Showing posts with label lost wax. Show all posts
Showing posts with label lost wax. Show all posts

Wednesday, July 15, 2009

Sculpture 1 lost wax sculpture

Okay. In a six week summer course we have done coil building, slab building, bas relief, plaster molds, 3-d plaster molds (I didn't do one of those), free sculpture, and now lost wax bronze casting. It is so many hours, I barely do other art. The quick pace meant that we had only a morning to do our wax sculptures that we are going to cast. Everyone liked mine. I like mine a lot. I had Carly Simon stuck in my head* the whole time I worked on it.
Hard to tell the scale, isn't it? It's perhaps 7" tall.


I used to make little polymer clay marionettes and sculptures, so this was not the first figure I've sculpted, but in this course I have not done one because I don't know the fundamentals of proportion so I would just disgrace myself in front of the intermediate and advanced students. So, for this, I carefully overemphasized and exaggerated proportions. Then, because wax dips remove material when you leave it in for a while and add it when you dip quickly and let in cool, the original proportions got all changed, and now it looks quite like my proportions if my legs were thinner or farther apart. A classmate asked, "Who is that? Just some random person?" well, yeah, actually. I like my body, I realized today while trying to justify my choice, the way people like their country or their dog. It's nothing special, but it's theirs, so they get attached. Everyone else made very simple sculptures: a star, a mushroom, an acorn, a leaf. And they are kind of nice, but idk, bronze! It is a metal! I felt pressured to come up with something more personally meaningful because metal is so permanent.


This is what it looks like dipped in acid, fine sand, acid, fine sand, acid, and coarse sand.
*Oh dear. I just youtubed this to make sure it was what I was thinking about, and hey, only part of the chorus is about me, the rest is some bs about like clouds.

Sculpture 1: Lost Wax Casting

Bronze casting is quite fun, so far, and a little tricky. Basically you make a wax sculpture, make vents and such from wax, coat it in acidic something and sand, melt out the wax and kiln fire the shell hard, then melt bronze in a crucible and pour it into your mold. It is pretty much the easiest metal mold process ever, but it is still a bit tricky on your first go, even with an instructor and everything in the studio set up really well.

First you ladle out a bit of wax onto the shallow basin of water.
This basin is made from plaster.


Then when it has cooled but not entirely, you pull it out and dry it off, then mold it. We were permitted to use hot water, soldering guns, and I used also dipping it in the wax even though that wasn't suggested. Basically I have played with wax and bees wax and paraffin a number of times, but never such sticky wax or with so many tools.
This is the other form of the wax, which is used for gates, vents, and sprues (I do not know the difference really) as well as for internal armatures. My first go didn't have an armature and the wax had some water in it and was basically just a mess, but on the second try it worked a bit better.
Then you sketch your project on a tracking sheet. This lets the instructor map out where you need vents for the air to escape in order for the bronze to fill the item properly. We also use the sheet to track how the ceramic shell is coming along, since that step happens over several days.

So this is the vat of acid. You have to wear gloves and turn off the mixer and then you dip your item and its whole mold casing thing.

Then you roll your item in fine sand (for the first 2-3 coats of the shell- after that you use coarser sand for strength.). Actually rolling did not work for mine because the vent joins were very small and thus the connection points were thin and weak. So after I resoldered those I just sprinkled with the sand.
Here are some sculptures drying after being dipped and rolled. Mine is on the right. The other ones visible are multiple sculptures sharing one gate because they are quite small and it saves time and bronze.