Custom Glass Castings from Digital Designs

This post is a follow up to a previous one about techniques that I have been exploring to transfer digital designs into cast glass objects. This began last year at a fellowship at  Wheaton Arts’ Creative Glass Center of America and was expanded upon this year while teaching at Pilchuck Glass School and in a workshop at Detroit’s College of Creative Studies. In particular, I have  focused on one particular technique; using a low cost desktop CNC machine to carve reusable graphite molds for glass casting multiples. There’s a few design limitations to this approach, but it is an amazingly cost effective approach to creating small to medium scale runs of custom designed glass tiles. The molds hold up for hundreds of castings, and possibly even more, so this is an exciting way of creating custom glass design objects and custom tiles for architectural applications. This will be a big focus for much of my work in 2017.

With a clean and simple design, these new geometric tiles channel the 1980’s era video game Qbert, Islamic mosaics, and leverage the material’s clarity and sparkle. I love the simplicity and the illusory way we see through the smooth top surface to see the relief texture on the backside. I am thinking this will become a set of tabletop design objects, with 6″,9″ and 11″ sizes that interlock. However, I am almost more excited to think of them as architectural tile. How cool would it be to have a wall made of these, or have them as accents embedded in concrete?

Below you will see some of this new carved graphite mold work, as well as some student work from teaching at Pilchuck this summer.  Design constraints of this method center around the fact that this process does not support forms with undercuts. Likewise, the machine can only mill material up to ~2.5″ thick and can only do straight plunge cuts as long as the longest router bit you can find. For most 1/8″ bits this means you cannot do any straight cuts more than 1.5″ deep. However, because graphite is a lubricant and it pretty impervious to heat, once the moisture leaves the material after the first few casts, these molds can be used over and over again, with beautiful results. For any schools or glass studios who are looking to create such a setup, I have created a bill of materials for creating such a setup, totalling under $2500. (BTW, I am available to teach workshops! )

The top of the casting is flat, perfectly magnifying the relief texture of the underside.

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CNC milling the graphite mold

Completed rough pass on CNC, ready for finishing pass

Ladling molten glass into the finished mold

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The tile on the left is upside down, showing the relief on the backside. The relief side is as nice as the front and they would make a beautiful glass brick wall.

I’ll end with some images from the TaDDDaa!!! class at The Pilchuck Glass School this summer. It was a three week deep dive into 3D modeling, scanning, printing and CNC carving. Here’s some of the class’ work with graphite for glassmaking:

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This was my first test with this technique at Wheaton Arts and the process used by students for the class at Pilchuck. Here we see rough and smooth CNC carving of the graphite mold, hot glass in the mold, and final product at room temperature.

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The TaDDDaa!!! class at Pilchuck was a three week deep dive into 3D modeling, scanning, printing and CNC carving.

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My TA Christian with Phirak and Rebecca, who will be teaching a 3D printing clay class at Pilchuck next summer

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Rebecca’s mold based on a victorian pattern

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Jameszie made a Ouija planchette

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Brent supervising his first carve

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John, Lee, Phirak and Nikki trying out their molds

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My student John was a master mold maker so he undertook making a two part blow mold and spent quite some time finishing the graphite to a polish

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Blowing glass into the mold

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Michael’s two part blow mold

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A pile of hot casting molds cooling down at the end of the class casting session

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A fishscale tile design I was playing with

CNC Carving Glitch Art

Greetings from the woods of Stanwood Washington where I am teaching in the remote paradise known as the Pilchuck Glass School. Session 2’s theme is Play and our class has been playing with methods of creating glass castings from digitally generated sculptures. 

As part of the class we are CNC carving graphite molds so I brought a bunch of graphite that I bought on eBay. I had previously carved blocks that I had bought from this guy with no problems so I was bamboozled when I started to have carving issues with my molds here. I spent the better part of the last two days wrestling with the XCarve, thinking the axis slipping was mechanical. Then I realized the carbide bit was totally shot and realized the problem. The CNC is finally back to carving the other/ softer graphite like it was butter. I finally carved this mold I’ve been trying to make, but only did the rough pass. I think I like the terraced stepping… What do you think!? 

