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|Screen Print Troubleshooting|
|How do I prevent the ink from clogging in my screen?|
|Water based inks are great because they offer really soft prints and require the least amount of equipment and cleaners to get the job done. Like most standard paints, water based inks air dry in about 10-15 minutes. That being said, once you’ve opened your jar and inked up your screen, technically your ink is already starting to dry! The speed at which it dries though is nothing to be afraid of at all, but there are definitely a few culprits that make this an issue. There are a few things to keep in mind and do while printing that will allow you to have more time and not get clogs in your screen.
MIX YOUR INK!
It may seem like a no brainer but each time you open up an ink new or old you should always give it a stir. The oily bits can separate from the main pigments over time and make for chunky chalky ink that will dry up right when you turn your back. Always mix and keep the jar closed when not using!
WET YOUR SCREEN
Giving a little water to the screen before laying out our ink is the best way to start water based printing. By giving a good solid misting of H2O, the emulsion will be hydrated in all it’s little pockets that hide inside the mesh and won’t pull from the ink to get a drink. As you are printing you can lightly mist occasionally if your ink becomes gummy to keep it fresh!
A standard maneuver while printing is to flood the screen. It may be hard to describe in text, but what you are essentially doing is filling your design/stencil with ink using your squeegee before you actually print. It’s easiest to accomplish when using a press or clamps and for some designs it may not be the right thing to do, just have to do test prints to find out the best way to apply the print.
With a solid grip, pull or push the ink across the screen with just enough force to move the ink but not push through the design. This is a great printing practice to ensure your design is evenly loaded with ink and consistently keeps your ink on the move. Once you’ve flooded then printed, lift your screen part way and flood again for the ink to rest in the stencil while you handle swapping a finished print for a new one. The time in between prints is the most crucial to keep your ink moist so leaving your design filled with ink while you put on another shirt or line up a sheet of paper is the best way of doing that. It seems counter intuitive to fill the stencil when your goal is for it to not dry in the design but actually doing this adds to the whole ink surface area and a big puddle of ink dries much slower than a small dot so it’s the same concept.
USING A FLASH DRYER
If you happen to have a flash dryer and press with only a few stations (1 to 2) you may be having drying issues even though you are doing all of the right things! This is a problem we hear about alllllll the time, and it’s one that can slip right by. If you are flashing your garments on the same platen you are printing on, chances are that platen is getting so dang hot that it’s drying your inks out. Every time you lay down that screen and press the mesh to the shirt laying on that hot platen you are transferring all kinds of heat that is just cooking your inks. You’ll get a chunky gummy consistency and major clogging and usually after just a little while of printing. Our best suggestion is to not cure the shirts till after you are finished printing. Since the water based inks air dry anyway, you can just lay them out in the shop or on a clothesline and comeback and use the flash dryer once you are finished printing and your inks are all cleaned up. This will save you a major headache. If you simply must do it immediately we suggest setting up a cooling fan to cool down your platen in between prints and actually turn down your printing speed a bit. Let the platen cool as often as possible and try to be really sparing with the flash dryer. If doing multicolor water based printing just get the ink barely dry to the touch before moving on to the next color and staying away from that flash dryer as much as possible. final cure can come later either way when it’s not going to affect your printing.
The easiest solution is adding a retarder to your ink. This is a clear additive that once adding no more that 20% will slow the dry time of your water based inks. This is a great fix especially for the inexperienced printer to not be worried about dry times while they get used to printing. The only issue with this is that since you are slowing the dry time of your ink on the screen, it’s also slowing the dry time of the ink drying on the shirt/paper after you’ve printed. You’ll have to wait longer with each print so you may run out of room stacking them around the shop. Also when you do your final heat setting of the shirt, the retarder can affect the curing since it’s an additive that needs to be burned off as well. This all shouldn’t be an issue, but make sure to give a bit extra time to the final heat setting of the item is a good idea.
