Jump to content

Wheel Head Leaving Dark Tarnish On Clay


Recommended Posts

My wheel appears clean and silver, with no visible tarnish. However, when I pull my clay off the wheel, there is black/dark looking clay or slip where it meets the wheel. It's as though the wheel head is giving off a tarnish or the clay is reacting to the metal.

 

Will this cause problems when firing?

Is there anything I can do to prevent this?

 

I know I could throw with bats but I don't currently have any. I will go that route if necessary, but in the meantime, just looking to figure out what this tarnish is and if it's going to cause problems.

Thanks!

Link to comment
Share on other sites

do not worry about it.  it is likely that glazenerd has a scientific description, i only have a working history with this.  it is simply a reaction between the clay and the wheelhead metal. 

 

you can see something like it when you look at a matte glaze on a plate and see the cutlery marks.

Link to comment
Share on other sites

Yes, Glazenerd will be along soon and give us a better scientific answer. For the layman's answer, it is aluminum oxide. The wheelhead is cast and machined aluminum, and the clay (whether through chemical reactions or physical abrasion) will cause a slight amount of the aluminum to rub off onto the bottom of the clay or your throwing sponge as the wheel turns. It is harmless, will not affect anything in the firing despite its dark color now.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.