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| sheltered |
 Posted: Tue Mar 27, 2007 9:14 pm |
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Joined: 16 Sep 2005
Posts: 86
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I've been exposing QTX at home with Halogen lamps sucsessfully for quite sometime now. I have my lamps kind of high to keep the heat down and its a fairly long exposure (13 minutes), but works great for a laser printed positive.
I am starting an screen printing program at the high school where I teach and I scored a Nuarc exposing unit from another school for free. (I was quite proud of myself for repairing the vacuum pump.) I ran some tests and I could not get a screen to expose properly. It seemed like the light is too intense for the laser positives and the image areas were difficult to wash out (1 minute exposure). I never did try like 30 second exposure. It appears that this unit has 4 black light flourescent tubes.
I want to print only water based ink for now. Does anyone use a similar setup?
I guess I should try some short exposures but it seems like I would underexpose the non image areas. Am I wrong? Should I try a different emulsion? I need to use the laser positives and a halogen lamp setup will take far too long for the number of kids I'm facing. (not to mention it would be a waste to leave that Nuarc unit sitting)
Thanks for any advice. |
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| skinny |
| Posted: Tue Mar 27, 2007 9:39 pm |
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Joined: 12 Sep 2004
Posts: 2706
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Light wave....
Each bulb produces its own wave pattern, in the manner it displaces light energy.
Larger high displacement bulbs produce a higher number of dense waves, usually a single bulb.....a high output bulb can burn exposures well but, from a distance.
Multiple tube style exposure untis dispurse multiple bursts of light. Multiple bulb exposure units put light waves closer to, and in more frequency, against exposures....You use them close to the work.
No simple answer, other than test some exposures, and shorten your standard exposure times in consideration of the postion of your new light source. |
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| Fool's Gold |
| Posted: Wed Mar 28, 2007 7:25 am |
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Joined: 10 Mar 2005
Posts: 284
Location: Ontario Canada
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| I used to use QTX and exposed in about 30 seconds with film. Laser positives might also be a problem |
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IRONCLAD GRAPHICS: Custom screen printed posters, apparel and stickers. |
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| sheltered |
| Posted: Wed Mar 28, 2007 5:29 pm |
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Joined: 16 Sep 2005
Posts: 86
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| I'll try cutting way back. Maybe even remove a tube or two. We'll see what happens. |
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| Fool's Gold |
| Posted: Thu Mar 29, 2007 12:55 pm |
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Joined: 10 Mar 2005
Posts: 284
Location: Ontario Canada
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| don't remove any tubes. That wil cause 'cold' spots in your exposure. I never liked QTX, terrible detail and it wouldn't stand up verylong to pressure washer blasting. I switched to QX1 and saved about $3000 a year, never had another problem, and got way more detail then I ever did with QTX. the one advantage to the QX1 with your exposure unit, is that the times are longer so it migth work better with a higher powered light source (I have hear of people shooting QTX in about 4 seconds with crazy 5000w lights) |
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IRONCLAD GRAPHICS: Custom screen printed posters, apparel and stickers. |
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| sheltered |
| Posted: Thu Mar 29, 2007 10:39 pm |
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Joined: 16 Sep 2005
Posts: 86
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Thanks Fools Gold. The QX1 is a dual based emulsion it says and will do UV water based inks. What exactly is a UV water based ink? I really only print plastisol myself, but want to limit the classroom to nothing but waterbased ink.
Have you seen http://www.victoryfactory.com/chemicals.htm ? Those prices look pretty good. |
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| Fool's Gold |
| Posted: Fri Mar 30, 2007 12:01 pm |
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Joined: 10 Mar 2005
Posts: 284
Location: Ontario Canada
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QX1 needs no mixing. It's resistant to plastisol, UV and solvent inks. It will stand up to waterbased decently, but that's not it's main function. Exposure time is about 2x that of QTX. It's fine for waterbased unless you are going to be running hundreds of prints. One trick with waterbased inks is to use lots of tape. Cover as much of the front and back of the screen with tape and leave the ink puddle sitting on that. If the water is allowed to seep into the emulsion, that's when it breaks down. So if the stagnant ink is sitting on a layer of clear tape, then there is no problem. Speedball inks don't seem to effect QX1, but high end inks like TW Graphic will wear it down.
Those prices look OK, I pay $50 Canadian for a gallon of QX1 which is less than the Victory factory page, but if you like online ordering then that is alright. You get so many screens out of a gallon that a few dollars doesn't make a difference. |
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IRONCLAD GRAPHICS: Custom screen printed posters, apparel and stickers. |
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| sheltered |
| Posted: Fri Mar 30, 2007 6:09 pm |
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Joined: 16 Sep 2005
Posts: 86
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| Thanks for the advice. I need to move a lot of kids through the program. I ordered 50 screens today. I'll get some sample and start testing. |
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| ogsk8r |
| Posted: Thu Oct 25, 2007 6:14 pm |
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ORDER OF THE SKULL
Joined: 06 Jan 2006
Posts: 2701
Location: las vegas, nv.
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| can anyone tell me what the best screen mesh would work for printing some high detail work on a deck???? |
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Yea Cornmelia !!!! |
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| burnitdown |
| Posted: Fri Oct 26, 2007 5:42 pm |
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Joined: 31 Jan 2006
Posts: 61
Location: IL
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| everybody seems to like 230. although, i normally have problems pushing ink through it |
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