Craters & pinholes

[Jeff Poulter]

I do a lot of layering, sometimes good, sometimes not so good.  I usually do tests on a tile first & then pick a few combos & put them on a throw away pot.  After that I will use it on a good pot.  Lately, I have been having some crater/pinhole problems.  It started with certain combos using some Spectrum glazes.  I have been respraying & refiring the problem areas, but then other areas pop up.  A couple of these pots have been glaze fired 5 times.  Does anybody out there have a magic glaze that will make these other glazes behave, since I can't take them off the pot?  Is there a glaze that I can pack into the craters that will make them smooth out?  Is it a clay problem?  I always do a 15-20 min. hold at the end of the cycle.  I have even had a few pinholes on a controlled cool down as well.  I wonder if it is time to get the hammer out.  Any help would be greatly appreciated.  Thanks,  jhp

[Jeff Poulter]

Hi Ceci,
I have never seen Gun Metal Green not craze on any body by itself, but I did a test with Mardi Gras sprayed over it & it looked pretty awesome. There probably was still some crazing, but not like when it is by itself. I only do decorative so I can get away with a little crazing. The test was on white bisqued tiles from Seattle Pottery Supply. They are the only ones I could find that have ^6 & ^10 bisqued tiles. I buy the seconds. After all, I'm just throwing glazes on them, nothin' fancy! I had used G-mix, but it was awhile ago & I don't remember what the issue was with it. It might have been cracking issue with the big pieces. Still haven't found a mid-range white that I like. A local production potter here had Laguna mix up his clay & he wants me to see how it does at ^5. It was developed to be a ^10R clay, but it rings pretty good even at ^6. I have a pot made with it that will get crystalline put on it tomorrow & we will see how it like crystalline. Then I will try it @ ^5/6. Lately I have been throwing Appaloosa from Coyote. It practically throws itself! I need to stock up on it before it gets too cold, otherwise I'm stuck with Laguna & Aardvark from the local supplier. Red B-mix 5 is pretty good as is Red Calico, but still looking for that elusive white. Maybe I will have to see how Imco Geostone works at ^5/6. It is great at ^8-10. I hope you at least got someting for your GMG. I would have paid you at least a few bucks for it. Let us know what the kiln guy says

[Ceci]

Oh now you tell me you would have taken the glaze. Ha. Here is a picture of what that GMG glaze did. Total fit issue! Let me know if you can see the picture. I wonder if I can get that Appaloosa from my supplier. Think I'll check it out in a minute...or I'll go to free freight pottery supply and buy 50 lbs to test it out. Thanks for the info

Kiln guy just left. Changed the relays and said everything else looks good. Will do my test fire tomorrow morning and will report back.

Ceci

Jeff Poulter said:

Hi Ceci,
I have never seen Gun Metal Green not craze on any body by itself, but I did a test with Mardi Gras sprayed over it & it looked pretty awesome. There probably was still some crazing, but not like when it is by itself. I only do decorative so I can get away with a little crazing. The test was on white bisqued tiles from Seattle Pottery Supply. They are the only ones I could find that have ^6 & ^10 bisqued tiles. I buy the seconds. After all, I'm just throwing glazes on them, nothin' fancy! I had used G-mix, but it was awhile ago & I don't remember what the issue was with it. It might have been cracking issue with the big pieces. Still haven't found a mid-range white that I like. A local production potter here had Laguna mix up his clay & he wants me to see how it does at ^5. It was developed to be a ^10R clay, but it rings pretty good even at ^6. I have a pot made with it that will get crystalline put on it tomorrow & we will see how it like crystalline. Then I will try it @ ^5/6. Lately I have been throwing Appaloosa from Coyote. It practically throws itself! I need to stock up on it before it gets too cold, otherwise I'm stuck with Laguna & Aardvark from the local supplier. Red B-mix 5 is pretty good as is Red Calico, but still looking for that elusive white. Maybe I will have to see how Imco Geostone works at ^5/6. It is great at ^8-10. I hope you at least got someting for your GMG. I would have paid you at least a few bucks for it. Let us know what the kiln guy says

