3D Printing Project: Steampunk Tap Valve Handle

So, the knob on our shower has a tendency to break over time. The other day it happened again and I had to turn off the water with a pair of pliers.

As luck would have it, on the same day I was sent a 3D printer (the mCreate from Makeblock) to try out and review. So, making the best of both situations, I decided to see if I could make a replacement tap handle using the new 3D printer.

It is probably worth noting that I had never used a 3D printer before, and the last time I had done any type of 3D modeling was over 20 years ago, so, yeah, I was pretty much starting at nothing.

My goal for this project was to design and create a cool, steampunk-inspired tap handle, kind of like the large round handles you might find on a big valve on a ship or something. Also, a lot of 3D printed objects look... well, 3D printed, which isn't necessarily a bad thing, but I wanted to see if I could make something that looked like it was actually made out of metal rather than layers of plastic.

Although I created this design to make myself a useable tap, I think it would also make a great decorative piece along with some other steampunk decor.

Disclaimer: Just because this worked for me and my tap, doesn't mean it will work for yours. Be aware that your success will depend on the materials and printer you use. I have no idea of the longevity of this design as a working tap handle, so be prepared for the possibility of it breaking and make sure you have a plan if that happens!

** We have been using the tap handle daily for 3 months now and it still looks and works great!!

Here are the tools and materials I used:

The stl files I made during the course of this project. They are on my website .
3D printer: I used a FDM printer, the Makeblock mCreate.
PLA filament: I used PLA for the main handle, dome cap, and swirly strip.
PETG filament: I used Overture PETG(paid link) for the part that connects to the valve stem, and the positive and negative molds for the swirly strip
Super Glue: For gluing the halves together, the swirly strip, and the nameplate
2-Part Epoxy(paid link) : To glue the connector piece to the handle
Sandpaper: I used 80 grit and 150 grit, and it wouldn't hurt to do 320 grit as well.
Paint: I like to use artists acrylic paint. I used Liquitex Basics: Mars Black as well as DecoArt Americana Decor Metallics: Vintage Brass (paid links)
Sealer: I used Pledge floor gloss (paid link)
Rubber Gloves: For applying the metallic paint, and while gluing.

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Step 1: Measure Once, Print ...3 Times?

As much as I wanted to get into the fun work of designing a really cool steampunk tap valve handle, I decided the responsible thing to do would be to make sure it was possible to actually 3D print a fitting that would fit onto the existing brass valve stem, work to turn the water on and off, and be strong enough that it would hold up to normal use.

In order to make a fitting that would....fit, I needed to measure as much as I could of the original handle and the valve stem, so that I could reproduce it in Tinkercad. You know what they say- "measure twice, cut once"? That's some good advice I probably should have followed....

Step 2: Turn Measurements Into Reality. Virtual Reality.

Once I had my measurements, I could start modeling in Tinkercad.

Can I say here that I really love Tinkercad? I know it does not have the features that more expensive programs have, but it is so intuitive. I was able to start modeling pretty much right away, with very little time spent learning from tutorials as I went. It really all works on the idea of adding or subtracting basic 3D shapes from each other. You can make any particular shape either a solid or a hole. When you group together a solid and a hole, the hole becomes....well, a hole in the solid. Too easy.

For example, I made the outside tube by subtracting a smaller cylinder from a larger one. I made the piece that needed to fit over the valve stem by taking a cylinder, cutting off the two sides with some cubes, and then turning that cut off cylinder into a hole and subtracting it from another cylinder.

Step 3: Turn Virtual Reality Into Real Reality

Once I had the 3D model of the fitting for the tap, I printed it out. As much fun as it was to finally be printing something out, I should have done a little test to make sure I had my measurements right.

Once printed, I tested it out and quickly realized that the flat-sided hole for the valve stem was slightly too small.

The second time I worked smarter rather than harder. Instead of re-printing the whole piece after adjusting the size of the hole, I just printed out a small slice of the section I needed to check. It was a good thing too, because the hole was still a tiny bit too snug, and I had to adjust and test one more time before it was perfect.

There is going to be a lot of twisting force on the centre cylinder, so when I sliced this object, I made the infill of that center cylinder 100% until it reaches the wider section.

Step 4: A Slight Problem With PLA-stic

While I was trying to get the fitting exactly right, I noticed that the brass valve stem would get very hot while running hot water. I decided it might be a good idea to check the heat resistance of PLA - the plastic I was using in my 3D printer. It turns out that the glass transition temperature of PLA plastic is 65 deg C (150F), which is a temperature that water coming from the tap can reach. This means at 65 degrees, the plastic would be soft and formable. Not exactly what you want when trying to turn off the hot water!

I found another type of 3D printable plastic called PETG, which is more resistant to heat, so I ordered a roll of that. PETG is a bit trickier to print with, so it took me a fair bit of time to get it working, but eventually, I got my piece printed! And it fit. And it turned the water on and off. And it didn't get soft and mushy. Finally, Success!

