Use the degreaser designed for screen applications. Dish-washing liquid is less effective and also produces a lot of unnecessary foam that only adds to the time of the task. Cheap can be more expensive and less effective.
Use the degreaser designed for screen applications. Dish-washing liquid is less effective and also produces a lot of unnecessary foam that only adds to the time of the task. Cheap can be more expensive and less effective.
It’s a rush job and the press operator is on your case, the boss is on his case, and the customer is on the boss’s case. “We can’t do the job without screens! Where are they?”
You try to explain that you have pinholes and has anyone seen the bottle of block-out? And isn’t it Murphy’s law that the bottle of block-out was thrown out by the cleaners over the weekend because it looked old and had been sitting around for a long time?
In addition to always having block-out close at hand on the shelf with a “Do not touch my block-out” label on it, there are things to know about preventing pinholes. First of all, it’s almost never the fault of the emulsion — no decent emulsion manufacturer includes pinholes as an ingredient. It’s usually one of these things:
Take care of these basics and your &#!!*@! pinhole disasters should be few and far between. Blaming the emulsion is barking up the wrong tree — unless you bought some really cheap rubbish, But you’d never do that, would you?
If you have any doubt about matching an ink with a fabric (something that’s critical in today’s world of never-before-seen-fabrics), help is available. Stanley’s has access to Wilflex’s laboratory facilities where they can quickly test the fabric and advise on the best ink to use. Don’t risk the job if you’re not certain about the fabric — get expert help.
When coating screens using a hand-held trough, consistent pressure is better than maximum pressure. In fact, if the pressure is too high you can damage the mesh. But if the pressure is too low, you could end up with an uneven coat. So, a consistent, firm (but not too high), pressure is best for an even coat.
Screen cleaning is possibly the most unpopular job in a textile screen shop performed in possibly the most despised location — the “swamp”. For many years now dip tanks have been promoted as a means of making life easier and more efficient for swamp dwellers, but do dip tanks live up the hype?
It’s generally assumed that a shop should be “larger” before a dip tank can be justified. This is not necessarily true as dip tanks can be bought in a variety of sizes so that even small textile shops can consider one — which is most of the Canadian textile screen printing industry. The more important consideration is efficiency and labour time. The primary purpose of the tank is to soften up the stencil and ink at the same time so that while screen one is being rinsed, screen two is soaking and will be ready for rinsing when screen one is done. This obviously makes sense and is bound to make screen reclaiming more efficient. But there are other considerations.
Before ordering a tank, weigh the cost of it against the number of screens your shop recycles in, say, a year. Of course you may hate the screen-cleaning process so much that you’d pay a premium to make it easier — it’s your choice but at least be aware of the cost-benefit aspect. Then there are issues such whether the dip tank costs less in chemical consumption, whether the tank chemistry is safe to discharge into the sewer system, and how long the chemicals in the tank remain powerful enough to truly make it an effective dip-soak-and-rinse process (if the tank doesn’t consistently meet this standard then there’s not much point in having it).
Ask for contact information for dip tank users before buying one. Ask the tough questions. A dip tank could be a useful addition to the efficiency of your textile shop, but do your homework before deciding. Any one of Stanley’s branches can help point you in the right direction: Cambridge 1 877 205 9218 ; Calgary 1 877 661 1553; Edmonton 1 888 424 7446; Richmond 604 873 2451.
Save some money. If you use a dip tank, don’t leave the screens in for longer than, say, three minutes (until the stencil starts to break away). Take them out and pressure wash. If you leave the screens in until all the ink and emulsion comes off, you’ll be going through a lot of unnecessary top-up chemical.
This is not a popular topic, but it is a necessary one . . . What may your textile screen printing shop pour down the drain and what may it not?
We’re talking about chemicals here — the kind of stuff used in the screen reclaiming process in particular. And it doesn’t matter whether your shop uses a dip tank or a bucket and brush, the safety and pollution issues are the same. In fact, some printers erroneously believe that dip tank chemistry is more drain safe than bucket and brush chemistry.
And, most importantly, labels can’t be relied on to keep you on the right side of your conscience and the law. Just because a container is labelled “drain safe” it doesn’t mean that it is flushable in your jurisdiction. It all depends on local laws. It’s therefore your responsibility to find out whether the chemicals you use are allowed to be flushed into the sewer system.
If the chemicals in question are not flushable into your local sewer system, you have decisions to make if you are to stay on the right side of the law (and there’s also the matter of conscience). You will have to either change chemicals or find an alternative method of disposal. This is of course likely to result in additional expenditure, but consider the alternative – – fines, potential forced downtime etc.
