Jump to content


Mossyrock

Member Since 22 Aug 2010
Offline Last Active Nov 12 2016 11:46 PM
-----

Posts I've Made

In Topic: Terra Sig Not Buffing Shiny

12 November 2016 - 11:48 PM

Mossy rock,
I hope you read the above post. It seemed to disappear right after I posted it.There is a lot of good information in those 3 pages even if they date back to 1993.

Marcia

Thank you Marcia.  I will read definitely read and thank you for taking the time to post them.


In Topic: Terra Sig Not Buffing Shiny

11 November 2016 - 03:44 PM

 

Are you saying that after the glaze firing, the white sig you're using takes on whatever color it is applied over?  Say if it was applied over a green underglaze, the sig would be green after it was glaze-fired?  If that is the case, would you mind sharing which ball clay you use or do you think any would work?  She glaze fires to 05.

 

 

 

Yes, that's what I'm saying. Certainly, it does so over red clay body when fired to cone 03, and I can see no reason that it wouldn't do the same over a coloured slip. Well worth some experimentation, I would suggest. I always apply the sig to a bone dry body.

The ball clay I use is something called Hyplas 71, but then I'm in Europe. That may or may not be available on your side of the pond. Essentially, it's a low-iron, white firing, high plasticity ball clay. I doubt if the exact make/type matters much, to be honest. I've always followed the Vince Pitelka method for making sig, but again, I doubt if that makes any difference to the end result.

My only concern might be that cone 05 could be a little low to lose the milkiness of the sig - only one way to find out!

 

--->> It's just occurred to me to suggest that your friend decants a small amount of sig into a cup before trying this, in case the brush takes up some of the (dry) stained slip, and transfers it back to the sig - you don't want to ruin a batch of sig with stained slip dust!! (Does that make sense? I think so...)

 

Thank you!  It's definitely worth a try.  I'll see if I can find a similar ball clay and run a few experiments.


In Topic: Terra Sig Not Buffing Shiny

11 November 2016 - 11:38 AM

I use a terra sig on the foot-rings and lid galleries of my majolica - I like the silky sheen it gives, and it helps seal the otherwise still porous body. The clay body I use is red, but the sig is made from a white-firing ball clay. After biscuiting, the sig remains a grubby white, but after glaze firing it has taken on the colour of the body - a gorgeous smooth red, with no sign of white or milkiness.

It could then be worth your friend staining the slip under the sig, rather than the sig itself. This might depend on the temp fired to - I glaze fire to cone 03 well and truly down, so 1105 deg C (2014 deg F) ++.

Are you saying that after the glaze firing, the white sig you're using takes on whatever color it is applied over?  Say if it was applied over a green underglaze, the sig would be green after it was glaze-fired?  If that is the case, would you mind sharing which ball clay you use or do you think any would work?  She glaze fires to 05.


In Topic: Terra Sig Not Buffing Shiny

11 November 2016 - 11:26 AM

Thanks for the help everyone.  After reading the comments, I believe it is probably the addition of the stain that has made the sig "unbuffable".  If that's the case, how can she get a black sig?  I know I've seen it used on other potter's pieces.  She bisques to Cone 04 and glazes to Cone 05.  

 

The reason she started applying white slip to the Stans Red clay was to save on the base glaze.  She only had to apply one coat (brushed on) of the base white glaze if the slip was on the piece.  Otherwise she had to wait until the glaze dried then brush on another coat.  She uses Stroke & Coat as her decorating glazes.

 

Need to do a little experimenting......try the black sig on a test piece...... slip applied only to part of it and apply the sig across both areas.  See what happens.