In the meantime, please enjoy my latest work with graphite glitches….







Explorations of Processes for Digitally Created Glass Castings

I spent much of 2015 taking a year long flexible fellowship at Wheaton Arts’ Creative Glass Center of America developing ways to cast glass from computer generated sculptural forms and wanted to take some time to share these learnings. I worked extensively with glass many years ago but now create most of my art with 3D scanning and printing. The Wheaton Arts’ fellowship was a unique opportunity to bring these two practices back together.

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Wheaton Arts is home to the Creative Glass Center of America in Millville, NJ, where I had a fellowship this past year to conduct experiments and create a workflow for casting glass from computer designed objects.

My work in the last few years has used a combination of 3D modeling techniques. I usually begin with 3D scanning,  primarily structured light scanning with Primesense/Kinect style devices and occasionally photogrammetry for non human subjects. Other non-organic forms are just modeled directly in the computer using my software of choice Zbrush. Next I will digitally manipulate and sculpt the 3D scans in the computer. Finally the work is output as a 3D print. My investigations this year took these techniques further, so that these digital sculpts were then realized as cast glass forms. I tried a few variations of lost PLA casting, as well as CNC milling graphite to make reusable molds. Enjoy.

Lost PLA Kiln Casting

The first technique I chose to explore is what people are calling “Lost PLA”, basically an evolution of the traditional lost wax kiln casting technique. Starting with a 3D printed positive of the form I want to cast in glass, I created a plaster/silica mold around my 3D print.

The actual recipe for the mold by weight was:

  • 16  parts water
  • 6 parts Hydroperm
  • 6 parts Plaster
  • 6 parts Silica (or olivine sand)
  • 1  cup 3/4″ fiberglass strand

This could be done with just a 50/50% plaster-silica mix, but as I understand it the Hydroperm foams and creates air pockets in the molds to make them lighter. The fiberglass strand helps strengthen the mold and helps wick out the moisture so the molds dry more efficiently.

I began by plugging any holes in the surface of the 3D prints with microcrystalline wax and waxing the prints down to a table. I then just cut strips of tar paper and hot glued them down to form a wall around the print, leaving room for about 3″ of mold thickness. I mixed a small initial coat of mix with no fiberglass strand to use as a splash coat over the object, then mixed subsequent buckets of mix to fill the molds completely. After the mold was filled, I let it set before tipping the molds on their sides to dry (having fans helped this).

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3D Print affixed to the table with wax and surrounded by a cylinder of tar paper

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3D prints and tar paper prepped for casting molds

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Splash coat on the 3D print

 

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Mold ingredients being dry mixed before the water is added

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Completed molds drying

After a minimum of one day drying (and preferably more like a week), the molds were ready to be loaded into the ovens. The PLA was still on the inside and needed to be melted out. With lost wax casting, the general practice is to steam the wax out of a mold. I tried this with the 3D printed PLA and barely got it to move at all. Steaming out PLA is not an option so it has to be burned out in an oven.

Even though PLA is a biodegradable corn starch, the burnout is smoky and not good to be around so it had to be timed to happen overnight when the studio was empty. I would begin by soaking the oven at 300˚ for about three hours and then pushing it upwards at about 100˚/hour. At about 450˚ I would go in (wearing gloves, glasses and a respirator) and use pliers to pull out some big chunks of plastic as it started melting. I had to be careful not to damage the mold in doing so. At about 700˚, I would go in with a stainless steel turkey baster and suck out as much molten plastic as possible. The oven would then go to 1000˚ for an hour and be fully burned out. Because burn out in an oven is pretty nasty smelling at its peak and I can’t really recommend it as a best practice. However, I just became aware of Moldlay– a 3D printing filament designed for lost wax casting. It’s expensive but I would like to check it out.

