Purpose of this Guide
This screen printing t-shirt guide will illustrate how to screen print on a t-shirt with minimal tools using card stock as the light blocking stencil. If you have ever tried ordering a few custom printed t-shirts from your local screen printer, you will find that the price is expensive. The reason being that it takes a lot of manual labour to set up the job to enable the screen printer to print your 2 or 3 t-shirts. Material cost is not a major factor in the cost equation. You can save yourself a lot of money and enjoy the thrill and satisfaction of your project coming to life by Doing It Yourself DIY. Screen printing t-shirts is not hard, you just need to follow these simple instructions. Please note that this guide is not an indication of how a professional screen printer would do the job. This screen printing guide is written to minimise the equipment needed for the hobby screen printer who wants to print a few t-shirts.
Step 1: Collect the Equipment
Things You Will Need:
A screen. Dual cure emulsion/ Water resistant emulsion. Squeegee to coat screen with emulsion and to print. A flat piece of glass or clear plastic. Water base textile printing ink. Masking tape. Cutting blade or pair of scissors. Card stock for blocking Ultraviolet UV light. Black cloth for wrapping screen during transport. You can get these items from Gumtree, Ebay or Craiglist for cheap. There are many hobby screen printers who sell their used equipment on these sites regularly. Just be patient and keep checking, eventually, a kit will come up for sale at reasonable prices. There is no need to buy new and pay two or three times the cost.
Step 2: Prepare the Artwork
Start off with a simple design for the first project. I have decided to go with the "DIY PRO" design in Machine font. I have chosen Machine font because all the edges are straight lines which enables me to cut out the shapes from cardboard easily with a blade and ruler. There is no need to keep to straight lines in your designs, whatever shape you can cut out from card stock with a pair of scissors will work with this method. The pieces of cardboard will be used as the stencil - Ultra Violet UV light blocking stencil. Cut out the holes first from letters like A and O. Followed by the letters.
If you have an inkjet printer or laser printer which can print onto clear transparency, use that. Home printers do not have the right settings or a dense enough black ink to make perfect stencils. The solution is to print two copies and stick them together. Print stencil the right way and the other mirrored. Then stick them together so that that ink side is facing each other. Do not print them both the same way and stick them one on top of the other, if you do this undercutting will occur. Helpful guidelines on preparing artwork for screen printing can be found on an earlier blog post on artwork requirements for custom t-shirts printing .
Step 3: Prepare the Screens
Wash the screens thoroughly with a cleaner like Windex. Wash the complete screen, frame and mesh. If there is dust on the frame, it can work its way into the mesh when we coat it with photo polymer emulsion causing pin holes in the completed screen. Dust particles block Ultra Violet UV light just like our cut out card stock. There will be spurious holes and ink will be printed through these holes, ruining our print. Leave the screens to dry. Use a hair dryer to speed up the process if necessary. Keep the hair dryer about 15 cm from the mesh whilst constantly moving it side to side and up and down.
After the screen is dry inspect the mesh for dust particles. Take the screen a place where there is no direct sunlight. We have to work in a Ultra-Violet UV free zone. Fluorescent lighting or any home standard lighting is acceptable. There is no need to work under red lights like for photo developing. Note that Sunlight is practically the best source of UV light, so even indirect sunlight needs to be avoided.
Now it is time coat the screen with photopolymer emulsion. If you have a scoop coater, by all means use that. If not, repurpose the printing squeegee as a makeshift scoop coater. Spread the emulsion on one side of the squeegee evenly along the edge. Put on enough so that there is enough to coat the screen in one stroke. Stand to the side and hold the screen firmly at an angle on the floor and start from the bottom pulling upwards. First hold the squeegee for little while at the bottom of the stroke so that emulsion flows to the screen from the squeegee blade then while gently pushing the squeegee blade against the screen mesh pull the squeegee upwards at an angle to the top of the screen frame. Do this one time from the outside of the screen (the side facing the t-shirt while printing), then one or two more times from the inside of the screen (side where you put your ink in). Remember outside first, then inside. Not the other way around because you want the emulsion to be sitting on the outside of the screen. If you are using coarse mesh eg 42T or 100 threads per inch mesh, one coating on each side is sufficient. The t-shirt side of the screen should be glistening. If you have used a squeegee, you will notice that emulsion will have run off the edge of the squeegee, forming a very thick deposit of emulsion. Use a piece of card stock to scoop off the excess emulsion from the edges - both sides.