WATER BASED SCREEN OPENER & INK CLEANER
If you do have some dry issues and clogging occurs, you can try a little water and rubbing the complete area of the screen that’s having an issue. If the water isn’t working for you there are water based aerosol screen openers. The combo of the aerosol pressure and the ink degradant can knock out a clog no problemo, but use sparingly as this combo can also hurt your emulsion! Lastly if you’ve left your screen unattended for a while and find that there are clogs from dried ink, you can try a water based ink cleaner to try and take care of it. It’s less abrasive than the screen opener but should still have the chemical strength to get most dried ink out.
Sometimes you just gotta print in a basement or in Arizona so needless to say it’s HOT. Obviously the heat will be affecting the dry time of your air dry water based inks so keep that in mind. Using the combination of all the things mentioned here will definitely give you a leg up in managing your dry times and not make you wanna tear your hair out.
|What kind of ink do I use for printing paper, cardboard, bags, etc?|
|Flatstock like posters, cardboard, bags, glass etc are probably the easiest to work with and only have one ink type before graduating to the really nasty chemical inks. Waterbased acrylic is the primary ink used and has all the same properties as waterbased fabric ink but reformulated to lay down smoother on non-porous substrates. Acrylic needs to be used on a higher screen mesh since flat stock is less porous than fabric and it’s recommended to use a stiffer squeegee like an 80 Duro as well. Even with higher mesh counts large areas of print can cause paper to buckle from the amount of ink so it’s wise to use a thicker stock paper as well.|
|Which mesh count should I choose?|
|The easiest answer is;
The lower the number, more ink but less detail.
The higher the number, the less ink but higher detail.
The screen mesh is super important in any job you are working on but with so many options and variable it’s sometimes difficult to stray away the few that have worked for you in the past. Other than the initial low and high breakdown there are important things to consider that will affect your choice and can make or break evan an easy print job. Think about ink type, ink color, garment color, design coverage, detail, detail detail. It’s best to first decide if your general choice should be in a high or low realm and then let the other factors push your screen around in that area. On our screen burn page we’ve planted a little skeleton on the right that has examples and notes of the differences in mesh and how to compare your artwork to some ready samples. Below we will throw out some bullet points of quick answers that may raise or lower your mesh choice
Low detail - Low Mesh (110/160)
White Ink or Underbase printing - Low Mesh (110/160/200)
Thick ink like Low Bleed or Opaque - Low Mesh (110/160)
Glitter Ink - Low Mesh (110/160)
Highly textured surface like Canvas - Low Mesh (110/160)
Higher Detail on Dark Garment - Medium Mesh (160/200)
Layers on top of Underbase - Medium Mesh (160/200/230)
Thin Inks - Medium Mesh (200/230)
High Detail - High Mesh (230/280/305)
Non Porous surface like Paper - High Mesh (230/280/305*)
Fine Details Close together - High Mesh (230/280/305*)
Process Printing - Highest Mesh (305)
|Why aren't my screens washing out properly after exposing?|
|Screen burning is definitely an art all on its own. From prepping the art, to degreasing, coating, and burning, each part needs to go well in order to get a final product that can be used before the actual print job even starts. When you get past the coating and drying process and finally burn your screen it’s pretty devastating to only have all the hours spent in vain when your screen won’t wash out or the whole sheet of emulsion just washes down the drain. A number of things can have happened along the way so let’s try and knock them out in order as well as offer a simple tool to keep your time out of the drain too.
It may seem tedious, but screen degreasing is super important to ensure a solid emulsion coat and long life for your screen. Using a simple degreaser, simply wet, scrub and completely wash the screen. Set to dry flat and off the ground in a dry, or dehumidified room till completely devoid of water. This is cleaning any junk that may have been on the screen and primes the mesh to hold on to that emulsion for dear life. We’ve heard people complain of emulsion coming off in a giant sheet from not degreasing the screen and giving that coat something to grab onto. This is especially important for screens that have been reclaimed
So many no-brainers get overlooked in this whole burning process that they need to be mentioned first. It’s like asking if you made sure “it was plugged in” when your iron isn’t working. Emulsion is light sensitive so obviously all activities you do with it need to be handled in a dark room or light safe area. We use ceramic yellow bulbs to give us visibility when working with our emulsion. When using emulsion/diazo combo for any standard two part emulsion be sure to spend some time on the mixing itself. Directions should be on the tub for your specific emulsion, but typically you fill the small Diazo container half with water and slowly mix into the larger emulsion tub. Take special care to scrape the bottom, sides, and any goo that was on the lid. We try and spend at least 10 minutes working the diazo in thoroughly and evenly pouring in parts to ensure it all has been exposed to the chemical. Let the mixed emulsion sit for at least 1 hour to settle. With how much work burning takes, it’s the most annoying to discover that bad emulsion ruined your process way earlier than you realized.
