SiC copper reds questions

[Rebekah Krieger]

I am about to mix up some SiC copper reds for mid range oxidation firing to test out. I would love to know if anybody has discovered ways to prevent the common carbide bubbling and pinholing that is known to occur before I begin my testing journey? Some suggest fast cooling, some suggest slow.

my guess is that a hold will help develop more red but I rear it may cause the carbide bubble effect. Has anybody done testing on this? Ask if my mesh is finer than a recipe (say I have a 1000 mesh and the recipe calls for 600) Would it mean I should try adding less to account for the better encorperated product? I plan to test but I’m hoping to avoid some kiln runs. Thanks!!

 

-Rebekah 

[liambesaw]

Slow fire from 1200-1700f which is the period when carbons burn out, probably will still get some bubbles like you see in John Britt's book, but won't crater like a textural SiC glaze (hopefully).  Also the finer the particle size the easier it will come out.

[Rebekah Krieger]

Thanks, I will try that. I’m thinking of doing a test in a sagar and one outside to see the variation too.  I have been trying to get the bloodiest blood on my pots for years and the lack of variation on commercial reds and mason stains make them look so uninteresting. 

[liambesaw]

Could experiment with rutile or titanium dioxide along with red stains, would add some variation

[docweathers]

I use John Britts silicon carbide copper red all the time. I've never had a problem with pitting etc.

This could beca se I use slow heating and cooling a standard practice, a somewhat modified Stephen Hill firing schedule.

I have experimented with adding more silicon carbide It really doesn't make any difference in color or anything else.

 

[Rebekah Krieger]

6 minutes ago, docweathers said:

I use John Britts silicon carbide copper red all the time. I've never had a problem with pitting etc.

This could beca se I use slow heating and cooling a standard practice, a somewhat modified Stephen Hill firing schedule.

I have experimented with adding more silicon carbide It really doesn't make any difference in color or anything else.

 

 I imagine it might if you have more copper to reduce. I am testing out his recipe as well as Tom turners recipie (cone 9) I’m going to take a stab at converting it down .... 

[hitchmss]

13 hours ago, Rebekah Krieger said:

I imagine it might if you have more copper to reduce

More copper does not = more red. I fired at cone 10 redux for my reds, so my experience may not be as applicable at 5/6 ox. However, if you are seeking those bright, fire engin'ish color reds, then adding more copper will yield a more green color than a bright red. If you are having trouble getting consistent reds across a pot, then adding more copper may bring that consistency in check....copper volatilizes at a low temp, so if you dont achieve reduction at the proper temp, you will burn off the copper needed to produce the red colors. Again, Im creating a reduction atmosphere at a certain temp, whereas you are using temperature to convert SiC into a localized reduction atmosphere; without having much experience with oxidation copper reds I cant say that the same principles apply from ox to redux.

Do a line blend and post your results here. Most of my copper reds have tiny amounts of copper in them (relatively). 

[Rae Reich]

@hitchmss, doesn't the copper remain in the glaze whether or not it reduces to red? I have refired improperly reduced disappointing not-reds and achieved red the second time without reapplication of glaze. I think you left the impression that the copper burns out -

"so if you dont achieve reduction at the proper temp, you will burn off the copper needed to produce the red colors,"

when actually the firing went past the necessary reduction period without having been reduced, leaving the copper unchanged.