There are two main types of emulsion. Those which need diazo added which makes them water resistant for water based inks and those which do not, for plastisol inks. As a beginner it is better to start off with water based inks as it is easier to wash up and you can dry with an iron and hair dryer. plastisol ink will require chemicals to clean up and proper screen printing equipment to cure via a conveyor dryer or flash dryer. You will make a mess of it the first few times. Accept this. Just wash out with water, dry and start again. Practice makes perfect. When you have an even coating of emulsion, it’s time to dry the screen. Use the hair dryer again. 15cm away from the screen moving constantly to prevent overheating. If you burn the emulsion by overheating, the overheated areas will not wash out. You can see the emulsion changing when it dries, from a shiny coating it becomes a matt finish. After a few minutes it will be dry to touch, dry a little longer for insurance.
Step 4: Exposing the Screen to Sunlight
Stick the cut out card stock on the ink side of the scree. Use the master cardstock from which all the little letters were cut out as a guide for lining up the letters. Remove the main piece of cardstock and inspect for alignment and spacing of letters. When everything is lined up properly, hair dry from the t-shirt side if you have used glue.
Now it is time to expose the screen to UV light. Sunlight is one of the best sources of UV light. Better than halogen lights and even better than most professional metal halide exposure lights. The problem is reliability. As a professional screen printer you cannot afford to take a day off just because it is a rainy day. Place the clear piece of glass of plastic onto the cardstock. Ensure it has not shifted the letters. Wrap the whole apparatus in one piece of black material and take out into sunlight. Wrap it in such a manner that when unwrapped, the ink side of the screen is sitting on the black material. We still want the black material behind the screen so that it absorbs the sunlight and prevents it from bouncing back up and curing the inside of the screen. Leave in sunlight from 3 to 6 minutes. The time it takes to expose the photopolymer emulsion depends on whether it is a sunny or cloudy day. The time of the year also matters, there is more UV radiation in summer due to the angle of the earth facing the sun. Exposure time should vary between 3 to 6 minutes. When the time is up, quickly wrap the screen up again and take indoors.
Step 5: Washing Out Screens and Taping Up
Wet the screen both sides and leave for 3 to 5 minutes. Spray water every minute or so. You will see the stencil developing almost instantly. The parts of the screen exposed to sunlight will not change in appearance. The parts blocked by cardstock will become milky. After 5 minutes pressure wash the screen.
If the whole screen becomes slimy and you wash out parts of your design, you have under exposed the emulsion. You need to increase the sunlight exposure time. If the design does not wash out or is very difficult to wash out - parts of the design with fine artwork are blocked, you have over exposed the screen. If the screen is under exposed, it can still be salvaged. Wash out the details very gently with running water and a soft sponge. Brush very softly. Pad dry with newsprint. Blow dry and take it out to the sun for a second round of exposure. If the screen is over exposed there is not much you can do to recover it. Sometimes you can use really high pressure thorough a pressure washer. A suggestion is to take notes for future reference. Write down the time of the year, whether it is a sunny or cloudy day, the temperature and humidity and of course the exposure time. Higher humidity will increase the exposure time. Higher temperature will decrease the exposure time. A bright sunny day will decrease the exposure time. Summer will decrease the exposure time and Winter will increase it. If you have two screens, you can sacrifice one to get a ball park figure of the exposure time required on that particular day. Expose for 4 minutes with the sacrificial screen to see how it washes out. Then with the good screen use the adjusted exposure time. Dry with hair dryer and tape up the ink side of the screen with masking tape. Now you are ready to print your first t-shirt.
