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Ibwalk

Cremation Urrn

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Ibwalk    0

I am making an urn to hold the cremains (ashes) of a client's husband. Shape and size has been determined as well as the glaze. Client wants the ashes to be "hermetically" sealed. As you know, when glazing, the two pieces would be fired not touching and probably having rims of both the urn and the top with no glaze where they would fit together

 

Question: If I hand dipped each piece as well as the inside rim of the urn but not where the ashes would rest, then poured the ashes in the urn, placed the two pieces together (remember, no resist being used), and fired it so the urn itself and the top would fuse together into one - Would the whole thing blow up at some point because of built up pressure during firing? If it didn't blow up at that point, could the vessel have a higher than normal pressure when it cools down and therefore be more prone to fracture or blow up later? Lastly, after researching the cremation process I discovered the temperature used to render a human body to ashes is about 1650 F. I use cone 6 when firing, about 2355 F. What would happen to the ashes? Remain the same, coalesce into a lump, melt?

 

Any past experiences would be appreciated,

 

ibwalk

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Mark C.    1,807

I have made urns for people and animals

I suggest sealing the lid with silicone seal after the ashes are in fired pot. Its waterproof and seals very well.

As far as over firing ashes its a bad idea as they will melt at some point and loose the ash quality.

Mark

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Sadly, I spent yesterday making an urn for a friends little dog. For two months there were reports of sightings of this sweet dog along a 2 mile stretch. We were so sure she would be reunited until a kayaker found her. As it turns out, she probably was never really sighted. Closure, although it is welcomed, came in such an unexpected manner.

 

it is sunny and warm here so there was a good chance for it to dry somewhat even though I had to form all parts while they were more wet than I normally do (hand built) . I even made a backup in terra cotta just in case I couldn't get two firings in before they went to pick up the ashes. Planned a slow bisque, hit Start and pop! The fuse on the controller burst. Replacing the fuse was not the issue-- why it burst was the question. Thank goodness I got a quick response from the kiln company and it was only a loose wire. I just started the firing and even though I will be up very late tonight, I want this to go right.

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Mark C.    1,807

I will also say I have cremated my own two cats in my gas kiln so I have some experience in this .

Mark

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Ibwalk    0

Thanks for the touching, feel good replys but can anyone out there actually answer the questions with certainty in the original post in regards to pressure and explosion possibilities and the condition of the ashes after being exposed to the high temps of glazing? I've considered the silicon and epoxy options.

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Mark C.    1,807

Thanks for the touching, feel good replys but can anyone out there actually answer the questions with certainty in the original post in regards to pressure and explosion possibilities and the condition of the ashes after being exposed to the high temps of glazing? I've considered the silicon and epoxy options.

 

 

The deal is nobody here has fired human ashes to 2355 as you noted(cone 6 is around 2250)-I will say that they will flux out at that temp and be a glob of fired glaze like stuff that is ugly and rough.

As to your firing a sealed vessel question that also is a bad idea-put a pinhole size pinhole in unglazed bottom part to relieve pressure as you would not want this to crack

which is most likely what it can do. I have fired a pot that ran all around the lid and its fine still 20 years later but cracking can occur. So if cracking is ok go for it. If fluxed out ashes are ok go for it.

Maybe a better idea is make the glaze from the ashes and fire that-that can also work well.

One other point is to test a small vessel and fire some ash in it also as a test. Then tell us the answers.That way we will all know.

Mark

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TJR    359

ibwalk;

I am pretty sure that you will get a lava like, cruddy mess. That is the direct answer to your question. I have made several cremation urns, including one for my own mother. The jar was 5 pounds of clay with an overhead lid with knob. The jar is glazed on the inside as well as the outside.After it comes out of the glaze firing. the ashes are placed within and the lid is sealed with Epoxy on both surfaces. Because this jar is buried, I always make two. One is kept by the family.

If you seal the jar and fire it in the kiln without an air hole, you have a good chance of it blowing up.

Tom.[TJR].

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Marcia Selsor    1,301

I have made several urns for family and friends.

I agree it is a bad idea to fire the ashes.

Mark's idea of silicon seal is the best in my opinion.

