3D Scan to Bronze — Lost PLA process

Bookmark and Share

We used a 3D print — instead of a wax — to make a successful bronze casting.

Successful bronze casting, from the “lost PLA” process.


From photos to bronze!


First Karl placed the sculpture by Moises Orozco upside down, and then took many photographs of the simple face in the round.

Sculpture by Moises Orozco, upside down.

Then he uploaded those photos to 123D Catch to make a 3D scan.

The 3D scan looked really ugly.

The “scanned” 3D object was messy, so after he downloaded it, Karl cleaned it up in Wings3D.  Then in Meshlab he “decimated” the file (Filters> Remeshing> “Simplification and Reconstruction”> “Quadratic Edge Collaspe Decimation”), to make it smaller.  Both those softwares are free.  Meshlab also has a 3D viewer for both the iPhone and Adroid.

Originally Jeremy scanned the sculpture in David, using an arduino innovation to assist the process.  However, we did not want to pay $500 to stitch all the scans into a single object.

Then Karl uploaded the improved digital sculpture to Tinkercad.

Moises’ digital sculpture on Tinkercad.

We downloaded that digital sculpture from Tinkercad, and 3D printed it in PLA on the Ultimaker at Xerocraft.

We printed the head at a 45 degree angle, with lots of support material, on the Ultimaker. The process was ugly, but it worked.

The 3D print above the original sculpture.



Naturally the small sculpture would look better in bronze.  Thus we pretended that the 3D print was a wax, and continued with the ancient “lost wax” process.

Materials for investment casting.

Ernie made a cone out of wax, placed it on a Mason jar lid, and heated the lid up so that the wax would stick to it.

Fixing the main sprue to a Mason jar lid.

Then he attached the PLA print-out to the wax cone, and added other, smaller green wax sprues.

The sculpture with sprues, next to a piece of steel pipe that will encase it.

Ernie painted dish washing soap on the piece.

Brushing dish soap on the PLA print-out.

Then he washed the dish soap off.

Washing the dish soap off.

He placed a section of pipe over the piece, and sealed the bottom with more wax.  Then he mixed the dry investment with water, until it reached the consistency of egg nog, and poured that investment slurry into the pipe.

Pouring investment into the pipe that surrounds the piece.

We let the investment set up and dry for two weeks.

The investment had to dry for 2 weeks.



October 3rd we cast the piece at the Sculpture Resource Center.

We placed the pipe into the furnance, so that the wax and PLA would melt and burn out.  Note that Ernie put the pipe on top of bricks, so that melted residues would not mess up his furnance.

Pipe with investment and sculpture, placed inside the furnance.

It took 4 hours to bring the furnace up to 1400 degrees.

The furnace had to reach 1400 degrees.

We filled the crucible with bronze, added borax to it, and set it on ceramic bricks, preparing to heat it up.

Preparing to heat up the crucible, with bronze inside.

We melted the bronze with a propane torch.

Melting bronze with a propane torch.

Time to take the pipe out of the furnace.

Taking the pipe out of the furnace.

Gonzalo turned the pipe, so that the sprue hole faced upwards.

Gonzalo turned the pipe upside down, so that the sprue hole faced upwards.

Ready for pouring.


After the pour.

We waited until the exposed bronze cooled down to a dull cherry red, before dunking it in water.

Cooled to a dull cherry red.

Still hot, Ernie grabs the pipe with tongs.

Dunking in a can of water created all kinds of steam.

The investment fell off; pulling the bronze piece out of the water.

This is what came out of the water.



The casting after we scraped all the investment off of it.

Grinding the sprues off.

The final bronze casting next to the original sculpture.

This project proves that we can cast small bronze objects directly from 3D prints made on Xerocraft’s Ultimaker.  No molds, no waxes are necessary!  Moreover, the “lost PLA” process will let us cast in any size the Ultimaker prints; whereas with the traditional “lost wax” process, one would have to make a different mold for each sized casting he wishes to make.

Now we have to attempt a “lost PLA” casting, like Solid State Depot did (the hackerspace in Boulder).

Mary Neubauer, art professor at ASU, apparently casts 3D prints using some kind of “lost plastic” process.  The detailed piece below was on display at the Generation XYZ show, which opened in Tempe on October 5th.

Bronze casting from 3D print by Mary Neubauer

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply