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A Pipe Light

July 17, 2016
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Following the room prep for the B.A.D., for the next task I wanted to create some kind of dramatic light. And for years, I’ve wanted to create a huge “hanging centerpiece” for a big dinner, something that would be large & sculptural but not interfere with sightlines across the table – not block guests from seeing each other. Incorporating reused materials is a preference as well.

We have an abundance of silk screen frames, and with ceiling height over 13′ at the dinner table, I sketched up an idea of an assemblage of different-sized frames hanging high above the table:

Sketch of silk screen frame assemblage

Sketch of silk screen frame assemblage

Oh, and I wanted to incorporate small LED modules to create light. If I could align some of frames at the same height, I could put the LEDs all in a row. With enough lumens, the white tablecloth would be illuminated, light would reflect up to guests faces, and it could be the only lighting for the entire space. And it would be cool if the LEDs were almost invisible, with the frames drawing all the attention. At least that’s the way I was envisioning it.

I found a great online source for LED parts – LEDsupply.com, they had so many options to pick from it was a bit overwhelming so I just called them up and asked for their recommendations. I told them what I was looking for, and they gave me a few options; they were so much help. The only pieces unknown were whether or not I should use spot, flood or no lens to focus the light, and since the various plastic lenses were less than a buck each, I bought both kinds and I could test them with a mockup.

While waiting for the parts to arrive I kept sketching out various details. One issue was the heat buildup – the LED modules would either need a heat sink, or be open to air. I figured I could drill a hole all the way through the silk screen frames to allow heat to escape.

A detail at right to allow heat to escape

A detail at right to allow heat to escape

While LEDs create a lot less heat than incandescent fixtures, the small amount of heat they do create will shorten their lives. And wood is not a good conductor of heat so without an escape route, the LEDs would get pretty hot.

The parts arrived within a few days – and I couldn’t wait to wire them up!

The diode on circuit board, and the black plastic lens holder.

The diode on circuit board, and the black plastic lens holder.

 

The actual Light Emitting Diode is quite tiny – it’s the little yellow domed piece in the center. The “star” shape is a metal core printed circuit board, which is what I had to solder the tiny wires to. It’s about 3/4″ diameter. After all soldering was done, I could glue the black plastic lens holder to the circuit board, and then the different lenses pop into the holder.

Wiring/soldering them together requires some skill, and it’s very important to keep all the wires organized; in addition to a power transformer, LEDs require a driver component, and I was also including a dimmer (a potentiometer).

Proof of concept - they work!

Proof of concept – my circuit works!

Now that I have working LEDs, it was time to mock them up upstairs to figure out two things: the best height above the table, and if they should be paired with the spot or flood optics, or have no lens at all.

This light effort was going on at the same time as the room prep, and the table wasn’t ready yet. So Sue & I put the table top on some trash cans at the appropriate height, and laid out one of the white tablecloths. I hot-glued the metal circuit boards in a row on a 2×4, and attached two spot lenses, two flood, left one LED bare, and made two varying-height PVC tubes as custom light cut-offs for the remaining LEDs.

LEDs and various optics glued to a 2x4 for testing.

LEDs and various optics glued to a 2×4 for testing.

Then when it was dark enough in the evening, we turned off all lights, plugged in the LEDs and then held the 2×4 over the table to see how the light patterns shone down.

It didn’t take long to decide what worked best; the goal was to light the whole 48″ width of the table, but also not have the LEDs be harsh to anyone’s eyes. The spot lenses were too narrow – they made a visible circle of light on the table. The bare LED had soft illumination, but because it output light in all directions, it was hard to look at. The PVC tubes worked just as well as the lenses but without the clean professional look of the manufactured lenses. So we chose the flood/wide lenses, and figured out that mounting them around 6′-8″ above the floor placed the light cutoff just beyond the edge of the table without shining on guests’ faces. (Sue & I took turns pretending to be dinner guests.)

