Step 1. Find the Right Size For Your IKEA IRSTA Lights
I probably wouldn’t have had to make this mod if I’d measured the available space under my shelves accurately in the first place. The total depth for the IKEA IRSTA lights, with all hardware attached, is about 14-3/8″ from the rearmost mounting clips to the front of the attached lip when tamped down.
My shelves only have 11-7/8″ of space underneath, so I decided to cut the lights down to a total depth of 11-3/8″, removing exactly 3″.
I should note that the LED bar by itself can make a perfectly serviceable sconce light or backlight; if you are very tight on space, consider using just the LED bar, perhaps with a small slice of the diffuser / softener panel covering the LEDs for appearance.
Step 2. Unpack and Unwrap the Diffuser Panels
Be careful opening the box, as I had one light with its panel facing the seam. You can remove the contents and use the box as a work surface if you need to. Finally, remove the protective film from the diffuser so that you can take it apart.
Step 3. Disassemble the Diffuser Panels
You need to remove the side clips carefully; they are somewhat sharp and made of aluminum, so they can cut you or bend if you are too forceful. Wear gloves if necessary.
The three panels are, in order from closer to the metal frame -> closer to the outside: 1. reflective white sheet 2. plexiglass plate 3. light diffuser / softener plate
You will be cutting these three panels, plus the metal back and the side clips, down to size. Set any other parts aside. Do not cut the LED bar or front clip.
Step 4. Mark Out the Cuts
A) Mark the side clips closer to the back end, about a couple inches away from the LED bar clip slots. This will improve overall strength of the diffuser assembly vs having all cuts in the same location.
B) Mark the metal plate towards the front end (the end with the stop against which the diffuser plates abutt) but a couple inches back from the very front; this should help the larger piece support the weight of the diffuser assembly during installation.
C) Mark the diffuser panels at the front end (the end without filleted corners) as the fillets are needed for the LED bar clips, and the front end will be partially covered by the front cover, hiding any imperfections.
I planned to cut 3″ out of all the pieces in order to leave a bit of leeway in my installation.
Step 5. Cut and Clean Up the Side Clips
These pieces can be cut with a rotary tool, a metal circular saw blade, or hacksaw.
Cleanup of the cut ends is important as large gaps will be clearly visible when light leaks between the two pieces. It will also prevent excessive scratching of or catching on the diffuser plates during re-assembly.
Step 6. Cut and Clean Up the Metal Plate
Mark the metal plate for cutting. I found that I got good results from using the excised middle section from one of the side clips as a ruler to mark the cut size here. You will probably end up with the metal plate a little shorter than the plexiglass plate if you do so; as long as they’re within 1/8″ or so this is fine.
I found the front edge cover to make a handy straight edge for marking the various plates as its lower lip is straight and smooth, and as long or longer than the width of the various plates. If you do so, perhaps use a dry erase marker (or have a strong solvent on hand) so that you can clean pen marks off of the lip after using the cover thusly.
I cut this plate with a circular saw designed for light metal; a rotary tool or hacksaw would probably work but with my saw guide I get very straight cuts. Beware of flying metal slivers and wear eye protection!
After cutting, clean up the two edges that have been cut and set the excised section aside. The two matched edges don’t need to make a precise fit but they should be parallel and burr free. Sorry, no pics of the cut metal plate as I got interrupted here; just the complete set of cut parts and LED bar components:
Step 7. Cut and Clean Up the Plastic Diffuser Plates
The reflective white plastic sheet, the thinnest of the plates, can be cut with scissors but I recommend using a utility knife and a straight edge to cut it cleanly.
I tried the score-and-break method on the second diffuser plate and the results were awful. I had chips, shards, and rough sections everywhere (see below). The results using my metal circular saw blade were much better, so I would strongly recommend that approach for both the plexiglass and diffuser plates. They both cut cleanly with a circular saw.
