Making an Urn, Help

[AndreaB]

Hi everyone,

It's been a while!

My mother-in-law passed lst year, straight after I had a spinal fusion. My sister-in-law asked me to make an urn for her ashes. This was 3 months after the op. It's now been 8 months and I've just had Carpel Tunnel Release in my right hand and my left is due to be done in 2 months.  My problem is that they are getting a tad inpatient with the delay. 

So here's what I've tried (unsucccessfuly)... Throwing (came out too small), Slabbing into a bisque form and joining two of them, slabbing around a pvc pipe (couldn't stretch it without cracking), coiling, this has been my latest attempt.  Coiling has never been a strong part of my work but now doubely difficult due to the CTS (my hand has now taken a lot of strain), they keep turning into bowls.

My thoughts today were to slip cast into a bisque mold and join two of them, remove the top and bottom adding a foot and opening where I can form a lid. Problem .. thickness, the altering part, the pouring and using a bisque mold.

I'd love to create a really elegant piece to honor her memory.

Suggestions please..

TIA

Andrea

[GEP]

Have you ever tried what I call a “dowel tube?” I’m sure there’s a better term for it. Start with a large coil of clay. I use pugs straight out of the pugmill. Insert a dowel through the middle of the clay lengthwise. Lay it down on a table and start rolling it like a rolling pin. The dowel will open up the clay from the inside, creating a hollow tube of clay. Then attach a floor, neck, lid, etc, however you want to finish it. It’s a (relatively) easy way to make a large vessel.

I make these large vases with this method. 

[Gabby]

33 minutes ago, GEP said:

Have you ever tried what I call a “dowel tube?” I’m sure there’s a better term for it. Start with a large coil of clay. I use pugs straight out of the pugmill. Insert a dowel through the middle of the clay lengthwise. Lay it down on a table and start rolling it like a rolling pin. The dowel will open up the clay from the inside, creating a hollow tube of clay. Then attach a floor, neck, lid, etc, however you want to finish it. It’s a (relatively) easy way to make a large vessel.

I make these large vases with this method. 

How big was the coil you started with and how tall are these?  I would like to try this as well.

[GEP]

51 minutes ago, Gabby said:

How big was the coil you started with and how tall are these?  I would like to try this as well

The larger one starts with 5 lbs of clay, and I build it to be 12 inches tall. After drying and firing, the final piece is about 10.75 inches tall. I know 5 lbs sounds like a lot, the walls of the piece are fairly thick and heavy. They need to be in order for the clay to support itself as a tube when it is being rolled horizontally. I like to challenge myself to make the walls as thin as possible without collapsing. At least a heavy vase is less likely to tip over when in use.

The smaller one starts with 3.5 lbs of clay, and I build it to 10 inches tall. When fired, it’s just under 9 inches.

Edit to add one more note: as you roll out the tube, the clay will develop a lot of small cracks on the outside. At least it does for me. After I attach the floor to the vase, I spend a lot of time with a soft rib (red Sherrill rib) smooting out the cracks. 

[Min]

Mitch Lyons has a good video showing how to do this.

https://www.youtube.com/watch?v=cHViU5oHk1o

[Pres]

Andrea,

Another thought since you seem to be able to do bowls either with slabs or with coils is to use two bowls, with a short section of slab in the center to create the form. This way you could cut out the base of the top bowl and coil a rim for a lid, making another bowl for the lid.

 

best,

Pres

[Denice]

I gave my nephew a medium size coiled pot with a tight fitting lid.  I wasn't made as a urn but could be used as one.  My sister wanted to be scatter across several states  so it was more for storage than a final resting spot.  When her daughter died she wanted me to make a urn with in a weeks time.   So I bought one of the slip poured urn type pots  and glazed it,  when I gave it to her I told her it was only temporary.    After a couple of weeks she decided to sprinkle the ashes and didn't want another urn.    Have you thought about making several smaller urns and letting different members of the family have one.    I have read that is one of the latest trends in dealing with the ashes of loved ones.     Denice

[Pres]

I have some urns that I have posted on my blog. I am now working on one that my Dad has requested for himself. I have been slow making it, I think understandably. He is 91, and driving his motor home down to a State Park near me for a wedding next week. Will be a 3-4 hr drive for him, but then up til last year he was driving to Florida in the Winter.

 

best.

Pres

[AndreaB]

Hey peps,

Thanks for taking the time to reply. Here's what I've now done. It's still at the hard leather hard stage and I'm forming the lid, which will dome upwards.

Gaby - you don't need to start with such a big piece of clay. I've made several standing vases standing 17". What you do is : using a pvc pipe wrapped with newspaper for easier removal, roll the slab, wrap around the pipe, roll the whole thing onto a sheet which you wrap around firmly. Then roll the whole lot in a piece of foam I've used craft foam and an old yoga mat cut in half. secure this with a couple of thick elastic bands. You can now pick up the whole lot and carry it around, stand it up or lay it down. Because of the support from the sheet and rubber there is no stress on the clay and it keeps it's shape.

