Color! Using Dyes on 3D Printed Vinyl

Material for the SD300 is offered in a very limited selection of colors, so naturally I was intrigued by Sean Michael Ragan's blog post Stain PVC Pipe Any Color You Like.  So I bought an assortment of Sculpt Nouveau solvent dyes and tested them on 3D printed vinyl parts from the SD300.  They emerged brightly tinted in candy-like colors!

Solvent dyes are very highly concentrated, but they're formulated to be diluted with solvents--like the name implies!  I tested a variety of PVC solvents, using disposable pipettes to measure similar volumes of dye.  Not surprisingly, I got the best results from the most powerful solvent, SCIGRIP 2007.

The solvents I tested, starting with the most satisfactory:

• SCIGRIP 2007 (formerly Weld-On 2007) tinted the SD300's vinyl parts very quickly, reaching full color in 15-20 seconds.  It also strengthens 3D printed parts and leaves a glossy finish.
• Oatey Un-purple Primer was almost as effective as SCIGRIP.  It's a PVC pipe primer without the usual purple stain; instead it contains a UV-sensitive fluorescent dye that makes treated parts glow under blacklight.
• PVC Pipe Cleaner with THF (various brands) was substantially less effective than the solvents above, and it took longer for parts to absorb the dye.  Look for THF or tetrahydrofuran under the caution label.
• PVC Pipe Cleaner without THF was least effective.  It took more time, it did not strengthen parts, and it did not leave a glossy finish like the choices above.

After testing such a wide assortment of solvents, dyes, and tints, I made dozens of these little test puzzles so I handed them out at this year's International Puzzle Party in Ottawa.

I've also been experimenting with a subtle green tint, trying to imitate the appearance of real glass.

Success 2 - Its' Nuts!

In May I blogged how I built an enhanced copy of Oskar van Deventer's Cooksey Tribute D puzzle.  Oskar already owned a copy of Cooksey Tribute D, and so did I, so Oskar suggested I send the third as a gift to Jerry Slocum, a renowned puzzle enthusiast and author.

Coincidentally two other puzzle enthusiasts, John Rausch and Tyler Barrett, had recently persuaded me to build a small quantity of bolts with trick nuts like the ones in my Wrong Way Nut video so I chose to send one to Jerry.  That way Cooksey Tribute D would be a gift from Oskar, and Wrong Way Nut could be a gift from me.

For reference, here's the Wrong Way Nut video:

Jerry telephoned me immediately after he'd received the puzzles and asked if I could possibly build 120 copies of the bolt and nuts for the Puzzle Party.  I was thrilled!

We agreed the puzzle needed a name because I had originally adopted "wrong way nut" as a descriptive phrase, not an actual title.  Jerry researched to ensure we wouldn't infringe any trademarks.  I liked his suggestion Its' Nuts because it used an apostrophe in a nonstandard way, which was a subtle puzzle in itself.  Had it been intended as the contraction It's Nuts or a possessive term Its Nuts?

Each nut is embossed with "Its'" on one side and "Nuts" inverted on its opposite side so the puzzle's title appears when the nuts are correctly threaded onto the bolt.  Can you work out the probability of correctly assembling the bolt and its nuts so they say Its' Nuts?  (It's not just 1 in 2, as you might guess.)

It's customary for entries in the Edward Hordern IPP Puzzle Exchange to carry the name of the person exchanging them and the date of the IPP event when they were exchanged.  The bolts I built for Jerry are custom-embossed with IPP32 and the year 2012 on one face, and From Jerry Slocum on an opposite face.

With Jerry's approval, I added my own name to the top of the bolt head to identify myself as the creator.  Pay attention to how thin those letters really are, forming narrow strokes less than 1mm thick.

I deliberately made those hollow areas are narrower than 1mm so they wouldn't be sufficiently wide for the SD300 to apply anti-glue inside those narrow channels.  Consequently the letters are glued into the solid bolt head when the SD300 builds them, forming subtle outlines that can only be read by carefully examining the sheen of the top surface.

Screw threads need a slick finish, but the SD300 ordinarily builds layers with sharply-defined edges so I dipped every single nut and bolt in Weld-On 2007.

The solvent smooths and seals the layers, but after a few uses the solvent also tends to fog up the glossy top surface--an undesirable side effect.  To avoid fogging I learned how to dip the bolt only up to the sides of the hex-shaped head, but that left the side walls of the bolt head with a half-glossy/half-matte appearance.  The solution?  I wiped the side walls with ordinary PVC Pipe Primer from my local plumbing supply--it contains just enough solvents to impart a uniformly glossy appearance, and it includes a neat applicator.

This was a big project.  It took over a week to build all those bolts, and almost two weeks more to build all the nuts.  The nuts were more trouble than the bolts because I had to manually clear 72 layers of leftover support material from the center of each nut, tearing out the layers with a pointed probe as illustrated in this previous blog post.  It went at least twice as fast if I heated the model in my microwave oven for 30 seconds, a tip I learned from Jason Harris.

After the various pieces had been built, I assembled them into completed Its' Nuts sets.