Let’s not kid ourselves. While it’s a lot better than it used to be, we all know that the textile screen printing process relies on certain chemicals, some of which can be pretty nasty. To be safe and compliant, it’s best to establish with the local authorities what your shop can and cannot dump into the sewer system.
It’s on its way! Wilflex is releasing a white that can pretty much serve as your all-purpose, one-white-for-everything, low-cure ink. It’s a response to today’s tri-blend, 100% Polyesters and other challenging fabrics. Stanley’s is expecting to have it soon.
High-density prints can look really cool and wow customers. But you must avoid the temptation to make the stencil too thick. 200-micron film can give you great high-density prints. Any thicker and it becomes difficult to print sharp edges and fine details because of light scatter during exposure.
Plastisol ink has been known to print beautifully even after being in storage for over ten years. So, use up your older ink if you can but always stir it well. False body can build up over a long period of storage but a good stir will take care of it.
Avoid placing those small plastisol ink containers on flash cure units or dryers. Take the extra trouble and place them in the coolest place – the floor. It might not always be convenient when you’re really busy but if the ink warms up it’s going to gel and become thick and unusable.
As the warm weather of summer approaches remember to keep plastisol inks (especially fast-flashing and lower cure inks) away from heat sources like warm outside walls. Heat can trigger the gelling process in the bucket.
When you inspect your screens both before and after coating, a light box with yellow safelight sleeves is a good way to do it.
Don’t neglect the de-greasing stage of screen preparation – even if you’re in a hurry. And use a soft nylon brush to apply and work the degreaser over the mesh. Using a scourer is not a good idea. Oh, and use a concentrated degreaser made for the job, not dishwashing degreaser.
Keep your screens in a dry environment after coating and before exposing; over 40% humidity is too high. If the coated screen absorbs moisture before exposing it will not expose properly and then you can expect pin holes, stencil break-down and other problems.
Before coating with emulsion always make sure that the screen is completely dry if you want to avoid fisheyes.
Last week I received an online newsletter from an organization dedicated to improved sustainability in the fashion and textile industries. To cut a long story short, they had done a magnificent job of producing a Tee that was as organic, eco-friendly, and sustainability-compliant as you could hope for.
It was an impressive effort, except for one thing. They claimed that part of the sustainability excellence was that the Tee had been screen printed in a manual shop using water-based inks because: “Unlike harmful plastisol inks, water-based inks are durable, feel soft and are low-impact on the environment.”
Some investigation and an exchange of emails with the newsletter editor and the printer, revealed that the water-based ink was from a small foreign manufacturer.
It has long been a problem that people assume the word “water” suggests that water-based ink is environmentally superior. Well, we drink water so it must be okay, right? No, wrong! Some water-based inks also contain nasty chemicals. And you won’t know the truth until you examine at least the MSDS.
Anyway, below is my final email on the topic which casts some light on the whole water-based ink versus plastisol issue and how some manufacturers can misrepresent the differences. Since it’s not my intention to denigrate anyone but just present information, I’ve omitted names.
Good morning Xxxxxxx:
Thank you for the response.
I have been in contact with Xxxxxxxxx and it seems that we have a mutual concern for sustainability in the fashion and textile industries. She seems to have gone to a lot of trouble to search out environmentally friendly products for her screen shop, including Xxxxxxxx water-based ink.
I dealt with ink companies for over twenty years and have to tell you that some salespeople and web sites will say anything to sell their product. I don’t believe in taking anything at face value. For instance, the only way to confirm that Xxxxxxxx’s ink has GOTS certification is to ask for the registration number and then search it on the GOTS site. I’d be interested in having this if it can be located because we’ve been unable to find them on the list of GOTS-certified manufacturers.
I visited Xxxxxxxx’s web site and have the following comments:
I didn’t mean to open a can of worms but since we’re all concerned about the environment and the sustainability of the fashion and textile industries, I thought it worth pursuing the topic. And I don’t mean to imply that I’m advocating for plastisol over water-based inks—I’m not (personally, I much prefer my water-based Tees). I just believe that if we are to make informed decisions about environmentally friendly printing, we need to explore the facts and not rely on salespeople and web sites with vested interests.
This morning I sat in on the Wilflex webex preview of the ISS show. If you are going to the show (and you really should be) you’ll definitely want to visit the Wilflex booth. It’s number 1517 next door to M&R.
