Chapter 12
Choosing And Caring For Your Squeegees
It is important to fully understand how squeegees work in screen printing tee shirts or other textiles to achieve the best print quality with ease. Choosing the correct squeegee durometer, size and shape is most likely one of the single most overlooked details for beginning screen printers. The durometer measurement is not the only thing to consider when choosing a squeegee for any print job. And proper maintenance and care will also affect the squeegees’ ability to do its job right. The following is geared more toward textile screen printing but may also be relevant to other printing applications as well.
1- The first factor to consider when choosing the squeegee is the durometer. This is simply a measurement of hardness. These measurements are represented by two-digit numbers. A 60 durometer squeegee is much softer than a 95 durometer. The lower the durometer is the softer the squeegee is and more ink will be printed. The higher the durometer is the harder the squeegee is and less ink will be printed. Knowing this when choosing the squeegee will help you optimize print results. Now it may also be helpful to know that rougher substrates to be printed on will require a softer squeegee in general. And contrastingly smoother substrates will need a harder squeegee for best performance. It is also important to note that harder squeegee durometers will be the most resistant to chemicals, inks, and other solvents.
2- The second thing you need to look at is the squeegee shape. For the most part a rectangular, cut edge squeegee will suffice for many screen printing applications on flat surfaces of all kinds. When printing bottles or other cylindrical items a "V" shaped squeegee is used in most of the printing. Yet another type of squeegee shape is called "ball nose" or rounded. This shape will tend to leave very heavy deposits of ink with less resolution. That means it will print more ink but the edges of the print areas will be less sharp. There are what is known as a standard squeegee and a dual durometer. The dual durometer squeegee combines the values of two different durometer squeegees into one. There are also triple durometer squeegees.
3- The last property to think about when picking your squeegee for printing is the size or length. This is another point many people fail to recognize as an important issue. But the bigger the squeegee the higher the friction is between the mesh and the squeegee blade. That can cause stencil drag which causes mesh distortion and thus registration problems. It will adversely affect not only the registration but the overall clarity of the print and even the consistency of the ink deposit.
Believe it or not the urethane materials squeegees are made of are absorbent. They can swell and deteriorate with prolonged contact to inks or other chemicals. That is why it is very important to clean squeegees immediately after printing and to allow them to "rest" between long print runs. When possible, use a different squeegee daily for printing duties in your shop. Meaning use a particular one on Monday and then rotate to a different squeegee on Tuesday and so on for the entire week. Rotating squeegees will not only prolong their life span but it will also improve performance. It is also recommended that you keep the blade edge sharp when using rectangular squeegees for screen printing.
It can be daunting to think about all the major and minor details one needs to consider when screenprinting tee shirts. If you can remember to take the time to work smarter, then your print results will be not only better but much easier to achieve too.
VIDEO: Choosing Squeegee Size
VIDEO: Squeegee Summary Synopsis Rundown
For most manual and automatic textile screen printing applications a rectangular cut edge squeegee will be the perfect choice. These squeegees are perfect for printing textiles. The cut edge shape is optimal for yielding the finest in print definition. Unlike rotary cut edges that leave a serrated pattern on the edge, a one-stroke cut leaves a perfect print edge. The cut edge squeegee will be the best option in squeegee shape for best print definition and ink sheer.
VIDEO: How To Screen Print: Squeegee Tips
VIDEO: Cleaning & Maintaining Squeegee Tips
VIDEO: How To Choose Your Squeegee Tips
VIDEO: Controlling Squeegee & Ink On Screen
VIDEO: Making Wood Handle Squeegees
VIDEO: How to Reuse Wooden Squeegee Handles
More About Squeegees
This is one of those topics that veteran screen printers may be divided over. Some printers believe that squeegee durometer does not affect ink coverage or opacity. It may not be as important as having the squeegee blade sharp but there are physical properties of squeegee durometers that can affect your print.
In general, a softer squeegee will transfer less force and tend to leave the ink on top of the fabric rather than pushing it into the knit. Softer squeegees give more and as a result make the printer stroke accordingly. This is a softer stroke to avoid over bending the flexible squeegee.