The burning process requires films to be so dark that light is blocked where you want to have ink print through while harding everywhere else on the screen. Printing the films at a high quality needs to be a priority otherwise all the other efforts in burning are useless. When holding up your film If you can see light or make out clear details from behind it your films probably aren’t dark enough.
If you need to outsource something quick and really cheap people often go to copy shops and order a transparency. Usually you will get something that may show up on your elementary school overhead projector, but that’s about it. If that’s your only option then we suggest getting 3 printed and taping them onto of each other to get them as dark as possible. It is difficult to get them perfectly lined up, highly do not recommend if doing half tones , and by the time 3 are stacked up together you have a pretty thick piece of transparency that can cause other problems like edge shadowing.
If you wanna try a home printer it needs to be an inkjet and you can order some nice transparencies to use. Since home printers are set up with CMYK ink cartridges you’ll notice that the other colors are used a lot more than they should be to get a solid black no matter how you adjust the print settings. To get a dark dark film you may need to get a nice printer with an external ink system like what Cobra Ink offers or install the system on your existing printer if possible. Cobra Ink reconfigures standard high quality printers with their external refill system allows you to manually refill the cartridges with all black rather than the Cyan Yellow Magenta that is causing your prints to come out too light. With a nice set up and using all the best print settings you should be able to print super dark films that are able to do the job, but if you are still having trouble we also offer film output services and some educational videos
Different meshes mean larger or smaller holes, so when you applied your emulsion you probably noticed the difference the amount of emulsion that laid out on your screen. Lower ones like a 110 usually have a really thick coating of emulsion which is something to note when burning. The lower the mesh the longer the burn and vice versa for high meshes. Often times people don’t realize and burn all their screens the same time since it’s the same emulsion on every screen but that’s a mistake that can make all the difference in getting those real fine lines to come out crisp and complete.
The last step in the process is the burning itself and choosing the time for your maiden voyage can be tricky. We have an exposure calculator to help get your best first try and hopefully it will be nailed after that. Otherwise you can just guess your times and hope and if it’s wrong you can do it all over again, and again, and again. All those hours. The calculator is simple, just download, print the film, and read the directions. It’s got some important calculations to do but the idea is simple. The Exposure Calculator has 10 rows of the same image of different important line types like text dots, dashes etc. Simply attach the film to the screen like any other film, and cover all but the first row with an opaque paper. Burn for a calculated time determined by the directions like 2 minutes, then move down the opaque paper to expose the second row of the film. Now burn again for another time determined from the calculations, let’s just say 30 seconds, and continue to add 30 seconds for each row until the whole sheet is complete. Now wash out the screen and see which row worked the best and do the final calculations to find your perfect burn time. You’ve basically burned the first row for the longest and the last row for only 30 seconds to find your “burning window”. Things that have burned too long won’t wash out, things that wash out too much haven’t been burned long enough! This is an amazing tool that saves hours and hours of heartache and irritation. Don’t forget that different meshes hold different amounts of emulsion so their burn times vary. Low meshes tend to burn much longer than a high mesh, so when doing the calculator try and do something that’s in the middle. Thank you exposure calculator!!