I vacuum packed the bolt sets in groups for convenient shipping to Jerry.

For their final presentation Jerry repackaged Its' Nuts into individual prescription-drug containers, playfully labeled Slocum Pharmacy.  It included a caution, "Be sure to take with 1 grain of salt."

Jerry Slocum increased his order to 135 sets of Its' Nuts and I managed to build all 135 of them without any rejects or second-quality parts.  I sent him every single bolt I had built with the custom "From Jerry Slocum" inscription, and I forgot to keep one for myself!  I'm happy to build more bolts, but I wouldn't allow myself to build any more of Jerry's bolts--I regard them as a work-for-hire.

So I negotiated a puzzle-swap: he traded me one of the customized IPP bolts and in exchange I gave him this one-of-a-kind bolt that was professionally built via SLA, polished, and lacquered by a professional bureau.  To commemorate the occasion, I paired it with the very first nuts that had ever been inscribed with Its' Nuts.

Epilogue...
Jerry Slocum won me over to the name Its' Nuts because the odd placement of the apostrophe struck me as a clever piece of word-play.  He later confessed that it originated as a typo.

Antichron

A year ago I probably wouldn't have attempted to build something as twisty and complex as Bathsheba's Antichron model.  But someone sent me a reduced-size model of it, and I confidently devised a small set of peeling cuts that should have made it an easy build on the SD300.  Not so easy, as it turned out.

I got it mostly right.  I'd divided the model into four zones in each of the upper and lower sections, so the support material peeled away effortlessly at first.

But when I got near the middle section I found layers of support material permanently wrapped around sculptural features I'd misinterpreted.  If it had been properly planned, there should have been additional cuts to divide the support material but I hadn't instructed the SDMove software to make the proper cuts.

Was it necessary to discard the model just because I hadn't set up the build software properly?  Probably not, but I decided to free the model so from the rest of the material to get a better view of the trouble spots.

The support material was thicker than the walls of the model so I couldn't just remove them by brute force.  So I decided to separate the support layers and snip them one-at-a-time with a small knife.  This was tedious but it would free the model after cutting through dozens of layers on each side.  That would take a while so I put on an old Edward G. Robinson movie (Scarlet Street) while I worked...and it took most of the movie to free the two models I'd built.

Because I'd scaled down the model by 50% the walls were dangerously thin, about 1.4mm.  Somehow I managed to free the first model without any damage, but cracks appeared in the second model while I was cleaning it so I stopped several times and applied Weld-On to strengthen its weak spots.  When I finished cleaning the second model (below right) I dipped it in Weld-On 2004 to heal the cracks and give it a nice sheen.

Orange, Green, and Blue Marble

George Bell graciously took several sets of my Bag of Marbles puzzles to the International Puzzle Party in Berlin this year. Currently I have three styles of marbles, distinguished by color.



Orange Marble was my first design, a puzzle with two interlocking pieces that slide together unintuitively. It was created by accident as part of a design that I abandoned while studying Bram Cohen's Trapped Marble prototype. Although the two pieces are different from each other, they can be flipped relative to each other and they slide together symmetrically.


Green Marble is another two-piece design. This time the two pieces are identical, but they only fit together when the pieces are oriented in one specific orientation.


Blue Marble is based upon the same curves as Green Marble but divides a sphere into three pieces instead of merely two. Most people fit two of the pieces together easily, but instinctively try to insert the third piece upside-down...which doesn't work.


Here's how a batch of Blue Marble pieces looked shortly after I'd removed them from the SD300 and removed some of the support material.


Unprocessed pieces have a translucent sidewall finish. It's attractive, but I wanted a shinier smoother finish.


To smooth the side walls I dipped each piece in Weld-On 2007 solvent for 30 seconds.


After their solvent bath I laid the pieces on baker's parchment to dry. Parchment is non-absorbent and the wet pieces don't stick to it, so it's an ideal disposable drying surface.


Eventually I plan to add other Marble styles (and colors) to the series as I think of new challenging features to add.

Improved transparency for the Cooksey Tribute puzzle

EDIT: Just to clarify, I only built the transparent rings in the pictures. The brightly-colored maze cylinders were purchased from Oskar's store at Shapeways.

In a previous post I described how I'd made transparent rings for Oskar's Cooksey Tribute maze puzzles. The transparency enhanced the puzzle, but they were only semi-transparent at best.


I had sprayed the previous parts with Weld-On 2007 to improve their transparency, but I soaked a second set in the solvent for 25 seconds and then permitted it to air-dry for an hour. The results were substantially more transparent.


There's some optical distortion where build chatter has been transformed into wavy lenses, but the new part is more transparent.


So now I'm building a new set of enhanced transparent rings using the solvent soak-dip.


I had discovered the value of a solvent dip long ago, but I'd been using a simpler solvent-spray to make it more convenient. The dip requires a relatively large volume of Weld-On 2007 welding solvent, a solvent-resistant surface, gloves, and ample ventilation. But these results are worth some special effort!

There are additional pictures of Oskar's Cooksey Tribute in my PhotoBucket Album.

