Inexpensive Ceramic Shell: Aluminum Casting with Drywall Joint Compound

We’ve been aluminum casting at the Milwaukee Makerspace since November, and I have cast several things since then.  For simplicity, we started by using a lost foam casting method, wherein the form to be cast is fabricated in Owens Corning Foamular 150 (Styrofoam), and is then tightly packed in a reusable, oil bonded sand called petrobond.  The molten aluminum is poured directly on the styrofoam, vaporizing it.  Because the mold is made of sand, the surface texture on the cast aluminum part has the “resolution” of the grain size of the sand.

Ceramic shell is another technique often used in art casting.  The positive of the form to be cast in metal is first created in wax, which is then dipped repeatedly in a silica slurry, that slowly builds up to the desired ½” thickness.  The surface detail reproducible is much smaller/better, as the silica has a much finer “grain size.”  The piece is then put in a kiln to burn out the wax and harden the silica, thereby forming an empty mold.  Typically the mold is cooled, inspected for leaks, patched, and then is buried in regular sand.  Note that to avoid fracturing the mold, it must be heated before pouring.  With all these steps, this process is relatively time consuming and is also somewhat expensive.

Recently, I read a blog post about a quick and low cost ceramic shell alternative that substitutes one or two coats of watered down “Hamiltons White Line Drywall Texture mix” for the tedious ceramic shell process outlined above.  While I couldn’t find that exact product, 4.5 gallon buckets of Sheetrock brand lightweight drywall joint compound (DJC) are omnipresent.  Note that some bags of quick setting drywall joint compound are actually just plaster, and cannot be substituted. I first assembled all the parts needed to make a quick test of the process.  I decided to make some aluminum packing peanuts:

Aluminum_Peanuts_parts

I hot glued the pyramid shaped sprues to the round cup and to the peanuts themselves:

Aluminum_Peanuts_together

I removed half of the 43 Lbs of DJC from the bucket, and poured in 10 lbs of water, taking care to mix it thoroughly with a spiral paint mixer connected to a drill.  Then, I just dipped the whole styrofoam assembly into the bucket, let it dry overnight, and dipped it in a second time.  Immediately after the first dip, I took care to brush the surface of any especially undercut areas, to prevent air bubbles from sticking to the surface.  In the future, I may consider pulling a vacuum on the bucket of DJC to de-gas it.  This may help prevent the formation of air bubbles on the surface of the styrofoam parts.  In addition, I could have first dipped the assembly in surfactant. After two dips, the 1/8” thick shell on the assembly looked like this:

Aluminum_Peanuts_coated

It was a week before the next aluminum pour at the Makerspace, during which time I poured a half ounce of acetone into the mold to dissolve the polystyrene packing peanuts and styrofoam, producing an empty mold.  This step is only necessary when casting packing peanuts, as their polystyrene tends to rapidly expand out of the mold and catch fire, while the pink styrofoam (also polystyrene) is made for homes, and so is much better behaved.  I buried the now-empty DJC mold in ordinary sand, and Matt W fired up the Bret’s furnace, melted a #16 crucible of aluminum, and poured it (Thanks guys!).  After fifteen minutes, I pulled the mold out of the sand, and found the DJC was a little darker.  The act of pulling the mold out of the sand an leaving it to cool over night left it somewhat cracked:

Aluminum_Peanuts_cast

The DJC crumbled off so easily that I didn’t even need a brush.  Also, I noticed that there is more yellowish surface tarnish on pieces left in the DJC to fully cool.  I recommend removing the DJC immediately after the aluminum solidifies.

Aluminum_Peanuts_cleaned

After making a few more, I’m almost ready to safely pack valuables, such as my “Marquis, by Waterford” crystal stemware:

Aluminum_Peanuts_in_use

Finally, check out the phenomenal surface detail that this process can reproduce.  For scale, this peanut is 1.5” long.  The surface texture on the front face is about ~0.002”!

