Contemporary Ceramic Techniques by John W. Conrad

Last summer, after reading both Paul Wandless’ book Image Transfer on Clay and Ceramics and Print by Paul Scott, I decided that I wanted to try screen printing my own ceramic decals to fire onto my clay work.  I have had the decal paper and screen supplies for over a year, and haven’t yet attempted the process.  I’ve been hung up on trying to find a commercial lead free overglaze to use on functional pottery, but have become frustrated at the lack of available products.

I discovered Ferro, a company that offers a variety of products for ceramic applications including a lead free onglaze collection called Samba Plus.  Ferro mainly caters to production ceramic companies that produce major lines of dinner ware, though their stains are available in small quantities through some ceramic suppliers.  After contacting the company, I was given the name of the US rep, but it sounded like I would have to order a large quantity which might not be wise since I’m in the experimenting stage.  What if I hate the process?  I could end up being stuck with 100’s of pounds of product.  The only company that I found that sells Samba Plus online is CerdXpress, out of Germany where the product is sold in 1,000kg increments.  That’s a whole lot of onglaze!

After a few failed searches and multiple week long pauses over the past year, I decided to resume my quest for a lead free overglaze a few weeks ago.  I did a quick search for decals on http://www.potters.org which turned up several threads about making decals, commercial decal providers, custom decal companies, along with a variety of different possible decal options from laser prints, screen prints, direct drawing on decal paper and more.  I eventually found several references to ceramic ink recipes in John Conrad’s book, Contemporary Ceramic Techniques published in 1979 and now out of print.  I found a copy at the Denver Public Library and it appears that used copies can be purchased for as little as $1.91 through Amazon.

Last night, I had a chance to scan through the book and flipped to the screen printing section.  The ceramic ink recipes he mentions are essentially stain recipes minus the water - basically an oxide combined with a frit and possibly one additional ingredient which is then suspended in a liquid vehicle for silk screening onto some type of base. Note: The ingredients must be thoroughly sieved before using.

Green Stain Recipe from book, page 126

• Copper Carb 50
• Tin Oxide 25
• Frit 25  (he doesn’t name the frit - it would depend on firing temp and the oxide I imagine)
• total 100

Since this is a stain and not a glaze or overglaze, I sort of think that this is better suited for use on raw or bisqued clay vs. decals to be fired on top of a glazed piece.  In some ways, I’m back to square one.  It might come down to purchasing the Ferro Product at some point in time, if I insist on using silk-screened decals on functional work.  Obviously, it wouldn’t matter what kind of product I used for work that doesn’t come into contact with food.

For the liquid vehicle suspender, the author recommends using a commercial silkscreen oil based extender, commercial squeegee oil (whatever that is), decal lacquer, cmc or screening varnish and doesn’t specify an amount other than to say that the mixture should be viscous enough to be able to push through whatever mesh screen you’ve chosen based on the amount of detail of the image.  A detailed image requires a finer mesh than a simple graphic one.  He also writes that common household items will work as a vehicle too such as baby oil, liquid soap, Vaseline or liquid wax - but cautions that using these items will result in more frequent cleaning of the screen (pages 124-125).  Once the screen is ready, the ceramic ink is squeegeed through the screen either directly onto raw clay, bisque work, glazed work or decal paper.  Seems pretty simple, doesn’t it?  Of course this is after scanning the original artwork or photograph and exposing the screen - or using a stencil or other masking technique (tape, glue, paper, plastic) for the image/design.

For ease of use, I could simply use a colored slip, engobe or commercial underglaze if screening onto to raw or bisqued clay.  The dilemma is that even if I use a transparent glaze over the image, it becomes muted - whereas if I add a decal on top of a glaze, the image is crisper and the effect is totally different.  In a way, this obsessive trait of mine to figure this out is related to my insistance on understanding the technological side of blogging, my computer and all the other stuff that distracts me from making work - but that’s a post for another day. 

On a related note, I recently picked up a couple of books on Polaroid transfer techniques from the library, with the thought that this might be a possible application for clay.  Polaroid film is currently being phased out; however, although there are other film manufacturers that offer a similar product.  The problem for me with this technique is that it requires purchasing additional equipment to expose and print the images on top of the screen printing supplies - so I’m not going to go there.  I could probably manipulate an image similarly in Photoshop with less expense or effort.

I haven’t given up on relief printing either - I love this technique tremendously.  I simply want to become more efficient at decorating my work after realizing how much time it takes to hand paint designs.  Laser print decals are also certainly an option and much less labor intensive - the iron oxide in the ink transfers to glazed pieces after firing, though it is limited as far as color is concerned because the black ink fires to a sepia color.

Meanwhile, my after school kid’s clay class starts today - I’m ready to go and looking forward to the next 6 weeks.  I have a very small class this session - only 8 students, which will be fantastic since I’ll be able to spend more time one on one with each student.

I’m heading out to the studio for the next 4 hours,

~Cynthia

This entry was posted on Tuesday, September 16th, 2008 at 9:53 am and is filed under Ceramic Decals, Printing on Clay.You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.