Screen printing is an art form that requires the proper tools to create quality screen printing is an art form that requires the proper tools to create quality prints. Exposure units are one of the most important pieces in screen printing.
This DIY Screen Printing Exposure Unit guide will answer common questions about exposure units and provide product reviews, so you can find the right unit for your needs!
- Materials for Exposure Units
- DIY Cheap screen printing exposure unit
- Compression vs. Vacuum Exposure Units
Building your own exposure unit is relatively easy with the right instructions. The process of making an exposure unit will depend on how large you want it, along with where you get your light source from (fluorescent tubes work best).
What materials do you need to build a screen printing exposure unit?
Screen printing exposure units can be as simple or complex as you’d like them to be. The materials needed will vary based on the project and how much screen time needs to happen. Common items that should always be included are:
- Exposure unit box (cardboard, wood, etc.)
- Black electrical tape
- Plexiglass/UV blocking material for the top window
- UV lights (fluorescent bulbs work best) – Optional but recommended if using florescent tubes; use two T12 lamps at least 24″ long with a wavelength of 366nm for best results
Timer for DIY screen printing exposure unit
A timer is used to ensure that the exposure unit runs for exactly as long as needed. It’s important not to over-expose screens because this could cause the screen mesh to break down permanently, which would require purchasing a new one.
Timer lights can vary in price depending on how many features you need them to have (i.e., different time settings).
I currently use an inexpensive mechanical one with only two buttons: “on” and “off.” This works well since all I’m concerned about is having it turn off automatically when my exposures are finished! What kind of light source do you need?
What’s my exposure time?
Exposure units use different wattage light bulbs that emit specific wavelengths. In general, the higher the wattage of a bulb, the shorter its exposure time should be. The most common types used for screen printing are:
- T12 UV fluorescent tubes – these work well and have been around for years!
- UVC black lights – cheaper but not as effective as fluorescents so generally only recommended if on a budget or doing smaller jobs
How long do I expose my screens?
The amount of time you leave your screen exposed to light depends on how powerful your lighting source is. Fluorescent tube exposures typically range from 15 seconds up to 30 minutes depending on what kind of material will be printed onto it (fabric vs. paper).
DIY Cheap Unit for Screen Printing
To build this screen printing exposure box, cut a window in the top half of one side of the cardboard box and install plexiglass or another type of transparent material that blocks UVA rays but still lets visible light through.
Use black electrical tape around all sides except for two small holes at opposite ends to pass lights into the box. These will be used as “light traps” so that no stray UV wavelengths can enter when not emitting any visible
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My experience in creating a DIY exposure unit
Basically, this box is built with two-by-four frames. I got some pieces of wood on the outside to enclose it. If you, just need to make sure that the box, this box is 24 inches square.
And, I think that’s probably about 10 inches deep, but you want to measure your fixture so that you’ve got two inches of, the distance between the fluorescent tubes and the glass. So whatever depth that is, that you need for your fixtures and your tubes and plus two inches.
So that’s basically, the outside, I’ve got cords running in. I just drilled a hole. I’ve got my cords running in for my, fixtures that I plug into a timer.
The glass I got from a glass company, it’s a quarter-inch tempered glass it’s safety glass. So if it shatters it, won’t shatter into, um, sharp, pieces of glass. And I also had them babble the edges so that it’s not sharp. So make sure that it’s, unfiltered, tempered, plate glass.
The tubes look like regular 24-inch fluorescent tubes, but they’re a special black light tube. I ordered these especially from, a lighting supply in my area. You can order these online and these tubes at, right around 12 or $13 each.
Six tubes, you wire them together on the plug so that when you plug them in, you fire the whole thing. The other thing that I put in here, and you’ll see these here are two regular lamps with just compact fluorescent lights.
I use compact fluorescents. You can get them at any department store because they don’t produce a lot of heat.
If I want to clean up artwork or trace artwork, It backlights it. And then I can trace the artwork to create, to recreate the artwork for burning screens.
So that works out pretty well. You don’t need to do that, but I wanted to make a kind of dual duty.
Compression vs. Vacuum Exposure Units
The majority of commercial printers use compression or vacuum exposure units. These work by placing the screen on top of a rubber bladder that’s attached to an air pump, which causes pressure from below so your design can transfer easily onto the mesh.
The advantage of these systems is they remove all oxygen from around the emulsion and leave you with flawless prints every time!
Vacuum exposure units are different in that they suck out all oxygen instead of using pressure, but this also means it isn’t as effective since air always has some amount of gases floating around.
If you’re purchasing a new system I would recommend going with either compression or manual hand-pump unless you know there will be times when you’ll need a vacuum exposure unit.
WHAT IS A VACUUM EXPOSURE UNIT?
Vacuum exposure units are the most popular type of screen printing exposure unit on the market. They work by placing a piece of glass on top of an airtight rubber bladder, which is then attached to an industrial-sized vacuum pump that sucks all oxygen out from underneath and around your mesh (which allows for perfect transfers every time).
This system also gives you much more control over how long your screens stay under UV light because you can use a timer or pressurized bulb changer if needed.
Depending on where you live, commercial-grade systems like these range in price but average about $500-$2000 (not including any bulbs/timer/etc.).
WHAT IS A COMPRESSION EXPOSURE UNIT?
Compression exposure units use pressure instead of a vacuum to push your screen down onto the emulsion and remove all oxygen.
This leads to less consistent prints but they’re typically far more affordable than their vacuum counterparts at about $200-$800 (not including any bulbs/timer).
If you do decide on this type, I would recommend purchasing one with an air compressor since it gives you much more control over how long your screens stay under UV light.
What is the best exposure unit for my screen printing business?
There are a lot of great DIY exposure units out there, but if you’re looking for something that will last and is compatible with most screen printing inks then I would recommend purchasing either the Mighty Bulb Changer or T-Rex Exposure Unit.
Both have been around since the beginning of screen printing so they’ve had plenty of time to work out kinks and perfect their systems.
T12 – these work well and have been around for years!
UVC Black Lights – cheaper but not as effective as fluorescents so generally only recommended if on a budget or doing smaller jobs
The amount of time you leave your screen exposed to light depends on how powerful your lighting source is.
Fluorescent tube exposures typically range from 15 seconds up to 30 minutes depending on what kind of material will be printed onto it (fabric vs. paper).
Compression or vacuum exposure units are the most popular type of screen printing exposure unit on the market.
They work by placing a piece of glass on top of an airtight rubber bladder, which is then attached to an industrial-sized vacuum pump that sucks all oxygen out from underneath and around your mesh (which allows for perfect transfers every time).
Vacuum exposure units are different in that they suck out all oxygen instead of using pressure, but this also means it isn’t.