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Mold mid burnout

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Molds at 1000˚F after burnout

From there I tried two basic approaches to casting into the plaster molds. The first technique involved putting molten glass from a furnace directly into the molds. The second involved cooling the molds back down, packing them with chunks of crystal glass, then firing them to melting point. Each techniques has its strengths and weaknesses.

Lost PLA Kiln Casting Technique 1- “Hot Glass Lacrosse Casting”

Since buying crystal to kiln cast with is very expensive, I was trying to be more cost effective by using the readily available furnace glass to cast with. Basically, after the mold was burned out I would soak it at 1000˚ for several hours to burn out any chemical water, and then we would ladle glass directly into the molds. I found that even after I soaked the molds 10-12 hours at 1000˚, the chemical water in the plaster would still cause the glass to bubble up as we poured the glass in. We then resorted to a technique we called Lacrosse Casting. I would gather a ladle of glass, then dump the ladle into a second ladle someone else was holding. They would rock the ladle side to side so that the molten glass skinned up on the outside a little. They would then dump that back into my ladle and I would go to the oven and gingerly drop this “hot tamale” of glass into the mold. The center of the glass was still quite hot but the skinned up exterior was less likely to bubble. Unfortunately the molds are quite fragile and this can cause damage if there are a lot of delicate details to the mold. After the mold was filled, the oven would be sent up to about 1500-1600˚ to make the flatten out and flow into the mold. As soon as the glass flattened, the oven was crashed back down to under 1000˚ and an annealing cycle began.

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Passing off ladles full of molten glass in order to cool the exterior of the glass before dropping it in the fragile molds

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The 2300˚ “lacrosse” pass

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Dropping glass into the mold

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Crashing the oven after it reaches 1600˚F and the glass has flattened out

Issues with this technique

  • This process takes a lot of time! I was casting forms that took 2+ days to print, then there was mold making, casting and annealing.
  • The plaster molds are extremely fragile and can easily be damaged by the glass as it is dropped in the mold. This results with imperfect castings that often have bits of plaster encased in the glass.
  • If the ladles are not very clean, the glass will often have veiling from the ladle surface. Bubbles are also often introduced resulting in a very bubbly glass. In my case I liked the underwater look this gave.
  • Devitrification is a crystalizing of glass that happens at approximately 1200 degrees, making the surface of the glass fog up. Soda lime glass (Spruce Pine batch) is particularly vulnerable to this. In my case, if there was not enough radiant heat above the top of the mold and it took too long for the oven to heat up for the glass to level out in the mold, the surface would fog up.

Sample Castings (Unfinished work)

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Death (work in progress) 14″x 14″x 6″

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Creation (work in progress) 14″ x 14″ x 5″

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Untitled work in progress 14″ x 14″ x 4″

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The Gates of Heaven 24″x 19″x 5″

 

Lost PLA Kiln Casting Technique 2- Kiln Casting

The issues with molds being damaged by hot glass and devitrification lead me to acquire some crystal to kiln cast with. Casting crystal is expensive and usually formulated to not devitrify so in general this technique delivers more optically pure castings. I tried two glass formulas for kiln casting; Uroboros Glass’ system 96  and Schott optical crystal.

After the mold is burned out, I would let the oven slowly return to room temperature so I could carefully vacuum it out and pack it with chunks of glass (My glass came in large tiles so I cleaned the surface with alcohol and then used a torch to shatter them.

Bang! #glass @wheatonarts

A post shared by fredini (@fredini) on

The small chunks could then be loaded in the mold, and the oven slowly brought back up to about 1550˚ until they melted in completely and the worst of the bubbles came to the surface. At that point the oven was crashed back down to under 1000˚ and the glass is annealed (slowly brought to room temperature).

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Loading chunks of crystal into the mold

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Close up of mold and crystal chunks. I like how the mold picked up the layer lines from the 3D print.

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The oven is ready to be heated back up

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At about 1550-1600˚F, the glass is molten and flowing into the mold

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Its a delicate balance how long to keep the mold hot. You want to get the bubbles to rise to the surface, but also want to stop before the glass begins to devitrify and fog on the surface.

