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Beestie

Please Help A Frustrated Newbie

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Hi All, I'm not only new to the forum, I'm completely new to clay in general.  I've been in forums for years in my own industry (photography) and I do realise how frustrating these questions can be.  Please go easy on me, I've already paid it forward and done my time in the trenches helping newbies ;)

 

I run a photography studio in Australia, specialising in newborns and after 15 years in business, we've decided we'd like to offer simple clay impressions, framed with our images, to our line up.  

 

Sounds so simple in theory, but I'm really struggling with this.  Firstly I've not been able to find a clay that is really soft.  To my mind, I'm pressing way too hard on the babies foot.  I have been assured this is not the case, and have done a couple of online courses to see the best approach.  

 

After a few false starts, I did a couple of impressions last week that worked out beautifully...nice deep impressions with loads of detail and lines of the feet showing.  So three days later i go to check out how they are drying to find there's barely an impression visible!  The clay has flattened out again so that I can barely see a foot mark, let alone any detail. 

 

I REALLY want to crack this, but it just seems like I'm not getting anywhere.  Can anyone offer any reason at all why this might be happening?  I've had someone say that the clay may contain too much moisture, but then I've also had someone tell me that the clay can be wet to make it softer for baby's feet, and there was no mention of it being too moist.  

 

Please...anyone?  

 

 

 

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Hi, and welcome to the forum.

 

The problem you are running into, is due to the fact that clay shrinks when it dries.  Water is what makes clay flexible.  As it leaves the clay, the particles move closer together.  So the clay becomes smaller in all dimensions.  A slab of clay will become shorter, narrower and thinner.  Details on the surface that were once raised up, will become less pronounced.

 

For ceramicists, features are made slightly bigger, to compensate for the shrinkage.  This isn't possible for you, since you can't make the child's hand bigger and features of the hand deeper.

 

You would be better using a different material, like plaster or something similar. Plaster keeps a great impression, and does not shrink as it dries.

 

Best of luck in your venture.  I think it's a great idea to include with your photos!

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Thanks so much for your reply.  Ah, ok, so I understand about the shrinkage...so to compensate that, deeper impressions, or softer clay might help?  I really want to use clay, to make it a lovely, unique framed keepsake.  Many others are doing 3d plaster type moulds.   

 

I'm not sure we can push any harder mind you, I'm pushing on those tiny hands and feet pretty hard as it is.  

 

I'll keep practising and see what results different products bring, thanks again.  

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I think what Benzine may have meant was that if you do the original casting with plaster, you can then use the plaster cast to make the ceramic piece. This allows for making multiples (for grandparents etc) and you can use any type of clay you like with the plaster. It's an age old pottery technique. You'll get a much higher quality cast than you ever could in one go.

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If you use clay there is no way I know of to avoid the fact that it shrinks as it dries. 10-15% in every direction. This is the reason people use plaster to do this.

One thing you might try is clay slip and pre fired tiles. Brush some slip on the baby's foot, press it on to the tile to make a pattern. It will still shrink but perhaps not as noticably as a whole big impression would be.

Tell the people this will happen and they might not care that it is not exact when finished ... It was exact when you made it.

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Thanks everyone.  Loads of great info here.  My head is spinning but I feel like I'm getting somewhere.  I have tried polymer clay in the past but it just doesn't give the same result I'm after.  I've attached images of what I'm trying to achieve.  It never occured to me these were created by taking plaster moulds first.  I've spoken to clients who have been to this artist and they tell me that she was working with a slab of clay and pressing the feet in, then firing.  No matter how hard I pressed, I could not get such a deep impression.  

 

post-75318-0-31442200-1456157303_thumb.jpg

post-75318-0-34645700-1456157323_thumb.jpg

post-75318-0-31442200-1456157303_thumb.jpg

post-75318-0-34645700-1456157323_thumb.jpg

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Those last images look to be tiles fired as that are white blue and beige

The clay looks very smooth like porcelain which is what you want.

I have seen these over the decades at art shows and not paid much attention to details as its not  in my field of interest.

The clay ones show less detail the plaster ones are sharper. 

As posted above plaster will not shrink as much as clay

what you need to try is making some test ones and see how they turn out

the issue with making a clay one form the plaster one is it will be a positive and if you make it again to a negative it will shrink even more.

I also suggest you get a clay person involved as the learning curve will be steep for a photohog.

 

The first photo of the white tile could be plaster. The material will not matter as its behind glass -mounted

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Most of the commercial clay you will find are at a working consistency for pottery. If I was doing hand/feet baby prints I would make a softer clay from my reclaim. But taking a fresh block of clay and making it a little softer (adding more water throughout) cannot easily be done.

