Wednesday, December 2, 2009

Pinholes again

I am so fed up with firing! Just once I wish I could open up a fucking kiln and be pleasantly surprised instead of having to start problem solving once again. I have pinholes again, this time in ^10. A lot of the pieces have pinholes. I used a slow bisque cycle, sieved the glazes, everything I thought would solve the last pinhole problem in the ^04 firing. But the worst part is this: the pieces that don't have pinholes have this: one of my new kiln stilts EXPLODED! into every single bowl. Not one survived. I don't know why, it went through a bisque firing the day before and candled for three hours the next day, no way it was wet. So, last time it was the shelf that cracked and now this. These are not even a year old. I have worked in studios for almost ten years and have never seen a shelf or a stilt do this. Are these manufacturer's defects? And shouldn't they reimburse me for all of the lost product? We are talking clay, chemicals, time and energy not to mention these were bowls I needed to sell this weekend. Arghhhhh!!!! So, I may have a few mugs and a couple of jars out of this firing but that's it. The rest is for the shard pile. And oh yeah, it's pouring rain this morning, yet again, so I'll put some pictures up of the carnage later. Right now I'm waiting on Axner to start business hours so I can call them.


Judy Shreve said...

Oh Tracey - I'm so sorry for your kiln disasters - what's up with the shelf cracking & post exploding - that's just weird.

I don't know how to resolve pinholing - but I know the first place to look is bisque -- how slowly it's fired - should you fire to a higher temp - is your bisque kiln vented - do you wash the bisque ware before applying glazes ???

Another culprit could be glaze/clay body fit.

I used to have problems with one glaze pinholing & for me the problem was zinc - when I removed the zinc from the glaze recipe - I no longer had pinhole issues. I don't know why that worked.

Glazing & kiln firing can be such a nightmare -- I know there are people highly skilled that are willing to help -- Ron Roy & John Britt. Both of these guys have helped me tremendously when I've sent emails with my problems.

I hope your problem is resolved soon.

Hollis Engley said...

Hi, Tracey. Bad news about the firing. I hate that. I'm with Judy on her suggestion that you email Roy and Britt. I'm not up on solving that particular problem, other than knowing that sometimes dusty work will pinhole. Which is why some people lightly wash their bisque before glazing. Which I don't do, by the way. As for an exploding prop, I've never had that happen. My props have been through hundreds of firings by this time and have never blown up. Believe me, I can't imagine it's your fault on that one. Sounds like a manufacturing defect of some kind.
Good luck with it. Wish I could help more.

heidi haugen: days with clay said...

morning tracey. sorry for you heap of issues but know that you are soooo not alone in this department. have a good cry, evaluate, and carry on like we always do. best wishes.

cindy shake said...

So sorry. I am of no technical value here but just wanted you to know I AM here for art-chick moral support! I can also say that if I had opened the kiln it'd be Alaska Amber time!

Linda Starr said...

So so very sorry about this, never heard about the stilts exploding before. I was just saying to myself the other day that I can't wait to get my new studio so I can be in charge of my own firings because of all the mishaps I have had to put up with from other's firing my work - now I am thinking - careful what you wish for. I am hoping all your problems are now out of the way and it will be smooth sailing for you from now on. I have started washing my work and have had better success with the glazes since then and I stir the glaze before I glaze each piece too. I think the best cone 10 firing I ever had was when the kiln was left to cool very slowly for a couple of days and the pieces were loaded with lots of open space around them.

brandon phillips said...

what glaze is pinholing? sometimes glaze with lots of organic material can pinhole if taken up too fast from 1200-1800. ball clay, earthenware clay(redart), ash all have a good bit of organic material. it may be helpful to soak the kiln at the end as well. i've had pinholing problems that i haven't quite figured out and i've decided to start taking my bisque up to 04.
i've never heard of a prop blowing up, that is bizarre. better get back to it and make more pots! good luck!

Ron said...

Sorry to hear about all this Tracey! Totally sucks. It would help to know what the glaze was that had the problem and if it was just one glaze or all of them. Hang in there, lots of support out here.

Jen Mecca said...

Don't ever give up!!

cookingwithgas said...

Ditto Jen!
It is just a big fat bump in the road!
Smash and knash your teeth stomp and cuss.
Then tomorrow start again.
Better things will come.

Dirt-Kicker Pottery said...

Total bummer :( And the timing couldn't be worse.
I've been fighting pinholing for 6 months. The only thing that seems to help is using less groggy clay and using very reliable glazes.
Eat some chocolate. It seems helps too.

soubriquet said...

I don't claim to be an expert but the first time I met pinholing was thirty-seven years ago.
I'd look first at the glaze immediately after dipping. Are there any bubbles or pinholes on the surface as it dries? If so, try squishing or rubbing them over before you fire.
Then , absolutely with Brandon Phillips, on this, look at a brief soak at your top temperature, maybe thirty minutes just below top. Slow the kiln down on that final step.
Think of it like a very big Raku, think how you see raku glaxes bubbling, as gases come out. What's happening in your firing is that maybe that bubbling hasn't quite finished when the temperature start to drop again.