No pain...no gain

It is hard to believe that I haven't posted an update in two weeks only because the summer seems to be going so fast and this project has been moving at a snails pace.  Almost all of last two weeks was spent simply waiting.  I was waiting for my new mold to dry and waiting for the vibration table to be finished.


After my last post I began making a new smaller and better tray positive.  As is often the case making it a second time was much faster, easier and the results were better than the first go around so while I was bummed to have to re-make, it in the end I am happier.  Once I made the mold it needed time to dry which was just as well because it was taking a long time for the vibration table to get finished up.  Robby completed construction about a week and a half ago but running the electrical from the motor through the vari-speed power switch required the UCA electricians which took a few days of scheduling etc.  While I was getting anxious about the amount of time it was taking I was also aware of the fact that beggars can't be choosers...I can't weld with proficiency or do electrical work so I was relying on the skill and kindness of others.  I spent about half of that time at home working in the studio on other projects/pieces.  It hasn't felt efficient by any means and my ambitious goal of getting the trays finished by the end of summer isn't really within the realm of possibility but I still think I can accomplish getting the pieces done and the event organized within a year.  We shall see.  So below you will see the events of the past few days!

Here is the beautiful vibration table made by Robby Burton with the first mold strapped down to it!

Here it is from a birds eye view all filled and drying.

As of today I have cast the new mold twice.  The good news is that the vibration table is doing its job and allowing me to cast the entire tray solid with no gaps or air bubbles.  The bad news is that the tray is cracking in the mold.  It is clearly from the slip shrinking around the mold as it dries in there.  For those unfamiliar with the process, after you pour the slip the clay immediately begins to shrink as moisture is being absorbed from the object into the surrounding plaster mold.  As the moisture is removed from the slip the cast object begins to shrink.  If I can figure out a way to get the piece out of the mold before it shrinks too much it may not crack, but the mold won't open until it reaches a certain level of dryness so it is either a very fine balancing act to find the perfect timing or it will never work.  Another option may be to use  a different casting slip, one with more plasticity.  We are using a new casting slip recipe in our UCA slip casting class this coming semester so it seemed reasonable to mix some up and try it in the mold.  This would allow me to use the UCA slip mixer which holds 300 pounds of slip while classes are in session, in other words the students and I would be using the same slip (It is also allowing me and another student AJ Sawatzky to do some test runs on the studio recipe before we unleash it on the class in the fall).  We are using Andy Martin's cone 6 casting slip which casts quickly and is super white. Part of what allows it to cast quickly is that it is less plastic, having larger clay particle sizes in the mix, I hope this is also what is causing it to crack so quickly in the mold.

Here is the first cast.  The straight lines I cut to check thickness but the squiggly cracks all along the edges of the tray are from shrinking in the mold.

On a positive note the tray cast solid successfully and the piece looks relatively the same thickness throughout.

The first cast that you see above I left in the mold overnight, I figured this one would crack, but I had run out of time (I thought) before I had to be home to pick up the kids from school.  When I opened it this morning it was all cracked into pieces so I cast the mold again this time planning on getting it out of the mold as quickly as possible.  I started casting at 11am on the vibration table and refilled it every few minutes for 30 minutes until 11:30am.  After that I let it sit upright on the table for an hour (not vibrating...it is loud...the table vibrates at 93 decibels...thank you AJ and your phone app), then removed it and laid it on its side on a regular table to dry (this is in hopes of casting more trays on the vibration table while the others dry in the future).  An hour after that I was able to open the mold, much sooner than I had expected, the tray was still really soft AND still cracked.  

This is the second cast.  The clay is still pretty wet, like I could roll this whole thing up and squish it back together wet and the cracks are still there.

Cracking detail-Yuck!

I am very disappointed I fear that I may never get this to work while simultaneously thinking about how I might fix it in my next try!  I am going to cast this mold one more time using the Andy Martin casting slip and see if I can un-mold it an hour after I cast it.  If that doesn't work I am going to try using the casting slip I use at home which is very plastic (it is actually a throwing/hand-building clay body that I also use as a casting slip).  Hopefully the more plastic slip will have a little more stretch in it and won't crack so quickly.  We shall see.  I am not ready to give up yet, surely there is a solution here, I just need to keep thinking it through and working until I find it. If there are any really seasoned slip casters out there reading this blog let me know if you think what I am trying to do is impossible OR if you have any great suggestions to offer please do!!! I am all ears and would love the help!!!  For the rest you please just keep your fingers crossed for me! 

Disaster...yowza!

Week number four was a disaster.  I managed to finish the mold for the tray which I was excited about.  It took me a really long time because I am not able to spend a ton of hours here in Conway (I am working at UCA because there is so much more space and a 300 pound slip mixer!) because I have family obligations (two awesome little boys and one awesome husband) as well as studio obligations.  So it took me about a week to make the positive and cast the two halves of the mold.  Plus there was a lot of wait time as you will read below.

