Problem with Electric Brown

[SSB]

I recently fired some pieces that I made out of Laguna Electric Brown. They were fired at Cone 6. My intention was to use a cold surface treatment.  When they were removed from the kiln, they seemed to sprout whiskers.  I tried sanding and "whiskers"re-emerge.  Can anyone explain why this happened. Also, is there a way to stop the whiskers from reappearing?  Would any surface treatment: acrylic paint, wax, keep them from popping out?. Thank you all for your answers and input.

[Min]

Hi @SSB and welcome to the forum!

That would be sand in the claybody that hasn't shrunk like the rest of the claybody has.

You could either look for a claybody that is described as smooth (no grog or sand in it) or burnish the Electric Brown when leather hard to push the sand into the body. This might not totally fix the issue but it will lessen it. Other thing you could do is sieve some slip made up of the claybody and brush it over the pot when soft leatherhard. Last option would be to take the piece outside, put a P100 mask on and sand it down. I know you said you tried sanding and the "whiskers" reappeared but try sanding again. When people use sandy or groggy clay to make pots with it's very common to have to sand the unglazed bottoms down to prevent them scratching tabletops etc.

[SSB]

Min,  Thank you for your quick response.  I will try sanding again.  The silica bumps seem to go away after sanding and then pop out again. It was suggested that I re fire at a lower temperature such as Cone 3.

[Mark C.]

With all beauty shops currently closed I think its just growing more hair/sand. Maybe. consider a self haircut

 

On a more serious not the bumps cannot grow more . Maybe you are just sanding into more bumps as that clay is loaded with sand it looks like. 

[SSB]

Thanks, Mark!

Perhaps it is an Easter miracle.  Will try to do a little more sanding . Reminds me of a Chia doll.

Laguna is closed because of the virus.  Really appreciate this Forum.

[Min]

2 hours ago, SSB said:

It was suggested that I re fire at a lower temperature such as Cone 3.

If the body tightens up and shrinks more than it is right now by re-firing it then this would actually exacerbate the problem rather than alleviate it. Silica sand won't melt or dissolve in the claybody by re-firing to cone 3.

[SSB]

Thank you.  Friend pointed out that Shigaraki ware embraces these weird protrusions.  One more technical question if I may?  When I sponge the clay down with water, it leaves a white haze similar to ocean water on rocks.  Is that from my water which is hard or the calcium/salt content in the clay?  So glad that I have scientists available to answer my questions.  

[Min]

18 hours ago, SSB said:

When I sponge the clay down with water, it leaves a white haze similar to ocean water on rocks.  Is that from my water which is hard or the calcium/salt content in the clay?

I've never had a moist clay change colour when working with it, not sure if you mean the wet clay changes colour or the fired clay. I'm guessing that it would take really hard water to contain enough salts to change the colour of moist clay. Any chance you have some distilled water you could try an experiment with?

I looked up your claybody, the Safety Data Sheet (SDS) for it is here. If you have a look at page 2 you can see the materials used to make the clay, notice how there is <2% barium carbonate in it. This small amount of barium is added to prevent soluble salts from migrating to the outside of the clay so when fired the white haze shouldn't be from the clay itself.

[SSB]

Hi Min,

It is vitrified clay fired to Cone 6.  It must be my hard water. Thank you for taking such an interest in my topic.

[Sorcery]

I would guess your sanding is filling in the depressions with dust, making it seem like the whiskers disappeared, when in fact they haven't. Reemerging when the dust clears.

Make Cats!

 

Sorce

[Barbie]

Electric brown is not an ideal surface for what you are trying to achieve.consider switching to IMCO's Night clay, also a dark clay body fired to cone 6. No grog, very smooth. Another person posted about burnishing your piece, I second that. Also do not sponge clean your work in the green ware phase if working with a sandy/groggy body. The sponge removes the fine particulate that is on the surface and drags the grog/sand across your surface leaving gouges (whiskers). Instead use the pad of your fingers and thumb to smooth down. If you're worried about hand fatigue invest in a silicone rib. Check out mud tools. 

[SSB]

thank you for your response.  I don't know IMCO Night Clay, but I'll check it out.  I didn't sponge the greenware, just after it was vitrified.  Love Mud tools.