Glaze Flaw

[April Rexroad]

Hello all, I just started soda firing after I got back from NCECA so I have only fired 3 or so kilns. It's going mostly well but I'm having trouble with a few of my glazes which on occasion will look wrinkled. It turns opaque and flat looking (it's a transparent glaze usually) and get these gross looking wrinkles. I'm sure there's a name I don't know for this glaze flaw but what baffles me about it is that:
(1) it doesn't always happen
(2) it doesn't appear to be tied to the amount of soda distributed on the pieces
(3) it was a very stable glaze before it went into the soda

If there's anyone who knows why this happens, I would really appreciate the info.

[Pamela Theis]

This is called pig skinning and it has to do with cooling while introducing the soda into the atmosphere. I got this effect when I pushed the damper in so far that it was almost closed during spraying. I did this for heavy reduction. My suggestion is to not damper down so far. Also how are you applying the soda? are you spraying a wet solution? This also drops the temp pretty rapidly and could be a contributing factor.
Pamela

[April Rexroad]

Thanks, that's really helpful. I'm actually using a "tuna salad" type consistency of soda and dumping it in off a large rail. My kiln did drop in temp quite drastically while I was sodaing so maybe I need to give it more time between dumps to keep the temp up or something. Does that sound like something that would help?

[Pamela Theis]

That sounds like it would help.

This is from Emily's earlier post on her process "Add soda into kiln when ∆9 is soft. Add 1 ½ angle irons full of soda mixture through each port. Wait 15 minutes between additions. Usually takes 3 turns to add in all of the soda".

I would also make sure that you are aware of where your damper is, while keeping in mind how much reduction you want. I'm guessing that it will most likely make a difference on how long to wait between soda dumps.

[April Rexroad]

Okay, I will try that next time. Thanks!