Friday, April 29, 2011

Lost Wax Bronze Casting

Cari Amici (Dear Friends),

I recently got the opportunity to cast bronze in Austin, Texas, at the Atelier 3-d with artist and teacher Steve Dubov. Always interested in process, Steve uses a different kind of investment mold and alters his technique for the lost wax bronze casting method.

So, I created a couple of new sculptures in wax. In my art post on April 15, you saw an image of me creating the sprue, the wax sculpture connected to a wax funnel that will all ultimately become bronze.

While I need my wax welds to be strong, these things are a bit fragile and oddly shaped, each sprue being individual. My bumpity dirt driveway that is almost a mile long helps nothing. So, I have transported the wax floating in a bucket of water. This greatly diminished the vibration and shock on the piece, although I still had water sloshing around in my car. Sheesh, I must continue to fill the driveway potholes with stone chips!

In this third image, air conditioning metal tubing has been used to create a “mother mold” (the outer supporting mold). I am holding my sprue to keep it from floating, pour funnel at the top opening with the sculptures deeper, parallel to the side walls. Steve is pouring a mixture of plaster, playground sand, and water into the mother mold. Once this mold has set, holes will be lightly punched into just the metal tubing to release steam later during the pouring of the molten bronze.

After the mold is ready, it will be heated and all of the wax will be melted out. Now the sculpture is then only an air space. Bronze will be heated to about 2000 degrees F so that it becomes a liquid. Then it will be poured into the funnel-shaped opening, travel down the air space, follow the sprue space to fill the sculpture space, and then chase air out the vents. The bronze begins cooling as soon as it is poured, so everything in the pour moves fairly quickly.

I did not attend the bronze pour since I was working in my studio on my stone carving. This fourth image shows you the bronze pieces after Steve cut away the mold and then cut apart each sculpture from the cooled bronze sprue parts. He left some of the sprue on so that I could put the art into a vice as I chase the metal.

“Chasing” means cleaning up all of the metal sculpture so that it looks as I intended. This often means grinding off all sprues and vents and re-sculpting those connection points as desired. On larger artworks, “chasing” also includes welding all parts of the sculpture together, and then grinding out all evidence of the weld in the visible areas of the sculpture.

In this last image, you may see that the investment mold cracked and allowed bronze to leak out beyond the sculpture and into the crack. It is too bad that I did not plan ahead for this… this bronze has a cool pattern. It is a bit nautical, like a merman’s fins, eh? I also like this photo because of the way the light is bouncing off of the various facets that I carved into the original wax sculpture. One of the things I enjoy about bronze is the ability to create a texture that is quite different from what I can create in stone.

This is likely to take me days to clean up to my satisfaction and later add a patina to my new sculpture. So, stay tuned . . .


Please join me on Sunday in Austin, Texas, for the release party for Origin Magazine. Origin features articles about quality living, such as yoga and fine art.

Whole Foods Rooftop Downtown Austin,
5th and Lamar
Sunday May 1st, 2 - 6 p.m.

Art, Music, circus, One of the largest Free Yoga Classes ever held in Austin led by National Teacher Christina Sell at 4 p.m. Costumes welcomed, Performers, Artists, Sponsors, Vendors, Connection, Celebrating 152 pages of Art+Community. We are debuting the same issue in 6 cities within 3 weeks. WOW! Djembabes play at 5:30pm.

This issue features 60+ artists, 90+ yogis and 152 pages of art, philanthropy, beautiful photography, conscious articles and a lotta love. It’s all free!
For more information, contact Maranda Pleasant at:


Gene P. said...

THANKS FOR SHARING KELLY! I enjoyed the write and learning. Loved the idea of "Origin" magazine and will try to contact to get a copy.
Gene P.

Kelly Borsheim Artist said...

Hi Gene, Thanks.
I have not yet seen the magazine and hope to get at least one copy on the Sunday rooftop event. If you are in Texas, it would be nice to see you again... if not, I will try to grab you a copy.
They may have some in San Antonio as well. I am not sure.
See you ... sometime!