John Britt Copper Red issues

[LadyLumpsClay]

I just tested John Britt’s copper red in oxidation. Fired with the attached schedule and got really weird results. My distributer gave me 60 mesh silicon carbide instead of 600 mesh and I wonder if that’s part of it. Also ran really badly on the kiln shelf. Any suggestions?

Edited January 27, 2023 by LadyLumpsClay

[Dick White]

Yup, 60 mesh vs. 600 mesh will do that.

[neilestrick]

Definitely a mesh size problem. The larger mesh size won't burn out properly, hence the crater effect. Copper reds are typically pretty fluid, so you may need to adjust the thickness of the glaze application or your firing schedule.

[Min]

If you want something to use up the 60 mesh and you make anything with an unglazed gallery mixing the silicon carbide with toothpaste then using it as a grinding compound will make the unglazed rims or galleries as smooth as glass. A few blobs of the silicon carbide toothpaste around the rim then rotate the rim several times then rinse it off well, lids will fit really well and won't make that grinding sound when you put them on.

[Kelly in AK]

I second what @Minsays, I use valve grinding compound (which is just SiC in some kind of goop, seems like glycerin) for lids and it works great. 

I also see bubbly lava glazes use SiC for the effect. Maybe it could be useful in that way too. 

[LadyLumpsClay]

Thanks so much guys!

[PeterH]

8 hours ago, Kelly in AK said:

I also see bubbly lava glazes use SiC for the effect. Maybe it could be useful in that way too. 

Perhaps it's worth glancing at this, which looks at the effects of different SiC mesh sizes in lava glazes.

Testing Silicon Carbide Grits in Cone 6 Lava / Crater Glazes
https://www.thestudiomanager.com/posts/testing-silicon-carbide-grits-in-cone-6-lava-glaze