Hi, on your question 1. a layer of flux seems to be fired in first and then whatever colours are required are then fired over this. But the initial layer of flux is fired unbacked. Surface tension holds the wet enamel in place. This is a method of getting graded colours in place. However a clearer finish is derived from starting with a pale tone of the colour required and grading darker over this.

bonjour

thanks  Jean but could you tell me which kind of flux.

Any clear flux that has a higher firing temp than the colours you want to lay over it. Most enamel suppliers have their own variety of clear flux and some offer soft/hard etc. Test some from a number of suppliers for clarity, firing temp, ease of cell filling etc on clean test scraps of whatever is your metal of choice, then test the best of them for laying your colours over them. Its horses for courses in these cases.

I favour using a pale tone of the colour to start and then grading which gives less layers of enamel and so more light, but this is not always an option.

Most suppliers will supply very small test amounts of the enamels they sell which are ideal for testing such as this.

thank you  Jean. 

I made a search on  the web. I didn't know what is a flux  , I knex what was a flux in soldering  but it couldn't be used in enamel.
 I realized that  it is what we called  fondant . I have plenty of it hard and soft. I   decided to start again with  enamels when I found my kiln and  almost  20 pounds of different enamels in my attics  during my moving house  !!!

by the way, what do you think about shiny paper ?

I'm replying about the Bullseye "paper" that your link went to at Bullseye glass.  FYI, I am a silversmith, PMC Certified Artist and Instructor, Glass Fusion Artist and an enamellist.  So I have a lot of experience in related fields.

I own and use fiber matting in my Glass Fusion work and have for years.  There are a lot of similarities between glass fusion and enameling and a lot of differences.  To start with, there is a definite difference in thickness.  Glass fusion works with the principle that glass wants to "pool" at 6mm or 1/4" inch.  "Pooling is defined as a tendency in any liquid to form a "sheet" of a defined thickness at a specific temperature.  Imagine that you have a perfectly level sheet of plastic, say a 4 feet round circle.  The thickness is not important, but the flatness/levelness and the smoothness of the actual surface of the plastic.  Now pour a few ounces of water in the middle.  That water will spread out and eventually achieve a uniform thickness so that all of the water is an identical thick layer.  The water will not pour over the edges of the sheet if there is not enough volume of water to cover the entire sheet.  If you continued to pour water slowly at the exact center of your sheet, you would be able to see the area covered by the water expand until it eventually does fall off the edge.

Glass works basically the same, except that glass does not have an absolute melting temperature as water does.  Glass starts to "slump" (move on its own behalf) at around 1300 degrees for Bullseye glass and achieves a full liquid melt somewhere well over 2000 degrees.  My kiln only goes to 1900 so I don't know what higher temps would do.  The fiber mat that Bullseye is talking about is used in conjunction of glass slowly slumping as the temperature is increased.  In glass fusion, the thickness of the glass will be roughly 1/4" or 6mm thick as you would want the glass to slump. but not to pool.  By using glass that is already at 6 mm you know that your sheet of glass is going to remain the same thickness as it has already assumed polling thickness.  Slumping also takes into account the fact that as the temperature of the glass is heated, you can predict the amount of slumping that will occur. But the main point here is that we are beginning and ending with 1/4" thick glass.  BTW, Bullseye is sold in 3mm and 1.5mm thicknesses so that the glass can be stacked to achieve colorations and patterns within the glass. 

Iridized and Dichroic surfaces are ultra thin metal oxides placed on the glass in 3.5 million dollar machines called vacuum diffusion chambers.  This film is extremely thin.  CBS (Coatings by Sanburg) makes this film coated onto thin copper sheets also.  The coatings barely bond to the copper and when the metal flexes are easily removed.  But they are thinner and far more delicate than gold leaf.  Glass that is coated with dichro or iridized do show a change in behavior due to the surface tension, but again, the coating is extremely thin and I can't imagine how you would apply that to an enameled surface other than sending your enamels pieces out to be coated in a vacuum diffusion chamber and that is extremely expensive.

