Fan in a UV box

Jeremy · Jun 17, 2004

I am building a UV light box according to the specs on Dead Link Removed

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.

Jorge · Jun 17, 2004

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.

Jeremy · Jun 17, 2004

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

andrewfrith · Jun 17, 2004

fan

Jeremy, i got my fan from grainger.com
the edwards engineering notes list part numbers i think. Search for those on grainger's site.

regards
-andrew

shinn · Jun 17, 2004

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.

Happy Days

mark · Jun 17, 2004

Aren't plate burners really really big? Much bigger than a UV box?

lee · Jun 17, 2004

computer muffin fans should do the trick

lee\c

wmlaven · Jun 17, 2004

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.

Good luck.

Deckled Edge · Jun 19, 2004

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) 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.

Jeremy · Jun 19, 2004

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.

sanking · Jun 19, 2004

Jeremy Moore said:
I am building a UV light box according to the specs on Dead Link Removed

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 really need a fan in the box. If you don't have one the bulbs will heat up during exposure and light output will fall dramatically, to less than 40-50% of output when the bulbs are kept cool with a fan. You can not see this with your eyes but if you have light integrator the fall-off in output is dramatic.

Regarding Bill's comment about the BL and SA tubes my testing has consistently shown that the BL tubes print slightly faster than the SAs. But many people agree with Bill's finding and as far as I can determine opinion appears to be about equally divided as to which bulb prints faster. However, there is a slight difference in contrast in the mid-tones between the two lights that results from more belly in the curve of BL prints. This information will be found in the appendix I did for the new edition of Dick Arentz' book on platinum printing which should be out in a few months.

However, if your intention is to print both Pd/Pd and one of the dichromate colloid processes there is no questio but that the BL tubes is overall much better.

Sandy King

Jeremy · Jun 20, 2004

There is definitely going to be a fan in the box. I'm actually thinking of putting in two as Shinn suggested. One on the left (when looking at the box) to suck air in and one on the right to suck it out.

Jorge · Jun 20, 2004

Jeremy Moore said:
There is definitely going to be a fan in the box. I'm actually thinking of putting in two as Shinn suggested. One on the left (when looking at the box) to suck air in and one on the right to suck it out.

Suck in, suck out grasshopper.....oush...

Fan in a UV box

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