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I use terra sig on the bottoms of my majolica pieces (Highwater's low-fire Stans Red clay).  I mix my own terra sig using Red Art.  Have not had a problem with it until this past bisque firing and had one plate where the sig flaked off about the size of a quarter.  The rest of the sig on that piece was fine.  

 

I'm thinking of trying to put sig on the bare spot before glaze firing it.  Has anyone ever used sig on bisque ware?  And, any ideas on why it would have flaked off in the first place?

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Hey,

Do you add the terr Sig while leather hard or bone dry? I suggest

leather hard. Sometimes when there is an issue with flaking its

because the terr Sig and clay is shrinking at different rates.

Sometimes the remedy is as simple as adding some of the clay to the

terr Sig slip..that should slow down the rate and make both clays

compatible. Hope this helps.

Alabama

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I've succesfully used terra sig on bone-dry clay and bisque-ware (Terra sig from the same clay body that I apply it to). I've also had it flake off where it was thick, but in that case the clay body had a higher shrinkage rate, which I'm sure is also a factor.

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Thanks for the help…..after reading the comments, I think I may have applied it too thick, layer-wise.  I put the terra sig on bone dry pieces and recently someone told me to just keep adding layers until the terra sig took a while to soak in, then buff it.  This last firing was the first time I had applied it that way….I usually apply only two or three coats, then buff.  Will go back to my old way of doing it.  

 

No one mentioned putting terra sig on bisque pieces ….. has anyone tried it?

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No one mentioned putting terra sig on bisque pieces ….. has anyone tried it?

I'm inclined to think there would be shrinkage issues leading to the terra sig to possibly flake off when it dried. Terra sig is just fine clay - nothing else. At leatherhard, it can bond, shrink and dry with the clay body. At bisque, the water is just going to evaporate and the sig is going to have a hard time adhering. Always worth a try on a test piece, though, just to see if it works.

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>>>>No one mentioned putting terra sig on bisque pieces ….. has anyone tried it?<<<

The closest of putting terra sig on bisque ware was when some of the students were painting colored slips

made from porcelin sludge and mason stains.  The question came up why paint the greenware with mason

stains and paint them again on bisque.  What they were actually doing was painting the greenware with the

pigmented slip and after they came out of the kiln, they were TOUCHING UP any bumps or dings while being

loaded in the kiln (this was a Jr. college)... After the touch ups everything was dipped in clear glaze then fired.

 

Just out of curiosity, is putting terra sig on Majolica new?  I thought it was done with red earthenware clay painted

with colored slips or glazes and fired in clear glaze to cone 06, oxidation. I'm familiar with 18th century pottery is

why I ask if its something new.

Thanks,

Alabama

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I've used it on bisque with no flaking (see my previous post). I should probably add that I bisqued to about cone 09, so the piece was fairly pourous. It may also work if you bisque higher, but like Bruce says, try a test piece first.

Sorry I missed that part on your previous post Pieter.  I'm going to try it on the piece it flaked off on…..can't hurt and it's non-saleable as is so it will be my test piece.

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12 hours ago, kathleencorcoran said:

Wow, this topic is old! I am doing some pit firing and was wondering if I could use terra sig on 05 bisque pieces prior to pit firing? I want to scratch a design through the terra sig. 

The sig will probably flake off of bisque. Give it a try, though, if you've got an extra piece to experiment with. One or two very thin coats may adhere.

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@kathleencorcoran I have used Redart sig on bisque, then fired to cone 6 with no problems. This may be different with more refractory clays (ball clay/white sig). Sig is very opaque (I think because of the fine particle size) so you do not need a lot to cover the clay body. You can experiment with different thicknesses but I would try to use it the same way you would on greenware. Since you are pit firing the sig may adhere better to bone dry clay

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