Now I had the guts of this light resolved, but still wasn’t sure what this thing looked like. I’d been noodling & doodling details for weeks, and I had too many doubts. I wasn’t sure how I could attach an assemblage of old silk screen frames without them sagging at their old corner joints, and I didn’t think we had enough identically-sized frames that would allow a design where the parts to contain the LEDs would end up at the same height. Power wire would have to be longer to travel up & down the frames so that they didn’t jump through the air to the next LED. And I felt like the whole thing would need to be built on the floor, and then pullied up to the ceiling. It was feeling way too complicated.

And then in one of those eureka moments – I threw the entire silk screen frame idea out and came up with a totally opposite idea – put the LEDs in a slim metal tube suspended over the table.

With just a single cable holding it up at each end, the light would be very minimalist and practically disappear.

We had a plethora of abandoned steel gas pipe hanging from the ceilings. I just had to get up there and cut a hunk out. And I love getting to use the big ass wrench.

Cultivating old gas pipe near the ceiling.

Cultivating old gas pipe near the ceiling.

The LEDs needed some kind of attachment or container within the steel pipe. I didn’t want then sticking OUT beyond the surface of the pipe; rather they should be INSIDE the pipe. But being hollow inside, I had to make something to support them. I came to call this device the “capsule”.

My instincts told me the capsule should be metal, mostly for heat dissipation and for precision and fastening. Which led me to readily available and easily-crafted copper.

So I went through the shop and gathered a variety of copper pieces – elbows, reducers, caps, couplers and straight pieces of pipe. Then I brought them into the comfort of our apartment living room and tinkered with how I could create a container to hold the LED+lens. Oh, and make it in way that I could take it apart in the future, in case an LED ever fails, or I want to upgrade, etc.

An assortment of copper pieces; figuring out the "capsule".

An assortment of copper pieces; figuring out the “capsule”.

 

 

I noticed that the LED+lens unit fit perfectly inside of a 3/4″ coupling piece. This could work; I just needed some way to hold it in position. I can’t remember exactly WHAT made me think of this, but I took the tubing cutter and ran it around a coupling, and if I stopped just short of the piece being cut in two, there was a ridge created on the INSIDE of the coupling, and I could possibly use this as a “stop” for the LED unit. A few sacrificial cuts/scores later, I figured out how much “cutting” was necessary.

I marked a bunch of couplings with the cut location, and went to town.

A coupling about to be scored.

A coupling about to be scored.

The "ridge" visible on the inside of the coupling.

The “ridge” visible on the inside of the coupling.

 

The ridge acted as a perfect stop for the LED and lens unit.

The ridge acted as a perfect stop for the LED and lens unit.

To hold the LED unit in place, I slid a “reducer” copper piece into the coupling, which basically squeezed the LED from the other side and pressed it against the ridge/stop.

If this reducer piece could stick through the top of the long steel pipe, it would be a heat chimney and prevent heat buildup within the capsule.

I took a short piece of the steel gas pipe to use as a mockup, drilled some holes in it to match the coupling and reducer diameters, and slid this temporary capsule into place. I needed some way to fasten the reducer and coupling together in order to continue this mockup.

In the vein of needing to dismantle the capsule in the future, I figured a screw would be good. But it would need to be tiny as to not protrude very much. Then I remembered “pop rivets” – which would be perfect because their heads are quite flat. But – I didn’t own a pop rivet gun, though I seem to recall seeing one in the famous Vavra uber bench. And it would be super cool if there were copper rivets in one of the drawers so that there wasn’t any galvanic action from dissimilar metals. If I needed to disassemble the capsule, rivets are easy enough to drill out and replace.

Score: Rivet gun AND copper rivets!

Score: Rivet gun AND copper rivets!

I sandwiched the LED inside the coupling and reducer piece, fastened with the free rivet, after cutting slots in the sides for the wiring to exit.

The first capsule prototype.

The first capsule prototype.

Back to the sampler piece of steel pipe, I inserted the capsule prototype into the drilled holes and started exploring various methods to attach the capsule to the steel pipe. I got & made a variety of “pins” to slide through the reducer piece that could hold the capsule from the top and extend out like little arms, resting on the steel pipe.

Prototype capsule suspended in test pipe.