[Jeff Poulter]

Now that is some serious fit issue! Luckily I have never had a glaze do that to me. Makes me feel bad whining about craters & pinholes. They are annoying, but what do you do when the glaze flies off the piece like that!?! It's hammer time! That would really suck! What is free freight pottery supply? I have never dealt with them. When I have had to bring clay in, most the time I have had to talk them into shipping me 2-25lb pugs in a Large Flat Rate Box. It's $14.50 on top of the clay price, but better than what UPS would charge. There have been a few hold outs. Standard's pugs won't fit, but they give me a break on the clay price to make up for sending it UPS. Stone Mountain has to scrunch their pugs to make them fit, but they do fit with a little effort. Georgie's will do it. So will Clay Planet & New Mexico Clay. I have even talked Laguna/Miller back east into doing the USPS Flat Rate thing. It certainly works for trying out different clays. Were the relays just worn? How old were they? I'm hoping mine will hold out until spring. Got all the pieces & parts to turn them over to an SSR, so I hope they make it. I suppose I could move the kiln to the garage to work on it, but it isn't much warmer in there. At least it's not like the frigid north where you have to use a heater to warm the control panel before you can even fire the kiln up. Will try & re-fire the acne rejects & let you know how that goes. jhp


Ceci said:

Oh now you tell me you would have taken the glaze. Ha. Here is a picture of what that GMG glaze did. Total fit issue! Let me know if you can see the picture. I wonder if I can get that Appaloosa from my supplier. Think I'll check it out in a minute...or I'll go to free freight pottery supply and buy 50 lbs to test it out. Thanks for the info

Kiln guy just left. Changed the relays and said everything else looks good. Will do my test fire tomorrow morning and will report back.

Ceci

Jeff Poulter said:

Hi Ceci,
I have never seen Gun Metal Green not craze on any body by itself, but I did a test with Mardi Gras sprayed over it & it looked pretty awesome. There probably was still some crazing, but not like when it is by itself. I only do decorative so I can get away with a little crazing. The test was on white bisqued tiles from Seattle Pottery Supply. They are the only ones I could find that have ^6 & ^10 bisqued tiles. I buy the seconds. After all, I'm just throwing glazes on them, nothin' fancy! I had used G-mix, but it was awhile ago & I don't remember what the issue was with it. It might have been cracking issue with the big pieces. Still haven't found a mid-range white that I like. A local production potter here had Laguna mix up his clay & he wants me to see how it does at ^5. It was developed to be a ^10R clay, but it rings pretty good even at ^6. I have a pot made with it that will get crystalline put on it tomorrow & we will see how it like crystalline. Then I will try it @ ^5/6. Lately I have been throwing Appaloosa from Coyote. It practically throws itself! I need to stock up on it before it gets too cold, otherwise I'm stuck with Laguna & Aardvark from the local supplier. Red B-mix 5 is pretty good as is Red Calico, but still looking for that elusive white. Maybe I will have to see how Imco Geostone works at ^5/6. It is great at ^8-10. I hope you at least got someting for your GMG. I would have paid you at least a few bucks for it. Let us know what the kiln guy says

[Jeff Poulter]

Duh, I just realized that Free Freight Pottery has the same address as Coyote. I'm just a little slow sometimes!

[Ceci]

Hi Jeff

HAPPY DANCE!!! I did the test glaze fire and it turned out perfect. Witness cones we right on and no pitting. I'm assuming at this point that the relays this go around ramped up & slow cooled correctly. Every single glaze was perfect on the test pieces. To summarize....replaced thermocouple & relays...bisqued to ^04, fired to ^5 with a 10 minute soak.

In regards to your clay...yikes, you always get that mailed to you? I guess you saw www.freefreightpotterysupply.com by now. Clay is a little more expensive but I think they adjust the price some to cover some of the freight cost. AND they have that Aardvark clay you like.

