Polishing experiment

[ketoi]

Made a batch of terra sigillata, then divided in 2 to make one black. The terra sig is applied by brush to bone dry clay, the more coats you put the deeper the sheen. The black pot has ten coats the polished with an ordinary plastic grocery store bag, no effort at all to raise a shine. The terracotta was fired to ^012, the hotter you go the shine lessens.

My favorite by far






Alternating coats of black and red terra sig


Tried antiquing


faceted red and black

 

[Boondock]

WOW!!!!!! I'm going to pick up some terra sigillata this week after seeing the results you have. Did you use Mason Stains as a colorant? I wonder if Red Iron Oxide or better yet Manganese Dioxide is milled enough to work?

I found some recipes for terra sig here, here and here.

They all use regular ball clay.

 

[ketoi]

I used red art clay for the base and Manganese Dioxide, Cobalt Carbonate and black copper oxide for the black. I've read where the mixture should be ball milled before application but it came out pretty nice with out.

 

[ketoi]

Slightly OT...while I was making the slabbed pot above my wife's cat walked across one of the sides and left her mark. As much as I wanted to I didn't through out the piece, instaed made a pendent for my wife, antiqued and polished. She loved it!

 

[bretts]

Don't know if you guiys have been here but this guy has some great info. Here is one about terra sig from Brian Gartsides web site
http://www.gartside.info/terrasigillatatext.htm
The downloads for these articles are great.

 

[ketoi]

Thanks for the link bretts.

Made a batch of mid-fire terra sig over the weekend, once the mixture evaporates some I'll do some testing.

 

[irene_b]

OK you guys are talking to techy....
Ca ya post pics of what you are talking about?

 

[ketoi]

Irene,
Can get even more techy, some recipes want you to measure specific gravity of the mixture. I do the simple version, by what it looks and feels like.

Basically you put dry clay in a bucket, add water to cover then a deflocculant(to separate the the particles of clay from heavy to light). Let the slop sit 24hrs and siphon off the milky top layer. The milky water is what becomes terra sigillata as it thickens up from evaporation

Here's some I siphoned off and put in clear jars, you can see the layers


Then apply to bone dry clay and polish with a plastic grocery bag

 

[irene_b]

Thank You for explaining and showing this stuff....I do love pots and what you and Boon are posting as well as the other potters really makes me appreciate them pots even more... I can agree that it is not something that just anyone can do (did try it once)....
Irene