Prototype capsule suspended in test pipe with a cotter pin I made out of copper wire.

This prototype would work, though I wasn’t totally satisfied it. The heat “chimneys” detracted from the sleek look I was going for, and it also seemed like these capsules could dangle like little “bells” because they basically relied on gravity and the various pins supporting them on the steel. Dangling could lead to slight misalignment and aiming of the light, possibly visible on the table.

Back to the digital drawing board to come up with a better design for the capsule.

I decided that a hole or opening on the capsule’s top wasn’t necessary for heat dissipation, IF I had a continuous metal connection with the steel pipe, effectively allowing the steel pipe to be the heat sink. If the capsule had a solid top, I could attach a screw from the top of the steel pipe into the top of the copper capsule. A bonus to this idea was that the top of the steel tube would only have small screws instead of big holes with “chimneys”, hardly visible since they would be over 6′-8″ high and above most folks’ line of sight.

Ditched original capsule design for a new one...

Ditched original capsule design for a new one…

The new capsule design required lots of small custom cut pieces – the couplings cut down by 3/8”, standard “caps” cut to just 1/4” deep, and regular straight pipe cut to 5/8” lengths. Based on the original mockup, I had only 1/16” tolerance on the overall assembly otherwise the capsules would not appear uniform, so I had to be very precise with my pipe cutters.

Production mode now for capsules.

Production mode now for capsules.

 

I soldered the straight pipe pieces to the shallow end caps.

Soldering the short straight pieces to the shortened caps.

Soldering the short straight pieces to the shortened caps.

No pics, but I cut slots into the sides of both the caps and the couplings – once closed tight with the LED module inside, the wires had to come out somewhere.

I tossed all the parts into a solvent bath for a few days. (Didn’t want any grease or flux to be an issue with the heat from LEDs.)

A solvent bath...

A solvent bath…

 

 

All clean!

All clean!

Before assembling the capsule parts, I needed to drill a hole in the top of the cap for the attachment screw from the top of the pipe. If I drilled this hole after assembly, there was a possibility I could hit the LED circuit board when the drill popped through the copper.

Predrilling hole in cap for screw

Predrilling hole in cap for screw

Just one more machining step in creating the capsules – drill the hole for the rivet that will hold the “sandwich” together. I mentioned earlier that I had a 1/16″ tolerance in overall length of the capsule, and the rivet location will set the overall length. So I had to get the rivet hole in just the right place. I pushed the LED all the way down to the scored “stop”, then slide the cap down in to touch the back of the circuit board, and aligning the wires with all of the slots. The copper pieces were slightly tight, which was good, because I could push or pull them to make slight adjustments to the length. Then I could hold it in place with the drill press vise.

Drilling final hole to secure capsule with rivet.

Drilling final hole to secure capsule with rivet.

There was no chance of hitting the LED components, they were all below the drill location. (Or in photo above, between the drill bit and the scored stop.)

And because little copper filings went everywhere, before final assembly I took the whole thing apart and blasted them with compressed air. Final step was to insert the copper rivet.

First finished LED capsule!

First finished LED capsule!

 


With the light capsules all ready to go, here’s what was involved with getting the steel pipe ready to hold the capsules.

I already mentioned acquiring the pipe from an old gas line upstairs. Setting it up at the metal work bench, I used an angle grinder with a cup wire wheel to clean it up, stripping away decades of gunk, exposing the original dark raw steel finish.

The light apertures on the bottom and the screw holes on both the top needed to be aligned as much as possible, otherwise the light pattern on the table could be offset. I’m not sure how others would do this, but I devised a method similar to “snapping a chalk line” except without the snapping and without the chalk.

I took a small level and marked a vertical line through the virtual center of each end. Then I got some industrial thread and taped it at one end, aligned with the top vertical mark, then stretched it tight along the top of the pipe, aligned it with the mark at the other end, then taped that in place. Essentially, I made a long line at the “apex” or crown of the pipe. You might have to zoom in, but the next photo shows that thread.

Thread used to align the holes.

Thread used to align the holes.

 

After measuring and marking the center points for each drill location, I used a center punch to create that dimple you need to keep drills from wandering when drilling metal.

