Discuss the different types of equipment needed for screen printing. Topics include manual screen printing presses, automatic presses, dryers, folding machines, starter kits and high end machines.
Ive been using the same emulsion for a couple months now. Mostly been kept in my garage but spent some time in my fridge as well. I suspect that its going bad because the last couple exposures I've done I cannot wash the image out. I am suspecting the emulsion of going bad? Because its like 110 in arizona and thought that may affect it. Does emulsion go bad gradually or all at once?
BTW- I am using the speedball greenstuff you get at the art store, not any kind of professional stuff.
We had some CCI dual cure diazo plastisol emulsion turn into a gel from sitting in our shop for several weeks in 90 degree+ weather. We keep all emulsion in the air conditioned office now. We also find that our screens expose themselves if left coated in hot/humid weather for more than a few days.
Diazos and Dual Cures crap out in about 30 days. Photopolymers last a year or more. I had a bucket of Autosol ONE for two years and still worked perfectly.
Diazos and Dual Cures crap out in about 30 days. Photopolymers last a year or more. I had a bucket of Autosol ONE for two years and still worked perfectly.
Our diazos and dual cures last about 2 months max.
That seems about right. I went and got some new stuff today and make a couple screens. The emulsion fell off like butter when I sprayed them. Oh I love when that happens
ok, but after 6-7 months or however long... how do you know when it goes bad? does it happen gradually? do you need to expose longer until it just doesn't work any more?
I just did an exposure for 80 minutes with 500 watt halogen?? I'm trying to figure out where and how to get 100 watt metal halide today.
I buy new ever 6-7 months and just toss the old. I only buy a quart at a time so I'm never throwing out much.
Not sure about the exposing time and bulb?
Maybe start over and do:
1) Buy or build a exposing box (tons of posts on building)
2) Get some emulsion from a screen printing supply house (they can help with exposing does and don'ts) Some suggested in this thread good.
3) Get a step-wedge exposure calculator Checkout this link, it also goes thru the process.
Use pure photopolymer emulsions like Ulano QTX, Saati Textil PV and others that have a shelf life of 1 year or longer.
I had a gallon of Autosol One that lasted well over a year and a half.
I was assuming we are all talking about after the emulsion is "activated". Most emulsions will last more that a year on the shelf ("stored in a cool dry place"). Tpitman, Do these emulsions last 1 1/2 yrs after activation?
I was assuming we are all talking about after the emulsion is "activated". Most emulsions will last more that a year on the shelf ("stored in a cool dry place"). Tpitman, Do these emulsions last 1 1/2 yrs after activation?
The pure photopolymers come premixed. You don't add the diazo. The downside to them is they're more expensive, and their exposure window is a lot tighter, but then you don't throw any away, and they're very fast exposing.
For the money, the best I'd ever found was Saati Textil PV. I currently use Ulano QX-1, which is a hybrid. Not as fast as the others, but works with solvent inks, and to some degree with waterbased. The Saati Textil PV, the QTX, and others generally hold up poorly to waterbased inks. They're pretty much plastisol only.
Thanks for the info! These emulsions you describe sound perfect for folks doing custom work and have short deadlines or a need to produce a lot of screens on a on going bases.
We only do our on line here. We only shoot screens a few times a year. That's why we only buy a quart at a time. We try and shoot all the screens we need for our designs with the fresh emulsion. That's probably why we've never looked much beyond the Duel Cure....
How long does emulsion last before going bad? 