 

Pres - I want to apply a white slip to the box, should I use porcelain casting slip or just porcelain slip? and at what stage should I apply it?

 

Thanks all, have a good day.

Andrea

[Rae Reich]

Ideally, slip should be applied while the piece is still wet, and not after leather hard. You want the slip and clay to dry together at the same rate. Your porcelain slip should mature at the same temp as your base clay.

[Gabby]

Andrea, why when you wrap around the covered PVC pipe does the clay not crack in shrinking? Are you saying the newspaper has enough give to prevent that?

[AndreaB]

Gaby, as long as you use a couple of sheets of newspaper the pipe will slide out easily and you don't leave the clay on the form until leather hard, just until it is firm enough to stand on its own. This way the clay hasn't shrunk right down against the pipe. Also by using the wrapping you don't have the clay pulling away and hanging if you know what I mean. Once I've wrapped the clay around the pipe and before wrapping the sheet around it, I smooth down the form, getting rid of any canvas marks. I really go to town with a soft rib and sponge. The advantage of the sheet is that it draws off a fair bit of the water I've used to smooth down the clay. Rolling the tube around on the canvas/sheet has the added advantage of compressing the clay.  Hope  this makes sense. None of the studios that I have been to has used thus method and in fact until I first did this I didn't have any success forming vessels.

[preeta]

Andrea with my experiments I’ve found slip applied to bone dry cracks. Casting slip cracks even more.  

Plain surface casting slip will do. Carved surface - casting slip will hide carving. 

I am still not very good with brushing on slip to get even coat so I like dipping in casting slip and making sure to take any extra slip off esp in bowls as the crack during glaze firing.  

I’m curious to see what The King of slip here says. 

[Min]

16 minutes ago, preeta said:

...with my experiments I’ve found slip applied to bone dry cracks. Casting slip cracks even more.  

 

You can alter slip recipes so they shrink less therefore crack less. Slips can go on wet, leatherhard, bone dry, and bisque if they are formulated to do so. (for bone dry and bisque they would likely be engobes as opposed to slips but are commonly referred to as slips in some countries). I've used Fish Sauce Slip on bone dry and on bisque without cracking. I've swapped out the bentonite in the original recipe for macaloid (aka Bentone MA) as it is much cleaner than bentonite. The recipe as is fires out fairly white but to make it really white add 10 +/- of zircopax. I've used it for lowfire also. 

fish sauce slip altered ^6 - ^10
  Minspar 200.................    27.50  
  Grolleg Kaolin..............    40.70  
  Pyrophyllite................     8.50  
  Silica......................    17.00  
  macaloid....................     6.30  
                              =========
                                 100.00

[Pres]

Whenever using clay around a form a barrier of newsprint or wrapping paper works well. if using clay round a cylindrical form it is helpful to roll the form gently on a flat surface after forming to stretch the clay very slightly as this will make removal of the form a bit easier. I would remove the form just before leather hard, sometimes called cheese hard as it allows you to smooth inside joins easier, and if needed the form may be reinserted to re-round the piece. Never leave the form in beyond leather hard.

If using clay over a plaster or bisque dome, always remove before leather hard as the shrinkage will crack the clay. Remember that porous forms really do not need a paper liner if dry.

 

best,

Pres

[Callie Beller Diesel]

Preeta, it sounds like the white slip recipe you're using has a different shrinkage rate than your clay body. A rough hypothesis, in the absence of knowing your recipes, is that your casting slip is a common ball clay/talc combo. Ball clay has a high shrinkage rate, which would lead to the problems you're describing. 

If you want that nice, smooth sheet of white slip you get from dipping, take a slip recipe that you know fits your clay, and add a few drops of Darvan. I work with a red clay that I apply a white slip to pretty regularly, and the slip I use is just a white stoneware from the same manufacturer of my red clay.  They have the same wet shrinkage rate.

And if that sounds roundabout, the Fish Sauce recipe is pretty magical. 

Added: fish sauce is quite refractory. I have used it successfully in cone 11 wood kilns.

[Pres]

I adapt a clay that I have that I know matches the shrinkage rates of the other clays I use. So I start by slaking some white stoneware down, then add 5-10% zircopax blender it till smooth, and still sieve it through a course screen. I try to never apply my slip to bone dry clay, and if need to pre-soak the piece that I am adding the slip to. Most times I apply at cheese to leather hard, then if engraving I wait til slip is near leather hard. I use a narrow wedge shaped wooden or metal tool to engrave with.  If lettering by hand practice lots before hand. If lettering with stamps do at cheese hard, support the surface underneath. I will also stamp, and then use a firm sponge roller to apply slip over the stamped areas, then use scraping to shape boarders.