Step 5: Draw a Design

Now that I was pretty sure I would have a working tap at the end of this, I could concentrate on the fun part - the actual design of my handle.

I wanted this tap handle to have the feel of an old, brass valve handle, like something you would find on some sort of industrial steam-powered machine or fantastical submarine! As much as industrial tap handles are typically designed for function, I wanted to inject some beauty into the design as well that would fit with the steampunk aesthetic. My designs almost always include some raised or recessed swirly decorative elements, and this project was no different. In fact, to push me to learn more about the limits of 3D design and printing, I decided to include both, in the form of some elegant swirl patterns around the perimeter as well as on the spokes of the handle.

In order to get the swirl patterns from my brain to the printer, I first sketched them out with pencil. Then I scanned them and traced them with a vector graphics program. After that, I could export them as an svg file and import that into Tinkercad, which automatically turns the flat vector art into an extruded shape.

*** Note: TInkercad does not accept all svg files, in fact, the svg files I created in Affinity Designer were not compatible. The workaround I used was to export from Affinity, import them into Gravit Designer (a free online vector design app) and then export them again as svgs, at which point Tinkercad would let me import them as an extrusion.***

Step 6: Create a Cool Recessed Pattern

I wanted to create a swirly pattern recessed into the spokes of the handle. This would be easy if the spokes were a flat surface but the curved surface made it slightly trickier. My process for creating the recessed pattern was as follows:

Import the swirl shape vector image to create a 3-dimensional extrusion
Stretch the extrusion along its vertical axis
Turn the swirly extrusion into a hole
Move the swirls above the spoke where you want to engrave them
Duplicate the spoke and make the duplicate invisible
Bring the swirls down so they cut about halfway through the original spoke - just make sure they are not coming out the back
Group the two together so that your piece now has the pattern cut quite deep into it
Make the duplicate of the spoke visible again and scale it down a bit so that the engraved section is only a mm or so deep. This fills in all but the very top bit of the indentation you made with the swirls.
Group the duplicated spoke with the original.
Duplicate the finished spoke to make the other two.

Step 7: Design Considerations

When I started this project, I imagined that I would be printing this in two parts- the handle as a whole and the section that connects it to the valve stem. The further I got into the build, the more I realized the limitations of trying to make the handle all in one piece. One of the big problems was that I wanted a raised swirly pattern going all around the outside perimeter of the handle. I used Tinkercad to make a model with the swirls as an integrated part, but when I printed some test sections, I couldn't get them to look nice and crisp and clean. Yes, I could use supports and print it that way, but my goal was to make this not look like a 3D printed item, which meant I needed parts to look smooth and edges crisp. It's all good on the larger parts that can be sanded but on the swirls, it just wasn't looking promising. What could I do.....

Step 8: Using PLA's Low Heat Tolerance for Good Instead of Evil

Remember in the beginning when I realized that the PLA plastic would become soft at a relatively low temperature? Well, that experience gave me an idea. I decided that rather than trying to print a complicated design on the curved side of my tap handle, I would print the design flat, then heat it up and bend it around the handle. I did a quick trial, heating up some water in a pan on the stove and then holding the PLA in the water until it softened. Once soft, I had a few seconds to shape it after coming out of the water.

The results were quite good, but I figured I could get even better results if I made a form that I could press the softened plastic into....but we'll get back to that later :)

The strips aren't long enough to go all the way around the handle, so I needed to print 3 of them

****I think one of the most useful features of PLA is that when it's heated, it gets soft enough to be really quite floppy, yet it still retains its basic shape and does not get sticky.****

Step 9: Making the Valve Handle

Once I was pretty sure my plan would work with bending the swirl strip around the handle, I decided to split the valve handle in half horizontally, so that I wouldn't need any supports to get a good print. Also, I figured that the seam would be nicely hidden by the swirls that would go over top.

I printed the two half-handles, then applied super glue to the flat side of one half and held the halves together until the glue cured.

In hindsight, I should have made some pins or something to help align the halves during gluing.

Step 10: Sanding, Sanding, Sanding....

I actually thought it would take longer to sand the plastic than it did, which was a very nice surprise! I started with 80 grit paper and then went to 120 (ish) grit paper. (It wouldn't have hurt to use 320 grit as well) I wet sanded everything to keep the dust down and to stop any overheating of the plastic due to the friction of sanding.

Mainly I was trying to get rid of the layer lines from the 3D printing process, especially on the outside perimeter where I would be gluing the decorative swirly piece. Once glued, it would be pretty much impossible to get in behind there to smooth it out!

Step 11: Making a Form for the Swirly Piece

In order to get my swirly strips perfectly formed, I decided to make a positive and negative mold that the strip would be pressed into. In theory, the positive part could have been the handle section that I glued together in the last step. However, it was made from PLA, and I was planning to submerge the mold in hot water so I didn't want to risk the actual handle deforming. Instead, I made the mold in PETG plastic for higher heat resistance.