The lights in most exposure units actually get a little bit weaker every time they're turned on, so if you've tried all of the above it may be time to replace the bulbs. Depending on the quality of the unit and the amount of use it's getting, the lights can actually weaken as quickly as 8 months after replacing them. It’s a problem that can drive you nuts as you tight all the other bolts in the burning process and realize you aren’t doing anything wrong at all! Replacing bulbs can of course get expensive, so you may be better off just adding a little bit more time to your exposures to ensure the screens come out properly.
|Why is my plastisol print fading or cracking after washing?|
|As you probably know plastisol requires a cure temp of 320 degrees to be fully dried and locked onto a garment. This doesn’t mean that as soon as it hits 320 that it’s magically cured, it’s just the temp it needs to start to cook. After doing your first print it’s a wise idea to check and make sure your shirt is properly cured which luckily is really simple without having to wash the garment. Simply grab a portion of the design in two hands with your thumb and forefinger and pull the print and see if it cracks. The plastisol when fully cured should have an elastic quality enough to withstand the “stretch test” and not crack under the strain. If your garment does crack it means that the top layer has dried but the deeper inks aren’t fully cooked. There are a few different ways to ensure your print is nice and cooked for each method of curing so let's go over those.
HEAT GUN - Using heat guns to cure shirts is inexpensive but time consuming and has a lot of room for error. The max temp on one of these can easily scorch a shirt so you definitely need to keep moving while trying to cure. Since it only offers a beam of heat, a grid pattern of cooking needs to be established to make sure you cover every area of the print evenly. Often this is still not enough time to cure since avoiding the scorch doesn’t allow one to hover in an area too long. Chances are the deepest points aren’t getting cured, but an easy way to remedy this is to turn the shirt inside out and cure the underside as well. We recommend getting the print dry to the touch, set it aside, continue printing, then do a full cure later. This way you can avoid heating up your pallet too much which can cook your inks while printing. Check out our FAQ on “Screen Clogging/Ink Clogging” for a more in depth look at ink issues like this.
FLASH DRYER - The flash dryer is going to be a bit easier to cure your garments since it’s a solid block of heat that usually covers your whole design. We use ours when live printing plastisol since it’s pretty efficient and easy to transport. This does have the same problem as the heat gun in that if you are using the same platen to print and cure you may have ink drying issues. Getting the print dry to the touch, setting aside and then doing a final, inside out cure once all other printing is complete is a great way to reach a full cure without complications.
CONVEYOR DRYER - A conveyor dryer with all the bells and whistles will of course be the easiest to get a full cure on a print. With belt speed adjustments and temperature controls you can set you dryer to however high or low your garments will ideally cure at. Sometimes though you either have an old unit or short heating chamber so even with slowed belt speed and higher temps you may not be getting the maximum cure. The first thing you can try is lowering the gates. Some people don’t realize that there are even entrance and exit gates that can be lowered to trap in more heat and just leave them in the position that they came in from the factory. By loosening and lowering these gates to leave just enough room to let the shirt through, you can trap a lot more heat in the heating chamber and hopefully turn your small dryer into a powerful curing machine.
If the doors still don’t do the trick, you can always throw the shirts all through the conveyor a second time and inside out once you’ve completed the other printing. It takes more time than a printer would usually wanna take after spending all the time printing but sometimes it’s just what you gotta do and it’s better than you’re client coming back with a blank shirt.
|Why is my print coming out smudged or bleeding?|
|When you get a screen all unwrapped, prepped and print your first shirt only to lift it up and see a smudged bleeding print, you might be a little bummed. We get this call all the time, but luckily there are pretty easy ways of fixing this!
A factor that many beginners aren’t aware of is off contact. Actually it’s one of the top 3 answers for most printing issues. A screen needs to have a bit of space between it and the garment you are printing on for a number of reasons, one of them being splotchy bleeding or missing prints. In some of our DIY days we would place a screen on a shirt flat on the ground giving us consistently random results. When a screen is flush with the shirt the channel of ink that leading from your screen ink all the way into the shirt fibers you’ve printed is never disconnected so lifting it up can actually pull out the ink you’ve printed. If not pulling your design away, your ink may have nowhere to go and spread outwards making your fine lines bloody and chunky.