  • This technique definitely yielded the best casting results for Lost PLA
  • More expensive- both in the time consuming process, oven time and  most significantly the cost of the casting crystal
  • Devitrification can still be an issue, depending upon the glass used
  • The final casting still requires extensive grinding, polishing and finishing work
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Angel/Mermaid (work in progress) 14″ x 14″ x 6″

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Funny Face (work in progress) 14″ x 14″x 6″

Hot Glass Casting into CNC milled graphite molds

I quickly realized that the lost PLA technique was time consuming and disconnected from all the excitement and spontaneity that I associate with hot glass work. Lost PLA castings also required extensive work divesting from the mold, then grinding and polishing. I had long wanted to experiment with CNC carving as opposed to 3D printing, and set out to experiment with milling graphite to create reusable molds as a more cost effective approach for casting glass with.

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CNC milled graphite molds for glass casting; rough pass carving with 1/4″ endmill, finished mold cut with 1/8″ ball mill, molten glass in the mold and annealed, cooled glass casting

I decided to purchase the Inventables XCarve  because it is an open source CNC machine, and I wanted to support Inventables great work in making CNC software more user friendly. I opted for the 1000mm version with the heavy duty Nema 23  motors and Dewalt 611 spindle which has enough power to even mill aluminum. I had a lot of trepidation about building a kit as some of the 3D printer kits I had built in the past were not well documented, but Inventables documentation was excellent and it worked pretty well right off the bat. A few support calls and posts on the message boards got me through the few small hiccoughs that I did encounter.

However, I was concerned about milling graphite as the dust is electrically conductive. If that dust got all over as I was using the machine, not only would it make a mess, it could also fry the Xcarve Arduino controller, and even the laptop driving the setup. I had no choice but to rig up a robust dust collection system. I ended up buying a dust shoe from KentCNC to mount around the spindle (Yes, I could have made my own but was running out of time at Wheaton by then). This then attached to a Dust Deputy cyclonic dust collector and a shop vacuum. The result was a powerful dust collection system that captures nearly all the graphite coming off the spindle as it cuts, and 95% of it ends up in my new favorite tool, the Dust Deputy.

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The newly assembled X-Carve, still in need of some wire management

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Unlike 3D printing, CNC milling has the machine doing multiple passes. Shown here is the rough pass, done with a 1/4″ endmill.

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The finished mold, cut with a 1/8″ ball mill

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The big test… Trying out the mold for the first time!

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Torching the glass as it sets up in the mold

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It looks amazing!

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The final result- a cast glass tile from a mold that will stand up to hundreds of castings!

Coming out of the last year of experiments, I’m most excited about this process as it has a lot of potential for small run computer designed glass objects and custom tiles for architectural use. There are some design restrictions in that molds cannot have undercuts and the Xcarve can only cut about 2 1/2″ at the deepest, but because these molds can be quickly and comparatively cheaply generated and used to create cost effective editions, I think this approach has a lot of promise. I look forward to continuing to experiment with these techniques as I share them with my class this June at the Pilchuck Glass School.

 

TaDDDaa! A Class in Digital Processes for Glass Casting at Pilchuck Glass School

Kahl,Fred-Image-10I’m please to announce that I will be teaching a class at the Pilchuck Glass School in June of 2016. The class will cover a lot of the digital to physical techniques that I have been working with over the last few years, particularly this past year with my fellowship at Wheaton Arts Creative GLass Center of America (Stay tuned, I will be publishing my finding soon).

The intensive 3 week class will take place in June of 2016. Pilchuck’s session 2 this year has a theme of Play, and we certainly will be playing with ways of bringing the 21st century to glassmaking’s 19th century traditions.