Yippee....today is a glaze day. Um....never thought I would say that and be so happy. LOL

Ceci




Jeff Poulter said:

Duh, I just realized that Free Freight Pottery has the same address as Coyote. I'm just a little slow sometimes!

[Jeff Poulter]

Hi Ceci,
Glad you have your problem solved! I haven't had time to redo the acne rejects yet, too many hours at my day job. I did manage to squeeze in another crystalline & it turned out better than I had hoped. Still not exactly where I want it, but I'm getting closer. My goal is to be able to walk out to the kiln & pull out a crystalline pot & not have to separate it from the pedestal or do any grinding. I have tweaked 1 glaze combo that stays on the pot, but it still over-nucleates. I have so little time to do pottery & I don't want to spend it throwing catchers & pedestals. The next firing I do, I will have to pay more attention to the relays, I hope they're not bad. If I don't get Laguna or Aardvark from the local supplier, I have always had to pay for shipping on each box. It's just what I have had to deal with. I did order a couple hundred lbs. of Appaloosa from FFPS & it was like getting a whole box for free. This last crystalline test I did was on this local potter's white clay & the crystalline worked real well on it. The only problem I have had with it is 1 of the 2 piecers I did with it came out of the bisque with the seam showing pretty bad(it wasn't that way when it was green). I was going to junk it, but decided to do a layer test with it. I'm glad I did `cause it got me 1 step closer to where I want to be on crystalline.

Well, I've taken up enough of your glazing time, so I'll let you get back at it. jhp

[Jeff Poulter]

So I got 4 out of the 7 rejects re-sprayed & re-fired. All 4 of these were the Amaco glazes with ash on the top. I sprayed a little Ironstone & Peacock Green & did a longer controlled cool down & "voila", all the pits & craters are gone. In fact they are all glassy & smooth like a baby's bottom. I don't think it was so much the glaze(although I think it helped), but the longer controlled cool down(especially when it's in the 20's outside)(where my kiln is). The crystallines automatically get a controlled cool down, so I adapted it & gave these ^6 ones a little bit of a cool down as well & I think it really helped. The final test will be on these last 3 as they are the worst. I will let you know. btw, the ash glaze look was diluted with the overspray of new glaze, but it looks better than the craters jhp

[Ceci]

Hi Jeff....hope your Thanksgiving was great. I blogged about mine since it was the trip from HELL. Anyway, glad you were able to fix the pinholes. What was the cool down schedule? I may need to try this if I have a problem again.

Ceci


Jeff Poulter said:

So I got 4 out of the 7 rejects re-sprayed & re-fired. All 4 of these were the Amaco glazes with ash on the top. I sprayed a little Ironstone & Peacock Green & did a longer controlled cool down & "voila", all the pits & craters are gone. In fact they are all glassy & smooth like a baby's bottom. I don't think it was so much the glaze(although I think it helped), but the longer controlled cool down(especially when it's in the 20's outside)(where my kiln is). The crystallines automatically get a controlled cool down, so I adapted it & gave these ^6 ones a little bit of a cool down as well & I think it really helped. The final test will be on these last 3 as they are the worst. I will let you know. btw, the ash glaze look was diluted with the overspray of new glaze, but it looks better than the craters jhp

[Jeff Poulter]

Hey Ceci,
Sorry about the trip from hell, the biggest problem I had was keeping the turkey fryer lit. I decided to get a new one this year, `cause the burner was about shot on the old one & the new one has a timer on it that only lets it run for 20 minutes at a time. I went out to stick the chile rellenos & onion rings in & I had forgot to turn the timer on again, so the oil had cooled down. The turkey had to go almost an hour, so I had to remember to turn the timer several times. What a pain! I will be performing surgery on that gadget before next Thanksgiving. I don't have the schedule in front of me, but it was a fast fire to ^5 with a 20 min. hold. I know I came down 75/hr. for a couple of hours & then went to 100/hr. to 1650, then off. If you were doing an RIO glaze I guess you could put a hold there. On the 2nd batch, I was in a hurry & dumped the program at about 1725 & it didn't seem to make any difference. I think the slow cool is more important at the top end so that the blisters can heal over before the glaze gets too stiff. Someone told me that you are never disappointed with doing a slow cool down. I know it takes some extra juice, but it sure beats a re-fire all to ..... It's still snowing & I am sure glad I got the roof over the kiln when I did. Now all the snow just slides off of it when I am firing! jhp

[Ceci]

Hi Jim

Thanks for the info on the cool down. I will need to try that. Mmmmm, never ever had deep fried turkey but it looks delish!!!