 

Marcia

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Idaho Potter    62

I am finishing an urn for my son-in-law's ashes and will ship it to my daughter to finish her arrangements. In talking with the funeral home, she was told that after the cremains are put in the urn, it would be sealed with a wax. The reason behind this is that often times people want to scatter the ashes at a later date (but keep the urn as a momento of a life well lived), or later, be joined with their partner's ashes after they have passed.

 

In my opinion, the urn should be finished and turned over to the client for final decisions.

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lbwalk, reading this thread through, it seems to me that you were in an anxious state. Had I realized this initially, I would not have added my post. Two things though--First, the thread title is about cremation urns in general. Secondly, Mark and Neil had already answered your concern.

 

Sorry for the misunderstanding.

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yedrow    8

I'm just throwing this out there, in case it can be applied without negatively affecting your client's wishes.

 

What if you used a very low fired glaze to seal the lid; some kind of glost glaze perhaps. Put a pin hole in an unglazed part of the pot and seal that pinhole up with epoxy after firing?

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Very interesting information on this thread, thank you. I am designing an urn for my father's ashes but am not sure what volume I should allow for nor how best to work out the dimensions of the form to accommodate this (the maths for ellipsoid volume calculations gets too complex for me!).

Can anybody advise me please? I have in mind a very simple, roughly egg-shape urn in a clay (Oxidising St Thomas from Potclays, UK) that will be earthenware fired.

Thank you in advance.

Chris

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Cass    5

the amount of ash varies, but generally speaking its 150 cubic inches, imagine a 1/2 gallon milk carton...if it is an egg shape maybe about 12" to 14" tall will be good

 

to be 100% sure you could get the ashes in a temporary container and make the urn to suit

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Cass    5

as for sealing the cover, i tested some Museum Wax, i am finding it to be perfect. it sticks, but you can still get it open if need be, and the formula is made to not change 'forever'

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When I made an urn, the funeral home was happy to put the ashes into the urn and seal it. There is no way I would take responsibility for the ashes, much less put them into my kiln where so much could go wrong.

 

For what it's worth, I did put small lugs on the urn and got some nice cord to sort of macramé the lid to the urn.

 

For size, figure a cubic inch per pound of body weight.

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Benzine    610

Very interesting information on this thread, thank you. I am designing an urn for my father's ashes but am not sure what volume I should allow for nor how best to work out the dimensions of the form to accommodate this (the maths for ellipsoid volume calculations gets too complex for me!).

Can anybody advise me please? I have in mind a very simple, roughly egg-shape urn in a clay (Oxidising St Thomas from Potclays, UK) that will be earthenware fired.

Thank you in advance.

Chris

 

 

As stated by Diane, one cubic inch per pound of body weight is the formula for figuring urn space. The math beyond that, is up to you. Don't forget to carry the one.....

 

I like the idea of making two matching vessels. I may have to start doing that.

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I had made the urn but was concerned it might be too small. To figure volume, I filled the urn with water, measured the water, and then used calculations available online to determine volume in cubic inches. Measuring pieces you already have can give you some idea of the size needed.

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I will also say I have cremated my own two cats in my gas kiln so I have some experience in this .

Mark

 

I don't mean this to sound callous or judgemental, I'm just curious, did you really do this? Having just lost a dog a bit ago, I can imagine this must have been difficult. Thanks for your response.

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Mark C.    1,807

I will also say I have cremated my own two cats in my gas kiln so I have some experience in this .

Mark

 

I don't mean this to sound callous or judgemental, I'm just curious, did you really do this? Having just lost a dog a bit ago, I can imagine this must have been difficult. Thanks for your response.

 

 

Let me tell you my story about my cat Xeno. He was my pick of the litter and was Abyssinian .