TADDDAA! 
May 31- June 17
3-D Modeling & Printing, Lost PLA, CNC, Kilncasting, Hot Casting

Digital sculpting and 3-D printing tools allow artists to visualize prototypes, manipulate scale, and replicate with precision. This course will introduce an assortment of tools including Zbrush (an organic sculpting software), 3-D printers, and 3-D scanning methods of photogrammetry and structured light. Students will learn to scan, manipulate, and print objects and ultimately kilncast and hot cast them in glass. This class is for glass artists who wish to explore digital fabrication and 3-D artists who wish to explore glass.
http://pilchuck.com/summer_program/courses/session2.aspx

The class will cover:

  • 3D Modeling with Zbrush
  • 3D Scanning with structured light and photogrammetry
  • 3D Printing
  • Moldmaking
  • Glass kiln casting with lost PLA
  • CNC milling of graphite molds for hot glass casting

It’s going to be an awesome class and I’m looking for two teaching assistants. Applications for TA’s are due February 3. I would like to find one TA who is well versed in 3D modeling and 3D printing (its a + is you own or have built a 3D Printer), and another who is familiar with glass kiln casting. Please help spread the word!

A Process for Glass Casting from 3D Printed Positives

I wrote recently about being selected for a Creative Glass Center of America Fellowship, but thought it was about time to show off some experimental castings I made there last fall that helped get me the fellowship. Last Summer I blogged a first test of this process, but this Fall I was able to do some more substantial castings and learn some more. Here’s some process shots:

Wheaton Arts is home to the Creative Glass Center of America in Millville, NJ, where I will have a fellowship this year, based on these experiments that I did this past fall to create a workflo for casting glass from 3D printed objects.

Wheaton Arts is home to the Creative Glass Center of America in Millville, NJ. It lives in this building, a recreation of a 19th century glass factory.

Hank Adams is the Creative Director of CGCA and he does an amazing job running a world class glass shop. Boola just likes eating scraps and thinks she's a person.

Hank Adams is the Creative Director of CGCA and he does an amazing job running a world class glass shop. Boola just likes eating scraps and thinks she’s a person.

While at Wheaton, I got to stay in this lovely vintage Airstream Trailer!

While at Wheaton, I got to stay in this lovely vintage Airstream Trailer!

These were my two successful casts. This slideshow will walk you through the process of creating them and attempt to share my learnings from the experience.

These were my two successful casts. This slideshow will walk you through the process of creating them and attempt to share my learnings from the experience.

I started with 3D prints. This is Makerbot's Artist figurine Zee, which was given to me by Rob Steiner at Bold Machines. I customized him with some devil horns made out of wax.

I started with 3D prints. This is Makerbot’s artist figurine Zee, which was given to me by Rob Steiner at Bold Machines. I customized Zee with some devil horns made out of wax.

I had three 3D Printed PLA pieces to cast altogether- A 24" tall Luna Park Tower (printed in sections), Mat Fraser and Julie Atlas Muz 18" tall figure (printed on Makerbot's Z-18 printer), and the Zee figurine. I used some cardboard and hot glue to piece together a reservoir for each print before going to make a mold around each.

Altogether, I had three 3D Printed PLA pieces to cast- A 24″ tall Luna Park Tower (printed in sections), Mat Fraser and Julie Atlas Muz 18″ tall figure (printed on Makerbot’s Z-18 printer), and the Zee figurine. I used some cardboard and hot glue to piece together a reservoir for each print before going to make molds. I also used some brown wax to smooth some rough areas of the prints.

It was a beautiful day in the shade of the Studio's smokestack.

It was a beautiful day in the shade of the Studio’s smokestack.

I made some small sprues as air vents for the fine details on the tower.

I made some small sprues as air vents for the fine details on the tower.

I also cut wire mesh to reinforce the molds with.

I also cut wire mesh to reinforce the molds with.

I just used a cardboard box for a form for Zee.

I just used a cardboard box for a form for Zee. The bigger molds used tar paper as a form to cast the plaster around the 3D prints.

The classic mold material is a 50-50 mix of Plaster and Silica with wire lath as something to strengthen it. I did a first coat a little wet as a splash coat to make sure I really have the whole surface.

The classic mold material is a 50-50 mix of plaster and silica, with wire lath as something to strengthen it. I did a first coat a little wet as a splash coat to make sure I really have the whole surface.