Another huge difference between glass fusion and enameling is COE, or Coefficient of Expansion.  With glass fusion you need to control the COE of the glasses you use so that there is never more than a 2 to 3 COE variance (plus or minus) between the pieces of glass that you are using in your project.  Art glass comes in the following COE's: 35, 80, 90, 96, 104, 121 and 134.  The higher the number, the "softer" the glass.  Softer glass has a lower working temperature as a rule and it has more muted colors.  Italian art glass from Venice is COE 104.  Window glass is in the 80-85 range and Armstrong makes colored glasses to sue with their window glass.  Bullseye is COE 80.  HOWEVER, Bullseye NEVER gives a COE number for their glass and only states that their glass is all "compatible" in COE.  And there are a number of other manufacturers who make glass at this COE.  Roughly 18 months ago I was at Thompson Enamels and had the opportunity to talk to Tom Ellis for 2 hours.  In regards to COE Ellis told me that Thompson enamels for Copper, Silver and Gold (1000 and 2000 series) range over a 40-50 COE range and that they simply are not designed to be used in applications where the thicknesses cause COE issues.  That is why there is 2020 clear for silver and 2030 clear for copper.  The COE of these fluxes are designed to match the COE of silver and copper. And if you have ever coated silver with 2030 or copper with 2020 you will have notices that the enamel pops off. 

There is a product that the Bullseye link did not cover and that is Kiln paper or shelf paper.  The thicker fiber mats that the link to Bullseye did discuss remain the same as the piece is fired.  However, shelf paper does not.  Glass Fusion for the most part, if not used in a mold, requires a dead flat surface in a dead level kin.  So fiber shelves are used.  These are roughly 1/2" in thickness and can be a variety of materials.  These shelves need to be coated so that the glass does not stick to the shelves.  You can use a kiln wash, a powder that is mixed with water than painted onto the shelf surface multiple times until a sufficient surface is achieved.  All glass fusion molding uses kiln wash.  The second alternative is to use a "paper" that is fairly thin compared to fiber mat.  The kiln paper can easily be cut with a knife to get the size that you want.  The paper is placed on the top of a kiln shelf and the glass placed on top of the paper.  In the kiln during firing this paper is reduced to a fine powdered material that the glass simply does not stick to.  If you were using a new kiln shelf that was really flat and used this paper you could do plique à jour enameling on this surface.  However, this technique will give you a rough glass surface, not a nice smooth surface.

I have done plique à jour enameling using the extremely thin copper sheets that CBS uses to sell their dichroic films.  I used silver for the piece, carefully wrapped the bottom side of the silver with the copper foil.  I then treated this assemblage the same as a champleve  project and when I finished the enameling I used Ferric Chloride to etch the copper off the bottom of the piece.  It did work.  But I would not say this technique is one that I would spend much energy trying again. 

One final note about fusion glass.  glass used for glass fusion looks identical to glass for stained glass.  And some manufacturers make both.  BUT glass sold for stain glass work is made with no regard to COE except within the specific sheet that you are using.  Two different pieces of glass intended for stain glass will have radically different COE's and most likely will not fuse without cracking/popping/exploding when the glass cools.  You can safely slump and fuse pieces of stained glass cut from the same sheet.  Bullseye makes both types of glass.  And the stained glass from Bullseye is cheaper than the glass fusion glass.  So be careful if you are bringing different glasses into your studio that you know what they are.  Glass fusion, Lampwork, and glass blowing require that you tightly control your COE into the plus of minus 2 COE.  contamination of your materials with a second COE glass is a definite failure.  Most warm and hot glass artist only work in one COE to avoid this contamination.  Or if they do use multiple COE's, they have multiple studios.

Thanks a lot Trish.

Thanks a lot Janet.