Center punch to create drilling "dimple"

Center punch to create drilling “dimple”

I used commercial bi-metal hole saws in the drill press, with lots of cutting oil, to cut holes large enough to fit the 3/4″ coupling – the light capsule.

Holes for the light capsules.

Holes for the light capsules.

I didn’t need to do a lot of sanding or finishing on these holes – just some touch-up to remove burrs. No one would be able to touch the edges since the copper capsules will sit in the holes.

Just for fun, I took a pic of the chaos of the metal work bench. This is what it typically looks like while I’m in the middle of a project.

The chaotic metal work bench mid-project.

The chaotic metal work bench mid-project.

Though, last year, it was pretty bad with a giant pile of rusty pipes and fittings.

I repeated the same thread-pulled-tight, center punch and drilling holes for the opposite side of the pipe, and these were smaller countersunk holes for the screws that would fasten the capsules from the top.

Once all of the machining and oily/dirty work was done, it was time to clean the pipe. It was pretty easy to clean the outside with rags & solvent, but the inside was trickier. With all of the drilling, and accompanying cutting oil, the inside of the pipe was probably pretty oily. But I thought I could come up with a good cleaning method.

I was thinking of a way to pull a solvent-soaked rag from one end of the pipe through the other, and I was looking at connecting some metal hangers taken apart and twisted together. Rope wouldn’t work, because I needed something that would work in tension and compression – I’d need to stick in in from one end, attach the rag, then pull it through.

Ready to cut & twist several hangers together, suddenly I thought “Wait – I HAVE a long metal thing meant just for this purpose!” and I got out my trusty electrical fish tape.

It worked perfectly!

Fish tape worked perfectly to clean inside of pipe.

Fish tape worked perfectly to clean inside of pipe.

I passed the solvent-soaked rag through the pipe about 8 times. (With each pass, I squeezed and re-soaked the rag.) With each pass I could see the rag coming out less and less oily.

Running a solvent-soaked rag to clean the inside of the pipe.

Running a solvent-soaked rag to clean the inside of the pipe.

With the pipe all cleaned, next step was to apply a finish. In the past I’ve used a spray-on clear coat, but this time I wanted to try something a little more “natural looking” and less glossy.

An old-fashioned paste wax seemed right for something that would have little human contact. It’s a general purpose wax, used for leather and all kinds of materials.

Johnson's multi-purpose paste wax

Johnson’s multi-purpose paste wax

The wax can be applied at room temperature, but if it’s applied when the material is warm or hot, the wax will liquefy and get deeper into the structure of the surface. So I opted for the hot method, because I always like working with fire.

Heating up surface prior to waxing

Heating up surface prior to waxing

I had to heat up just a foot or so of pipe at a time; but it went fairly quickly. A few times I could hear the wax “sizzle” when I applied it to the pipe.

Wiping on the paste wax

Buffing out the paste wax

After I had a section of pipe waxed, then I’d take a clean cloth and buff out the wax; this removes excess wax and brings out a beautiful luster to the finish.

The pipe was “finished”, and it was ready for putting in the LED capsules.

To pull the wires from one capsule to another, THIS time I did use a bent coat hanger. I needed a little more dexterity to be able to pop through from one hole to the other, and the electrical fish tape was a little too stiff. I just made a little hook on a coat hanger, made a slight curve in the length of the wire, and hooked the wires of the capsule.

A coat hanger used to pull wires form hole to hole.

A coat hanger used to pull wires form hole to hole.

After all of the LED capsules were wired, the “driver” needed to be shoved in and hidden as well.

The driver component was the last piece to go in the pipe.

The driver component was the last piece to go in the pipe.

 

Before going further, and with all electrical components stuffed into the steel pipe, time for one final electrical test to make sure everything is still working.

Another success! Installed lights still work.

Another success! Installed lights still work.

Before closing the ends, the cable supports needed to go in. I used typical cable terminals, which have little jaws to hold the cable, and are then hidden by a cone-shaped collar. The cheapest version I could find had an “eye” at one end, but that will be hidden inside the pipe.

