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jo4550

Member Since 08 Sep 2010
Offline Last Active Jul 02 2014 05:58 PM
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In Topic: Decal Help Please!

17 May 2014 - 01:16 AM

wish I could find out more on ceramic toners. There seems to be a company in China that is shipping them but they have no prices or ordering routine setup and calling china seems daunting and possibly confusing. 

 

A few companies package them together with printers offering an expensive 'system' but it really just seems that one could use a mason stain/materials mix that can be put in a color laser printer cartridges.

 

Just not sure what that mix would be to make it fuse to the decal paper. The systems also show them spraying a clear coat over the decal before putting on pot. 

Stephen, ceramic toners  will not work in a conventional laser printer.  The printer needs to be altered to accommodate the use of the ceramic toners.  I believe some Ricoh printers are retrofitted for this.   The polymers (plastic bead like substances) adhere the colours to the decal paper.  Mason stains are not milled fine enough for laser toners and they need to be mixed in specific proportion with the polymers.  There are also 2 different systems out for ceramic toners.  One has a flux in the toner mix which allows the decal has at approx 800.C.  The other has a flux in the covercoat which is applied after the printing.  This allows the decal to be fired at the temp required, eg for glass, overglaze or inglaze temps.

Regards

Johanna


In Topic: Decal Help Please!

17 May 2014 - 01:02 AM

 

You can print on any laser decal paper with an hp laser printer. You can do a search to find wich printers work the best.
I think Bel and Decal paper dot com intentionally leave out that detail because someone holds that patent for fired laser printed decals.
It will not work with color, and looks like a sepia print when fired

To determine compatibility with laser printers, look up the MSDS sheet for the toner cartridge the specific model uses. Some laser printers use polymers as the main pigment ingredient. These won't work. Others use iron, listed as ingredients beginning with the prefix "ferr." This what to look for. The HP I have uses 45% iron in the toner pigment.

 

As I understand it the polymers, when melted, are the binder of the colourant to the paper in laser printers.  Originally carbon was used as the colourant for black and this is still used by most laser printer manufacturers.  However HP definitely uses iron oxide (also written as ferrous/ ferrous/ferrite) for their MONO laser printers.  To add to this, the reason a colour laser is not suitable, is that the printer drum has to go to a higher temperature to melt the polymers used for the other colours.  This higher heat melts the laser decal paper onto the drum thus rendering the printer useless. 

Regards

Johanna


In Topic: is gilding / gold leafing food safe ?

19 April 2014 - 06:56 PM

Hello Kennedy

It is normal for some glazes to change on a refire especially when you are approaching the softening point (I do not mean melting point) of the glaze.  This is the point where the fluxes start to be active.   This has become very obvious when running the laser decal classes and searching for the softening point for the decal to adhere.   There is a fine line where the glaze doesn't react and this is at the lower end of the temp scale.   I would hazard a guess that your glaze has a flux that has a very wide firing range and it is perhaps Gerstly Borate.  You seem to have reached a point at cone 06 in your glaze where the glaze is already outgassing and the cooling at 06 halts the process and and traps the gases changing both the colour and the integrity of the glaze.   

 

To resurrect this glaze AND burn off the lustre find a cool spot in your glaze firing and take back up to top temp.   This should restore the glaze.  I say cool spot as refiring is almost like going a cone higher than the original firing.

 

I would have attempted to save the gold and platinum surfaces by adding a couple more layers (with firings in between) and firing to your gold firing temperature before I took the drastic step of burning the lustre off.  To remove small areas of lustre it is common to use a gold eraser but it has to be used carefully as you can "matte" the surface of the glaze that you are rubbing.  Lustre can also be removed by using hydrofluoric acid but I personally wouldn't go down that path for H&S reasons.  It also mattes the surface of the glaze where the lustre has been removed.

 

Cheers

Johanna


In Topic: Your Best Guess On Overglaze/Lustre Technique

05 June 2013 - 08:19 PM

There are a couple of issues here but I would like to start off by pasting an excerpt from the Heraeus fact sheet on Lustres as I have run out of space to add any more attachments. This can be found in its entirety at http://tinyurl.com/lvt6m7c
Heraeus is one of the largest overglaze and lustre producers/suppliers in the world. They are based in Germany.



1 General Information
Lustres are based on metallic compounds dissolved in organic solvents. After firing they form a very thin layer (less than 0.1 μm).
Typical characteristics of lustres are their brilliance as well as their metallic iridescent brightness which occurs after firing on smooth substrates.
The lustre loses its iridescent effect on matt surface and appears matt.
Lustres are suitable for the decoration of glass, porcelain, bone china, earthenware

2 Firing Range
480-630° C / 896-1166° F for glass and lead-crystal.
650-900° C / 1202-1652° F for porcelain, bone china, earthenware and tiles.

3 Precious Metal Content
Lustres contain less than 6 % precious metal or are precious metal free.

4 Properties
4.1. Mechanical Resistance
The mechanical resistance of lustres does not achieve the same standard as most
ceramic colours and precious metal preparations because the formed lustre film is
very thin. Therefore, we recommend that customers test the decorations under
their own conditions to achieve the required resistances.

From this excerpt you will see that lustres applied to tiles used as a splash back may be a short term measure as constant cleaning with an abrasive will soon wear off the lustre.


However I am assuming that you have taken this into consideration.

I am finding it hard to get a good image of the tile to show that it has a creamy base so I cannot comment on how many firings this would have had but I suspect only one overglaze firing.

As you can see from the excerpt lustre can be fired anywhere up to 650-900° C / 1202-1652° F depending on the surface it is on. The controlling factor is the softness of the glaze that it applied to at the temperature you are firing to. The softer the glaze becomes the more the lustre will sink in. This is especially so for low earthenware glazes.

As I have said in previous posts Duncan products are rarely, if ever, used by the porcelain painters (the main users of Overglaze techniques). They buy products that are are manufactured by the suppliers and not just repackaged and rebranded as in the case of Duncan overglaze products. I have also never heard of lustres being described as Lustre Overglaze.

Regarding Duncan's instructions that you supplied here are my thoughts.

1. Any glaze or surface is overglaze compatible. (I don't understand the need for this statement)
2. The firing temperature is suspect. Maybe it is a typo and it is meant to be cone 016. I don't know whether they are offering a normal lustre because lustres starts to burn off after 900.C and they state to fire to 1000.C I would normally recommend firing a cone 6 glaze to 760-780.C however I have refired them successfully to 810.C In your situation where you will need extra mechanical strength I would suggest you run a test and see how the cone 6 glaze interacts with the MOP at 900.C. It is a chore but you won't know until you try as each glaze behaves differently.

The MOP that I use is a Fay Good product and can be purchased in the USA from China Painting today. Here is a direct link http://tinyurl.com/mg3ml75.

#Ceramics Monthly January 2013 contains a techno file on Lustres
#Pottery Making Illustrated May-June 2013 has an article on how to use lustres.

Johanna DeMaine

In Topic: Videos of people making relief decorations in monochrome...

21 May 2013 - 09:01 PM

Here is a youtube link of an old Wedgwood 1930's film that shows you the sprigging process.


Here is also a link to 2010 CAD archived feature on sprigging
http://ceramicartsda...-making-sprigs/

Johanna