Aluminum_Peanut_closeup

Thanks to Jason G for this last photo.  Also, a big thanks to Dave from buildyouridea.com for letting me know that one or two dips will do it!

Bay View Gallery Night

Bay View Gallery Night

Summer is just around the corner, and that means it’s time for the first Bay View Gallery Night of the year, and now that Milwaukee Makerspace is located in the heart of Bay View, we just had to get in on the action, so we’re inviting you to join us in what we sometimes refer to as “16,000 sq feet of Art”.

And hey, it’s not all art, as we do a zillion things at Milwaukee Makerspace, as long as it involves being creative and making things, we do it. We’ll have plenty to see and experience, including our group show titled: Awesome Things From the Makerspace.

If that’s not enough to convince you, we’ll also be hosting a show from our friends at the Bay View Arts Guild, so yeah, even more art!

It’s all happening Friday, May 31st, 2013 from 5pm to 10pm. And as always, we’ll have some sort of magical surprise to knock your socks off!

(Note: If you’re not wearing socks, we can’t be responsible for what might happen to your feet. You’ve been warned!)

Staying Stocked Up

The idea was simple: make something to help keep track of our supplies so we know when we’re running low on the essentials.  After weeks of kicking the idea around and various rough doodles, this project finally took shape.  Two days after the first cut on the laser cutter, it was complete.


Made from multiple layers of acrylic, cardboard, and wood, the “Milwaukee Makerspace Consumables Super Analog Status Board” is a clipboard-sized device with nine sliders installed in enclosed slots.  Sliding the tabs right displays more green to indicate “full” or “lots” and sliding left reveals the red acrylic below to indicate “empty” or “low.”  The user can carry the board around the Space with them as they check on supplies and when done, a large hole centered at the top allows the board to be hung up and displayed on a wall.

The hardware holding the whole thing together can be loosened and the layers disassembled.  The cardboard insert that the text resides on can be swapped out should we decide to change the list of items we want to keep tabs on.  The supplies being tracked currently include:

  • Toilet Paper
  • Paper Towels
  • Hand Soap
  • Welding Gases
  • Welding Wire
  • Propane
  • Soda
  • Duct Tape
  • Painter’s Tape

A digital version may or may not be planned for future release.

Art Night

Art Night

If you happen to be out and about on Friday, April 19th, 2013 you might want to swing by Milwaukee Makerspace at 2555 S. Lenox St. in Bay View.

While we aren’t officially part of any gallery night events this time around, we’ll be open to the public on Friday from 6pm to 9pm for anyone who wants to stop by and take a tour, or check out some of the art (and art making tools!) we have at our space.

And if you want to see us in full art swing, you’ll only have to wait until the end of May. ;)

Art Jamboree [Time Lapse]

The Jambo at Krambo!

Well we certainly had a good crowd for the Art Jamboree that Art Milwaukee held at the space a few weeks back.

Don’t believe me? Check out the crowd in this time-lapse video we shot during the evening with a GoPro camera mounted in the welding area.

We actually had a lot more going on that you can see in this room. Pretty much every space in the 16,000 square foot building got put to good use showing off something cool.

(Here’s a view of the other large room, the camera angle is not quite as wide, but just as many people.)

The Art Jamboree is Here!

Art Jamboree

When we say “The Art Jamboree is Coming” we really mean The Art Jamboree is Coming! That’s right, Art Milwaukee is bringing the next Art Jamboree to us. Mark your calendars for Friday, March 29th, 2013 when the Art Jamboree will take place at Milwaukee Makerspace.

This one is titled “The Maker” and besides the usual awesomeness that includes the best in Milwaukee art, there will also be raffles, food & drink, and free low-fives(?) We’ll also be adding our own maker-related art to the mix. Expect some some interactive pieces as well as art in mediums you may not be used to. (Sure we like paint, but we also like lasers and molten plastic and beer.)

This event is free and open to the public. (All ages are welcome, but keep an eye on the kids. We have a lot of rotating blades, but we’ll do our best to keep them powered-down during the event.)