The mold is filled with mix and sets up.

The mold is filled with mix and sets up.

Because of the silica, a mask is very important!

Because of the plaster and silica, a mask is very important!

It was a very long day of mixing plaster in 5 gallon buckets. The big molds were extremely heavy so I set them by the furnace to dry out some. I was sore that night!

It was a very long day of mixing plaster in 5 gallon buckets. The big molds were extremely heavy so I set them by the furnace to dry out some. I was sore that night!

They were so heavin, in fact that we had to tie them onto the fork lift to lower them in the oven!

They were so heavy that we had to tie them onto the fork lift to lower them in the oven!

Hank is an expert with the fork lift!

Hank is an expert with the fork lift!

The oven they gave me was about 3 feet deep, so we gently lowered the molds in.

The oven they gave me was about 3 feet deep, so we gently lowered the molds in.

Here you can see the bottoms of the 3d prints in the molds. The next step is to burn them out overnight.

Here you can see the bottoms of the 3d prints in the molds. The next step is to burn them out overnight.

There's the bottom of the  Zee figurine.

There’s the bottom of the Zee figurine.

Overnight, the oven went up to 1000 degrees, then back down. It was about 24 hours of waiting until I could open the oven, but the molds burned out very nicely.

Overnight, the oven went up to 1000 degrees, then back down. It was about 24 hours of waiting until I could open the oven, but the molds burned out very nicely.

The Pla burned out extremely cleanly. Yu can see there are some cracks in the molds as the  PLA does expand and contract some as it heats so for the future, I can print with less infill and play with some other mold material formulas to try to minimize this cracking.

The PLA burned out extremely cleanly. You can see there are some cracks in the molds as the PLA does expand and contract some as it heats. For the future, I will print with less infill and play with some other mold material formulas to try to minimize this cracking.

We lost some mold material between Zee's legs, but the mold burned out very cleanly.

We lost some mold material between Zee’s legs, but the mold burned out very cleanly.

The molds were packed with cullet- chunks of the glass they use at Wheaton. Its a Spruce Pine Soda Lime glass. It would be nice to do some castings with optical crystal, but these were just tests so I was focused on what was available and cheap.

The molds were packed with cullet- chunks of the glass they use at Wheaton. Its a Spruce Pine soda lime glass. It would be nice to do some castings with optical crystal, but these were just tests so I was focused on what was available and cheap.

The GB4 computer is the standard oven controller and has been for over 30 years in the glass and ceramic world. I would LOVE to see someone make an internet connected Arduino oven controller with a mobile phone web interface. These things are archaic! If you're an Arduino Hacker interested in exploring this, please contact me.

The GB4 computer is the standard oven controller computer and has been for over 30 years in the glass and ceramic world. I would LOVE to see someone make an internet connected Arduino oven controller with a mobile phone web interface. These things are archaic! If you’re an Arduino Hacker interested in exploring this, please contact me! I have given this much thought and would like to work on bringing glass studios into the 21st century.

Because of the mass of the molds, they have to be slowly heated and cooled. It took another 12 hours or so to bring the molds back up and begin to melt the glass.

Because of the mass of the molds, they have to be slowly heated and cooled. It took another 12 hours or so to bring the molds back up and begin to melt the glass.

We first brought the oven to about 1200F and as the glass melted down in the molds I kept dropping more in.

We first brought the oven to about 1200F and as the glass melted down in the molds I kept adding more chunks in.

One design flaw with these molds was that they were so deep. It would be more ideal if the molds were shallower and the glass did not have to flow down so far. I ended up bringing the ovens up even hotter in an attempt to get the glass to flow all the way in.

One design flaw with these molds was that they were so deep. It would be more ideal if the molds were shallower and the glass did not have to flow down so far. I ended up bringing the ovens up even hotter in an attempt to get the glass to flow all the way in.

It was freakin' hot in there!

It was freakin’ hot in there!