The hole for the support was 3″ from the end of the pipe, two far to get my fingers in to manipulate the piece. It was also just a bit too tall to slide into the pipe; even after grinding away part of the eye end, I had to wiggle it a lot. I stuck the eye on a long reamer tool, which gave me good control to maneuver it, with the added bonus that the reamer held the the whole piece in place while I tightened the first nut.

Cable support had to be wiggled in.

Cable support had to be wiggled in.

The last step in the pipe assembly was to close up the ends. Recent trips to Lowes and Home Depot were unsuccessful in finding an acceptable closure piece. I checked electrical, plumbing and general hardware departments, and nothing fit my needs. I wanted something clean and unfussy. A copper cap would work but I couldn’t find one large enough.

One evening I thought I’d try making something myself, using a scrap from the sheet of copper I harvested from the roof.

Quick test at making my own cap.

Quick test at making my own cap.

After a few minutes of hammering, it didn’t feel right – I wanted something that was a little “neater” or machined-looking. Granted, I spent less than 5 minutes so maybe if I’d invested more time it would have worked. Instead, I decided to call a plumbing supply house the next day and just go buy a few large machine-made copper caps. Maybe some future project will lend itself to more rustic copper hammering.

The new caps were a bit too long. Not a big issue aesthetically, but functionally – I wanted the potentiometer (dimmer) to be mounted in one cap, and if the cap was too deep, no one could get their fingers to reach the dimming knob.

It was pretty easy to cut the caps in half with a hacksaw.

It was pretty easy to cut the caps in half with a hacksaw.

For the cap that held the potentiometer, I needed a hole in the center for the stem mounting, and a second smaller hole to prevent the device from spinning.

Potentiometer fits inside one cap.

Potentiometer fits inside one cap.

After sanding the copper cut edges to a fine luster, I coated them with the same wax that I used on the steel pipe, in hopes that it could slow down a patina forming.

Then I found some thin cork sheet material to use as a semi-flexible gasket to hold the caps in place. Since no strength was needed, they were just going to sit there, a pressure fit would be fine. I cut a few thin strips of cork, blackened the edge that would be on the outside, cleaned off the wax from the area on the cap where this strip was going, coated all mating surfaces with Super 77 spray, stuck the cork on the copper cap, then pressed the cap into the end of the pipe.

Gasketed cap ready to close up pipe.

Gasketed cap ready to close up pipe.

It had the perfect firm fit, which I had to twist back & forth to go in. And if I needed to take the pipe light apart, I could just grab the lip of the cap with a pair of pliers. I pushed it in until it was flush with the steel pipe end. The blackened cork kept the cap perfectly centered, and added a cool dark gap between the steel and the copper.

One of the finished ends.

One of the finished ends.

For the potentiometer end, same process & materials, except I needed to attach a knob to the stem of the dimmer. I had a few knobs around that would fit 1/4″ stem, and I bought a pair of “retro stereo” looking knobs on my last trip to Radio Shack. I showed my options to Sue and she picked the Radio Shack retro stereo; I agreed. This knob needed a set screw from the side to secure it to the stem, so I had to drill a small access hole in the side of the copper cap so that I could insert a tiny screwdriver and tighten the set screw. I rotated the cap so that the side hole wouldn’t be visible when the light was mounted high.

The other finished end with knob to dim lights.

The other finished end with knob to dim lights.

Finally, it was time to attach the pipe to the ceiling upstairs and power it up.

The location of the light was somewhat predetermined by the location of the dinner table, which Sue & I determined to be best for drama, view of the sunset, and flow and access. So I only had a few inches to play around with in finding the best anchoring spot.

Most of the square footage of the ceiling is hollow clay tile, so I prepared to find that at the first drill location, and I had large toggle bolts ready. But luckily, I hit solid concrete at both mounting locations, so I could use stronger expansion anchors in the concrete.

The cable assembly at the top consisted of a short angle attached with the previously mentioned anchor, with a second hole in the down-facing leg, then a “quick link” to take the whole thing down if needed, then a turnbuckle, to make fine adjustments to get the pipe level, and finally, the cable itself.

