Accidents happen

Crash!!!

"Oh no! I was going to bring that to a meeting with Phil Spencer next week."

The Herker model from Insomniac's latest game Sunset Overdrive had been proudly displayed on the publishing art director's shelf all week when suddenly tipped over and fell 4 feet to the ground. The art director's meeting was on Wednesday where she would be showing it to her peers and executives. The guys at the model shop had gone home for the weekend, the print itself took almost two days to print, and it cost quite a bit of money in materials. There was no way we could print a new one in time.

Herker model digitally sculpted by Maxence Fleuret from Insomniac
Posed and prepared for printing by myself

Printed on an Objet500 Connex at Microsoft model shop

"No problem Louise, I'll fix it over the weekend and you'll have it back in no time" I said.

I collected up as many pieces as I could find on the floor, carefully put them into a box and quickly drove home to get started. This was Friday evening and the art director needed a Herker model by Wednesday morning.

I had a plan...

CX5

I had recently backed a Kickstarter project by the amazing sculptor Adam Beane for his new sculpting material called CX5 and had an unopened package of it waiting to be used. I thought this would be a great time to try it out on the parts that were either too damaged or missing on the broken Herker print.

I carefully started gluing large pieces together on Friday night using super glue. I wanted to make sure the glue was fully cured so I waited a few hours before gluing more than two pieces together.

Starting to glue broken bits together with super glue

More parts glued together

So many pieces!

That's about as good as it gets with superglue

By Sunday morning I had glued as much as I could together and decided I should really test CX5 out before going any further. The Microsoft model shop had given me a few rejected polyjet parts to play with and I thought gluing them together with CX5 would be a good enough test.

CX5 in a skillet to warm it up

It turned out to be more of a challenge to sculpt with CX5 than I had thought. This was my first foray into sculpting with hot tools, so I had a lot to learn in a short amount of time. What I found most challenging about the medium was the working temperature. One second CX5 is scalding hot and burning my fingers. Then it cools off slightly and behaves like a hard oil based clay. Then a few seconds later it is rock hard again. 

What I was hoping to do was heat up the CX5 to a liquid state and then thinly brush it onto my parts. Unfortunately, because it kept cooling too fast, I ended up with thick gobs of medium on my parts and the rest just stuck to my brush. The stuff on my brush is rock hard and I'm not sure if heating it will melt the clay off or just burn the bristles of the brush.

The dvd that came with the CX5 was incredibly useful in getting me up to speed on how to work with CX5 and what equipment is needed. I ended up buying a small electric skillet to keep the clay warm. I also bought an alcohol torch that I filled with denatured alcohol so I could heat up my metal tools and 3M sanding sponges. I have since picked up a dental waxer but have not yet had a chance to use it.

Finally, after a lot of hand sculpting and sanding I had glued the two parts together with a smooth to the touch seam. It was time to get to work on resculpting the missing Herker parts.

Testing of CX5

The area that had the most damage and missing elements was the giant backhoe claw hand. That is where I spent most of my time resculpting. I began with using some two part epoxy putty to cement the tip of the claw to the rest of the hand. I used epoxy because when it cures it is incredibly strong. This took up a few hours on Sunday evening so all of my sculpting would have to take place at home on Monday.

Superglued parts

Completed epoxy work. That hand is rock solid!

Monday morning I began working with CX5 in ernest. After my initial tests the previous day, I knew this would be a challenge but I was still confident I could get something presentable done in a day. I started out heating the CX5 in a skillet until is was maleable. I quickly massed out the missing forms with some of my sculpting tools. Using an alcohol lamp with denatured alcohol to heat up the metal tips of my tools I worked with CX5 in short bursts until the tool tip cooled too much. I would then heat the tip up in the flame to continue working.

Initial sculpt of hand using CX5

I then used hot sanding to start polishing the parts and blending it together with the original 3d print. Hot sanding is where you heat up sand paper using your alcohol torch before sanding the medium. The hot sand paper quickly smooths the clay, creating a uniform and smooth surface. 

I bought 3M sanding sponges directly from Adam Beane but also tried out emery boards that are used for manicures. I cut the emery on angles (pictured above) so that I could create more mechanical looking planes in small hard to reach areas.

Polishing CX5

More polishing...

Finished resculpt of claw

I discovered why the Herker had fallen over in the first place. The pins that attached the feet to the base were never glued. The model is so top heavy that eventually the pins popped out of the base and the whole thing took a nosedive. So next time I have a heavy print to deliver I'll make sure to glue it securely to its base. With the claw fixed on the print, it was time to attach the large sections of the print together. This time I used a liquid epoxy to fix the parts together and waited for it to cure before continuing.

drill holes on base for better adhesion with epoxy

drill holes on foot for better adhesion epoxy

Epoxy the feet to the base. That print is never going to come off of that base!

Epoxy the arm to the body

Epoxy the arm to the body

There were a few seams and cracks left on the model which I quickly smoothed over with some more CX5 late into the night on Monday.

laying down some CX5

After smoothing CX5

Other view after smoothing CX5

Once the Herker was put back together I had to carefully pack it up with lots of foam. I definitely could not afford to fix anything else as it was now Tuesday morning and I still needed to paint the model and let it dry.

Very careful not to break this print!

The model shop at Microsoft has a great spray booth room that I was able to use. I took the fixed model back there and sprayed the whole thing with a matte grey car paint primer. All I had left to do was wait for the paint to dry and get it back to the art director before her meeting.

With car paint primer

Very cool sculpt by Maxence Fleuret!

Look at all those amazing details pop!

The end result is a seamless fix. I was able to get the Herker back in time and as an added bonus, the matte car paint greatly enhanced the details of the sculpt. The original polyjet material is quite translucent which means most of the details were hard to make out. The Herker 3d print now proudly sits in the display case at Microsoft Studios.

As for CX5, I have mixed feelings towards it. On one hard it is very versatile, it can be sculpted, machined, painted and sanded. It can also be cast directly without the need for doing a lost wax copy. On the other hand, the small window in which the medium is workable made it difficult for me to really enjoy working with the clay. I'm sure I just need more than a days worth of practice to be comfortable with CX5. I've also picked up some of Adam's new CX5s which is a softer version of CX5. I need to try them both out and see which I prefer.

Since this project I have also picked up a block of sculpting wax and some modeling epoxy upon the recommendation of some other traditional sculptors. One day I'll get around to trying out these other mediums to see which one works best for my needs. In the meantime I hope none of our other 3d prints have any accidents.

Broken 3D print? I have no idea what you are talking about...

Looks good to me!