In recent years, there’s been a renewed interest in mug presses for sublimation. This is especially true with the advent of edge-to-edge imprinting and the introduction of a wider variety of imprintable products. These include several steins and some new cup designs.
Those of you who sublimate a lot of mugs will likely agree that mugs create a lot of problems not found with other products. There are coverage issues (especially near the handle), uneven heating problems and imaging problems due to the fact that mugs are round and available in different sizes and shapes. Many of the mug heat presses on the market will do a good job on some styles of mugs, but not on others, which adds to the shop owners’ headaches as the selection of sublimation-coated mugs grows, along with the demand for them.
In 2005, Johnson Plastics introduced a mug press called the JP 500, which is manufactured by Nova Chrome, Pleasant Hill, CA. The press, shown in Figure 1, was designed to accommodate a wider variety of sizes and shapes than other presses on the market. In these pages, I’ll attempt to share my impressions of this press and how I sublimated a variety of different sizes and shapes of mugs, steins, etc. using the JP 500.
The press offers some distinct advantages over other mug presses, including ease of use. This press has the ability to easily shift from making the standard 11 ounce cups to 15 ounce mugs and then to a variety of steins, including the “rope” steins.
Over a three-month period, I tried every kind of cup, mug and stein I could think of in the press. Here are my experiences.
As Americans, we always ask about price first. We should, of course, be asking other questions first, but to get it out of the way, this press sells in two versions. Both are special orders, but they ship quickly from the manufacturer. The two versions are identical except for one feature—an outlet on the back of the press that allows a “satellite” unit to be plugged into it. The outlet adds an additional $100 to the base price of $895 and I highly recommend you make the extra investment (Fig. 2).
The additional $100 allows a satellite unit to be attached to the JP 500. The satellite unit is simply a second heating chamber that holds a second cup or mug that can be purchased for around $499. Since all the electronics are housed in the base unit, it’s like buying a second mug press for about half the price. This adds greatly to the productivity of the unit.
And now, a new satellite unit is being offered too, one that imprints decorative plates. Unfortunately, a plate unit wasn’t available when I was working on this article, but perhaps we can bring that to you in an upcoming issue. Decorative plates have been very difficult to imprint consistently in the past, yet promise to be a lucrative market, especially in tourist areas or commemorative applications such as church anniversaries. Even if you never actually add a mug or plate satellite unit to your heat press, it’s worth $100 to have the option.
During my use of the JP 500 I noticed several things. First was its biggest advantage and second was its biggest disadvantage. Its biggest advantage is its ease of use and flexibility and its biggest disadvantage is that care must be taken to protect the heating element from premature burnout (Fig. 3).
Mug presses have been around for a long time. Over time, many advancements have been made in both technology and ease of use. Likewise, there have been advancements in the coatings on cups as well as the variety of cups and steins available, not to mention the advancements in sublimation itself.
The recommended method of imprinting coffee cups, mugs and steins is inkjet sublimation. Although laser sublimation, various photo transfer methods and Seiko hybrid sublimation using dye impregnated film to create a transfer will work, inkjet clearly produces the best image at the lowest price. In this quest, both Sublijet IQ inks by Sawgrass Technologies and ArTainium inks were used with very similar results.
Like all modern mug presses, this press is fully automatic and includes a digital timer and temperature control (Fig. 4). The only things the user must do are: apply the transfer, set the appropriate time, insert the mug properly and remove the mug as soon as the buzzer goes off.
The press is very nicely made and should deliver prolonged use over many years. The press portion is made from machined aluminum parts and is both beefy and cleanly made (Fig. 5). No burrs or sloppy workmanship here. The base and housing for the electronics is made of heavy gauge metal, well painted and professionally labeled. The device is available in both 110 and 220 volt configurations.
The thing that seems to separate the men from the boys in mug presses is their ability to successfully provide edge-to-edge coverage (Fig. 6). Cups that have a solid image from the top edge to the bottom edge are the most difficult to successfully sublimate. This has long been in heavy demand by sublimators, but somewhat elusive since the problems delivering edge-to-edge sublimation on mugs lies as much or more with the cup than with the press itself.
Early press designs didn’t allow for edge-to-edge printing for a variety of reasons and rightly so, since most cups were of such poor quality, they wouldn’t support edge-to-edge printing anyway. Even with new designs in mug presses, the cup remains the Achilles’ heel. Although the appearance of these new presses may seem about the same as the earlier generation, the distinct difference is in how much of the heating blanket is actually wired for heat.
Early designs sported heating blankets taller than a conventional 11 ounce cup, but actually only had a heating capability of about 3.5", leaving about .5 " at the top and bottom of the blanket that didn’t get hot enough to print on the top and bottom of the cup. New designs include a heating capability that exceeds the size of a 15 ounce cup (a bit over 4") making it capable of imprinting steins as well.