So attaching it was straightforward and didn’t take more than an hour. The one problem that I hadn’t fully resolved was getting power to the light fixture. My worst-case-scenario was that I’d run an extension cord up the wall, across the ceiling and then down. Admittedly, that plan would have been an easy solution with the first giant sculpture made of silk screen frames, as the space would have been so visually busy that a power cord would not be too noticeable.

But minimalism seemed a better approach now.

I hadn’t noticed this before, but there was an old metal cover plate on the ceiling, just a few feet away from one of the anchor points. If there were wires in the box it covered, I’d be so lucky if they were hot, and second-best would be if I could just replace a fuse to power them up. BUT, when we were removing the roofing last fall, we found several electrical conduits that had become rusted out, corroded and filled with water. Perhaps that’s why this one had been abandoned.

Possible power from an abandoned ceiling box?

Possible power from an abandoned ceiling box?

But it’s definitely worth checking!

I pulled down the first couple of wires and tested them for power – nuthin’. But I could see more black wires coiled up in the darkness, stuck my tester up in there and it lit up! There was power!

Checking wires in abandoned ceiling box.

Checking wires in abandoned ceiling box.

If I could get the power adapter plugged in here, I could run the thin low-voltage wire that came out it over to the metal angle, then down the cable and into the steel pipe. (I’d already drilled a hole in the pipe for the power.)

I could just jimmy it all up in a big mess and just tie it together, but that would look bad, and probably be more noticeable than a neater solution.

Figuring that I had saved parts from previous electrical demolitions over the years, I toured BAB digging in electrical parts containers.

And voila! I had an original duplex receptacle mounted to a round cover plate. Perfect.

But, it wasn’t going to fit on the recessed box with all those wires in the there, so I had to go by an extension ring. But the rest was pretty easy, mounting the ring and then adding the duplex receptacle on top of it.

BAD_Light_Attach-04

Power now ready to go, and close to the anchor!

Just one more task and the light would be complete – running the power lines. The “wall wart” of the AC adapter could just be zip-tied to the new power receptacle, and then the power line run straight to the metal angle and zip-tied to that to keep it from sagging. I had to add an extension line for the distance I needed down to the pipe, and I used the thinnest gauge possible with my circuit. I used super thin bare metal wire to make little spring-like “ties” to hold the wire against the cable, it was practically invisible unless you were looking for it.

And the wire going into the steel pipe was protected from chafing by a little grommet, that I found again in the Vavra drawers. (In a drawer labeled “Grommets” of course!) In the next photo you can also see a small screw – that secures the lighting capsule in place. Much better than the earlier “chimney” idea.

The cable connector, power wire, and a small grommet.

The cable connector, power wire, and a small grommet.

Final test and everything worked perfectly! Now for the big dinner!

The practice setup the night before the big dinner.

The practice setup the night before the big dinner.

 

The light doing its job for our B.A.D. guests.

The light doing its job for our B.A.D. guests.

I’ve been asked what I’m going to do with the pipe light now; haven’t really thought about it. We will probably incorporate it somewhere when we renovate upstairs, perhaps over a kitchen counter.

It was a a fun project even with its many challenges, and I’m very happy with the final result. I can’t wait for my next custom LED opportunity!

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4 Comments leave one →
  1. Rick Peterson permalink
    July 17, 2016 4:20 pm

    Looks great Tom. You did a fantastic job.

    one question, why didn’t you use 1/4″or 3/8′ copper pipe to hang the light with and push the wires thru ?

    I’m more surprised you didn’t buy a 6′ drill bit to use to clean the inside of the pipe out or cut the fish tape and attach it to a drill

    • Tom permalink*
      July 17, 2016 5:04 pm

      Thanks Rick.
      If you mean copper tubing as a suspension system, that seems somewhat rigid. And the inside of the steel pipe didn’t need to be wire brush cleaned, all I was concerned about was the excess oil.
      Thanks for reading!

Trackbacks

  1. “It started out as a pencil holder…” | B. A. B.
  2. Another use for the Pipe Light | B. A. B.

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