Most T-shirts and other imprinted garments contain a blend of heart, soul, creative genius and sweat. You have created, nurtured and massaged it (well, squeeged it). It is yours, your baby, nothing will ever harm or hurt it.
At first you pretend not to notice. There’s nothing there. There can’t be. It couldn’t be. Say it isn’t so. Then reality (and depression) hits; there is an ink smudge on your baby. Your immediate response is of course thoughts of suicide, or even worse throwing it in the garbage, which is no way to treat your baby.
By now any seasoned screen printer who has been around the block, or in fact one who has just turned down the first street, knows about spot cleaning guns. Sometimes called “blow-out”, “knock-out” or simply “spotting guns”, these compact units are the surgeon’s scalpel to screen printers, able to instantly cut away unwanted ink and soils from the fabric. Just like surgeons though, spot cleaning guns do have their limitations. Some times it simply isn’t practical to remove a large design or ink mark, as it would take more cleaning fluid and time than the garment is worth.
Spot cleaning is accomplished by shooting a high-pressure jet of a specialized cleaning fluid through the offending soil. The chemical is forced into the ink, breaking it down and then by the sheer pressure of the fluid stream, it is blown out of the back of the fabric. Because of the way in which these guns work, they are only effective on porous fabrics that have been woven or knitted. Vinyl, plastic or any type of leather or animal skin cannot be cleaned in this way.
TRICKS OF THE TRADE
OK so you’ve researched, shopped and then laid down your hard-earned dollars for the best spot cleaning system your money can buy. Now what! Spot cleaning guns are as important as your printing press. You own the press for one reason, to make you money. If you get a mark down or a spoiled shirt you are loosing money. The gun recovers that lost profit. The first step is to determine if the time and material cost to salvage a print is cost effective. If you are intending to remove a complete back design from a $3:00 T-shirt, it probably isn’t, however, if it’s a $35.00 jacket, it becomes far more viable.
When spot cleaning plastisols, always make sure that the ink is completely dry and cured, otherwise it will run and give you a bigger mess to clean up. Other inks such as water based and catalyst inks, should be tested prior to printing. First try it cured; if the results are unsatisfactory then try it uncured. For small spots, smudges or fingerprints, place the shirt over the exhauster (or a dry scrap shirt). Using a pin point jet, holding the gun about 6” from the fabric, start circling around the soil, spiraling into the center until the ink has been completely removed. Care should be taken not to allow the jet to hit any part of the image, as this will damage it and “really” destroy the shirt. To avoid the formation of a ring, especially on darker shirts, the following feathering technique can be applied. Immediately after spotting, adjust the nozzle to the widest fan setting. Spray around the edge of the damp area in a continuous manor, spiraling out and away from the fabric. The results should leave a smooth transition from wet to dry, with no sharp edges, and when dry, no ring
For marks that are very close to the image a slightly different approach is needed. This is where a steady hand is needed, so early to bed the night before. Adjust the nozzle so that it produce a spray pattern of about ½” from a distance of about 6”. Start spraying on the side of the mark furthest away from the image; slowly move through the soil until it is flushed away. This will take slightly longer than usual, as less pressure is being used. An advantage of this technique is that the softer spray has less potential to damage the image, should it momentarily contact it. This same technique can be used to eliminate ghosting or double imaging, caused when a screen misaligns over a shirt and transfers some built up ink. Simply run it along the edge with a medium spray until the shadow has gone.
Never! Never! Never! run the shirt back through the dryer to dry it. This, besides the obvious risk of a flash fire if a flammable solvent is being used, will guarantee one thing… a ring! To dry the shirt, use an exhauster, air dryer or a combination of both. The faster you dry the shirt, the cleaner your cleaning will be. If you do not have either drying device, you can use a clean airline or even the cool setting on a hair dryer. If all else fails then wave it in the air, this will dry the shirt and also let your customers know that you surrender.
Spot cleaning guns are not miracle makers. They are not a replacement for good housekeeping in the print shop, nor will they keep the printers hands clean. They are however, a first line defense against markdowns due to soiling. Like anything else they are tools that need to be used correctly and safely. By following the above guidelines, spot cleaning can be accomplished very effectively and cost efficiently. Remember to keep in mind that it was ruined before you started, so you really can’t make things any worse.