UV Exposure Box

Introduction

uv_exposure_box_sketch The South Africa trip in the end of 2013 was basically what started all of this as mentioned earlier. The mbira was a reason to build an amplifier and the amplifier was the reason to build an UV exposure box. Buying the circuit boards would have been a lot cheaper but far from as much fun.

The material used is the same wooden board as the biltong box was made from. This was probably not the best material to build it from and it might very well happen that it will be rebuilt in MDF or something similar in the future. There are tons of instructions on how to do these online but whatever, let’s get started!

The picture shows an initial sketch of what the box will look like. There are two chambers, one to the left with two flourescent UV lights in it and one to the right where all the starters and the reactor will go. On the lid there’s a foamy material pressing down against the glass over the lights.

What’s Needed?

The UV chamber has been designed to be as small as possible. The lights should be separated by at least 4.5 cm and it should be at least the same distance from the lights to the glass. This and the 12 mm thing boards gives the dimensions below. Yep, metric system again, it’s the only thing that makes sense really.

uv_exposure_box_partsA: Front + back (27×9.5 cm)
B: 2 sides (31×9.5 cm)
C: Bottom (24.6×31 cm)
D: Divider (31×8.3 cm)
E: Lid (33.4×27 cm)

Glass (17.3×31.5 cm)

 

2 flourescent UV lights for circuit board etching
4 flourescent light holders
2 holders for flourescent light starters
2 starters
1 flourescent light reactor
Cables
Reflective material (i.e. tin foil)
Some kind of foamy material

A bunch of tools

Building the Box

uv_exposure_box_assembly_01So this is basically what it’ll look like in the end. There will be a side to the far right as well.

 

uv_exposure_box_assembly_02If you have a wood router, use it! Or even go buy one. Seriously. It’s worth it! Without it you have to improvise, like with one of these Japanese hand saws. You should definitely get one of those anyway, they’re great!

 

uv_exposure_box_assembly_03A Dremel was used to make the tracks wide enough for the glass.

 

uv_exposure_box_assembly_04I can’t tell you too many times, get a wood router! This would have been a matter of minutes instead of hours!

 

uv_exposure_box_assembly_05The cables will be hidden inside of the bottom of the box. Once again that wood router would have come in handy. Get one!

The black spots doesn’t serve any purpose, it was just to try the paint.

 

uv_exposure_box_assembly_06This is where the glass goes.

 

uv_exposure_box_assembly_07The inside of the UV chamber should be covered in a reflective material. Tin foil can be used but in this case a sound dampening material covered with a heat reflecting aluminum film was used. The film could be removed and cut to fit in the UV chamber. It was simply attached using double-sided tape under the glass on both sides. The holders for the lights keep it in place as well.

 

uv_exposure_box_assembly_08Attach the aluminum film so that it creates rounded corners in the bottom.

 

Cut out and attach the film to the sides of the chamber as well.

 

uv_exposure_box_assembly_11The holders and the cables are in place.

 

uv_exposure_box_assembly_10The front of the box has been nailed to the bottom (mind the cables) and the sides of the chamber. The back will be fastened using screws so the box can be opened easily.

 

The sound dampening material (2 cm thick foamy material) covered with the aluminum foil will cover the inside of the lid. The glass is about 1 cm down into the box so that when the lid is closed it is compressed and presses the copper clad board and the pattern against it.

 

uv_exposure_box_assembly_13The back attached to the rest of the box.

 

This is a great way to cover up any gaps between the sides. Mix sawdust and wood glue and fill it. Once it has dried you can sandpaper it and it won’t be visible (at least not after painting it).

 

uv_exposure_box_assembly_19The screws for attaching the hinge for the lid has to be short to not damage the glass. Lacking short ones it was time to improvise again.

 

uv_exposure_box_assembly_15That’s about the right length.

 

uv_exposure_box_assembly_16Once again it’s time to use the Japanese saw. Yes!

 

uv_exposure_box_assembly_17Use a chisel to cut out room for the hinges.

 

uv_exposure_box_assembly_18The hinges and lid in place.

 

uv_exposure_box_assembly_20The back of the box is screwed to the rest to make it easy to open it.

 

uv_exposure_box_assembly_21The right side (not adjacent to the UV chamber) is attached to the back using screws but…

 

uv_exposure_box_assembly_22…the front is attached using dowels, once again to make it easy to open the box. Just unscrew the back and the side can easily be removed.

 

uv_exposure_box_assembly_23All the components in place. By installing them this way there is more room for power cables etc. on top of them under the lid later.

 
uv_exposure_box_assembly_25A power switch and connector for a power cable was added to the box as well.
 

uv_exposure_box_assembly_24And here’s the final result. Oh, right, there’s a lock to keep the lid and the foamy sound proofing material pressed down against the glass. The back of it is adhesive so it was just to cut it to the right size, put it on the glass with the adhesive side up and close the lid for it to end up in the right place.

uv_exposure_box_assembly_26 One more thing, add pieces like these to a few places in the right chamber. Make them a little taller than all the components and cut out and put a thin board on top to…
uv_exposure_box_assembly_27…create a perfect storage space for power cables, extra fuses etc. Yes, there’s still some more painting to do.
There are ideas on how to improve this box in the future so it might very well be a continuation to all this…