Dave’s How-To Corner: Making A Combination Light Box/Drawing Table

In episode 7, Ian and I were talking about Dad skills and putting together Ikea furniture. Along those lines we also talked about a combination drawing table/lightbox that I’d made and I promised to put some of the process pictures up here on the website.

When I started to make the table, I looked online for help with the lightbox – particularly with the electrical – but I could find very little advice or technical details. In the end, I had to make it up as I went along. Of course I made some mistakes as I went, particularly in the electrical end of things (O! short circuits!), but I wanted to share what I’d learned so that anyone else out there who wanted to do this could do this. Even if you just want to build yourself a light box, there’s lots of information here.

The main incentive to making a new table was that I already had a base and wouldn’t have to build one. Quite a while ago, a friend had given me the base of some sort of antique table. I think it may have even been used in an architectural office, but I’m not sure. The incentive to building a new light box was that my old one had been made by me when I was nineteen and was very dimly lit and very difficult to use. In fact, each time I wanted to use it I had to lift up the glass to switch on the light. Very inconvenient! Tracing and re-tracing my drawings is a big part of how I draw. I also ink straight onto a sheets of bristol from the pencilled roughs taped on the underside. So having a nice, bright light box was important.

Well, let’s begin at the beginning shall we? It’s often the best place to start (unless you’re a Quentin Tarantino movie).

I started out with a sheet of 19mm (3/4″) maple plywood. You can see how  beautiful it was with that lovely grain pattern. I used my original drawing table as a template for the width, and the length of the table base as a guide to the length of the table top. Although you can see a table saw on the left side of the picture, I prefer to do my cutting with a circular saw and a straightedge. It’s so difficult to control the cutting of heavy plywood sheets on the tablesaw. On the right of the picture, you can see one of the legs of the table base (not yet painted) and in the back of picture, a bookcase (upside down) that I was making for my youngest daughter’s room.

I had a partial sheet of 13mm (1/2″) plywood that I was able to use for the bottom panel of the light box. I trimmed it to size on the table saw and then cut it to length with my panel cutting jig. I always to prefer to work around a pre-cut piece rather than rely on my shaky math skills. With the bottom piece cut it was simple to figure out the correct measurements for the light box sides.

Here is the cut panel bottom – ready for primer and paint.

Next, I set up the table saw for the final cutting to size of the light box sides. Although the circular saw does a fine job cutting up the big sheets of plywood, I prefer to use the saw to do the fine tuning.

Two sides cut to final size – waiting for the dado saw. (And there’s my daughter’s bookcase, still waiting for paint. It was my plan to paint the inside of the light box and the bookcase white at the same time.)

The light box sides are ready to be rabbeted. The rabbet helps to make the glue up stronger. This can be easily done with a router, but I prefer to use a dado blade with the table saw. Although looking at this picture, I realize that there’s a lot of set up involved!

Here is a close up of the rabbeting. You can see how the rabbeting increases the gluing surface. No matter how many screws or nails you add to a piece of furniture, it’s the glue that really holds it together.

All the light box sides, cut, rabbeted and ready for primer and paint. See? Things are really cooking! (Hey, wake up in the back!)

I’m using a belt clamp to glue the light box. You can see the brad nailer sitting nearby, but it’s all about the glue, baby!

The light box is finished! (Mostly) The bottom can’t actually be attached yet, but it makes you feel like you’re making progress when you put it all together.

Here is the table top cut to final width and length. The next step is to cut a hole for the lightbox. You can see the router with a straight bit and a straightedge ready for work.

The hole is cut. I didn’t take a picture, unfortunately, but using a straightedge and some wooden pieces clamped to the table, I created a frame and simply cut out the hole in several passes, making the cut deeper each time. (Man, look at that mess on the floor. A project of any sort usually involves more and more chaos with me.)

Here is the light box attached to the table top and painted. Using the same method as I did with the hole, I also routed an inset around the edge of the box so the glass top can sit level with the drawing surface. You can see I used masking tape to protect the table top from the paint. (Remember to burnish it well – a spoon works – if you use this technique.)

Here are the three crosspieces needed to make the table top more rigid and to help make it a tilting table.

I made a little sanding jig to use my belt sander to round off the corners of the crosspieces. I don’t think it had any functional purpose, it just looked purty. I suppose a person is less likely to bang their leg on the rounded corners though.

I saw this when I went to our local hardware store. There are drivers and then there are pick up truck drivers. What dickheads!

Anyway, in order to attach the crosspieces to the table it was necessary to countersink the screw holes. This took some measuring because I didn’t want the screws coming too far out of the bottom and coming up through the top of the table. That would be “screwing up”. As I said before, the screws are important, but glue is even more important. Unless you plan to take it apart later, always use glue when constructing furniture.

I flipped the table top upside-down to dry fit the crosspieces. Once again, it’s easier to make adjustments to fit the actual, physical object rather than try (and fail) to do some complicated math.

