the difference between: wheel-throwing verses slip-casting

So I have a 'confession' to make.  It's the kind of dilemma that's been running through my head since I first embarked on making ceramics full-time.  It's the whole wheel-thrown verses slip-casting debate.  It's a discussion I've had with numerous ceramic people and I thought I would bring it up on my blog. To get started, my mugs in question.  The two images, one slip-cast, one wheel-thrown.  Photographed at different times so the lighting in one is darker than the lighting in the other.  Although the clay is slightly different so my glazes are a little brighter on the porcelain than 'porcelaineous' clay body.  You be the judge- is one 'better' than the other?  Can you tell the difference in how they were made?

About 2 years ago now I embarked on my first slip-cast project.  I had a wheel-thrown and altered bottle vase form that I wanted to make multiples of.  The drying time on this form, being altered with a new bottom being put on to oval it off, was taking way too long and I really wanted a 'blank canvas' to put glaze designs on.  The more I thought about it, the more it made sense to look into making a mold out of it.  So I got in touch with Russell Hackney, a master mold-maker who's worked on making prototypes of intricate clocks for the Queen, no less.  It was a pricey venture to get it the master and molds made, but I didn't want to fuss with my own lack of skill in the mold-making category- I wanted to put my best foot forward and come out with a near exact replica of my original design. 

In 2010 I decided, after much deliberation and months and months of sitting down with each little wedged 1 lb ball of clay, making hundreds of mugs with the same 2 basic forms, not ever quite keeping up with my orders because I didn't have time to make other things, to make my 2 mug designs into molds.  This was the hardest decision for me yet.  I really love looking inside a wheel-thrown mug and seeing throwing lines on the inside.  My outsides are pretty void of throwing lines because I use a rib to smooth them out since my glazing method works a lot easier if I have a smooth surface, so the outsides would generally be the same.  But the insides would be, different.  Perhaps a little too manufactured.  Regardless, I needed a break.  I was beginning to dread making mugs all the time. My body was telling me it needed a break from throwing, and my head was saying it didn't make financial sense for me to wheel-throw each and every piece that I make.  So I took the plunge and made my mug designs into a mold and have been slip-casting them since last spring.  Just the tall mugs, not the little latte mugs, or my cups, or my bowls, or my platters, or my teapots, or my espresso cups, or my plates.  
Now slip-casting itself was no small leap for me to make.  I had to find a good slip recipe and mix slip by hand (measure out dry materials, sieve it, mix with a drill mixer for 2 hours, allow for air bubbles to settle for a few days before mixing for another hour).  The trial and error of this process ruined a lot of work before I started to see results.  The molds themselves are not a cheap investment to make.  And I still pour them, pull them out of the mold, clean up the seams, put handles on them before they can be bisqued and glazed by hand.  But the big advantage is the drying time.  They don't need take nearly as long to dry out as wheel-thrown work does.  And they are all the same size so if someone orders multiples or comes back for a second mug, it will be the same size.  The handles always feel great and are big enough for different hands to hold it.  The whole process has freed up some of my time to work on new designs and new glazing patterns.  In the end I feel like it was the right decision to make, but sometimes with a twinge of guilt.  I know there are some amazing ceramic artists out there who make their work exclusively with molds.  I also know die-hard wheel-throwers/hand-builders that wouldn't touch a mold and put down the process as being too 'manufactured'.  In general the work I see coming out of undergraduate schools these days is all slip-cast.  Generally people don't seem to have the time to invest in throwing on the wheel to make a form they have in their head, so they become mold-makers and slip-cast.  And in the world of design, it's a widely accepted practice.  But I still sense a stigma attached to slip-casting as though it's a cop-out, or easier somehow than wheel-throwing. 

In the studio the other day, putting on handles...

So I'm curious what your impressions of slip-casting are.  Do you place value on slip-casting verses wheel-throwing?  If you make ceramics, have you tried both wheel-throwing or slip-casting and do you choose one over the other? 

little dahlhaus is on it's way...