Step 6: Printing the Design
For this project I have used Permaset water based inks. It is a professional quality screen printing ink used by many commercial screen printers in Australia. Other good brands available around the world are Matsui and Virus. Just visit your local art shop for advice. If you have bought your screen printing kit second hand, it will usually come with some water based ink.
Find a way to secure the screen so that when you push or pull the squeegee for the final print, the screen does not move. If you have picked up a screen printing jig that is ideal but if you have not you can just park the screen firmly against a firm surface when printing. Print with one or two strokes for dark coloured ink onto light coloured garment. If you need more than two strokes, you have done something wrong along with way. Perhaps not loaded enough ink into the screen, not back flooded after the previous print leading to caking or simply working too slow so the ink has dried up. If you push too much ink into the t-shirt, the ink can spread under the stencil and your next print will be muddy. Printing more than one stroke can also result in the ink seeping into the other side of the t-shirt, thus ruining your t-shirt. Each stroke needs to be in the same direction. If you are pulling the squeegee on the print stroke, you need to also pull on the second stroke. Do not push on the second stroke. Also try to keep the squeegee angle the same if doing multiple strokes. Things to remember when printing with water based inks. Water based inks dry quickly so you need to work fast. Set up everything before you put ink onto the screen from the tub. Collect the apparel that needs printing. Work out a rough idea of where you need to place the screen on each garment. Work out a place to leave the screen with ink on it between prints etc. Back flooding after every print is essential for water based inks. After every print, you need to remove the screen from the t-shirt and gently spread the ink over the exposed areas of the screen. We need to keep the exposed areas filled with ink so that ink does not dry out and block the stencil. So the procedure is to print with a single stroke, lift the screen from the t-shirt, back flood with ink and then reload with another t-shirt. If you do not back flood, after a few prints the dried ink will block some of the holes in the mesh and your prints will be ruined. Work fast and back flood. Always print on test pieces of scrap material before attempting to print onto good t-shirts. Be prepared to have 10 failed prints before your first good one. Yes I know it all looks so easy on Youtube or when your friend does it. It is not difficult, you just need experience. Always have a piece of spare cloth lying around for wiping away excess ink on fingers, clothes, hair, squeegees, screens etc. As a beginner ink will get everywhere but on the t-shirt.
Step 7: Drying the Print
Water based inks need to be heat set after all the water has been expelled to ensure a durable print. After printing you can hang dry the t-shirt or speed it up with a hair dryer. Hang drying is not enough - it needs to be heat set afterwards. Once it is touch dry you can place a baking sheet over the printed area and iron over the print to heat set it. Final cure only occurs after all the moisture has been expelled so you need to keep ironing for a little while longer even if you don't see any steam escaping from under the baking sheet. Some hobby screen printers have had success utilising a tumble dryer for final cure, others have used a heat press which should work much quicker.
Wash the t-shirt. If the print comes out looking like it did when you put it into the washer, you have a properly cured garment. Congratulations.
Step 8: Final Words
Screen printing your own t-shirts can be a very frustrating process when things go wrong. When you start off, everything and anything will go wrong and you will be wondering why you even bothered to attempt it, we have all been there. On the other hand it can also be a very rewarding process. Nothing feels better than wearing a t-shirt that you have designed and printed from scratch. A t-shirt which is one of a kind which will last you many years of wear. If you have printed the t-shirts for a group, there is the opportunity to save a lot of money. The cost of screen printing is mostly due to the labour involved, not the cost of materials which is very little. For this project material set up costs are approximately $3, cardstock costs less than $1, emulsion $2. Ink will cost approximately 50c per print. Blank t-shirts cost $3-5. Imagine the cost savings compared to ordering from a screen printing shop.
Screen printing is all about your mindset. Work slowly and carefully. Experiment. Take notes. Troubleshoot. Then you will succeed in your t-shirt screen printing endeavours.