Here is another view of the crosspieces. You can see that I attached the light box to the underside of the table with maple cleats secured with screws and glue.

These are the table supports that will allow the table to be tilted at a variety of angles. I’ve cut them, rounded both ends and now I’m drilling the holes the dowel will go through with a Forstner bit. For uniformity, I taped the three supports together while I did all this.

Now the supports are in place, bolted to the crosspiece. I hadn’t drilled the holes through the apron yet (yes, that’s what it’s called). To do this, I tilted the table up and centred the first hole at both ends of the table, clamping it in place. Then I drilled the holes (much easier that way). It seems I didn’t get a picture of the finished underside. I had to cut, paint and install two extra pieces for the centre support to attach to.

In order to cover the laminated edges of the plywood, I added some maple banding. I could have used a veneer tape, which is very thin – almost paper thin – wood that can be ironed-on to the plywood edging. The advantage of the maple banding though is that it provides extra stability, and with the length and weight of the table, that’s exactly what I needed. Because the wood had a pronounced arch, you can see I had to weigh it down with two heavy piles of Mojo magazine. That magazine is heavy!

I’ve sanded the entire table top (and covered everything else with a fine layer of sawdust). Sorry this post is so long, but we’re getting near the end…

…and possibly to the part everyone was waiting for: wiring the lightbox! Here are all the light fixtures and the bottom of the lightbox painted white.

And here are the fixtures, all in place and ready for wiring.

The first step is to use these little plastic doohickeys (I can’t remember their actual name), which prevent the wires from being frayed by the sharp metal edges of the light fixtures and catastrophically shorting out.

Next, using 14-2 gauge electrical wire, I make the first connection. This is a very simple wiring job with only one switch and the power coming through the switch – even I can do this job! White connects to white, black connects to black and green (ground) connects to the bare copper wire.

You do the same thing for each of the fixtures, You can see here that I have the wire stripped and ready to insert into the next light.

And now I’ve finished wiring each of the fixtures together. The only difference after the first fixture is wired is each of the next four fixtures need a wire bringing the power in from its neighbour and another wire taking that power out to the next light. The final fixture that I wired (but the first fixture in the circuit) has a wire going out to the switch. Here is a close up of the connections:

As you can see, the pattern is repeated – only with an extra wire: white connects to white, black connects to black and green (ground) connects to ground. In electrical parlance, black is “hot” and white is “neutral”. Remember that electricity travels in a “circuit”. So the black wire conducts the electricity to the power point and the white wire carries that electrical charge back to the source.

Once all the wiring was finished, I carefully tucked all the wiring back inside the fixtures and replaced the covers. Looks nice and neat now, doesn’t it?

While I was doing the wiring, I also added a clear coat polyurethane finish to the table. Shiny!

Here is another shot of the finished table top. I ended up doing four coats of polyurethane because I wanted a rugged finish. Look at that beautiful grain!

Once the table top was varnished, I could finish the wiring and hook up the switch. To bring in power to the switch from an electrical outlet, I bought an extension cord and cut off the “female” end, leaving the “male” end to plug into the wall. Unhelpfully, the extension cord did not mark the wires as white and black, but it’s actually completely arbitrary which is which. The colours are a way of organizing electrical systems. However, arbitrary it may be, once you settle that a wire is “black” (hot) or “white” (neutral), it has to stay that way or the system will short circuit and all you’ll do is blow a fuse. So, you hook up your wires as follows: The black from your light fixtures is connected to the light switch. The “black” from your electrical source is also connected to your light switch. The two white wires, the white wire from the lights and the “white” wire from the outlet, are connected together – separate from the switch (see photo). Finally, the grounds are attached together. There will be three of these wires: one from the lights, one from the power source and one connected to the switch box, where it does the actual grounding. The wiring is finished!

The plexiglass, which I had custom-made for me at a local glass shop, fits perfectly into the cut out for it. (It fit perfectly because I had the plexiglass made before I cut out the inset and traced the shape of the glass onto the board around the box.) The ten fluorescent lights throw a lot of light. I can easily trace a light pencil drawing onto my favourite sheet of bristol. My only regret is that I didn’t get actual glass. The heat from the lamps is beginning to warp the plexiglass (it’s also a pretty big, unsupported piece, so that doesn’t help).

I’m finally finished! The support pieces can be seen in place – actually supporting the table (notice the piece of dowel through the table apron). The table is quite long, but I had the space for it and I love having the large work area. I’ve learned while using it that I need some stoppers on the bottom of the table to keep papers and work tools from falling on the floor. One of these years I may even add them. You can see my old Staedtler art table behind. My parents gave me that when I was in high school so I was a little sad to be moving on, but the new one is such an improvement.

Finally in place. A gigantic drawing surface and a huge lightbox. What more could I want?

Well, I hope this wasn’t too long. Personally, I’m fascinated by process posts and love to read these things. If you have any questions or would like to share some links to your own drawing table or light box building posts, please feel free to write in the comments section below. I’d love to hear from you!