Step 12: Bend Those Swirls

In an old frying pan, I heated up some water to 70 deg C (158F). I kept a digital thermometer in the water the whole time so I could monitor the temperature.

I put on some insulated, waterproof gloves- mine were just some wool gloves covered with some nitrile gloves.

I submerged the negative half of the mold in the water, and then pushed the swirly strip into the mold under water with my gloved fingers

Then, while the mold and strip were still submerged, I took the positive side of the mold and used it to squeeze and hold the swirly strip in place while I removed the whole contraption from the water. I gave it a couple of seconds to cool, and then I could remove the perfectly shaped swirl piece. Or, at least half of it was perfectly shaped. The swirly pieces are longer than the molds, so the process needed to be repeated for the other half of the swirl strip.

Step 13: Glue Down Those Swirls

I used super glue to glue the swirly strips down to the handle.

There were some places that didn't stick down the first time, so I went around with my glue and put a few drops beside any unglued sections. I then pressed and released the section a few times to help draw the glue underneath it. Once the glue was under, I held that section down tightly until the glue cured.

I used two full-length strips to go completely around the handle, and trimmed a third strip down at both ends so it would fit the final gap.

Step 14: Design a Dome

You may notice that there is a hole through the center of the tap handle. That's where the bolt goes through to hold the handle to the valve stem. The problem is that the stainless steel bolt doesn't go at all with the look of the new handle, so I needed to make a cover that would fit with the overall aesthetic. And to complicate things for myself just that little bit more I figured it should have my LostWax name engraved on it.

I tried just engraving the name right into the dome, but I found that the combination of small-sized lettering and the curvature of the dome always ended up in lettering that wasn't very clear. After many prints, I finally ended up making a curved cut out on the top of the dome using the same technique I used for the indented swirls in step 6.

Then I made a flat piece with my name on it that I could print out separately and glue in later.

Step 15: Finish Off the Dome

The dome fits into the indentation in the center of the tap handle with a friction fit, so it is important that it is neither too tight nor too loose. I sanded around the outside edge of the dome until it was a nice snug fit.

You will notice I designed the fake nut on top of the dome to have a small hole through it, this is so that if it is hard to remove the cap, you can stick a wire through that hole and then use the wire to pull it out.

I then sanded the rest of the dome cap smooth and glued the little nameplates into the cutouts with super glue.

Step 16: Backplate

I wasn't really planning on this, but I decided the new tap handle would look really out of place with the old chrome backplate, so I plopped the old backplate on my scanner and traced the cutouts necessary so that the new one would fit properly.

*Another lesson learned the hard way: Don't forget that you might need to mirror the image if you are scanning the backplate from the back.....

Step 17: More Sanding

With everything now printed out, I spent some time sanding all the pieces so they would be ready for painting.

Step 18: Glue the Connector Piece to the Valve Handle

I needed to attach the handle to the first piece I made - the one that goes around the valve stem and turns it. It was important that the handle was positioned correctly so that the arrow on the handle would be pointing down when the tap was off.

I slid the connector piece into place on the valve stem on my bathtub, and then lined up the handle the way I wanted it to be when the tap was turned off.

I marked that position with a marker on both pieces so that I could line them up again when I glued them. (It was too hard to see the line on the black piece so I put a strip of tape on it first)

I used two-part epoxy to glue the pieces together. With two-part epoxy, make sure to squeeze out equal parts and mix them very thoroughly.

Step 19: Paint It Black

I painted everything with black artists acrylic paints. There are lots of other types of paint you could use, but the acrylics worked well for me. I like that they are relatively thick because it fills in some of the sanding marks, compared to the thinner layer you get when using spray paints.

Step 20: Turn It Into Brass

My favorite metallic paints tend to change over time, but right now I am liking DecoArt Americana Decor Metallics Vintage Brass for the brass look.

My technique for creating an antique metal look is as follows:

Put on a tight-fitting rubber glove. This keeps your hands clean and prevents fingerprint smears in your metallic coating.
Put a small blob of metallic paint onto a piece of scrap cardboard or paper.
Dip your fingertip lightly into the paint and then rub it onto a clean section of cardboard. Rub in a circular motion until almost all the paint is off your finger. It is especially important to watch the tip of your finger because paint can build up there, so you want to rub off any accumulation that occurs.
Rub your finger on the parts that you want to paint. Slowly build up the metallic colour, repeatedly going back and getting more paint on your finger.
If there are places your finger can’t reach, you can use a small, dry paintbrush. Dip the brush in the paint and then dab most of it off on the cardboard. Use a vertical dabbing motion to apply the paint, again building it up slowly. It is good to stay away from inside edges as the antique look requires sections that would get less wear to look darker.

Once the paint was completely dry I applied a coat of Pledge floor gloss to seal and protect the paint.