Wilflex has made it particularly enticing for you to visit their booth with some special features:
Here’s a tip concerning the sample prints on display . . . they search far and wide for prints excellent in both technical rendering and design (they obviously want to show off their ink as advantageously as possible) which means that you get to see ideas from all over the world – ideas you can take back to your shop. For instance, they have a print from Russia that seems pretty interesting.
Doug and Wendy will be at the show and the Wilflex booth would be a good place to leave messages for them, meet with them, and enjoy Wilflex’s hospitality at the Friday and Saturday evening happy hours.
Enjoy the show, but if you can’t attend, feel free to call them when they’re back and ask for an update on what’s new.
Kiwo will be showing their new emulsion, Kiwocol Poly Plus MP, at the Long Beach Show on the 20th to the 22nd of this month.
The “MP” stands for “Multi-Purpose”. Multi purpose because it’s a high resolution, diazo-photopolymer, dual-cure, emulsion for use with all textile and graphic inks including the newest water-based and discharge systems.
All inks you ask? Yes, all inks! Plastisol, water-based, discharge, UV, and solvent-based inks. The whole lot! And that’s not all. It has high solids for quick build-up and smooth stencils, excellent resolution and exposure latitude, high mechanical resistance, and is easily reclaimed.
If you’re having a hard time wrapping your head around this, think of it in terms of that old printers’ bugaboo – white plastisol. Imagine only ever having to keep one white ink in your shop that will print on every conceivable fabric, is 100% bleed resistant, is nice and creamy to work with, will go through any mesh, and will give a nice soft hand. That’s what this emulsion appears to be – the ultimate all-purpose emulsion the world has been waiting for. One emulsion for all your printing.
Now, the big question on your mind is likely the one about price. We’ve been conditioned to expect new and amazing products to break the budget and so you’re probably expecting the worst. Well, it will please you to know that it’s about mid-range among all the emulsions you likely use for different printing applications. This adds up to a great technological advancement and a great convenience, and all at no extra cost.
Doug and Wendy of Stanley’s will be acquainting themselves with Kiwocol Ploy-Plus MP at Long Beach later his month. If you’re not going to be fortunate enough to be at the show, wait until they get back and then ask them about it.
It can happen that when you’re printing with a low-bleed or bleed-resistant white on dark Tees, you can end up with “ghost” images on the back of the garments.
Most people assume right away that the print has somehow penetrated all the way through the Tee to the back. Usually that’s not the case at all. What often happens is that the garments are stacked as they emerge from the dryer. Because the dye-block ink film is still hot and therefore the dye-block chemicals are still active, they “bleach” the dye in the back of the shirt stacked on top. The result is a “ghost” image on the back of the shirt.
The solution is quite simple and only requires a change in the stacking routine at the end of the dryer. Instead of building a single stack and completing it before starting a new stack, have five or six stacks going at once and stack them in a rotating pattern. In other words, the first garment goes on stack number one, next one on stack number two, next one on stack number three, and so on. By the time you’re back at stack number one the last print will have cooled off enough so as not to “bleach” the back of the next shirt on the stack.
No need to call Ghostbusters.
If you’re thinking of leaving your screen printing job and opening your own shop, there’s something you need to know about pricing. Don’t make the mistake others have made when leaving a job to open their own shop. You can’t just charge for a print what your former boss charged or what the competition down the road is charging. Your new shop probably has a whole different cost structure (leases, rent, and other overheads) from the shop where you worked. And the guy down the road may be mindlessly low-balling his prices – do you want to follow him down the path to failure? Calculate your prices according to your circumstances and then see if you can be competitive, not the other way around.
Look, we all know that no matter how many washing labels we hang or print on a T-shirt about washing in cool water with mild detergent on the gentle cycle, that Tee is going to be tossed into the wash with the towels, socks, and dog’s blanket on the heavy cycle in hot water.
And we also know that if the print on the Tee wasn’t properly cured, some or all of it, along with your reputation as a textile screen printer and whatever washes out of the dog’s blanket, is going down the drain.
So, you need to do two things to ensure that all your prints are properly cured. First, test your dryer at least a couple of times a day to ensure that it is still reaching cure temperature. The best way to do this is with a Thermoprobe (see post of November 24th). The second thing to do is a wash test, particularly on critical jobs when there may be a lot at stake in terms of money and reputation.
A good way to do a wash test is to cut the print in half. Wash one half with three heavy bath towels in hot water and liquid detergent. Tumble-dry the load on high for thirty minutes. When you compare the washed half with the unwashed half, there should be no cracking or loss of part or all of the print. If there is, the print wasn’t properly cured. Then you can establish the cause and correct it.
It’s much better to have a failure in your washing machine before the Tees are delivered, than afterwards in the customer’s customers’ washing machines.