Even though the squeegee may be soft and flexible, you do not want to bend the squeegee blade at severe angles. It should remain almost straight with a slight curve as you do the print stroke. It should never be bent. All of this lends to a heavier ink layer being deposited onto the shirt fabric.
Harder squeegees will transfer more of your force to the ink pushing it into the knit much more than a very soft squeegee. Harder squeegees may be easier for beginners to learn with and it is possible to get the same results as with a softer one.
In manual screen printing there are many variables that can affect the print. One of those variables is the manual flooding and stroking of the ink. Whatever squeegee you end up using, it will be your skill in using it that will ultimately be the determining factor in your end results.
The one factor that is very important to the squeegee is the condition of the blade edge. It should be straight, clean, and sharp. There should not be any nicks, grooves, chips, or marks at all. A sharp squeegee blade will "sheer" the ink off in the open mesh, with a better deposit, allowing it to pull nicely through the screen.
Squeegee durometer is based on a 2-digit number system. The lower the number is, the softer the squeegee will be. 60 durometer is very soft and 80 durometer is hard. 70 durometer is a common textile squeegee for manual printing.
Squeegee comes in different shapes like ball nose, single bevel, and double bevel. The best style squeegee for textile would be rectangular in shape. Squeegee can also vary in the way it is made. Single durometer is the most common. It also comes in dual and triple durometer styles where 2 different durometer squeegees are combined. This gives the squeegee the benefit of having some of the characteristics of each different durometer. For instance, you could have a soft blade part with a firmer over all feel.
To conclude, I would say a sharp blade edge is most important in textile printing. But the very fact that squeegee does come in so many shapes, sizes, and durometers would lead me to believe that technically it does make a difference in what type of squeegee you choose.
Squeegee Blade Sharpness And Stencil Drag
The condition of the squeegee and what is known as the squeegee blade are important factors in getting sharp, clear prints. A sharp squeegee blade will also shear the ink better during the print stroke action and result in a better, more controlled ink deposit.
A sharp squeegee blade will control ink flow through fine, detailed stencils increasing resolution and overall print quality. A blunt or rounded blade edge will cause the ink to smear because it generally pushes more ink through the mesh. Some squeegee blades are made round or "ball nosed". For most standard textile screen printing applications, a rectangular cut edge squeegee is best.
Squeegee blade edges that are rough or have cuts in them will produce inferior prints. Streaking, smearing, and irregular ink deposits can result from a poorly sharpened blade edge. Misuse or bad management of your squeegees can damage them.
Squeegees should always be cleaned well after each use and any excess ink wash should be removed. Leaving your squeegees covered in solvents or plastisol ink will degrade and ruin them over time.
There are several different ways to sharpen a squeegee. Blade cutters, emery belts, and polishing cloths can be used to sharpen blade edges. Many screen printing supply companies make squeegee blade cutting machines or emery belt type units to maintain your squeegees.
Excessive squeegee pressures can cause registration problems as well as poor resolution. There is a certain amount of drag between the squeegee and the screen itself that pulls the stencil in the direction of the stroke. In manual printing this often makes it necessary to compensate for things like wood frames with inadequate tension or an old sloppy press by flooding and stroking in such a way as to eliminate the effect of the excessive drag.
- Squeegees should be positioned in the center of the stencil so that they are 1/2 to no more than 1 inch wider than the stencil on each side.
- Using too wide of a squeegee on a smaller stencil may also cause distortion.
- Harder squeegees tend to exhibit more drag and wear stencils down faster.
Many printers overlook the condition of their squeegees. However, much like everything else in screen printing, having good tools can help you create high quality prints easily and consistently. Take care of your investment in squeegee material by storing and cleaning them properly. Having your selection of squeegees clean and ready to go before you start any print run makes things go easier and faster too.
VIDEO: How To Clean Multiple Squeegees In The Washout Booth
VIDEO: What Is Stencil Drag? What Causes It?
VIDEO: How Much Squeegee Pressure Is Too Much?