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Its 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. Or, as I write this, airports could be shut down due to too much snow! What this means for us as 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 your emulsions chemistry you can see a number of different results when opening your container. I touched base with Ross Balfour of Saati to help fill in the details.
1: Recognize that all emulsions will freeze. It's what happens when they thaw out that will let you know if its gone bad.
2: Emulsions that have gone bad, when thawed, have one of the following characteristics.
a: It may gell into a rubber ball or have a thick rubbery consistency that is difficult to break apart.
b: It may separate into different layers and when mixed. It will not stay mixed together. It will re-separate out and look like it did before.
c: It may feel and look grainy. There will be tiny clumps that will allow you to coat your screen but the emulsion will NOT crosslink. If you feel this is what your emulsion did and you need confirmation - coat a single screen and see if it will properly expose.
3: While uncommon - If you are using a dual cure or adding diazo, you may also see your diazo is no longer a fine powder and has turned pretty 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 your 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. Then test with a single screen to ensure the emulsion has not gone bad.
As for stencil remover, during the freezing process, the active ingredients can crystalize and you may notice crystals at the bottom of your container. If you do, warm it up to room temperature and give it a good shake until the crystals are re-dissolved into the rest of the solution.
So, taking all this into consideration, you want to plan your order placing so your supplies are on a delivery truck for as little time as possible. If you can, don't place your 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. This is when we see the great majority of issues with emulsion and stencil remover.
Thanks for reading Screen Printers!
Both emulsion and emulsion removers can and will freeze. Most emulsions are not Freeze/Thaw stable. Depending on your emulsions chemistry you can see a number of different results when opening your container. I touched base with Ross Balfour of Saati to help fill in the details.
1: Recognize that all emulsions will freeze. It's what happens when they thaw out that will let you know if its gone bad.
2: Emulsions that have gone bad, when thawed, have one of the following characteristics.
a: It may gell into a rubber ball or have a thick rubbery consistency that is difficult to break apart.
b: It may separate into different layers and when mixed. It will not stay mixed together. It will re-separate out and look like it did before.
c: It may feel and look grainy. There will be tiny clumps that will allow you to coat your screen but the emulsion will NOT crosslink. If you feel this is what your emulsion did and you need confirmation - coat a single screen and see if it will properly expose.
3: While uncommon - If you are using a dual cure or adding diazo, you may also see your diazo is no longer a fine powder and has turned pretty 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 your 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. Then test with a single screen to ensure the emulsion has not gone bad.
As for stencil remover, during the freezing process, the active ingredients can crystalize and you may notice crystals at the bottom of your container. If you do, warm it up to room temperature and give it a good shake until the crystals are re-dissolved into the rest of the solution.
So, taking all this into consideration, you want to plan your order placing so your supplies are on a delivery truck for as little time as possible. If you can, don't place your 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. This is when we see the great majority of issues with emulsion and stencil remover.
Thanks for reading Screen Printers!