[ARTICLE] Build your own UV exposure box

[mixos]

Ever wondered to have your own UV exposure box to be able to develop your pcb at home? Read this guide that explains you how to build a professional UV box with digital timer and a total light power of 19,2 W.

You can find the guide here: http://www.electronics-lab.com/articles/uv_box_fluo/index.html

[dsantos]

The diagram of UV exposure box not indicate the part number of
transistors.
---
Los transistores de la caja de exposicion de UV no tiene numero de
parte,
podrian darme el numero y tipo ?

dsantos

[mixos]

The transistors are general purpose PNP transistors.
You can use:

BC556 or BC557 --> Download Datasheet

[pfrost65]

Hi,
Can I use a single 36w ballast to drive two 10w UV tubes or does the power rating of the ballast have to be exact i.e 20w.

Paul

[crazy_azz_mat]

for the 5V/1A power supply for the timer i noticed that it has an input voltage of 220V. Im assuming this is a Euro based tutorial so if i was just to change the transformer from a Input 220V output 5v/1a to a 120 in and 5v/1a out it still would be the same yes? Also the UV Lights where am i likely to find them? The lights are regular black light uv lights right?

[Alun]

Yes you'll be ok if you use a 120V transformer as long as you use a 120V balast to power the tubes too, and you might have to change the tube circuit to suit your ballast it should come with a manual that should give you the correct circuit.

Warning!
The tubes used in this project emmit the wrong wavelength to be usefull for developing PCBs. The G15T8 tube emmits UVC radiation at 253.7nm  (which is also very harmful to your eyes and skin) this is great for erasing EPROMS and killing germs but it's not good for exposing PCBs.

For this you need a blacklight which has a peak emmision of 365nm in the UVA part of the UV spectrum and is fairly safe. These tubes are either dark violet/black or white when unlit, the white ones should emmit a sky blue colour and the violet/black ones emmit a deep violet/blue colour when lit. The germicidal one used in this project is made of quatz and is transparent so has no phosphor on it. A blacklight has a special phosphor coating that converts the UVC in to UVA.

In general it's ok to use the tubes form insect killers or those violet ones seen in clubs that make your clothes glow. Avoid any un-coloured transparent or rock hunting tubes (these will apear violet when lit and unlit but will be transparent and won't make white paper glow). A UVA tube will be marked BL or BLB so a BL15T8 or F15BLB-T8 will be perfect for this project.

UVC is not very good because it will be absorbed by the traceing paper or transparent plastic film you place the artwork on, it is also blocked by glass and most plastics. It will work to some extent as the UVC lamps do emmit some UVA radiation but it will be no where near as good or safe as UVA lamps.

[Kate MOSfet]

Hi! I'm up to constracting a similar UV exposure box in order to print photos with the cyanotype method and other alternative printing methods. My problem is that I need to use UV emitting lamps(Phillips Cleo Fluorescent) of 40W and I don't want to use a ballast for each single lamp. Is it possible to follow your diagram and use a ballast of 80W for each two lamps or this would be a problem? Thanks in advance

[Alun]

Yes you can providing the lamps and ballast have the right rating, often you'll see a diagram for two 40W lamps on the datasheet for an 80W ballest.

[Alun]

Could you please modify this  article to include the correction I've posted above?

[ivanrancic]

hi
i was wondering can i use comon fluo tubes used in homes and ofices
becouse in my country its hard to find special ones?

[Alun]

They still havn't corrected it, oh well perhapps an email to mixos might help.

ivanrancicm,
You could always try one but I don't think it'll be very effective, surely you can get hold of the UVA tubes used in insect killers - they're the best ones to use by far.

[ivanrancic]

i tried with 4 tubes, 10 cm above board for about 10 min and it works
thanks for advice it helpd me       

[Alun]

Just out of interest which tubes did you use in the end? Ordinary or UVA insect killer tubes like I suggested?

[ivanrancic]

i used Ordinary 18w tubes