Printing Direct Flock

Not many printers work with flock today, giving those who take the time to understand the technique and its design possibilities a potential advantage over their competitors.

I have been a judge for the Golden Image Awards at the SGIA show longer than anyone I know. Part of being a judge is having the ability to evaluate the entries to see what is new or popular or, even more importantly, what printers are doing that is innovative.

At the last two SGIA shows, I noticed some wonderful photorealistic direct prints using flock. Interestingly, none of these award-winning entries had come from the US. They happened to have been produced by a client of mine in Istanbul who had submitted a variety of prints that included direct flock and flock combined with other special effects (such as gel ink) to create some very interesting looks.

I try to encourage my clients and seminar attendees to do what most other shops aren’t doing. It can help you develop a strong image for your company and allows you to charge a premium for the work, since most of your competitors either aren’t capable of doing it or are just not interested. Flock is one of those things that can differentiate your business. Some companies use it -- especially brand owners such as Nike and Affliction, which put out their own garment lines -- because flock makes it difficult to knock off their designs. Not many custom printers use flock, however. The most common reason is that printers don’t understand the procedures or the possibilities of the technique. Other reasons include the supplies and equipment that must be purchased and the mess that flocking creates when it’s not done properly in a confined area.

All in all, these are not very good reasons to avoid working with flock. You don’t need to do extremely complex work to wow a client. One-color flocking isn’t very difficult; once mastered, multicolor flock isn’t much harder. Producing the types of pieces I saw at SGIA won’t happen until you have a firm mastery of the process, but that won’t stop you from making money or offering things to your clients that your competitors can’t until they, too, acquire the equipment and knowledge.

Getting Started
You don’t have to spend a lot of money to get started in flocking, although automating the process is another story. Here is a rundown of what you need.

A hand-held flock gun costs about $1500-2500, depending on the size of the canister(s). That’s not too bad to set yourself apart from other shops. While you can use hand-held guns on an automatic, with a person standing at the press and doing the flocking at one station, these units are usually used on manual presses. The operator gently moves the gun over the open area of the screen and flock shoots out.

Flocking is an electrical process that requires a charge. The gun has an on/off button that initiates a charge when pressed, sending the flock into the printed adhesive on the shirt. The applicator at the end of the gun, which holds and strains the flock, also has an electrode. In order to complete the charge, the ground wire on the gun needs to be attached to a piece of metal underneath the garment. If you want to use the gun on your manual press, you either need to have metal platens or you can lay a piece of sheet metal across the platen and attach the ground wire to it. Or, you can take the garment off the press, lay it on a piece of metal that has been wired, and do the flocking there with or without screens. (By the way, the electrical charge isn’t strong and can’t hurt you, but using too much electricity will have the flock going not just through the screen but also up your arm.)

Depending on what brand of automatic press you have, optional flocking heads may be available. They require a much higher investment, but you’ll only need to face this issue if your flock orders grow to a massive level. The cost per head is about $25,000-30,000, and you’ll need one head for each color.

If you’re considering an automatic head, keep in mind that you can often print flock faster on a manual than on an automatic. The automatic heads work through brushes that move the flock back and forth, shooting it out of the screen openings. It often takes five brushings to get proper opacity on a dark-colored garment and as many as 10 on light-colored ones, which slows down the entire job. When flocking manually, the operator can control how much flock is applied by adjusting the amount of electricity going to the gun on the unit’s control panel.

You’ll need a printable flock adhesive, a very important part of the process to understand. The adhesive must be soft and flexible, and you will be printing a very thick layer of it so that the flock fibers will embed deeply into the adhesive and not fall out when the garment is worn or washed. You can choose between plastisol and water-based flock adhesives. Most American printers use plastisol because they aren’t comfortable working with water-based products. Water-based adhesives are much more common outside the US because they are less expensive and printers in other markets are used to working with water-based inks. The only advantage of water-based adhesives for this application is their ability to continue hardening after leaving the dryer, which could strengthen the bond of the flock fibers.

To cure the flock adhesive, you’ll need a dryer. Gas-fired units are best with flock, but electric dryers will work as well. It’s important to test the print after it comes out of the dryer and cools down a little to make sure that enough heat has gotten through to the adhesive, one of the biggest challenges of working with flock. You need to print a thick layer of adhesive and take extra steps to ensure a complete cure, as I’ll discuss in the next section.

You’ll also need to remove excess flock from the garment after applying it. A special vacuum is available for this purpose, but as we’ll see, it’s expensive and not the best option for those who are just starting to work with flock.

