Barrel Firing No Color!

[SteveL]

I just finished my first barrel firing and I got almost no color. I followed what seem to be the common instructions: 6 inches of sawdust, pots, Miracle Grow, Salt, Ferric Oxide, cover with sawdust. Chicken wire for protection, then build a standard campfire. I fired for about 9 hours and then let the barrel cool over night. This morning, almost nothing! The clay was still the same color with very little evidence of the firing, save a few dark spots and very few orange spots...as in very few. The good news is that I can refire the pots, but what did I do wrong? I fired "greenware" and I'm using paper clay. The pots seem to have "ceramicized" for lack of a better term. They have a nice ceramic ring to them when I thump them, so they are now ceramic. Any help would be appreciated. Thanks

[Pres]

I just finished my first barrel firing and I got almost no color. I followed what seem to be the common instructions: 6 inches of sawdust, pots, Miracle Grow, Salt, Ferric Oxide, cover with sawdust. Chicken wire for protection, then build a standard campfire. I fired for about 9 hours and then let the barrel cool over night. This morning, almost nothing! The clay was still the same color with very little evidence of the firing, save a few dark spots and very few orange spots...as in very few. The good news is that I can refire the pots, but what did I do wrong? I fired "greenware" and I'm using paper clay. The pots seem to have "ceramicized" for lack of a better term. They have a nice ceramic ring to them when I thump them, so they are now ceramic. Any help would be appreciated. Thanks

 

 

I think the term you are looking for is "vitrified". A lot of the vitrification depends on the cone level of the clay you are firing, and how hot your "barrel fire" got. I imagine that you didn't get color flashing because of the vapors escaping before effecting the pottery. Assuming this-how closed was the firing environment?

[SteveL]

Yes, vitriey. The barrel only had about 6 1/2 inch holes around the bottom ring. By the time the fire got down there, there was a pretty good set of coals on top of the saw dust/pottery layer, but you may be right, I just don't know as I am quite the novice at this. I'm going to try aluminum saggers on the next firing. Interestingly enough, there was a pot on the very bottom of the barrel when I removed it from the ashes this morning. It had been placed upside down and the sawdust underneath was still black. The inside of the pot was black as well, which suggests that the smoke was in contact with the pot longer than the chemicals I just sprinkled in with the sawdust. I'm thinking the fire never got hot enough down where the pots were and the chemical vapors escaped too rapidly. No worries, I'll figure it out. Any other thoughts would be appreciated. Thanks for the reply.

I just finished my first barrel firing and I got almost no color. I followed what seem to be the common instructions: 6 inches of sawdust, pots, Miracle Grow, Salt, Ferric Oxide, cover with sawdust. Chicken wire for protection, then build a standard campfire. I fired for about 9 hours and then let the barrel cool over night. This morning, almost nothing! The clay was still the same color with very little evidence of the firing, save a few dark spots and very few orange spots...as in very few. The good news is that I can refire the pots, but what did I do wrong? I fired "greenware" and I'm using paper clay. The pots seem to have "ceramicized" for lack of a better term. They have a nice ceramic ring to them when I thump them, so they are now ceramic. Any help would be appreciated. Thanks

 

 

I think the term you are looking for is "vitrified". A lot of the vitrification depends on the cone level of the clay you are firing, and how hot your "barrel fire" got. I imagine that you didn't get color flashing because of the vapors escaping before effecting the pottery. Assuming this-how closed was the firing environment?

 

[Pres]

Yes, vitriey. The barrel only had about 6 1/2 inch holes around the bottom ring. By the time the fire got down there, there was a pretty good set of coals on top of the saw dust/pottery layer, but you may be right, I just don't know as I am quite the novice at this. I'm going to try aluminum saggers on the next firing. Interestingly enough, there was a pot on the very bottom of the barrel when I removed it from the ashes this morning. It had been placed upside down and the sawdust underneath was still black. The inside of the pot was black as well, which suggests that the smoke was in contact with the pot longer than the chemicals I just sprinkled in with the sawdust. I'm thinking the fire never got hot enough down where the pots were and the chemical vapors escaped too rapidly. No worries, I'll figure it out. Any other thoughts would be appreciated. Thanks for the reply.

