As a designer, Stefan Fahrngruber of SFA understands how nice it is to have a light table. I can attest to how nice they are when picking out tiny vinyl cut shapes after plotting. Unfortunately, light tables can be hard to come by inexpensively, and difficult to make. Sure, you can put a light under a glass table, but it doesn’t always work well, the light isn’t distributed evenly, and can still be expensive if you don’t already own a glass table.
Stefan designed a light table that you can make for under $80 using standard decorative LED strips. The idea is to arrange them in a small grid which gives off even lighting while also keeping the construction of the table lightweight. You’ll also have the ability to dim the lights and change the colors.
The table is made with an A3 tempered glass cutting mat, size 16.5″ x 11.7″. Stefan writes that you’ll also need:
-LED strip approximately 10 feet long. Make sure to pick one which generates the light out of one LED surface, really cheap ones use three separate LED’s to mix the light, which doesn’t work at close distances. Also make sure the control unit of the LED strip fits in the box, and the strip is able to be arranged to fit inside your box.
-5 foot LED strip connection wire (those are special wires with four color coded lines in the right distance, you can also buy ready made ones but they are rather expensive)
-2m of wooden rectangular profile in 5x30mm and 5x35mm (actually you can go crazy on the box, I tried to build it as slim and light as possible)
-One aluminum plate 2.5mm thick, 490x310mm (the stronger the plate the better the heat is derived, this has to be metal, believe me!)
-One milky acrylic glass plate (5mm strong, 450x300mm) make sure to plan a gap so the glass falls in place easy. Make the glass at least 5mm so it can support your weight while drawing on it. Thicker is an option, it will make the light more diffused but also weakens the brightness.
-Glue or paste to fix the wooden profiles (fitting the edges with a mitre is nice but more advanced, up to you)
-Small screws to fix the baseplate to the frame.
-Four rubber feet
2 thoughts on “How To: Building A Light Table Under $80”
A better view of how the bottom plate is mounted would be helpful. Also, letting us know what LED units were used would give a good starting place for picking one for our own projects. Not everyone is familiar with all the possible LED assembly styles available and their methods of interconnection. By the way, what is acrylic glass? Is it plastic, glass, or some combination of the two.
I’m not sure why she says it is acrylic. Earlier it says, “A3 tempered glass cutting mat”. That is clearly not acrylic.
I think she means Lexan or high end plexiglass.
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I hate to be a terminology nerd for the sake of simply correct another’s post, but I think I might be able to help clear up some of confusion concerning the usage of the term “acrylic glass.”
To my knowledge, “Plexiglass” is simply one of several brand names (Lucite and Perspex are others) of a thermoplastic generically referred to in the US as “acrylic”. In the past, the prevailing generic term for the material was “acrylic glass.” This may currently be the casein other regions. As the designer of the light table is Austrian, this might explain the use of that term.
If you give the article a re-read, it’s clear that the “A3 tempered glass cutting mat” and the acrylic are 2 separate components. Tempered glass cutting mats are, well, cutting mats made of tempered glass. This component is the top of the light table/box on which you will directly place your work. A3 simply refers to the size (the entire world except North America uses the ISO paper size system). I’d guess it’s necessary to find a transparent cutting mat; the “milky” white translucent acrylic piece goes below and diffuses the LEDs’ output.
To nerd out a bit further, “Lexan” is a brand name of another thermoplastic, generically referred to as polycarbonate. It’s often sold in sheets similar to acrylic/plexiglass, but is far more impact resistant (it’s what’s used for bullet proof glass in bank branches and similar). It’s more expensive than acrylic, heavier, and contains BPA and produces toxic chemicals when burned (when cut by laser or even by machining).
I would disagree that it’s hard to get light tables inexpensively. There a plenty of decent light boxes for way under $80. Check out Porta-Trace / Gagne light boxes. How much is your time worth? If it’s in the satisfaction of reinventing the wheel, go ahead.
I just recently made light-up hopscotch and did a lot of research on consistency of light. You can not only get cheaper than $80, but you can get a more consistent light buy using a 0.25″ clear acrylic that is laser etched (your local maker space can help if you don’t own one) with a moiré pattern that is denser in the middle than the edges. Simply use the RGB lights around the edge to side light the acrylic. You’ll also want to add high brightness paper under the glass to help reflect (not tin-foil or meta) any light that hits the bottom. Once you have that, you put a thin 3mm milky acrylic on-top and it simply glows. This would save you 10 of those LED strips. I hope to make an instructables of it soon too:
I stuck a fluorescent bulb in a discarded flatbed scanner.
Was going to make one to use as a white light trans illuminator, but tablets have great apps which give uniform edge to edge illuminators. Am using the “Lightbox” app on a nexus 7. Great RGB colors and really bright light.
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