And of course, you need the flock itself. Flock is a short-cut textile fiber used in a number of industries other than garment printing and sold by a variety of companies that you can find in an online search. You can also contact the American Flock Association at. For textile purposes, several types of flock are available, including polyester, rayon, cotton and nylon, though the techniques I discuss below are meant for polyester and rayon fibers. Flock is available in lengths from 0.5 to 6 millimeters. Most textile applications use the shorter lengths of 1 millimeter and under. Occasionally, threads as large as 2 millimeters will be used. I recommend using shorter fibers when first starting out because they are easier to work with and still provide a good result. It’s also easier to get a full cure of the adhesive with the shorter fibers.

Production Techniques
Prepare artwork for flock orders very much as you would for other screen-printed garments, but avoid fine detail until you become very knowledgeable about the process, since you’ll be using a coarse mesh for both the adhesive and the flock. Vector art works best for beginners, so Illustrator and CorelDraw tend to be the programs of choice. Printing halftones is possible, but they have to be coarse in order to hold the flock. With halftones in the range of 20-30 lines/inch, you can hold a bit more detail and still get good results.

Use a very coarse mesh with a thick stencil so you can lay a thick layer of adhesive onto the garment. For the adhesive screen, I recommend mesh counts between 60-86 threads/inch with 71-micron thread diameters. I like to use 200-micron capillary film rather than direct emulsion for this application.

Choosing the right squeegee to deposit a sufficient layer of adhesive is also very important. A soft squeegee works best. Printers often choose 60-70 durometer blades, but I prefer using a triple-durometer 55/90/55 squeegee at a very deep angle with just enough pressure to clear the screen. This gives me the even, thick deposit I want.

When printing manually, flood the screen with a strong stroke to load it with the adhesive and then hit it more than once, using a lot of pressure on the first stroke, followed by one to two softer strokes to build a high ink deposit.

Now you’re ready to apply the flock. For a one-color job, the easiest but messiest way is to print the adhesive and then shoot the flock onto the garment without using a screen. This is fast and eliminates one screen from the job, but the flock goes everywhere. The other method is to create a screen with a 60 lines/inch mesh and the same image as the screen for the adhesive, and shoot the flock through that screen. The flock will only go where the adhesive is printed, with minimal mess.

For a multicolor job, you definitely need to apply the flock through screens. Prepare the screen for the adhesive as if it were an underbase for printing on dark garments, meaning that the stencil needs to include every part of the design that will receive flock. Then, break that image into individual colors the same way you would for a multicolor design printed on top of an underbase, with each flock color getting its own screen.
Make sure you set these screens up with enough off-contact that they come close to the adhesive without touching it. You can buy magnets of specific thicknesses corresponding to the length of the flock fibers you are using and attach them to the bottom of the screen to help maintain the right distance. You could also use magnets on both sides of the mesh to keep it in place. (The top magnet won’t be in the way since you aren’t using a squeegee.) Print the adhesive, without flashing, and then position the first flock screen over the image and shoot the first flock color. Then bring down the second flock screen and shoot the second color, and repeat for any additional colors in the job before removing the garment and sending it through the dryer.

Test the first print once it comes out of the dryer to make sure the flock is holding. Getting the adhesive to fully cure is the most confusing thing about working with flock. Since the flock sits in and above the adhesive, it acts as an insulator, meaning the adhesive will need to be exposed to considerably more heat than a regular ink would. In order to get to the required temperatures (275-325°F throughout the entire adhesive layer for plastisol), you’ll need to increase the dryer temperature or slow down the belt speed, or both.

To test for cure, try to scratch the flock with your fingernail. If you can get it off without too much difficulty, then the adhesive isn’t cured and you need to adjust the dryer settings.

Another common source of problems comes from the relative humidity inside your shop. The ideal range is 50 to 70 percent. If the shop is too humid, the flock will clump together and become lumpy. If the humidity is too low, flock will scatter everywhere. Make sure you have a hygrometer close to where you are working with the flock so you can monitor this. Having a dehumidifier or a mister near the press may help if the humidity in your shop isn’t in the desired range.

Finally, you need to remove the excess flock from the garment. The best way to do it is with a special type of vacuum with brushes that you rotate the garment over to remove the unwanted flock. Unfortunately, these vacuums are expensive (about $6000). When you’re getting started, the best option is to use compressed air to blow off as much of the flock as possible and then apply wide masking tape over the print to remove the rest.

Get Creative
Offering something distinctive to your customers can help you get their business at a premium price. Learning to work with flock will give you capabilities many of your competitors don’t have. Plus, with experience and some creativity in design, you can combine flock with other printing techniques to produce some unique results, as the award-winning shirts in this article demonstrate.

View a photo gallery with exceptional flock prints and illustrated steps here.
 

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