I just finished my first barrel firing and I got almost no color. I followed what seem to be the common instructions: 6 inches of sawdust, pots, Miracle Grow, Salt, Ferric Oxide, cover with sawdust. Chicken wire for protection, then build a standard campfire. I fired for about 9 hours and then let the barrel cool over night. This morning, almost nothing! The clay was still the same color with very little evidence of the firing, save a few dark spots and very few orange spots...as in very few. The good news is that I can refire the pots, but what did I do wrong? I fired "greenware" and I'm using paper clay. The pots seem to have "ceramicized" for lack of a better term. They have a nice ceramic ring to them when I thump them, so they are now ceramic. Any help would be appreciated. Thanks

 

 

I think the term you are looking for is "vitrified". A lot of the vitrification depends on the cone level of the clay you are firing, and how hot your "barrel fire" got. I imagine that you didn't get color flashing because of the vapors escaping before effecting the pottery. Assuming this-how closed was the firing environment?

 

 

 

Yes I would bet that the bottom pot was heavily reduced from the lack of oxygen in the heat. This is not from the smoke so much as the lack of oxygen. You are firing with a technique that uses oxygen for combustion as opposed to electric. You can set up a kiln so that you burn in an Oxidation, Neutral or Reduction atmosphere. Reduction is harder to reach temps with as it chokes the fire. Most kiln are fired with a neutral or oxidation atmosphere to a certain point, then put into reduction for so long to bring up the colors and textures desired in the ware. Then the kiln is fired in an oxidation atmosphere for a short time to clear the atmosphere and then shut down when reaching temp.

[SteveL]

Sorry if I wasn't clear. I'm firing in a barrel, a 55 gallon drum, and using the techniques found here and on other web sites. I realize that the one pot blackened because of lack of oxygen, but my curiosity is that there was no color on any of the other pots, save a tiny bit of blackening. Since I used Miracle Grow, Salt, and Ferric Oxide, I expected some colors, but nothing. Any additional thoughts would help. Thanks

[Marcia Selsor]

Dear Steve,

When I have done this technique, I used a 55-gallon barrel with 4 holes in each of the three levels of the barrel form. I followed Piepenburg's description of using a brick(s) and BBQ grate on the bottom and begin stacking pots, sawdust, newspapers, sticks, charcoal briquettes,copper carbonate, salt, continually combined to fill the barrel. Started the fire with newspapers at the bottom. Covered the top with kiln shelves with a little breather to keep the air going. I plugged the holes with ceramic fiber and controlled the burn by opening and closing the holes. Is the surface of your clay burnished or are you using terra sig? What type of clay are you using? To what temperature are you bisque firing?

 

Marcia

[SteveL]

I'm almost embarrassed by all the attention, but I have to be truthful. This is my first EVER attempt at pottery/firing. I've done lots of other art and decided it was time to get to know pottery, so off I went. I'm not sure of Piepenburg's description (I may have read it on the net as I have been reading a lot), but I started out with 6 inches of pine sawdust on the bottom of the barrel, next were the pots (made from Cone 04 sculpture clay from Archie Bray), followed by sprinklings of ice cream making salt, Miracle Grow, and Red Iron Oxide. I covered the pots with more sawdust and more salt, Miracle Grow, and Ferric Oxide and then put the chicken wire over them to protect them from falling wood from the fire. Next, I put down 2 fair sized logs, newspaper, smaller firewood, newspaper, more small firewood, more newspaper and then more logs, followed by more newspaper and kindling. I lit the whole thing and let it burn for hours, intermittently adding more firewood and putting the barrel cover on and taking it off. I kept thinking that I needed a hotter fire so I kept removing the cover to let in more oxygen. Since it was a newer barrel, I could watch the progress of the hot part of the fire as it burned away the paint on the outside of the barrel until it reached the bottom where the 1/2 inch holes were. By the time the bottom of the barrel was hot, I could see the bottom of the barrel from the top looking inside. There were lots of coals, etc. Knowing what I know about how fire works, I may have left the cover of the barrel off the fire too much and the fire burned too quickly, thus not giving the chemicals time to "sit and smoke" for lack of a better term. I'm curious about starting the fire at the bottom of the barrel that you mentioned, and the holes going up the barrel. Oh, since this was more of an experiment for proof of method, I just used the few pots I hand built, so they were in the green ware state. Some of the pots vitrified , but a couple did not. The pots were neither burnished nor did I use terra sig, they were just raw course pots. I intend on trying another fire this weekend so I'd like to get some pointers before Saturday. I'm also considering wrapping the pots in aluminum foil as I have read to increase the time the chemicals vaporize and stay in the immedicate atmosphere around the pot, but everything is up for grabs. Thanks so much for any help you can offer.

