Using Red Iron Oxide along side cone 5 glazes

[Julie T]

Hello! I need some specific help with using RIO. I typically use stoneware clay #50 from Laguna and bisque to 06-04 and glaze to cone 5.

I have applied RIO to my bisque ware and attempted to fire directly to cone 5 alongside glaze. The result was that the RIO had burnt off completely. So, I need specific steps:

Bisque normally, apply RIO, re-bisque? What cone? Apply glaze and fire to full cone temp? Do I need to add flux to the RIO? I read 50/50 RIO and Gerstley Borate was needed to prevent the stain from burning out. Please advise. I cannot find any step by step help!

[Magnolia Mud Research]

I use a mix of red iron oxide and water to mark my logo on my ware, and for decorative marks.  Treat the mixture like  using  water color on paper.  To get a good colored mark requires a good application.  My mix is about 1/3 of a peanut jar of dry RIO and fill the jar with water.  Shake shake shake.  I apply on green ware, bisqued ware, and over glaze applications.  Works for me at Raku, cone 3, cone 5, and cone  10 +.  All kinds of clay body’s.  
took a few test marks before I got the hang for making good marks.  
LT

[Julie T]

Thank you Magnolia Mud! I assume that my applications are too light and that is why they burnt off before. I will go for another application and then, should I run it through a second bisque before a glaze firing?

[JohnnyK]

Hey, Julie...Here is what happened to a couple of my little flowerpot gremlins...the one on the right has 3 coats RIO on ^04 bisque fired to ^06.  The RIO was just a tad chalky. So I thought it would be a good idea to put a clear glaze (3 coats) and refire to ^06. The result was the mottled yellow and black one on the left. I have done RIO and fired to ^10 and the result without clear was a semi-metallic gun metal gray color that was permanent. Something to consider...

[Min]

3 hours ago, Julie T said:

I will go for another application and then, should I run it through a second bisque before a glaze firing?

If you aren't glazing it then no it isn't necessary to re bisque fire. If you are glazing the iron can smudge if not bisqued on first. Do a test tile at the same time, try a heavy dark application, a medium one and a light one, try one coat and two or three, see what happens. If you glaze over an iron wash or apply the wash over a glaze if there is a high amount of calcium in the glaze the iron will tend to "bleach" out and go a straw colour.