 

Do you remember my 'mold-making project' that I've been working on? I've been working on a little mini-series of a child's breakfast and lunch set while brushing up on my mold-making skills at the same time.   While I've had a few plaster disasters along the way,  it has been a good little project to embark on.  And the boys are loving each design that I bring home for them so that's a good sign.  I just finished the mold for the cup and should be able to have a whole little place-setting finished in the next couple of weeks.  Glaze-wise, I've been working on a lady-bug, a turtle and this mama Owl and her baby so far.  My method (painted with Cone 6 glazes using my 'stencil/masking' technique) makes them food-safe, dishwasher safe, microwave safe and all-around kid friendly, especially because they stack and have sturdy bottoms and sides for little clumsy hands.  There's more to come so stay tuned...

Making pretty molds

 

 Mold-making is something I don't normally do to make my ceramics, but it's a skill I'd like to develop.  Every now and again when I've done an intense stint of steady wheel-throwing, trimming and glazing and I get that nagging feeling in my wrists and elbows and a sore back I realize that my body has limitations.  I can't always do it all. And yet, the work doesn't just make itself.  

I got into slip-casting last year when I had a master mold-maker make a mold of a bottle vase form that I'd been wheel-throwing and then altering for a while.  It was an investment to get someone else to make the molds for me, however, the molds that he made were... perfect.  With barely a seam to clean up, and with the prototype being exactly 12% (shrinkage rate) larger than my original, it was a good intro to slip-casting for me. 

I've been wrestling with the idea of making other molds, for instance,  making my mug designs into a mold, but I can't really get over the lack of throwing lines on the inside of my mugs that wouldn't be there in a molded mug.  There is something about holding a mug and seeing the hand of the maker and the process that I get all nostalgic about.  Being that I feel so strongly about the work of mine that would be handled the most staying the most hand-made, I decided to give some slip-casting on a 'mini-series' or a little grouping of vessel forms that are outside of my regular work a try.  

So here's the start of this process- I'm working on a little set of dishes for my kids- and most likely other kids out there once I work out the kinks.  A small plate/bowl/cup, all 1 part molds to keep things simple and stackeable.  The molds above are the handle and bowl, I'm working on the plate and then cup over the weekend.  The molds all have to dry out before I'll be able to tell if they worked, but it feels like a good place to start. 

 

About the process: I used a broken plastic sheet from a flourescent light as the forms around my mold. Basically I used clamps to keep it 'round' a plastic bat or base. You have to seal the seams with clay so the mold won't leak when you pour in the plaster, but the pattern of the plastic make your mold look real pretty!  This idea is great for 1 part molds but L shaped forms are best for 2 or more part molds.

To make 2 or more parts to a mold, you can use "Murphy's Oil Soap" brushed onto the plaster approx 3 times (letting layers dry in-between) so the plaster doesn't stick to itself.  I also cast an 'overhang' top- no technical terms here, but a portion that allows the slip to stay above the lip when I'm pouring it in.  I cut off the excess with that top part on and it allows my lip to be even and nice.

Scenes from the studio

A few ideas in the works.  I've made some time this month for some new work and ideas- it doesn't quite feel right to start the year off without some 'experiments'.  Today I hope to try to make a 1 piece plaster mold to get back into mold-making processes.  This video was the inspiration.  I'm also hoping to make a little mold-stamp out of the bottom of this vintage bottle I found- 'Made in Canada' which I only recently actually turned over and 'discovered'.  And a few vase form ideas inspired in part by Lucy Rie and also a 'bulb vase' concept. 

Breaking My Mold..

This past month I've embarked on a mold project with a 'master moldmaker' that has his studio down the street from me (I'd give you his website but he doesn't have one, contact me if you want details). Mold-making and slip casting is quite foreign to me- I am a potter at heart and have always loved making work on the wheel. Last year at this time I met Russell and thought about what it would mean to take some of my designs and make molds out of them so I could produce larger quantities without the same kind of physical labour that throwing involves. However, last year my ceramic studio was all of 190 square feet, and multiple molds take up space on cupboards. Furthermore the whole process of mixing up slip and pouring molds is really different than wheel-throwing and I really felt that my studio wasn't equiped for me to go down that road quite yet.
This year, I have a better idea of which designs I want to invest a mold into and I have the space to embark on this idea, so I took the plunge. Here's how it has looked over the past 2-3 weeks - step one being make a plaster mold 12% larger than the original (shrinkage rate), make lovely and perfectly sealed 2 part mold from plaster master model, part 3, the first pour. So we'll see how the rest turns out- with clay, the minute you change one core element, all the rest have to be considered. Here's hoping I can find a great slip recipe that goes with my current glazes!