Here is the link to part 1 of my trip from hell blog. It's a funny read whenever you have time...kinda long though

http://cecisartandothermagicaladventures.blogspot.com/2010/11/plane...

and part 2....

http://cecisartandothermagicaladventures.blogspot.com/2010/11/plane...

We LOVE chili rellenos!!!!! Especially made with Hatch green chilis. I use to drive up to Old Mesilla in New Mexico (just up the road from El Paso) and pick up fresh chili's ....THE BEST!

We're expecting snow all week and I have to set up for a month show on Wednesday. So much to do and so little time. My glaze fire finished about an hour ago and I will turn around and do another load tomorrow. Sheesh, won't I ever learn?

Glad your new roof is working out for you. Fire on!

Ceci



Jeff Poulter said:

Hey Ceci,
Sorry about the trip from hell, the biggest problem I had was keeping the turkey fryer lit. I decided to get a new one this year, `cause the burner was about shot on the old one & the new one has a timer on it that only lets it run for 20 minutes at a time. I went out to stick the chile rellenos & onion rings in & I had forgot to turn the timer on again, so the oil had cooled down. The turkey had to go almost an hour, so I had to remember to turn the timer several times. What a pain! I will be performing surgery on that gadget before next Thanksgiving. I don't have the schedule in front of me, but it was a fast fire to ^5 with a 20 min. hold. I know I came down 75/hr. for a couple of hours & then went to 100/hr. to 1650, then off. If you were doing an RIO glaze I guess you could put a hold there. On the 2nd batch, I was in a hurry & dumped the program at about 1725 & it didn't seem to make any difference. I think the slow cool is more important at the top end so that the blisters can heal over before the glaze gets too stiff. Someone told me that you are never disappointed with doing a slow cool down. I know it takes some extra juice, but it sure beats a re-fire all to ..... It's still snowing & I am sure glad I got the roof over the kiln when I did. Now all the snow just slides off of it when I am firing! jhp

[Jeff Poulter]

That was too funny(not for you, but for us to read!) I'm glad you made it back in 1 piece. My in-laws are from New Mexico, so we always have chilis around. If not from the freezer, as a last resort, the Hatch ones from the can. Usually in the fall, we'll go down & have a gunny sack roasted & then bring them back & put them in baggies in the freezer. Last year I ran across a gal from one of our local vendors whose brother raises them here locally & I got some from her. I used the last of them on Thanksgiving. They are the best & with a little bit of fire in them. Deep fried turkey is the only way to go. Last year I did a smoked, deep fried turkey & it was fantastic. I waited too long this year & couldn't find a smoked one, so I had to do a fresh one. It was OK. I have another crystalline test pot in right now, but I should get to the last of the acne rejects by the end of the week. Good luck at the show & make sure you keep the shovel handy. Too bad you didn't have a little can of Oust with you, not that it would make it past TSA & I don't think they make a liquid under 2 oz.!!! jhp

[Jeff Poulter]

Here are the 3 worst of the acne rejects(^5/6). I took some mostly dried out Milky White glaze & slathered it into all the craters & pockmarks. I ran it fast up to ^04, then a controlled cool & a little hold at 1650. As you can see most of the craters are gone, but there are still some residual pock marks(art imitating real life). The skinniest one really changed the glaze & didn't melt as well, so it got some more glaze & it went back in & this time it is going to ^5 with slow cool & a hold. Will see if it behaves a little better. Before.

After