 

This piece would shrink about 15% so the tiny prints get even smaller. Just ignore that, nobody really cares if their tiny one's prints have already grown by the time the piece finishes :-)

 

With the right glaze, even feint impressions come alive.

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Ok;This is a little crazy in terms of the amount of work, but...

 

I've made up a (trailing) slip from dry clay, a slight bit of water, and what ended up being a large amount of silicone--something like darvan, for example. For my purposes, I needed at least some water for it to adhere to the mugs, but you might not need that in this case. The silicone made the 'clay' very soft and stir-able, but eliminated most of the water component. You'd need to mix this with a blender for your purposes, and be super careful working with the dry clay dust (since you won't have water to keep it down). Perhaps you could test this with a small amount and have some handy ceramicist-type mix up larger batches.

 

This would still shrink in firing still, since the... chemical water trapped in the clay (I don't know how to explain this to a newbie :o), is still in there, but at least you'd keep the amount of added water down. But the shrinkage rate should be more on the <6-8% rate than the 15% rate. (Some chemist please help me out here.)

 

Sounds both crazy and interesting as I write... perhaps someone here will give it a try and test out feasibility and shrinkage rates for a siliconized-porcelain tile/mat for imprints.

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Try making a mother mold from alginate of the baby's feet. Then make a plaster mold  positive in the alginate. You get a resilant stamp you can press into clay as often as you want. Alginate is available from most very good pottery supply houses for sculpture work or if you want a medical grade (Think molds of teeth for dentures) from a Dental supply house (or Dentist). Generally you put 1 part water into 1 part alginate but mix it quick with a rubber spatula  and apply it to the baby's foot quickly.A  mixed alginate/water compound only has about a minute to mix and apply depending on it's formula. Since it's a medical type of compound it pulls off the model (baby) easily without remaining residue. You can get 4-5 high quality plaster molds out of it before degrading. Store the alginate mold submerged in water. The alginate is made from seaweed gel and will dry out otherwise

 

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I think once fired the detail will become more pronounced. As clay dried it becomes duller and smoother.

 

To get soft clay you really want to recycle the clay. That way you have a clay with excess water and you can dry out until the consistency you are happy with and get better impressions.

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+1 for making plaster casts.  It sounds like more work, but in the long run, it is quicker.

 

  1. Mix plaster
  2. Put foot hand onto plaster
  3. Allow plaster to dry - several days
  4. Pour clay slip into plaster
  5. Allow to dry, remove before cracks
  6. Fire

 

You'd then have a positive casting but maybe you want to be different from all the other folks doing this.  If you want negative space, you need to make another plastercast from the original, and then slip-cast from that.  Plaster is cheap, your time isn't, and although it sounds like a lot of work, once you are set up with cottle boards (see book below) it is like any other process.

 

http://www.amazon.co.uk/Essential-Guide-Making-Casting-Ceramics/dp/1600590772 -  try library?

 

Good Luck

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I want to point out that ^06 clay shrinks a lot less than ^6 or ^10 when fired. Not nearly 10%.

 

Fine detail often reappears after firing and glazing. Many of us have left fingerprints, some deliberate, in our clay. They are pretty accurate. Using a slightly tinted glaze will bring out the detail.

 

A thin wash of stain could also be applied and wiped off of bisque fired piece before a clear glaze is applied to accentuate the fine detail.

 

I think you should finish, or make more of your test pieces - bisque, apply glaze or stain/glaze and glaze fire. You probably will have a better idea of where to go from there when you have some results to study. Because of the many and time-consuming steps you'll need to go through to get a professional looking piece, better give yourselves a few months to learn and perfect for a consistent result.

 

The alginate master mold, used to make plaster stamps, would allow for several uses or editions as suggested above, but a single-use, foot/hand pressed into clay is a one-of-a-kind original.

 

I once made baby prints on a bisqued tile and mug by saturating a fine-textured sponge with stain, pressing hands/feet as you would on a stamp pad and then pressing hands/feet on the mug/tile. This is easy if Baby is sleeping, but the older and squirmier the baby, the more potential for mess.

 

A final thought: You could save yourself a lot of trial and error and equipment-buying if you could find an Experienced potter in your area to sub-contract out the firing and finishing to. They will be able to guide you to the appropriate necessities and, maybe teach you to do it yourself eventually.

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Thanks everyone, this has been really helpful.  Rae, I think you are right, good advice.  Taking a piece through to the finished product would be a much better learning experience.  I'm working with a local pottery supplies store who is advising on clay choices and doing the firing for me.  I really don't want to do go down the plaster/mold route as I worry about the extra time it takes to do this in studio.  I wasn't intending to glaze mine. I love the unglazed look in the link above, and you can see in that example that the print is perfectly deep and well defined.  I'd need to glaze if the print is remaining on the surface as mine is.  