Finally, the glass stopped flowing and I knew the molds were full.

Finally, the glass stopped flowing and I knew the molds were full.

The kilns need to be vented to crash them down to annealing temperature as fast as possible, otherwise the glass can "scorch" and devitrify, causing it to have a more milky appearance.

The kilns need to be vented to crash them down to annealing temperature as fast as possible, otherwise the glass can “scorch” and devitrify, causing it to have a more milky appearance.

I just turned off the oven and left it open for a few minutes at a time. The goal is to let all that heat dissipate and bring it back to ~960 asap. The problem was there was so much mass in those molds.

I just turned off the oven and left it open for a few minutes at a time. The goal is to let all that heat dissipate and bring it back to ~960 asap. The problem was there was so much mass in those molds and the refractory brick holds the heat. It was a couple hours of venting before I could start the annealing cycle on the computer.

The pieces took about ten days to cool down. Annealing glass involves soaking it at particular strain temperatures, then slowly cooling it down to room temp. I left and returned in two weeks to find this.

The pieces took about ten days to cool down. Annealing glass involves soaking it at particular strain points to even out the temperature, then slowly cooling it down to room temp. I left and returned in two weeks to find this.

The molds were so heavy and by now fragile that I just dicested them right in the oven.

The molds were so heavy (and by now fragile) that I just divested them right in the oven.

Luna Park Tower.. in glass!

Luna Park Tower.. in glass!

I was slightly nervous the oven might close on me- that thing was deep!

I was slightly nervous the oven might close on me- that thing was deep!

A couple process shots of divesting Zee.

A couple process shots of divesting Zee.

The mold materiam bloke off pretty easily.

The mold material bloke off pretty easily.

revealing what's underneath...

revealing what’s underneath…

Devil Zee!

Devil Zee!

I used a diamond saw to cut off the reservoir

I used a diamond saw to cut off the reservoir

The final Zee.

The final Zee.

Luna Park tower required a lot of picking and scrubbing to get all the mold material off. I also had to be careful not to clog the sink.

Luna Park tower required a lot of picking and scrubbing to get all the mold material off. I also had to be careful not to clog the sink.

Both final castings. I have a couple parts that broke off on the Luna Park Tower that I'd like to glue back on. but overall a good first experiment.

Both final castings. I have a couple parts that broke off on the Luna Park Tower that I’d like to glue back on. but overall a good first experiment. Above you can see Mat and Julie’s legs- they proved to be to skinny for the glass to flow into.

So what did I learn?

First, the work I will make in my fellowship will be shallower castings 9-12″deep at the most. I will be making relief panels cast from 12x12x12″ 3d printed sections. I think these high relief castings will be easier to produce and yield better results. Though I like the jade-like appearance of the glass in these, I would prefer more of a translucent glass appearance for my final product. The shallower molds will be easier to cast and cool so as to avoid devitrification. I also will do some more experiments with other mold formulas. Perhaps some other mold materials will crack less as the PLA expands during burnout. Finally, I’d like to explore casting with hot billets of glass as opposed to cold chunks of cullet. Basically, hot casting ingots of molten glass from a furnace so they skin up and stop moving, but are still quite hot when they are dropped into the molds. These ingots are then dropped in the molds and will more easily be heated to flow in. This should also yield a clearer quality to the glass.

So that’s it. I hope you enjoyed. I’m looking forward to using the process to make some work during this year’s fellowship!

PLA Perdue Part Two

Yesterday I posted about my experiments with “lost PLA” casting to make a cast glass object from a 3D printed digital design.

Today the oven cooled and I was able to remove them from the plaster silica molds. I’m quite pleased with the results. They could use some cold working to grind and polish them, but it’s an excellent proof of concept for this as an efficient and speedy workflow to quickly move from digital designs to physical object in any castable material including glass and metal.

Some shots of disinvestment and the final objects. The castings were very clean!

