.

http://www.rynnechina.com/

Their website is a little weird. To get to their glass enamels: try http://www.rynnechina.com/p57.html

222 West Eight Mile Road - Hazel Park, Michigan 48030
Phone (248) 542-9400 - Fax (248) 542-0047
Toll free for orders only (800) 468-1987

Email us at info@rynnechina.com

 

Bert Weiss’ Ferro Notes:

 

Bert Weiss is a long-time proponent of the Ferro Brand of glass enamels. He responds to questions about glass enamels frequently on the Warmglass.com board.  Increasingly, artists who read and contribute to the Warmglass.com board are starting to use the Ferro products. His notes on Ferro, and on a few other aspects of glass painting are listed below.

 

 
Overview of Ferro Sunshine series enamels.
 
·                Compatible with float, 90 COE, and 96 COE glasses.
 
·                These colors can be hand painted, screened, or sprayed.  You can develop a technique that looks like oil or water color painting.
 
·                19 mixable colors and clear flux.
 
·                Firing range from @ 1420F -1520F (you might get away with lower or higher with testing.)
 
·                Colors range from transparent blue to opaque white. They are mostly translucent but the opacity level depends on density of application.
 
·                The series is designed as china paint and the resulting glass is hard.
 
·                The colors are lead and cadmium bearing but if applied and fired properly they should pass food contact requirements. The flux is not lead or cadmium bearing and a clear cap would insure food compatibility.
 
·                The enamels come as powder and are mixed with a medium for painting, screening, or spraying.  Both oil based and water based mediums are available and good for all of those purposes.
 
·                Medium #1544 is a very slow (months) drying water miscable medium that is good for painting, screening, or spraying on large pieces of glass.
 
·                Medium 80841 is a faster drying water miscible medium.
 
·                Squeegee oil (I don’t know the number) is a pine oil based medium good for screening and can be thinned for painting or spraying.
 
·                There are also water thinnable spraying mediums. If you have a particular application, there are dozens of different mediums available to mix the colors with.  Ask for help.
 
·                Contact: 800-245-4951 ask for customer service, Linda Kimble
 
·                There is a $100 minimum order with 100 grams the minimum amount for one color.
 
·                A sample set of the Sunshine series costs $200 and is a bargain.  You get 100 grams of most colors and 50 grams of the expensive ones.
 

Ferro Enamels are available from

http://www.warmglass.org/Sunshine.htm

Per Brad:

Ferro has made it more difficult to order directly from them unless you're a previous
customer or you order 5 kilos at a time.  To make it easier for folks to
get them, we stock the full line of Sunshine Enamels at warmglass.org,
and sell them in 2 ounce containers.

 
 
 
·                You are buying direct from the manufacturer with no middle company markups.
 
·                The Fantasie series contains metallic sparkle micas
 
·                The Samba series is lead and cadmium free.  It requires a bit higher temp to gloss the colors.
 
·                The Versicolor series’s are glass colors that mature between 1050 and 1300 depending on the series. They are a softer glass surface. 

 

 

Sources of Classroom Instruction

 

Traditional Stained Glass Painting:

 

J. Kenneth Leap - http://www.jkennethleap.com/classes/workshops_menu.htm

Kathy Jordan - http://www.theartofglassinc.com/#!__theartofglassinc/workshops

Jim M. Berberich - https://www.facebook.com/painterglass

Join the American Glass Guild - http://americanglassguild.org/

Ask about training on Facebook’s Pictorial Painted Glass group - https://www.facebook.com/groups/212720382243386/?fref=nf

 

China Painting Techniques:

 

http://www.porcelainpainters.com/

 

If you intend to be a glass fuser and wish to learn to apply paint to fused pieces, do not discount the little old ladies in the porcelain painting schools. They have incredible skills, and a long tradition of teaching technique. Many of them paint on glass as well as porcelain. The techniques, brushes, and mediums work with  fused glass for the most part.  

 

 

[return to top of FAQ]