Large amount of iron oxide in slip

[rdrr]

I do a decent amount of work where I apply a thick slip made of the same clay body to create a varied textured surface.   The textured surface is somewhat rough with littler rivlets of slip sticking to the piece with breaks in between.  Once bisqued I apply a heavy coat of iron oxide wash (just IO and water) to the slip textured area . The pieces are fired to code 10 in reduction causing the io to flux with the result in that area being a dark metallic (black/blue/brown iron) sheen. 

 Lately I've been playing with adding a coating of colored slips to the surface before adding the texture.  This looks nice as it creates colored breaks in the textured areas but applying the IO in my typical fashion would eliminate the color peaking through.  I could add the IO in a more painstakingly fashion by applying it to the individual rivlets of slip but I would like to see if there is a way I could add a bunch of IO to the slip to get a similar effect.   I can and will begin testing increasing amounts of IO to the slip to see how far I could take it without it fluxing to much and running off the piece but I'm wondering if anyone has done anything like this?  Trying to figure out how much clay is needed to just keep the IO from running or if they have any specific recipes of this sort.  Currently using the clay bodies I work with as the texturing slip but if there is a better formulation for heavy IO content I would live to hear about that as well. 

[Min]

I have an iron wash recipe from Bob Kingsmill, image of one of his masks below with it. It doesn't run as is at cone 10 reduction but if you add a small amount of gerstley borate it does.

Kingsmill wash (I've used it from ^6 - ^10 ox and reduction). This recipe is from about 25 years ago, he might have changed it since.

One of his masks with the iron wash

 

[oldlady]

i have used rio to color the clay i used for a birdbath.   it was years ago and i just tossed a bunch of rio into some soft clay and wedged it in.   made places for the birds to stand in a very large slab  that i hung over a trash can on cloth.  came out great, the birds loved it while it lived.   i went to texas and heard it would freeze that night at home so i asked my daughter to bring it in.   she didn't.

[rdrr]

Thanks for the information @Min. I thought about using Blackbird/Barnard but saw that it started to melt at ^6 and was worried about how much it would start to flow at ^10.   But if that recipe seems to hold up I'll give it a try.   I was also a bit worried about going to high with the IO, I have some tests to fire at a 50/50 mix of body clay to IO.   Based off of what is in the clay in the recipe with the addition of 30% more that should put it up around 40+% so my fears are a bit alleviated.  

Sorry to hear about your birdbath @oldlady