Dear Steve,

When I have done this technique, I used a 55-gallon barrel with 4 holes in each of the three levels of the barrel form. I followed Piepenburg's description of using a brick(s) and BBQ grate on the bottom and begin stacking pots, sawdust, newspapers, sticks, charcoal briquettes,copper carbonate, salt, continually combined to fill the barrel. Started the fire with newspapers at the bottom. Covered the top with kiln shelves with a little breather to keep the air going. I plugged the holes with ceramic fiber and controlled the burn by opening and closing the holes. Is the surface of your clay burnished or are you using terra sig? What type of clay are you using? To what temperature are you bisque firing?

 

Marcia

 

[Deb Evans]

Hi Steve

you might be better off introducing your salts at the end of the firing ( sprinkeling the "dust" around the pots and than choking off the air. You need reduction to get diff effects.

How much breakage did you have???? even a soft bisque ^08-06 would help surviaval rate. You don't what the pots vitrified in bisque, need to get past chemical water but still in bisque state to survive the ups and down of temp in a pit fire. Good luck.

[SteveL]

Uh, that was the odd part. I had a couple of edges with dings, and one pot had a small blown out area the size of a quarter, but that was it. Since I'm working with paper clay, I intend to try some repairs and refire them. Can you explain what you meant about the pots not being vitrified in bisque? Thanks

Hi Steve

you might be better off introducing your salts at the end of the firing ( sprinkeling the "dust" around the pots and than choking off the air. You need reduction to get diff effects.

How much breakage did you have???? even a soft bisque ^08-06 would help surviaval rate. You don't what the pots vitrified in bisque, need to get past chemical water but still in bisque state to survive the ups and down of temp in a pit fire. Good luck.

 

[Deb Evans]

Steve

some questions....

are you using hard or soft wood/ sawdust?

hard wood gives more temp, soft wood might make it to 1200 degrees or so.

what temp is your paper clay?

bisque ^08 -04 -firing gets the ware past 1100 degrees - so water does not "melt" it.

bisque firing just protects the ware - can expand (heat up) and contract (cool down)in the kiln ( can, pit, pail, whatever) = less breakage.

Vitriviacation is when the the clay has been in the utmost heat before it melts - it holds water w/o absorbtion - it is metamorphic rock.

 

pit fire is notorious for fast cool downs so

when you reach high temp >you are looking for > pots that are glowing orange = approx ^08 or so,

sprinkel your colorents ( wear respirator, it's going to be toxix for a while) on the pots , add more fuel and then choke the kiln ( pail, barrel, pit, whatever).

Just stuff fiberfrax in most of the barrel holes or premade clay stoppers (must be prefired), sheet metal ( steel not alluminum) on top. if you have dirt or sand can pile it around.

Basicly you are controling/slowing down the cool down.

If you burnish (rub the leather hard surface w/ smooth river stone or silver spoon) you will have a "shiney" surface.

I learned a lot by getting small metal bucket and doing 1 piece firings then went on to do did bigger barrel firings. Hope this helps, happy experimenting.........enjoy............

[SteveL]

Steve

some questions....

are you using hard or soft wood/ sawdust?

hard wood gives more temp, soft wood might make it to 1200 degrees or so.

what temp is your paper clay?

bisque ^08 -04 -firing gets the ware past 1100 degrees - so water does not "melt" it.

bisque firing just protects the ware - can expand (heat up) and contract (cool down)in the kiln ( can, pit, pail, whatever) = less breakage.

Vitriviacation is when the the clay has been in the utmost heat before it melts - it holds water w/o absorbtion - it is metamorphic rock.

 

pit fire is notorious for fast cool downs so

when you reach high temp >you are looking for > pots that are glowing orange = approx ^08 or so,

sprinkel your colorents ( wear respirator, it's going to be toxix for a while) on the pots , add more fuel and then choke the kiln ( pail, barrel, pit, whatever).