I had him for 19 years-he was a great tabby tiger striped Manx with no tail-we were very close -we shower together -me every day he choose once a month. I have had animals my whole life and this cat was very special-he was more like a dog -followed me around and waited all day outside the potshop for me to finish up.-I bring home food from the sea and he liked fresh abalone /scollops and tuna with some salmon tossed in. As the years went by we became a close nit pair. He slept with me after his showers and always had a great attitude. As he aged he lost most of his hearing and when he was 17 he got into a tuff and had some nerve damage-I drove him 6 hours to UC Davis veterinary school in Davis Ca. He eventually healed up again. A few years later his heart started to get elliptical and smaller-eventually his heart gave out-but for a while i injected him with fuilds for months to keep him chipper. One knows the time when its time for them to check out.I knew his night has cone and slept with him and he died in my arms after taking his last breath in the middle of the night. I said and had my piece with him and put him in our chest freezer for about 6 months. After xmas I curled him in a large bowl and fired him to-ash temp. My good friend Woody the vet gave me the specs-We have been friends for over 40 years. I had made my urn and will take a photo of it in am.I spread some of his ashes in his favorite spots like in the rows of corn in garden where he snoozed the summer away waiting for me to come out of the studio. I have a rough draft of a story about this cat with another artist who is great with cat drawing and some day may put this cats story to book form-I have about 7 ideas all going at once these days.

as far as firing him (I also did my friend cat a year later) this ashes thing was not callous as I loved this cat more than some people. But you see I've spread both my brothers ashes as well as both parents and a stepfather and a few dogs so ones gets a bit used to the procedure-its never easy just part of life and in my case a bit to much.

Mark

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trina    20

I will also say I have cremated my own two cats in my gas kiln so I have some experience in this .

Mark

 

I don't mean this to sound callous or judgemental, I'm just curious, did you really do this? Having just lost a dog a bit ago, I can imagine this must have been difficult. Thanks for your response.

 

 

Let me tell you my story about my cat Xeno. He was my pick of the litter and was Abyssinian .

I had him for 19 years-he was a great tabby tiger striped Manx with no tail-we were very close -we shower together -me every day he choose once a month. I have had animals my whole life and this cat was very special-he was more like a dog -followed me around and waited all day outside the potshop for me to finish up.-I bring home food from the sea and he liked fresh abalone /scollops and tuna with some salmon tossed in. As the years went by we became a close nit pair. He slept with me after his showers and always had a great attitude. As he aged he lost most of his hearing and when he was 17 he got into a tuff and had some nerve damage-I drove him 6 hours to UC Davis veterinary school in Davis Ca. He eventually healed up again. A few years later his heart started to get elliptical and smaller-eventually his hear gave out-but for a while i injected him with fuilds for months to keep him chipper. One knows the time when its time for them to check out.I knew his night has cone and slept with him and he died in my arms after taking his last breath. in the middle of the night. I said and had my piece with him and put him in our chest freezer for about 6 months. After xmas I curled him in a large bowl and fired him to-ash temp. My good friend Woody the vet gave me the specs-We have been friends for over 40 years. I had made my urn and will take a photo of it in am.I spread some of his ashes in his favorite spots like in the rows of corn in garden where he snoozed the summer away waiting for me to come out of the studio. I have a rough draft of a story about this cat with another artist who is great with cat drawing and some day may put this cats story to book form-I have about 7 ideas all going at once these days.

as far as firing him (I also did my friend cat a year later) this ashes thing was not callous as I loved this cat more than some people. Bt you see I've spread both my brothers ashes as well as both parents and a stepfather and a few dogs so ones gets a bit used to the procedure-its never easy just part of life and in my case a bit to much.

Mark

 

 

i have tears.... T

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Mark C.    1,807

My pot in the moniker photo (the orangish one with bamboo handle) is an urn for some friends in Atlanta currently-It was a gift to them.

Porcelain fored to cone 10 reduction .

Mark

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bny    5

I would not try firing cremains in a sealed container.  In an experiment a few months ago, I mixed some nutritional supplement bone meal with feldspar and kaolin and fired a small amount.  I got a sort of ceramic foam: glassed outer surface, foam-like interior.

 

A quick look online suggests cremation temperatures of 1400F to 1800F, versus 1100C (2012F) for calcining bone ash.  A reaction with gas going into or coming out of the reaction seems likely, and you are nearly certain to have previously absorbed water coming out as vapor, even if there is no reaction.

 

Even if there is no reaction, nor evolution of water vapor, you must deal with the ideal gas law: PV=nRT.  R and n are constant, you say that you want to make V constant (sealed system), and you are proposing to make T large.  That is guaranteed to make P large (pressure increase).

 

All of that aside, ask yourself if there are any other circumstances under which you would try to fire a sealed container with a large interior void space.

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