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screen printing => Screen Making => Topic started by: ScreenPrinter123 on October 20, 2014, 09:33:47 AM
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We keep our Aquasol HV in a refrigerator and every time we need to coat screens the emulsion requires mixing due to separation. This then causes a bazillion little air bubbles and you know what happens if you try to coat a screen when the emulsion in your scoop coater is full of air bubbles, especially when you only do a 1+1 coating method.
Anyone have any suggestions on how to attack this poblem?
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don't put it in the fridge...we stopped doing that a long time ago
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It's been a long time since I mixed diazo into emulsion, but the instructions to let it sit for an hour to debubble would probably apply here as well.
Now, do you keep it in the fridge to thicken it, or to prolong its life?
Life on those photopolymer emulsions is pretty damn good with normal storage.
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unless youre adding diazo, that stuff will last forever at normal room temp or even warmer.
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We were keeping it in the fridge to prolong it but have also enjoyed coating with it thicker. For those who keep it at normal room temp do you have to mix it before coating?
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i will stir emulsion a little bit if it's separated, but for the most part it's good to go.
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light/quick stir. Don't actually mix it.
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light/quick stir. Don't actually mix it.
Yep, this
Most of the time I grab it by the handles and twirl it in a circular motion, this tends to get the stuff from the side into the middle & give it little mix without causing air bubbles.
Murphy37
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Thanks!
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light/quick stir. Don't actually mix it.
Yep, this
Most of the time I grab it by the handles and twirl it in a circular motion, this tends to get the stuff from the side into the middle & give it little mix without causing air bubbles.
Murphy37
I do this with the twisting but while holding the sides...with the lid still on. Had a handle pop out on me before.
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light/quick stir. Don't actually mix it.
Yep, this
Most of the time I grab it by the handles and twirl it in a circular motion, this tends to get the stuff from the side into the middle & give it little mix without causing air bubbles.
Murphy37
I do this with the twisting but while holding the sides...with the lid still on. Had a handle pop out on me before.
Lol.that would suck.
Murphy37
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Avoid the refirgeration part. As long as the room it is in is 80 or less there will be no issues with diazo added to HVP.
Putting it in the fridg as mentioned really thickens the viscosity but more importantly everytime you take it out and put it back in will cause condensation on the inside of the bucket. When the emulsion gets down to 1/4 of bucket it will more diluted than a bucket stored outside the fridg.
If no diazo is added don't worry about shelf life. It will have a shelf life of a year and can withstand temps in the low 100's with no ill effects.
Al
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We were keeping it in the fridge to prolong it but have also enjoyed coating with it thicker. For those who keep it at normal room temp do you have to mix it before coating?
not as a rule. A gallon of emulsion only last a couple of days here, so no on the refrigeration as well. If I'm remembering correctly from when we did not use so much, it was good for at least a couple of weeks, never got past that point. However, we did little water based work, and the Ulano 925-WR didn't like hanging around for a couple of months without turning into cottage cheese...
Steve