Just stuff fiberfrax in most of the barrel holes or premade clay stoppers (must be prefired), sheet metal ( steel not alluminum) on top. if you have dirt or sand can pile it around.

Basicly you are controling/slowing down the cool down.

If you burnish (rub the leather hard surface w/ smooth river stone or silver spoon) you will have a "shiney" surface.

I learned a lot by getting small metal bucket and doing 1 piece firings then went on to do did bigger barrel firings. Hope this helps, happy experimenting.........enjoy............

 

Thanks for the reply.

I'm using small softwood shavings which seem small enough to do the deed, along with split dry firewood. The shavings are quite small in size, but not complete sawdust per se. I think I actually used more firewood this time than last.

I did another firing yesterday/today with some methods and results that were different, but I'm not sure better.

I laid down a layer of charcoal impregnated hickory brickets on the bottom (some commercial brand). This morning, they were still keeping heat, 24 hours after the fire was lit and the pots I removed were quite hot to the touch.

This time, I wrapped the pots in chore boy scrubbers and then wrapped them in salt soaked rags. I then wrapped everything in heavy duty foil so in effect a foil saggar as I have read. When I removed them, the foil was burned away in spots, but still kind of solid in others. The salted rags had burned away for the most part.

I'm thinking the "chore boy" scrubbers are copper coated steel as some of the markings on the pots are black, but very little color again.

I'm going to take some pictures and will post for review by any "experts" or people familiar with the process.

I like your idea of a smaller barrel and am in pursuit of one today for my next experiment.

My paper clay is cone 04, but it looks like some of the ware is bisquing, while some is not??? I'm thinking uneven firing is the culprit here. Is it possible for a pot to bisque on one area and not on the other?? That seems to be the case with a couple as they ring when finger thumped in spots, but still have a dull thud in others??

I went back an re-read as many articles/books (including alternative kilns and firing techniques) as I could on the process to be sure I was on track. Seems so.

I'm thinking I need to get the temperature up, but I'm not sure how. I like your idea of hardwood, but aside from that any help would be appreciated. I'm also thinking about lining the barrel with wood and placing the pots in more in the center and keeping it fueled longer. Would partially burying the barrel help? I can't seem to find that out from what I've read.

My whole project is very low budget and obviously amateur, but I want to see if someone like myself can pull this off. My next idea is to stoke up the fireplace and put the pots in there....but I've got to convince the mother in law that's a good idea ;-) Thanks so much for your help.

 

 

[Deb Evans]

Steve - no worries - fireplaces have been firing pots for millinium.

 

Uneven firing is nature of a wood fire w or w/o pots in it. Hard wood (hicory) increases the temperature : more hard wood = hotter fire. You can also increase the heat by stoking during firing. Evening out the firing and getting color results are the hardest part.

 

Keep on experimenting - sounds like you've got a few successes - ck out today's PC post on pit fire..enjoy.

[Jlagrimanta]

So, I have a question for you that seems potentially overlooked. By paper clay, do you mean paper clay from the craft store, or really clay with paper in it?

 

I just finished my senior thesis with several successful barrel firings and no grate. I also found that there is absolutely no need to keep adding wood. If you want color ants that are flashing and or vibrant, you should wrap the vessels in a foil dagger, so that they get reduced in an enclosed atmosphere. This was the most successful way to achieve colors ra in a barrel that I have found. Also, I bisque fired all my wares to come 04 in an electric kiln prior to barrel firing. I used cedar chips from the farm supply store, other random combustibles for fun, and layered it like you've said you did. If you're not getting enough airflow, a shop vac can be you're best friend. Does that all make sense?

[Jlagrimanta]

I also just realized this is several years old now....

[Benzine]

I also just realized this is several years old now....

 

Haha, I was reading the first posts, and wondered why I didn't recognize the users.  Then I looked at the date, and realized it was two years, before I joined the forums...

 

Still, it's nice bringing up these old topics.  Someone might enjoy seeing the discussion.  Just because it's old, doesn't mean it's not relevant.

[Cavy Fire Studios]

Actually, this is a great thread to bump. I have been toying with the idea of pit firing out here, and what this person did/did not do is good reading for someone who has never done this kind of thing before. Thanks. :3