Fan in a UV box
I am building a UV light box according to the specs on http://www.eepjon.com/ubldit.htm
There they mention the need for a fan while on http://unblinkingeye.com/Articles/UVBox/uvbox.html Ed shows a box without a fan.
Do you have a fan in your box and if so, where did you get it? I'm trying to find one locally as I already have ALL of the other materials here. I just don't want to cut the plywood without knowing the size of the fan before I begin.
you have to have a fan Jeremy, otherwise it gets too hot and it burns the ballasts. I have one on mine. OTOH I dont know why you go through all the hassle when you can buy a plate maker on e bay for about the same price it costs to build the UV box.
I've been looking for a platemaker on ebay for about 2 months, but can't find one close enough to go check out beforehand as they all appeared to be heavily used.
Also, I figure the UV Box will last longer as I know where to cheaply replace the bulbs--finally, I just like building things :)
Jeremy, i got my fan from grainger.com
the edwards engineering notes list part numbers i think. Search for those on grainger's site.
I have two 4 inch fans I picked up through a computer parts catalog, one pulls air in and the other pushes the air out, I'm not sure if this is the right way to do it but when I got the first one I realized it didn't move as much air as Id like and after putting the other on I feel a bit better about it. I paid 12.00 each, you could try radioshack as well.
Aren't plate burners really really big? Much bigger than a UV box?
computer muffin fans should do the trick
When I built my UV box I installed a 4 inch fan I bought at Radio Shack and it has worked for years and years of printing. One thing to consider if you're building a hinged box, ie the bulbs are in a box hinged to a vacuum frame, is to place the ballasts with a fan in a separate box since they comprise the vast amount of weight in the box. That makes the part you have to lift much lighter. Unfortunately, I thought of it after I built it.
Consider, too, the type of bulbs you install which should be specific to the process. As reported in many online groups, Pt/Pd prefers higher nanometers (nm) than other processes. Many people and books recommend your typical "black light" bulbs which generate most of their light around 360nm while Super Actinics output a narrow spectrum near 415nm which results in faster print times for Pt/Pd. A friend of mine who prints with POP compared her UV lights (black lights) to mine (SA's) and found mine printed faster and with a small, but appreciated increase in contrast. I don"t know other processes and what spectrum they prefer, but maybe others on this group do.
I built mine without a fan, and I don't appear to need one. Mine is small, for 8x10 and 11x14 prints, with 8 closely spaced 18" BL bulbs. Even after an hour exposure (OK so my negs are bullet proof:D) the box is only warm, not hot. I painted the entire inside of the box with aluminum paint, so it's highly reflective, maybe that keeps some of the heat down. Perhaps if I made the big box with 12 24" bulbs I might consider a fan, as well as moving the ballasts further away from the bulbs, with a reflective barrier in between.
I'm looking into mouting the ballasts in a separate container from the bulbs to keep down on heat. It's been raining so much here in Texas that I haven't been able to cut down the wood yet--it's too large to cut in the garage with all of the crap in there.
The box will use 12 24" bulbs and 6 ballasts. This way I can do prints up to and including 16x20. I did do 2 cyanotypes in the sun today from the porch to avoid the rain. My only frame is 16x20 and I put both 8x10 sheets in there--perfect contact. I didn't notice any sharpness issues at all. My frame was made by David Kennedy.