To test the shelf life of your transfer prints, place the transfer in a hot box or a hot room for 100 hours at a temperature of 50 degrees C (120 F). This simulates a year of aging on the shelf. After the 100 hours, take it out and allow it to cool to room temperature and transfer it in the usual manner in a heat press. How it transfers will give you insight into performance after a year on the shelf.
For most Canadian textile screen printers the slower winter season is here. This means that there is time to do some maintenance tasks usually neglected in the busy summer season.
One of those tasks is attending to under-tensioned stretch-and-glue screens. When production is going full tilt it’s too tempting to use under-tensioned screens and get away with a few more jobs before facing the cost and hassle of re-stretching. Sooner or later you have to deal with it though because of the direct correlation between screen tension and print quality.
So why not schedule a screen tension testing project for the slower season? All you need is a tension meter – if you don’t have this vital item of basic textile screen shop equipment, now would be a good time to talk to Stanley’s about getting one.
Go through all your screens, note their tensions, and mark or put aside the ones in need of re-stretching. You don’t have to have them all re-stretched at once but going through this exercise will give you a much better idea of the state of your screen inventory and enable you to develop a plan to bring it up to snuff.
An inventory of properly-tensioned screens will be another step taken in the pursuit of excellent prints.
In all the discussions about getting the most out of the ink dollar, something that’s incredibly important but hardly ever mentioned, is the container lid. Leave it off a water-based ink and you risk evaporation and contamination. And while plastisol ink doesn’t evaporate, it will certainly become contaminated with all the stuff that floats around in a textile shop. And then there are those clumsy spills that can end up in an open ink bucket. Oh, and what about the company pet? Do you really need colourful paw prints on your new office carpet? It’s easier to just make a rule that lids always go on containers.
I’m going to take issue with a piece in this month’s Images magazine that advocates using a laser temperature gun for checking the curing temperature of ink.
The author recommends using the gun to check the temperature of the ink film as the garment exits the dryer. I’m suggesting that by then the film of ink is already cooling and is no longer at the optimum curing temperature the manufacture recommends that it must reach for proper curing.
There’s a better way to do it – a way that will tell you when and where in the dryer the ink film reaches the required curing temperature. And that certainly won’t be once it’s out the chamber. The better way of monitoring the temperature of the ink film is to use a donut probe (commonly known as a Thermoprobe) rather than a laser infrared temperature gun, temperature strips, or any other method.
Not only will a Thermoprobe confirm the temperatures encountered by the ink film as the garment progresses through the dryer, but it will also indicate cool spots in the dryer. A laser temperature gun will not do all that for you, particularly if you’re checking the temperature as the garment exits the chamber. How do I know this? Well, if you use a Thermoprobe to plot the ink film temperature every 5 seconds as it moves through the dryer, you’ll end up with a bell curve which is turning down by the time the garment is exiting the chamber.
A Thermoprobe has a “donut” across which is strung two thin wires in a cross formation. The donut connects to a digital readout by a long wire. You place the donut on the ink film with the cross wires on the ink surface (the critical temperature measurement is that of the ink film) and monitor temperature on the digital readout as the garment moves through the dryer.
Now, of course, the Thermoprobe can be about four times more expensive than an infrared laser temperature gun so the decision is yours – do it cheaply or do it properly. But either way, do it regularly. At least two or three tests a day will help avoid curing problems.
If you’re lucky enough to have a Roland printer/cutter in your shop, do this now. Make two signs that say “DO NOT unplug this machine!” Take no chances – attach one sign to the machine where it is in full view, and attach the other to the power cord where it plugs into the wall. Why? Because even when you’re closed for the holidays and the Roland is idle, it recycles the ink every twelve or thirteen hours to prevent clogging. If someone unplugs the power, it can’t recycle the ink and you could come back to clogged jets. A couple of signs could save you a lot of hassle and expense.
If you’re going to do 4-colour halftone printing, consistent screen coating thickness is important. One way to help ensure consistent coating thickness is to start coating each screen in the set with the same depth of emulsion in the coating trough.
Wood frames may be cheap to buy but they can’t hold high tension during or after use. And since high-tensioned mesh is essential for consistent images, don’t use wood frames; they’re not rigid enough. Use aluminum stretch-and-glue or re-tensionable frames.
The edge on your coating trough is very important. Protect it whenever it’s not in use. The soft aluminum edge must be kept smooth and free of nicks. A rounded trough edge will put down slightly more emulsion than a sharp edge but it (rounded edge) tends to be less prone to damage.