Actually I discovered metalclay some month ago and really love the technic. And I felt the need to  rework with enamels. In my attic I still had the very good and very expensive kiln I bought in gµermany in 1973 (Naber kiln, before I had an Uhlig)  and, amazingly,  IT STILL WORKED. I used it intensaly during 10 years  then  from time to time during  5 years, then I forgot it first in a cellar which is not so dry  then in the warm attics.  It gets perfectly to the right  temperature and the electronic still works !!! The  society is now called Nabertherm and they told me that if I get anyproblem they  can still repair it !!!
In the  70ties, we did the plique a jour with a moist enamel that had a little glue in it  and  on a mica sheet. So we didn't have to do so many lays. I have to learn everythin again , I love it and will put pieces

I'll try to  use this ceramic paper instead of mica anyway. I love making experiments.

the only thing is that as I worked a lot on copper, I have a lot of enamels ( several kgs some big amounts of one color and  a lot of little  boxes of different enamels and I don't know if they are soft or hard !!! I'll have to try them. it's ok I have a lot of ready copper pieces (several kgs).

I'm relatively new to enamel.  Less so on the other jewelry techniques I use.  I am educated in art, but ended up designing and building high-end furniture for over 20 years.  So the stuff I know covers a really broad arena, but for this end of things, it is fairly new.  I started enameling with some enamels that we originally bought for silver PMC work.  My life partner is also an artist and we both did the whole PMC thing starting about 8 years ago.  We also had our first introduction to silversmithing and lampwork at the same program.  We originally did silver PMC and moved over to copper and bronze.  Neither of us work in these media much anymore.  We found that the strength of the metal clays became a real problem and the cost of the silver is so high that we can't recover costs in our market.  Our kiln is a 8x8x8 front loading kiln with a programmable controller.  We use this kiln for PMC, silversmithing (annealing and burning out casting flasks), lampwork (annealing glass), glass fusion , and enameling.  The kiln is branded PMC, but it appears to be an Evenheat. 

And that is the key to this kiln, it does heat evenly.  A lot of older kilns out there don't do as good of a job as the newer ones with the even heat thing.  PMC and glass fusion require very precise temperature control.  I also do a technique on enamel that is a carry over from glass fusion and a carry over there from ceramics, and that is firing decals onto the glass/enamel surface.  A 10-15 degree variance with these decals can make a make you or break you situation in the kiln.  However, I do own a 20-30 year old burnout oven used in lost wax casting that a close friend has been using for enamels.  What almost never works is using an older ceramic kiln for metal clay.  One, it is way to big, but also too uneven in heat.  We know, I tried using one for a larger class I taught. 

On "hard or soft " enamels.  I've only used Thompson unleaded enamels purchased almost exclusively from Thompson. And the reason for that is two part.  First I am a jewelry artist.  90% plus of my work is designed to wear as jewelry.  And second I work and sell in California and that means zero lead in any jewelry.  I've been offered several times the opportunity of buying out older enamels from older artists.  BUT since they predate the California lead in jewelry law, technically I would have to prove that they are lead free.  The same problem exists in metalsmithing with solders.  No lead allowed and no cadmium allowed.  And both metals were once added to solder that was sold for silversmithing.  These metals made the solder flow better and gave a much better looking joint.  And in California, the burden of proof is on the artist.  I've never had a problem.  But then again, I do everything I can do to make sure that it stays that way.  So leaded enamels are a thing I'll never get to play with.  From what I've seen, the colors were so much more intense and the palette was so much broader. 

bonjour

 35 years ago I worked  a lot with enamels and did some plique à jour. I was used to fire those  works on a mica sheet.

I have  2 questions : 

The first one is about the following video

on this video, the enamelist holds  the wing  up instead of putting it on a mica foil when she  adds the wet glass.   It  seems that there is like a transparent  sheet  already stuck to the metal. There were so many  new material invented those last years that I'm wondering :  is it a kind of resin that burns completely during the fiiring (when yes  can you tell me  where toget it)  or a first  fondant   layer that was  put and fired  classically  on a mica sheet ?

Second question : Did you ever try shiny paper   to  avoid sticky enamel : i started doing metalclay  2 month ago (bronze  and copper clay that i want to start enameling but that is an other thema) and 3 days ago, i  bought silverclay (I want to start that  too, i think the enameling would be  better on silver than on bronze)  and I saw they sold something called shiny paper for fusing. you fuse the glas on it and  the glass doesn't stick thanks to the shiny paper. I found this document  about it   clic here

ok that's all for today, please excuse  the syntax and  spelling mistakes of an old french blond