The center plexiglass plate should be a little longer than the other two plates, so that its back edge makes clean contact with the LED bar. If this is not the case, trim the other two plates as necessary. As long as they are within ~1/8″ of the same lengths, it should be fine.
N.B.: If you should accidentally break the plexiglass or diffuser plates, it is relatively simple to shape patches out of discarded material after cutting, and superglue works very well with these materials.
Step 8. Reassemble the Diffuser
You may wish to prepare by cleaning both sides of the plexiglass and diffuser plates with window cleaning solution, as I’ve noticed that fingerprints between the two show up clearly when the light is turned on.
Start reassembly by stacking the diffuser plates in order: – diffuser plate (bottom, glossy face down) – plexiglass (middle) – white sheet (top)
The filleted corners should be mostly aligned, and the back edges should be about even (ideally with the central plexiglass plate protruding very slightly).
Place the two parts of the metal plate on top, with the filleted corners aligned and the front edges of the diffuser plates up against the wall of the front part.
(pic shows side clip attached, please ignore)
Aligning the front edge of one longer side clip piece with the lip of the front metal plate piece, try to sandwich both metal plates and all three diffuser plates within the clip. Make sure that plate alignments stay mostly correct — they can be adjusted later.
I found the easiest way to get each clip on was:
1. Ensuring that the “fat” side was up, slide the “skinny” side under the plates at an angle. The clip piece should be long enough to touch both parts of the top metal plate at once. At this point the clip piece should be rotated ~45 degrees longitudinally compared to the plates; the traction ridges will make it hard to press the clip straight on.
2. While holding the various plates together, lift the whole contraption up until all plates are resting on the opposite side from the clip, and the opening of the clip is facing down toward your work surface.
3. While pressing “up” on the “skinny” side (applying pressure from the diffuser side toward the metal plate side) try to rotate the clip until it is properly seated. This takes a little practice but once you get it the first time, the rest are relatively easy.
Once one clip is on, repeat the process with the three other pieces. They should all go on with the “fat” side on the metal plate side, and the “skinny” side on the diffuser plate side.
The smaller back pieces of the side clips should protrude a bit past the back edge of the metal plate, so that the cut holes in the sides align with the fillets cut into the various plates:
Step 9. Test Fit of LED Bar and Front Clip
At this point I found it useful to test fit the LED bar’s clips against the rear of the diffuser assembly, by alternately putting one side tab into its slot and making sure it seated correctly. Don’t do both or you will have to partly disassemble the side clips!
Also try placing the front clip into position. At this point there is no pressure holding it in place, but make sure that the side clips are not too far forward or back, and that they are both fully seated and don’t stick out much past the end of the front clip.
If any clip piece is too far out of position, try sliding it into place by finger pressure or, in the worst case, tapping with a rubber or wooden mallet.
Step 11. Test LED Bar
At this point it’s a good idea to plug the LED bar into the driver and, using a paired remote or the physical switch, make sure that all the LEDs light and the switches work, etc. It wouldn’t do to mod and install the light only for the LEDs to not work!
Step 10. Finish Installation Per IKEA IRSTA Instruction Sheet
Follow the instruction sheet from here.
Note: once all the screws are in place, it may be much more difficult to install the front clip than during test fitting. One approach is to get one end in place, and then gently tap the rest of the clip into position using the handle of a hammer and a rubber mallet. I used this method on both my installations and it worked quite well.
How long and how much did it cost?
$0 on top of the cost of the IKEA IRSTA LED lights, which were something like $212 including the two panels, driver, and remote.
What do you like most about the hack?
I didn’t have to return anything, and now I have exactly the lights that I wanted.
What was the hardest part about this hack?
Fixing the IKEA IRSTA diffuser panel that I partially broke while trying the scoring method on it.
What to pay special attention to?
Keeping all the cuts straight and near the same size.
Looking back, would you have done it differently?
I would have worn nitrile gloves during reassembly, to avoid fingerprint oil between the diffuser sheet and the plexiglass sheet.