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R&D: Developing a Workflow for taking Digital 3D Designs to Glass Objects

Greetings from beautiful Millville NJ! I’m down here for a few days at Wheaton Arts’ Creative Glass Center of America, where I had an artist in residency way back in 1992. My friends Jim Harmon and Hank Adams invited me down to prototype a workflow for taking digital 3D designs to glass objects. Take a look and see what I’ve been up to!

The TC Wheaton Glass Building at Wheaton Arts

The TC Wheaton Glass Building at Wheaton Arts

The Studio is a recreation of an 1880's Glass facotory and hosts world acclaimed artists coming to realize their work in glass.

The Studio is a recreation of an 1880’s Glass facotory and hosts world acclaimed artists coming to realize their work in glass.

I chose this Duchamp Chess Set Pawn (http://www.thingiverse.com/thing:305639) as a simple form to test how PLA prints will fare burning out of plaster molds.

I chose this Duchamp Chess Set Pawn (http://www.thingiverse.com/thing:305639) as a simple form to test how PLA prints will fare burning out of plaster molds. I wanted to have something with a wide bottom so we could easily inspect the interior of our mold. I am curious to see how much residue PLA 3D prints will leave behind when burned out of a plaster mold.

I used some wax to seal any  holes in the PLA Print, and then used a cardboard box to prep a form for casting plaster around the object. Note that I used some clay to fashion a resevoir/base for the 3D print.

I used some wax to seal any holes in the Print, and then used a cardboard box to prep a form for casting plaster around the object. Note that I used some clay to fashion a reservoir/base for the 3D print.

I mixed a 50/50 mixture of pottery plaster and sIlica as the mold will need to be fired to 1500 degrees Fahrenheit.

I mixed a 50/50 mixture of pottery plaster and sIlica- this is a standard formula for glass casting as the mold will need to be fired to 1500 degrees Fahrenheit.

I gave the form a wet splash coat of plaster first.

I gave the form a wet splash coat of plaster first.

I was nervous about the piece floating off the bottom so the splash coat was there to anchor it, then as the plaster becan to set I added more in on top.

I was nervous about the piece floating off the bottom of the box, so the splash coat was there to anchor it and capture the surface. As the plaster began to set I added more in on top.

Later Jim and I removed the castings from the cardboard and dug out the clay resevoir.

After the plaster set, Jim and I removed the castings from the cardboard and dug out the clay reservoir.

The PLA 3D print is just visible inside. Next up we loaded these molds in an overn and slowly brought them to 500 degrees, then all the way up to 1000 to completely burn off the PLA.

The PLA 3D print is just visible inside the plaster mold. Next up, we loaded these molds in an oven and slowly brought them to 500 degrees, then all the way up to 1000 to completely burn off the PLA overnight.

The burned out mold was perfectly clean in the morning.

The burned out mold was perfectly clean in the morning.

Next up, the molds were flipped and loaded with chunks of glass cullet.

Next up, the molds were flipped and loaded with chunks of glass cullet.

We picked chunks that were clear and as big as we could fit in the resevoir. This will help the casting be clear with fewer bubbles.

We picked chunks that were clear and as big as we could fit in the reservoir. This will help the casting be clear with fewer bubbles.

Ready for firing!

Ready for firing!

Jim programmed the oven to slowly heat to 900°, then climb up to 1500° as quick as possible, then hold there for four hours.

Jim programmed the oven to slowly heat to 900°, then climb up to 1500° as quick as possible, then hold there for four hours.

At that point the glass was all melted into the mold and we cracked the oven to "crash" it back down to the annealing temperature of 900° before the glass devitrifies.

At that point the glass was all melted into the mold and we cracked the oven to “crash” it back down to the annealing temperature of 900° before the glass devitrifies.

The oven was pretty hot!

The oven was pretty hot!

We are soaked the oven at annealing temperatures of 900° and 720° on the way down. Hopefully the pieces will be cool enough to remove from the oven before I leave tomorrow! Stay tuned to see how the castings come out- I can hardly wait to see myself!

UPDATE: See how everything came out here: https://thegreatfredini.com/2014/07/26/pla-perdue-part-two/