It is now Monday of week five and I have decided to make the entire positive over for a couple of reasons but I will let you read about last week first!

I started with a drawn template used to create some masonite forms cut on the scroll saw.  The masonite allowed me to have a perfectly smooth tray surface and limited the amount of plastiscene (oil clay) I would need to create the positive.  I needed the bumped separation part of the tray to be hollow and to be about the same thickness as the masonite (1/4") so I lined the masonite forms with tubing and started to apply plastiscene that had been rolled out to 1/4" over the tubing.  After I had finished putting the oil clay over the tubing I spent a long time trying to make it smooth and without undercuts, undercuts would act like little locks on the clay when cast causing the clay form to tear apart upon removal.  I probably spent two days trying to get it as perfect as I could...the better the positive the better the mold the less work you have to do on the clay when cast which is the goal...considering I need to cast this one hundred times a few days getting the mold as perfect as possible will save time fixing one hundred trays later!

After the tubing and plastiscene were in place and the pour gates added I coated the masonite in polyurethane to be sure it was watertight (if not the plaster would adhere to the porous wood) and let it dry.

 The next day I cast side one of the mold, thankfully Robby Burton, our studio tech. was around because I couldn't lift the plaster/water mixture up myself in a way that would allow me to pout it in any sort of controlled fashion (it was a little over 50 pounds).  The next day I came back, flipped the mold and removed the tubing so I could clean up the other side (what will be the back of the tray).

This revealed a challenge that I had not thought of, the removal of the tubing and the straight sides of the masonite left a very tight U shaped "tunnel", it was my intention to have a hollow channel (on the backside) separating the food areas of the tray but this one was going to be way too tight and narrow to successfully remove the clay cast and was to difficult to access to clean up the undercuts.  So I did one of the cardinal sins of slip casting...I removed the positive before I had cast the other side to I could bevel the edges of the masonite, when I returned it to the mold this allowed for a much more open U shape...more like a hammock... I think it will work.

So then I set to work smoothing the plastiscene, checking for undercuts and putting polyurethane on the backside of the masonite, this took another full day. After casting the second side and letting it cure overnight I was able to take the positive out (in pieces) and spent the morning cleaning up the inside and outside of the mold.  So far it all looked good, it was pretty clean in there, the positive seemed to come out with little signs of impending trouble and I thought I would just I wait until the mold was dry enough to do my first cast which should have been by the end of this week.  Then when I lifted this gigantic and very heavy mold into the drying box I wrenched my back!  The mold is so heavy and big I can really barely lift it.  This was the first sign of impending doom! I had to spend the next two days and then over the weekend at home because of my back!!! Yuck!!!  (As an aside, I spent the weekend thinking about my age and that I really need to reconsider the value of exercise time over studio time.  My body needs to keep up if I want to continue working in this physically labor intensive field...which I do!)

In the meantime Robby has almost finished welding a killer vibration table!  It looks really great, I think he is going to mount the motor on it soon!  At home with my back out of commission I did some color tests on my casting slip.  I want to try to cast the trays in an couple of different colors, I think it will look good, provide some variety amongst the trays, allow for consistent non-brushy color, (I have had some problems with uneven brushy application with some slips and I do not want that kind of mark making on these pieces) and limit the amount of time it would take apply two coats of slip to the front and back of one hundred trays!  I am going for light colors, something sort of subtle that will tie in well with the already existing decals.

As of today (Monday) I have decided to make all new positives.  When I got to school this morning I had spent a sleepless night thinking that the tray was really too big, the mold is so heavy and large I can barely move it myself and I don't really like the shape of the cup holding area.  The straw that broke the camels back was coming in this morning and trying to do a test cast.  The vibration table is not finished (Robby is on vacation) but I decided to give it a go anyway just to see what would happen, the first cast is always a waster/clean out cast anyway.  As I started pouring the mold all looked fine until I was about half full, then slip started pouring out of the bottom and all over the floor!

I managed to get it filled anyway but I am almost sure it is not going to work!  I think I need to pour with the tray on its side to allow gravity to work the slip to the bottom and throughout the mold but that puts a lot of pressure on those bottom seams.  I definitely need more straps to hold it together and I may need to pour it flat so gravity works in the molds favor instead of the slips favor.  Anyway it is very frustrating but I am learning through these failures.  I need to get over the fact that I feel so rushed for time and just slow down and take the disasters in stride and move on.  I'll let y'all know if the positive came out in any way close to the way it is supposed to look next week, and I will update you on the new smaller positives which I will thankfully be able to make much faster now that I know what I need to do and other progress by early next week!   Wish me luck!  I need it!