Inexpensive and (Relatively) Simple Box for a Laser

The goal of this box was to create a fume hood that was a fairly simple design, but especially that did not require a lot of tools or hardware. Of especial concern was the requirement for big cuts on wood. I could do a lot with an 8×4 sheet of plywood, but don’t want to have to cut anything.

Also, I kind-of already started this project.

I purchased an inexpensive laser and put it on a 2’ x 2’, 3/4” plywood project-board from Home Depot. It is a perfect fit, with little room to spare, but it adds a lot of weight.

Works nicely, however, you really shouldn’t run a laser without evacuating the fumes. You could, but your family might complain or think the house is on fire, if you are using wood. Other materials can create toxic fumes. Or not. Make sure you look up information on whatever material you are experimenting with, if you have not already done that.

Materials

Having started with the 2×2 project board, it needed sides, and eventually a lid, to become a box. I wanted them the box to be light, and temporary because the laser spends a fair amount of time perched on a shelf when not in use.

The plywood base weighs 7-8 lbs. itself, and if I were to use the same thick plywood for the walls it would triple in weight, and add it as a lid and you will weigh in at up to 32 pounds. And that is jus the wood; no laser, no fans or filters, etc. That could be fine for a permanent enclosure, but not for our purpose, as we are economizing on space and weight.

So, I want the walls to be light. That means thin. There are a lot of good thin materials out there. Plywood is cheap, and it is very light. Acrylic would be cool, but expensive. So I picked the best 2×2 plywood project board I could, and had someone at Home Depot cut them in half. I now had 4 (mostly/almost) 1′ x 2′ 1/4″ plywood pieces.

Later I discovered some other materials in a different isle. The Birch is way expensive, I am already in $16.50 for the 2 2’x2’s that I have cut in half. But those reversable chalboard/markerboards look nice, too. For $19.80 I could do that instead.

Unfortunately, there is a bit of a design flaw, but I will get to that later.

Design

There were a couple of things I was going for:

• easily assembled/disassembled
• light-weight
• minimal hardware
• off-the-shelf materials (except for the fancy 3d printed part)

In other projects I use a lot of 1/4″ – 20 thread screws and nuts. That is the standard size for camera tripods, and is pretty inexpensive; out of convenience I ran with that.

An easy idea for joining the sides that came to mind was L-brackets to bolt the two sides together. That would work fine, but it would require 2 sets of screws/nuts, and it would require precision holes to be drilled.

I have seen this kerf mount used as a table leg bracket and thought it could work here to hold sides. It turns out to work well, and with the butterfly nuts it is really easy to set up and take apart.

Once I saw that this design would hold the sides together I rounded off the edges, but I quickly learned the design was lacking. You can see in the picture of the assembled v1 corner above, the edges of the plywood are not straight and bow away from each other. Below you can see the bend in the edge on one side.

I am going to need something to fix that. There are lots of options for adding straighteners or stiffeners. An easy method would be to nail a 1’x1′ or something along the side edges. That would straighten it out, and add bulk. It certainly would not stack that well. Same problem if I bolt on some metal straps on the outside.

So I decided I would try incorporating something in the corners. To do this I would need some way for it to be held in to place, as well as the part. What I cam up with was an outer corner piece, with 1/4″ square rods at each end that nested in a similarly shaped divot in the corner piece. Here you can also see where the wood needs to be cleared for the screw to fit through.

The strange W shape is based on the limitations of 3d printing. Angles under 35° do not print very well, and I needed to somehow keep the square rod piece from levitating. This is basically a fat corner that has been sliced diagonally at the center. This gives the rise 45º which would give me a nice clean print.

The corners came together nicely and the sides straightened out.

It only takes a minute to assemble and disassemble, is sturdy and fits well. The edges at the bottom have some small gapes, but with enough ventilation these gaps should be fine letting air in.

Additional Thoughts and Finishing Touches

One thing that is nice is that the design is forgiving as to the thickness of the wood. The black & white revesable panels are a little thinner, but work fine. Or, another step will be to finish the wood, and a coat of paint will add thickness, and it will still fit (within reason).

The corners will also create a rest for a lid/top. I tried using two 1×2 panels, but that was a little unstable. I could make it work. A 2×2 project panel should fit perfectly. I have not figured out my lid, yet, but I will probably make it out of two pieces, hinged so that there is access from the front/top, with the ventilation built in to the top/rear panel.

One thing I do not like is how the boards need to be routed for the bolts in the corner to fit. I could come up with some design that does not mar a 2×1 side panel, but then the corners would not meet.