coloring clay for marbled pots

[Ginny C]

Years ago I made a marbled free form dish from a slab of white, brown and tan clay. I can't remember how I got the tan. I use B-Mix 5. Brown stain for the brown, obviously, but I think I used some red-iron oxide that my son sent me from a trip to Spain. It's all gone. I have a bit of a different dried up RIO from somewhere...Will a little of that turn the B-Mix a nice tan color?

I've attached a tiny bit of it...tried to attach the whole thing but kept being told (scolded) that the file was too large. It finally accepted this tiny bit. Sorry you can't see the dish, but at least you can see the 3 colors.

Thanks in advance for suggestions!

Ginny

[Babs]

Just do a test piece.

It will colour it but not the exact hue probably.

Do you remember the quantity added?

Would pay to do a few test coils of increasing amounts of RIO. Then you knmow what is best for you

[Min]

I'ld use red / brown clay instead of red iron oxide. Less messy working with it and you avoid the risk of adding too much red iron oxide and getting a brittle clay.

6 hours ago, Ginny C said:

I have a bit of a different dried up RIO from somewhere..

You lost me here, red iron oxide used in glazes comes as powder, could it have been a red clay slip you used?

[Babs]

7 hours ago, Min said:

I'ld use red / brown clay instead of red iron oxide. Less messy working with it and you avoid the risk of adding too much red iron oxide and getting a brittle clay.

You lost me here, red iron oxide used in glazes comes as powder, could it have been a red clay slip you used?

I did this Min i.e. a red clay and a white clay and the difference in shrinkage of the white and red clays made the clays split away from each other, esp. Slab work on bisquing , even being pretty careful with drying.

Thrown stuff fared better.

So I added rio to the white clay 

[Denice]

I have done some marble throwing in the past.   I use a red clay and white clay with the same shrinkage rate, cone and made by the same company.  Both clay's have to have the same moisture content.  I would put a half of block of each clay in a plastic  bag for a few days until they felt the same.  That isn't a very scientific method but I never had a problem with splitting or cracking.  Denice

 

[Babs]

10 hours ago, Denice said:

I have done some marble throwing in the past.   I use a red clay and white clay with the same shrinkage rate, cone and made by the same company.  Both clay's have to have the same moisture content.  I would put a half of block of each clay in a plastic  bag for a few days until they felt the same.  That isn't a very scientific method but I never had a problem with splitting or cracking.  Denice

 

Yes indeed but my large slab platters didn't like the two clays I had, obviously different shrinkage so that is a key fact to the success

[Ginny C]

I must not have explained my question well. I am talking about tinting Laguna B-Mix 5 clay with 2 colors—a brown Mason stain and some iron oxide hoping for a camel tan color, and using the white B-Mix plain for the 3rd color.  (Using the same clay for all 3 colors keeps it from separating.)

I originally used an iron oxide my son sent me from France (not Spain after all.) I don't have it any more. I'm trying to figure out what to order that might make a nice tan color with the white clay. The iron oxide bit I do have was a powder someone gave me that I had mixed with water for writing on bisqued pieces. There is only a tiny bit. Today I moistened it and wedged it into 3 small balls of clay in different amounts, for testing. But there isn't enough anyway. I need to order something. 

I see there is (on Amazon) a Yellow Iron Oxide, a Red Iron Oxide, and something called Roussillon Red Ochre Natural Mineral Pigment. That last MAY be what I had before. 

Here's my question: Does anyone have experience using any of these oxides with B-Mix clay? If so, which is most likely to give me a clay that will be tan after firing?

[Callie Beller Diesel]

@Ginny C What colour was the iron oxide your son sent you?

If it’s red, any red iron oxide should work. Red ochre might be overkill, depending on the price. Yellow iron oxide isn’t as powerful a colourant compared to the red, but a small amount will likely still colour your clay easily. 

Also, it would be a disservice not to point out that you can order materials from your local clay supplier, or from US Pigment, rather than Amazon. You’ll get better customer service.

[Hal Tenny]

I make marbled items such as mugs and bowls. I use a brown stain at 10% (by weight) to stain my white clay, and then use the same brown at 5% for a tan. So if you go the stain route just dilute for the tan. If you use a brown clay, try mixing equal portions of white and brown for your tan. I do that as well. Good luck!

[Ginny C]

Thank you! I will try that. I have also now learned that a bit of the old iron oxide I had left got the right tan also. 

And, Callie, yes I will follow your reminder and order from one of the ceramics companies!   :-)

ginny