There is today, an infectious fungus spreading throughout most screen printing shops. At first look it is only visible in the immediate area around the press. It takes on the form of a soft furry coating, infiltrating every nook and cranny of your press. Before long, it has spread to the dryer and then very quickly makes it’s way onto the walls and floors, infecting the light fixtures and ceiling on the way. What is this strange “Star Tre-kian” creature that is over-taking your ship, I mean shop? Is it fallout from some secret government weapons test, or is it something closer to home!
You interview everyone in your shop. Maybe It’s coming from the art department, or the dark room, or even from the screen reclaiming area. In desperation you talk to your top man, the ‘Big Kahuna’, the ‘Squeegee Puller’… your press operator! You ask him “Well, what do you think?”, In true technical printing jargon, he replies “dunno boss”. As you walk away totally befuddled, you notice that inauspicious can of adhesive that he has grasped between his knees.
You watch, and in one supersonic movement he grabs the can, sprays the pallet and returns it to his trusty knee holster. But wait, what is that fine mist that you see floating past his face, could this be the unlikely source of this ‘bubonic’ type plague that has infected everything that you hold dear in your shop?………… You bet it is!
If this colorful yet dramatic narrative sounds just a little bit to familiar, then you may be suffering from what is commonly known as “Glue Build Up @#$$”. Why does this happen?. Aerosols typically use flammable gasses as propellant, these by nature are lighter than air. When the can is sprayed, you are relying on the force of the spray to transfer the adhesive to the pallet. In tests, only approximately 50% of the adhesive gets on the pallet. The rest simply floats away to settle where it will. When you add this sobering statistic to the inaccuracy of the person spraying, the cost of aerosol, the cost of cleaning up the over-spray, and then factor in the environmental and health implications, the long term cost of using aerosols is much higher than the simple cost per can.
What can you do?. Well obviously the amount of over-spray and associated problems are related directly to the amount of aerosol you are using. If you are only using a few cans per year then your over-spray problem will be minimal. If you are going through 6 or more cans per month then you need to make some changes in how you apply glue to the pallet.
Accurate handling of the aerosol, can eliminate some over-spray as will careful mask-ing of the floor and machine around the loading station. The simplest way to eliminate the problems associated with aerosol adhesives is to eliminate the aerosols themselves. Alternative products do exist that will perform as well as, or even better than aerosols. There are available three basic alternatives:
- Double sided pallet masking tape
- Brush/Roller on adhesives.
- Bulk sprayable adhesives.
Double sided tapes tend to be very expensive and do not hold up very well under long term use or flashing. The brush-on or roll-on adhesives are OK as adhesives go, but have the disadvantage of being slow to apply, slow to dry and thus slow production times. If a solvent based adhesive is used, you re-visit a lot of the environmental/health problems associated with aerosols.
The third alternatives are by far the most desirable replacements for aerosol. There are systems available that can apply both water and solvent based bulk adhesives directly to the pallet. Some of these are air driven and others are airless electric. The airless units apply a very controllable spray of adhesive, however, as a result of not using air, they often have the disadvantage of applying it wet rather than dry. This delays the printing process and can cause transfer of adhesive to the shirt. This problem is far more prevalent when spraying the more desirable, water based adhesives. Solvent based adhesives often are high in V.O.C’s and due to the nature of the lighter than air solvent are normally flammable and once again add to the “floating adhesive” problem.
Imagine a system that could spray a long lasting, instant tacking, water based adhesive onto the pallet with virtually no over-spray. Well these systems do exist and are available now from Santa Barbara, California based Tekmar. A spokesman for the company reports that 1 gallon of its bulk water based adhesive, Tekbond TB10 will replace a minimum of 72 16oz cans of spray tack. The TB range of adhesive applicators are designed for all size operations, from small single manual press shop to companies running multiple automatic presses. What makes this system so unique is the utilization of its HVLP technology. HVLP or High Volume Low Pressure, allows the adhesive to be applied with a large volume of air, at low pressure.
This ensures that the adhesive is sufficiently dry for continuous loading of shirts, without the blast of air that would normally force adhesive all over the printing press and all over the shop. The Target bulk adhesive systems are the affordable replacement for aerosol adhesives. 1000’s of systems are in use worldwide, from some of the largest production shops here in the US, to facilities in England, Holland, Norway, Belgium, France, South America, Australia, Japan, China and Eastern Europe to name a few.