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Care and feeding of Emulsion?

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ZooCity:
Does anyone else notice that when you get toward the bottom of a gallon of high-solids emulsion you get all kinds of nasty little chunks on the screens?  I wound up tossing nearly a quart out of my last gallon of Aquasol HV because of this. 

I buy our emulsion parsed out into gallons every time, even though I buy by the five gallon (actually I think Westar sells me four gallons at a time, which is easier to ship in a box probably) to prevent this but I'm starting to see it happen more in the gallon buckets.  And it's been unseasonably humid around here lately.  I keep our emulsion in a temp stable spot, away from sunlight, often in an old cooler actually so I don't think that's the issue.  I even wipe the insides of the bucket lightly with a damp rag to keep any chunkies from crudding up along the walls of the container and getting into the scoop coater.

My thought was to pickup a bunch of the black vapor lock quart containers, open the fresh bucket, stir the living hell out of it and then fill and seal the quarts.  Bonus would be, if you weighed them out properly,  you could add diazo to a single quart at a time if needed without dedicating a whole gallon. 

It must be that I'm evaporating off enough of the water in the emulsion that, by the time you get near the bottom of the bucket, it's partially drying. 

Anyone have a fix for this?

mk162:
never had that problem, but couldn't you strain it back into a newer gallon?

Frog:

--- Quote from: mk162 on June 16, 2011, 02:17:12 PM ---never had that problem, but couldn't you strain it back into a newer gallon?

--- End quote ---

That could get messy.
When we used varnish die-stamping inks, we would have to strain through cheese cloth.
Would probably work for this.

ebscreen:
Zoo, yes I have run into this. I store emulsion in a nice shady spot too, and still the bottom
of gallons get gnarly. Usually end up chucking the last pint or so. I think you're on track with
the evaporation idea, pretty sure that's the only way it could happen. Makes sense to, as it seems
worse on the high solids emulsions.

One trick I have with waterbased inks is to put a couple drops of water on the surface of the ink
before closing the lid. Not sure how that would work with emulsions though, wouldn't want
to introduce new variables.

What I'm looking for is 5 gallon pails of emulsion with pour spouts on the bottom. One way air
vent on top. Anyone make these?

Colin:
What I found to be my problem was the emulsion on the sides and top of the container would dry out inbetween the times I needed to coat screens.  The longer the time between , sometimes as long as a week, I'd see more dry particles/chunks under the lid edge and on the sides.  These would usually get stirred back in if the person pouring the emulsion was not paying attention.  Conversely, the quicker I went through a container, the fewer chunks I would see. 

It became a habit of mine to always peel away dried emulsion when I found it.  As a result, I found fewer chuncks in my scoop coater at the end of the gallon.

If you have the oportunity, you can store the opened emulsion in a refridgerator.  That will slow down the drying/evaporation.

A side note: I always stored my un-opened emulsion containers upside down to make it easier to stir the solids back in when it had been sitting for a month or so (I'd always buy two at a time or pour off from a 5 gallon depending). 

Hope this helps.

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