What do you mean by locked emulsion in screen printing? Locked Emulsion in screen printing means the emulsion gets dried and sticks hard to the mesh, which becomes difficult to remove. And unless you remove it, you can’t use the screen further.
Screen lock is one of the frequent problems faced by screen printers. You are trying to reclaim a screen, and when you put it in the wash booth or pressure washer and reclaim it, the emulsion won’t come out. It’s not working. The screen is not reclaiming. If that’s happening to you, even the pressure washer is giving you a hard time. So, what should you do in that case?
Steps to Remove Locked Emulsion:
To remove locked emulsion in screen printing, follow the step-by-step procedure below:
1. High-pressure water:
You can use high-pressure water to remove stencils. You can use an outdoor car wash.
High pressure may remove the hardened stencil from the mesh. It certainly helps if you have a tight mesh that resists high water pressure.
2. Use Household bleach:
Use bleach that is used in the water pool. Not the scented bleach used for laundry.
Pour or spray the bleach solution and rub it with a scrub brush. No real deep scrubbing is necessary. Let the bleach stay for 30 seconds to 1 minute. Don’t let it dry out else; it could lock the screen again.
Then use a high water pressure or a car wash to melt away the stencils. In this way, you can reclaim screens without any issue.
3. Finally, cut out the mesh:
If you left the emulsion remover to dry on the screen, even the hard water pressure wouldn’t break the lock screen.
The only option left is to cut out the mesh from the frame using a razor blade. You can take the frame to someone who can re-mesh it or buy a new set at half of the cost.
02 Important Reasons for Locked Emulsion in Screen Printing:
Screen lock can happen due to making the stencil much more difficult to remove to actually being unable to be removed at all. Reasons for locked emulsion in screen printing as follows:
1. Underexposing Screens causes Locked Emulsion:
What is why sometimes emulsion gets permanently locked into the mesh, which you cannot reclaim? Screen lock is happening due to a couple of reasons that emulsion can harden prominently. The most common reason is that you are underexposing the emulsion to get your stencil off.
When you dry the screen and wash the stencil out and again dry the screen, the emulsion is still somewhat underexposed. That is to say, and it is not fully cured.
What happens is that when you go on press and start working, the chemicals like ink, solvents, etc., will absorb the emulsion or vice versa. Due to your emulsion being under-cured, it absorbs other chemicals.
So, when you work using a screen underexposed, you are basically putting these chemicals onto the emulsion. And, likely, the emulsion becomes prominently hardened, and you will be unable to reclaim/remove it.
2. Drying of Reclaimer Solution:
The other prevalent reason for the emulsion to become screen locked into the mesh is when you reclaim the screen, you go to the wash booth and spray some reclaimer on it. And for some reason, you walk away from the wash booth.
As a result, it allows the chemicals and reclaimer to dry on the emulsion before you reclaim it with a pressure washer. Well, that will most definitely cause a screen lock.
02 Methods to Prevent Locked Emulsion in Screen Printing:
Lastly, prevention is better than cure. Follow the steps below to prevent locked emulsion in screen printing.
1. Don’t underexpose of screens.
If you do underexpose, you can try to post-cure the emulsion. Some emulsions may not be responsive to post-curing. But you can do it on your exposure table, take your screen to the wash booth, apply water pressure and let it dry.
And before you go for press, just put it back in the exposure unit. You can also put in the sunlight in your backyard to dry. These steps will fully cure the emulsion. So when you go to press, it’s not going to absorb any chemicals.
2. Wash the reclaimed immediately:
And most importantly, don’t spray the reclaimer onto your screen and walk away from it. Therefore, these are some of the most common ways to prevent screen lock.