 

High Bridge Pottery, I was advised not to recycle the clay or use my offcuts for this, but only to use a slab cut from a fresh block to avoid air bubbles.  Was this not advice you would follow?  

 

I purchased a very soft clay yesterday, a porcelain clay that the potter said she would fire at a lower temp, but being behind a glass frame it would be fine.  This clay is almost too soft!  But I can see how I could easily get a better impression from it.  It's just much harder to cut and roll smooth than the earthenware I was using.  

 

I have another crash test dummy in studio today...lets hope for better results! 



 

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I know a potter who sometimes includes her pets' paw prints in her work. She said it does not work to press clay onto a paw, but rather the dog or cat must be standing on the clay with its body weight in order to make an impression. I don't know how well a baby can participate in this, but somehow the baby's body weight and gravity need to be employed. Maybe newborns are too young, and your clients need to be old enough to stand with assistance, or hold themselves in a crawling position for hand prints.

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There is going to be a sweet spot for moisture content. Too much and it will be sticky, to little and it will be too stiff.

 

Getting air bubbles out from clay takes a little practise but it is done by all potters if they have a machine or not. The easiest and least skill involved is drop wedging (mixing) cut the block in half and slam one half on top of the other and keep repeating till you can no longer see air bubbles stretching when you drop it.

 

You will need some kind of absorbent surface like a plaster slab or concrete floor to suck the moisture out of the clay.

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beestie, yes, if you use a slice from a pugged block of clay fresh out of the box, there should be no air bubbles.  to condition the block, a flat drop onto the floor will work well.  drop the flat side down and keep its shape as well as you can.  you will notice a change in the clay's stiffness after the drop.  once might be enough.

 

once the print is made, any excess clay can be kept and re-used.  there should be very little excess clay and you may find it not worth the trouble to keep it.

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+1 for making plaster casts.  It sounds like more work, but in the long run, it is quicker.

 

  1. Mix plaster
  2. Put foot hand onto plaster
  3. Allow plaster to dry - several days
  4. Pour clay slip into plaster
  5. Allow to dry, remove before cracks
  6. Fire

 

You'd then have a positive casting but maybe you want to be different from all the other folks doing this.  If you want negative space, you need to make another plastercast from the original, and then slip-cast from that.  Plaster is cheap, your time isn't, and although it sounds like a lot of work, once you are set up with cottle boards (see book below) it is like any other process.

 

http://www.amazon.co.uk/Essential-Guide-Making-Casting-Ceramics/dp/1600590772 -  try library?

 

Good Luck

DO you take the foot out of the plaster before pouring in the slip??

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By plaster, I guess you mean Plaster of Paris aka potter's plaster. Great stuff, great fun, quick to set, holds detail beautifully. But be careful. It sets slowly at first then hardens suddenly, so don't hold a hand or foot in it longer than a second or two. Do a couple of tests with a grape or something delicate like that and you'll quickly be able to judge the right time to do it. It also gets very hot as it sets - people have been badly burned in the past. Don't want to scare you - it's a great material and should be perfect for what you need. Just handle with care.

 

Best of luck!

Girts

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Hm, ok, maybe the babies are just too young, but the sample I posted above comes from a photographer who's clients are newborns.  And I do get a nice imprint, it just completely disappears as the clay dries.  

I went and purchased a new clay yesterday, very very soft porcelain, and it was a disaster!  I managed to get lovely prints, it's like marshmallow, but lifting them off the board to move to the racks to dry they just stretch and get all distorted.  I've tried three with this clay now, and while they do seem deeper and able to keep the impression even as they dry, they are stretched an unusable.  The clay is really hard to work with compared to the earthenware, being so soft and sticky.  I can't cut a fresh slab of it, it's just a pile of goo in my hands, and I worry about the air bubbles for firing. 

I'm doing three per client now, just to trial different approaches, but so far just not getting the same results as in the image I posted. 

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it really is hard to explain in terms a non-potter can understand.  do not lift the clay.   put the clay on a small support, a board or something it can then dry on top of.  do not try to peel it off of whatever it is on.  let it sit and dry thoroughly for days if necessary.  do not disturb the print at all.  

 

 

once it is totally dry, you can remove it from the board and fire it.   talk to a potter about this.

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I think this is why you need to recycle the clay. Don't worry about air bubbles as they never blow up anything in the kiln like is passed around. Much more to do with steam than air pockets. They may show up as bumps in the finished piece which is not what you want but it is not hard to get them out the clay in preparation.

 

Look up drop wedging, it gets rid of bubbles and is not too difficult.

 

Using clay as is out the bag you get no control how wet the clay is unless the supplier happens to supply it the right consistency. Like old lady says if you bend the clay it will remember and warp in the kiln. Make some wooden boards that you can cut the slab on, get foot impression and leave till dry without any lifting back up.

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