Adding some space between,even just an 1/8”, will allow your mesh to relax back into place after passing your squeegee across severing the connection of ink to give only what’s needed to transfer the image. If you are working on a basic setup or none at all you can do a quick printing hack of taping some quarters to the corners of your screen raising it up evenly on all sides. If you happen to have a press there is almost always some kind of off contact adjustment, even if it’s simply unscrewing the clamp head and repositioning it higher to have it locked in place with off contact. On fancier presses there are a couple knobs that adjust the front and back of your screens off contact so you can have a completely level screen which is the most ideal. If one side is higher or lower it can cause visible differences in the print. There are a few more notes about setting and important needs for off contact you can view here
Pallet adhesive is an important tool that we feel is one of the must haves in our kits. Often a smudge happens when a shirt is removed from being stuck to a screen once it’s been lifted up after a print. That last little second when you gotta pull it away to try and see your work actually winds up pulling and dragging a bit of ink ruining what could have been a great print. A small drizzle or spray on your platen will stick your garment to it’s flat pallet just enough to print keeping your shirt from sticking to your screen and works in conjunction with your off contact. As the off contact keeps your mesh from the garment, the pallet adhesive keeps the shirt from your mesh. We even have a video demonstrating exactly how this works, the best method to use it, and the punishment for skipping it.
If you still have bleeding even after correcting any of the other issues like off contact or pallet adhesive, there’s a good chance your mesh count is too low for the print at hand. Try using something at least one mesh higher to see if you can crisp out your lines. This seems to be especially problematic with paper printing as the lack of porousness really doesn’t allow for the ink to go anywhere but outward if excessive. Higher meshes are absolutely key in getting paper prints to work out.
Along with mesh count the squeegee durometer can correct issues with bleeding on low mesh counts especially when a mesh can’t be changed. A stiffer squeegee can control your ink flow enough to erase any issues you may be having. Making educated choices about both mesh and durometer can be helpful in not only fixing problems but even saving your efforts in getting a clean print and budgeting your ink to last longer.
|Why is my print not coming out cleanly at the edges?|
If your edges aren’t able to print, chances are the size of your design is a bit too large and may lie in an area with too high of tension to allow your screen mesh to make contact with the garment or paper. The best way to remedy this is going to a screen size a bit larger to give you a proper image area to work in. If that’s not an option you can try and change the size of the artwork to fit a screen you do have available.
It’s important to try and have an even and consistent printing technique with your squeegee to make sure your prints are as consistent as possible. Pressing harder with a dominant hand or varying pressure as your squeegee drags can make for clear differences in the way the ink lays. Grip the squeegee at even points near the edged, 45 degree angle, and try to lock your wrists using full arm and body to keep strain off your joints. When readying to pass your squeegee for print, the flood not only assists in complete transfer of the image but also as a lubricant for the squeegee to glide across the screen without skidding on the mesh.
If your image is about 3 inches away from the screen frame on all sides and you're putting even pressure on the squeegee, it's possible your squeegee size itself is not correct. Ideally your squeegee blade should be at least 2 inches wider than the widest point of your design.
|Why is my print not lining up after flashing my garment?|
|A secret killer of prints can be the ingredients of your garment. On certain cotton or poly blends once heat is applied your garment actually shrinks and makes any layer printed next not line up. It’s infuriating but a really simple fix. By pre flashing your shirts under your flash dryer once they are on the platen, they will shrink however much they need to and not have issues once you start laying down prints. It’s even a good idea to pre flash just to have a bit warmer of a garment to receive the ink and even out your curing.|
|Why is my water based print fading after washing?|
|Waterbased inks are great for so many reasons, one of them being their ability to air dry. However, just because they're dry to the touch doesn't mean they're ready for washing! Water based fabric inks need to be set with heat in order to make them bond with the fabric to withstand laundering. Any method you can probably think of to heat up a garment print will probably work great. Ironing on top of a heat resistant sheet, heat gun (not blow dryer), or throwing a dozen shirts in the household dryer for a full cycle can all get your garment to the heat threshold required to lock in your print. If you have equipment like a flash dryer or conveyor dryer they can work great, but know that waterbased cures best with forced air dryers as heating the ink doesn't do much until the water has been evaporated. If you don’t have a forced air flash or conveyor that’s ok, you can turn the shirt inside out and cook the underside of the print too or try to add a small fan to the exit end of your dryer to help add some air flow inside the chamber.|