Using a Pin Vise to clear small holes

For a while I disliked building parts with deep, narrow holes because leftover support material clings tenaciously inside the holes and solidly blocks them. There's common advice to simply clear the holes with a drill, not my favorite solution.

A colleague suggested using an ordinary drill bit in a pin vise. The pin vise allows the bit to be twirled freely, and the handle provides leverage and strength.



Because its a handheld tool, the pin vise gives tactile feedback that makes it easy to guide the bit to follow the intended path of the hole. I found it helps to run a peeling cut down the middle of the hole, which gives the flutes a loose edge to grab onto.


Surprisingly, the manually-operated drill bit clears away leftover material very quickly yet doesn't tend to cut into the model itself. The model is quickly cleaned up by scraping the drill bit against the sidewalls and withdrawing it to clean the flutes.

3D-printed decals and tiles

The SD300 is uniquely well-suited for making decal-like tiles of any arbitrary shape and thickness. When cut into thin tiles, they emerge from the SD300 still attached to the foundation layer like the picture below. So thin, it's clear and colorless.


I printed several sheets of square tiles and left them attached to the support material while I painted the exposed side. The support material acted like a perfect mask to keep the other surfaces clean.


The tiles look brilliant and glossy with the clear side facing outward, and the color visible through the clear material. I built some puzzles with cavities to accept the tiles, which fit so perfectly they didn't have to be glued: they just snapped in to the cavities. The SD300 built everything in this picture, including the painted tiles.


I built a thinner set of tiles for this hand-customized puzzle. These are only 0.33mm thick so they're not much thicker than standard decals, but they look and feel more professional than ordinary decals. I printed the puzzle name Cube 321 on the back side of one of the tiles before painting it, as described in a previous blog post.

Printing directly onto PVC

Mechanical puzzles often call for tiles, decals or stickers to distinguish the parts. (Think Rubik's Cube.) The SD300 should be able to create tiles of any desired thickness, so I cut a sheet of shapes suitable for a puzzle I built last year.


One of the tiles is supposed to be labeled with the puzzle's name. I used this custom-made guide to hold one of the tiles in my printer's CD-loading tray. (The tile is barely visible in the slot nearest the 'TOP' label.)


The printer uses delicate pigment-based inks, so I printed on the back side of the tile so the text would be viewed through it. This will protect the pigments after the ink dries. (Note: You can only print on plastic using a pigment based printer. Most ordinary ink-jet printers use water-soluble dye-based inks, which probably won't work on PVC.)

Barrel puzzle, now functional and tinted

In a previous post I got the barrel puzzle working by dipping it in welding solvent. But it isn't really a puzzle unless there's some way to distinguish the parts. Ordinarily I would cut and apply vinyl stickers.


But some colleagues admired the semi-transparent appearance, which would be hidden if I applied stickers over the surfaces. I experimented with several alternatives before getting an inspiration today.


I dusted the parts with Jacquard Pearl-Ex pigment, choosing "interference" colors that aren't visible unless light reflects off the surface at just the right angle. Then I misted the surface with Weld-On 2007 to embed the pigment permanently into the PVC. The puzzle in all these pictures has been tinted, but the colors were hidden in the pictures above. Below, the color is revealed when the light is just right.


Now it's possible to mix up the colors, creating a challenge to get them back to their original positions. (Like a Rubik's Cube, but simpler.)

Impractical Geometry, round 2

I bought two additional pairs of forceps after my experience peeling 'impractical' parts.

At top is the original set of forceps supplied by Solido. It's the most generally-useful of the bunch, with strong wedge-shaped jaws whose knife-edge slides easily between layers. Its jaws close flat, so it can spread force on a tightly-gripped sheet without tearing it.

The second set is an Xcelite 434 sharp-pointed tweezer. The point is useful for stabbing PVC material and applying sideways force to clear overhangs. The jaws are gently curved to concentrate grip at the end. It's prone to damage the part (and work surface, if dropped) but it's got special uses.

The bottom set is an Xcelite 7V with slender, curved jaws that can reach concealed areas through small openings. It can't grip as firmly as the other pairs, but it can reach places straight tweezers can't go.


The deep overhangs and hollow areas had been so difficult to clear last time because there wasn't enough free space to maneuver the material. This time I added wedge-shaped peeling cuts so I could pull material out of the part's openings, thus giving me room to reach in and work on the waste material embedded inside.


After building the part, I concentrated my attention on clearing material out of the wedge-shaped channels.


It took a few minutes, but it worked quite well. With this wedge-shaped opening I already had access to the interior of one of the overhangs.


I used the pointed tweezers to loosen material in the overhang, then used the curved tweezers to reach in and pull it out. The curved tweezers can't grip very tightly, but I learned to gently work the waste material back and forth until it gently broke free.


Unlike last time, the part emerged without any blemishes or rough spots. It took about 35 minutes, so it's not quick work, but it was much easier than last time.


I dipped the part in Weld-On 2007 to improve its transparency. I had overlooked a small piece of scrap material inside one of the cavities, visible through the sidewall in this picture. Unfortunately, the solvent dip permanently welded the scrap inside there. It's important to clear away all scraps before using any solvent!