hello,
i'm hoping some of you more experienced screen printers can give me a hand with some issues i have...

i made my own lighting box (after a model i found online) from combined knowledge i found around the internet (bulb spacing etc).
here's a picture of it: users.skynet.be/bk228346/s...ightbox.jpg
It has 8 unfiltered UV 15 watt blacklights fitted : users.skynet.be/bk228346/s...n/bulb.jpg.
info on the bulbs:
Sylvania
Blacklight
F15W/350BL-T8
UVA LAmp
www.sylvania-lighting.com

the height of the center of the bulbs to the glas on top, is the same distance then the spacing from each other. I read that on this forum that it's important for the spread of the UV.

we reckon we're around 2-3min for the exposure times. But we don't manage to get a screen washed out properly.
we tried both one coats and two coats but nothing helps. The biggest problem is that the exposure times create no consequent result. sometimes parts wash out really well, other times other parts do. It differs and there seems to be no pattern in...
we haven't succesfully been able to completely wash out an entire screen.

we leave our screens to dry for more then 12 hours.
the emulsion we buy from a local screen printer in belgium called "satichem textile HT fast." screens have both 77 and 95 meshes for textile printing(no difference noticeable).

we have played around with a couple of screens before with a similar emulsion and a 500w worklight. We burned the screens for 30ish min and we had a good result then. and used a way more detailed image for it even. Only problem we had was the image was burned into the mesh, and reclaiming the screens was hell.

This time we bough better emulsion, and have way better lighting then a 500w worklight and the result is worse...
here's a picture of the result: users.skynet.be/bk228346/s.../screen.jpg

does anyone have a clue what we're doing wrong perhaps?
thanx very much for any pointers...