It's that time of year again. There is a bite to the air, frost on your car windows, there might even be a dusting of snow outside your front door. What this means for screen printers is that we need to make sure our work spaces stay warm and we are conscious of both what we order and WHEN we order it.
Both emulsion and emulsion removers can and will freeze. Most emulsions are not freeze/thaw stable. Depending on the emulsion's chemistry, you can see a number of different results when opening the container. Ross Balfour of Saati shared four facts you need to know about emulsion in the winter.
Photo by Golden Press Studio.
1 — Recognize that all emulsions will freeze. It's what happens when they thaw out that will let you know if it has gone bad.
2 — Emulsions that have gone bad, when thawed, have one of the following characteristics:
3 — If you are using a dual cure or adding diazo, you may also see the diazo is no longer a fine powder and has turned solid. While this can happen even if it hasn't frozen, during freezing and warming the bottle could have some moisture condense within the bottle. If this is the case, the diazo has gone bad and you will need a new bottle.
4 — If you think the emulsion may be safe, mix it together until its a smooth consistency and wait 3-4 hours to see it the emulsion settles out or feels a little grainy. Test with a single screen to ensure the emulsion has not gone bad.
Don't forget about emulsion remover. While it freezes, the active ingredients can crystalize, sinking to the bottom of the container. If the emulsion remover has crystalized, warm it up to room temperature and give it a good shake until the crystals are re-dissolved into the rest of the solution.
Taking all this into consideration, you want to plan your order accordingly so supplies are on a delivery truck for as little time as possible. If you can, don't place an order so that items ship over a weekend as it will sit in an unheated warehouse or on a truck for extended periods of time. The majority of issues with emulsion and emulsion remover happen when they sit in the cold for extended periods of time. As soon as an order arrives, bring it into a warm space as soon as possible.
Hopefully this article has given you a better understanding of handling emulsion in the winter. In the end, it's best to be proactive about stocking up on emulsion before winter hits. Think ahead and you'll save money and yourself from a headache.