Mark your calendars for March 29th, 2013 from 7pm to 11pm. We’ll see you at 2555 S. Lenox Street in beautiful Bay View.

Pssst! Want to see who else is going? Check out the event on Facebook.

A Clockwork…Room Divider

A 6 foot tall, clockwork gear inpired, tri-fold room divider

Hopefully, we can use this as a backdrop for events like the Art Jamboree.

I’ve been toying with the idea of room dividers for a while now. I don’t exactly have use for one, but I think they look neat and it’s basically a blank canvas. Drawing inspiration from my Clockwork Boxes, I decided that a gear motif would best suit the makerspace, thus giving me a new use for the piece: as a backdrop at events we participate in such as Art Jamboree and the various Maker Faires.

A picture of myself, Jason, and Matt, standing around the room divider

There are 3 of us in this photo. Really.

The actual screens were cut out with a large-scale CNC router, while the frame was ripped from 2×4’s, with a dado groove down the center for the screen to slip into. Thanks, Jason H.!!

Assembly went well, although there were a few hiccups.  The drill bit wasn’t long enough, so some minor splitting occurred at a couple of spots. The frame was slightly warped and so needed to be clamped and glued before being screwed together.

After allowing the paint to dry overnight, myself, Matt W., and Jason H. assembled this thing just prior to heading to the Art Jamboree at the Hilton in Milwaukee.

EDIT: I’ve just entered this into the Furniture Contest that Instructables is running. Click the link. Vote. Be thanked. :)

LEGOlamp

LEGO_lamp_2_complete_dark   This is the assembled LEGOlamp.  It will be mounted as a ceiling fixture, with an internal bulb.  To light it for this picture, I used a desklamp to project light into the tube.

One idea I tried after the previous post, was slicing the tube into 16 rings.  The idea was to glue the bricks to the tube, with the bricks stacked vertically, then offset the rings after the bricks were attached.  That approach failed.  I was unable to cut the rings smoothly, resulting in large gaps between them.  When stacked, they looked horrible.

In the end, a simple change of adhesive and application made the difference.  First, I abandoned both hot glue and epoxy.  I discovered gel super glue has sufficient open time to position the bricks, but also sets quickly enough that clamping and supporting the bricks was unnecessary.  I addition, I realized the important joint is between the bricks.  If the bricks are firmly cemented to each other, the connection to the tube can be a series of comparatively weak joins.  Less glue on the end-face means less glue to smear, and less chance of accidentally gluing the template in place.

 

drillpress_dremel_saw  Many people have asked how I cut the LEGO bricks.  Initially, I used a sharp chisel.  That was tedious, as each brick had to be clamped.  After that, I switched to a rotary-tool held in a fixture, with a standard abrasive cut-off disk.  That worked well enough.  Finally, I hit on chucking a Dremel-sized circular saw blade into a drill press.  That provided a rock-solid platform.  Better still, once the height was set it didn’t vary.  Unlike the abrasive disk, the bricks weren’t heated by the saw blade.  No molten plastic flying around.  Using this method, the bricks required little-or-no touch-up work with a sharp knife.

Another Art Jamboree!

Art Jamboree!

It’s that time again, folks… Time for another Art Jamboree! Join us on January 25, 2013 from 7pm to 11pm at the Loyalty Building (Hilton Garden Inn) 611 N. Broadway, Milwaukee, Wisconsin.

The event is free and open to the public (and all ages are welcome) and there will also be a cash bar, prizes, art raffles, free hi-fives and some of your favorite Milwaukee Makerspace members showing off things they’ve made, many of which could be considered “art”!

We’ll also have some interactive pieces for you to experience, but we can’t give away all the details yet, because we’re all about secrecy and the element of surprise, so you’ll just have to show up and see what we do. (Safety glasses and ear plugs are highly recommended!)

Oh, and our friends at Art Milwaukee (who are putting on this event) have all the info on the Art Jamboree you’ll need. We hope to see you there!