Archive for March 2016

Taking a tumble: burnishing 3D-printed bronze

The Point, a 3D printed bronze sculpture - Kevin CaronMany sculptors work in bronze, but in my more than 10 years as a professional artist, I have worked in everything but. I have mostly fabricated in mild steel, but have also worked with stainless steel, Cor-ten (weathering) steel, aluminum, brass and copper.

Finally, with 3D printing, I have my first bronze! Well, it’s 80% bronze and 20% PLA resin, but the resulting print is clearly a different breed than the ABS and PLA resins I usually print in.

For one thing, it’s noticeably heavier. Seeing as I’m printed just two or three layers thick, it’s amazing how much heavier these bronzes are than if they’d been printed in the resin I usually use.

(Of course, that gets my mind going … if I could print a solid bronze, how much would it weigh? How would it compare to the weight of a traditional poured bronze? And we’re off and running through the grassy fields of my mind ….)

One of the big differences is that the sculpture isn’t done once the printhead rises ….

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3D Printing Bronze Brings New Challenges

bronze filament from Colorfabb - Kevin CaronI’ve been drooling over all the different kinds of filament out there, from the luscious translucents I’ve used on several of my sculptures, to rubber – Steve Graber gave me a cool “vase” printed in a single layer of rubber that’s a huge hit at events – to the new transparents.

Some of them aren’t really available to me for the Gigante, which uses 3 millimeter filament but for which I like at least 5 pound spools. (My company policy is to order at least three 5 pound spools at a time for the Gigante just to make sure I have enough in the same color lot to do a 4-foot-tall sculpture. Yeah, I have a lot of filament in my supply closet!)

Others, like wood, don’t turn me on.

But bronze? Yeah, I’m a sculptor, so bronze definitely interests me.

So I bought some bronze filament from ColorFabb ….

 

My Cerberus 250 runs 1.75 millimeter, but I wanted to use the bronze in my Gigante, so I bought some spools, even though I had to settle for 1,500 kilogram ones.

The bronze filament is more expensive than all of the other filament I’ve bought, and it’s heavier, too. That’s because it’s 80% bronze and just 20% PLA.

First I printed a small version of the form I call The Point that’s just 11″ tall. I was happy enough with it that I printed a 26″ tall version.

The Point, a 3D printed bronze sculpture - Kevin CaronWhat I didn’t anticipate was how much time and effort it would take to burnish them.

When they print, they look almost like wet clay. That is not the look I am going for – I want these sculptures to, obviously, look like bronzes. Yeah, I know they are bronzes, but I want them to look like bronzes, too!

I started out with steel wool and realized quickly I needed to start with something rougher. I grabbed some Abranet, a sanding material my brother, a wood turner, introduced me to. I used finer and finer grits and even tried wet sanding, which I’d read about online with 3D printed bronze, but it didn’t seem to help.

I kept working my way finer and finer in grit until I was back to using steel wool, then worked my way finer and finer in its versions to a very fine steel wool.

After trying various ways to hold the sanding material – wrapped around a pencil, a railroad spike, etc. – I figured out to put it on a simple metal rod with a piece of tape to hold it on. I put that into my drill, which I then used to burnish the sculptures.

I ordered some brass wool from Rockler and tried it on a test piece, but it didn’t do anything. Back to the steel wool.

I spent about 10 hours on the small Point, and 16 hours on the large one.

The biggest success, though, was when I put the small Point into my 100-year-old burnisher. Wow! It gave it an incredibly cool gleam.

I’ll share more about the burnisher in an upcoming post, but suffice it for now to say that I can’t fit the large Point into it. While the finish on it is OK, I see more hours of hand polishing in my future to get the look I want.

Next, I think I’ll order some copper filament ….

100-year-old machine solves my 21st century 3D printing problem

Scale - 3D printing blog by Kevin CaronSometimes working with 3D printing is like discovering a new continent. You never know what goldmine you’re going to discover – or sinkhole you just stepped into.

Fortunately, most of the time I unearth goldmines. This time, I found yet another. What I didn’t expect was that I’d be using apparently timeless 100-year-old technology to solve a 21st century problem.

For a long time, I’ve been a bit frustrated because my 3D printer host software tells me how many millimeters of filament a print will take.

That is only of limited help, though, because filament manufacturers sell their product based on weight (kilograms or pounds) ….

 

So knowing how much filament you need for a job has been a real conundrum. Armed with the magic of the Internet, though, I was determined to find some way to know how much filament I have and how much I need for a 3D printing job …..

I began searching for measuring tools, thinking I’d find something digital. I did, but I also found the perfect tool that just happens to be really, really old.

Enjoy this video, which explains what I found and shows how it works perfectly ….