The true challenge in printing edge-to-edge on the cups lies more in the cup than the press since most cups are really not as cylindrical as they appear. What happens is the heating blanket doesn’t make contact evenly with the exterior surface of the cup throughout its full circumference. This happens with the cups that taper from top to bottom. Realizing that transfer paper doesn’t evenly conform to a complex curve, you’ll end up with wrinkles in the transfer sheet and dropout in the final image that appears as white stripes, usually at the bottom of the cup. This is usually the fault of the cup’s shape, but fading or dropout at the bottom edge of the cup can also be the result of uneven heating since the base of the cup has so much more mass than the top. Possible solutions for these challenges are included in the step-by-step instructions that follow.
Making 11 Ounce Cups
The 11 ounce cup is the oldest style used for sublimation and has been around, virtually unchanged, for decades. Most cups are now made in Asia. To my knowledge, there’s only one U.S. manufacturer remaining.
Until a few years ago, all of these cups were just white cylinders with a plain handle. In recent years, there’s been the addition of some more interesting cup styles including the colored cup (this might be a blue or black cup with a white strip for imprinting) and cups with a variety of colored interiors. There is also a “morph” cup that appears black or dark blue until something hot is poured into it and the sublimated image appears (Fig. 7).
These cups range in quality from very good to terrible depending on the source. Some come with hollow handles making them overly prone to breakage. The really bad cups (often sold at a deep discount), fail the cylindrical test, making them very difficult to imprint. Give them the cylindrical test by measuring the diameter of the top of a cup and comparing it to the diameter of the bottom of the cup. Even cups acquired from trusted sources that I tested at random showed a variation of over 10/1000th of an inch. Although that may not sound like much, it can make a difference. Poor quality cups can vary much more. I’ve seen variations of 1/8" or more! Some cups still use what is referred to as a “soft” coating that imprints well, but isn’t dishwasher safe.
The standard 11 ounce cup is the easiest to imprint when the image area is not more than 3" tall and 8.5" long is printed around the center of the cup. This method compensates for many of the flaws that are common with sublimation cups.
To print a cup in this manner, print your transfer and cut it out so the transfer paper extends beyond the edges of the cup (4") and stays about 3/4" away from the handle on each side. This method will produce the least amount of waste and requires a shorter heating cycle than an edge-to-edge cup.
The pressing time used in my tests for this type of cup was 4.5 minutes at 400° F. Your time may vary from mine, but it should never be less than 4.5 minutes.
Edge-to-Edge 11 Ounce Cups
If an edge-to-edge imprint is desired, it will require several additional steps. Novice sublimators should master imprinting 11 ounce cups, as just described, before moving on to edge-to-edge printing.
Printing edge-to-edge cups successfully is dependent on several factors. One is the cup itself, but there’s also the issue of uneven heating due to the mass at the bottom of the cup and the inability of the transfer paper to conform to the multiple curvatures of the cup itself (even the best cup will have variations in its curvature). This results in considerably more waste than when restricting sublimation to the center 3" of a cup, but also can demand a higher price and be more desirable. Let’s look at each of these issues separately.
First, the cup. Buying high quality cups from reputable dealers is the best solution to avoiding excessive waste due to irregularly-shaped cups. No supplier can insure each cup is suitable for edge-to-edge sublimation, but the more attention they pay to the shape of the cup while it’s being manufactured, the less you need to worry when imprinting the cup.
Next is the issue of the base. When the cup is being manufactured, the soft clay is baked after the base has been inserted. This means there’s more mass at the bottom of the cup than at the top. As a result, the top of the cup tends to shrink more, making it slightly smaller than the bottom. This makes the cup less than a true cylinder. By virtue of the fact that there’s more mass at the bottom than the top, it also stands to reason that it takes longer for the bottom edge to reach the desired temperature than does the top.
One way to help deal with the variation in the cylinder size is to apply a small amount of water to the back of the transfer sheet after applying it to the cup. This softens the paper fiber and allows the transfer to better conform to any variations in the shape of the cup. This can be done using the “three finger method” (Fig. 8A). After taping the transfer in place, dip three fingers in tap water and lightly spread the water on the back of the transfer along the top and bottom edges of the cup. Immediately cover the cup with a sheet of plain white paper and rub the moistened areas with the heel of your hand (Fig. 8B). This will cause the transfer to conform to the shape of the cup. While the transfer paper is still moist, imprint the cup. CAUTION: The transfer should be moist, NOT wet!
Another trick I learned from the press manufacturer is to preheat the bottom of the cup prior to applying the transfer. This compensates for the extra mass that forms the base of the cup so when it’s inserted into the press, everything heats more evenly. An easy way to do this is to purchase a small electric kitchen griddle from a discount store (Fig. 9). I found a nice one for $20. Prior to applying transfers, allow the cups to sit on the warm griddle for several minutes. I found about 125°-150° F was sufficient and didn’t make the cup so hot it was difficult or dangerous to handle. On my griddle, this barely made the “warm” setting.
Specialty 11 Ounce Cups with White Exterior
One line of specialty cups comes in a variety of colors, but the colored portion of the cup is only in the interior of the cup, leaving the exterior white and sublimatable just like a standard 11 ounce white cup.
Another line of cups has unique handles attached to what is otherwise a standard white, 11 ounce cup and should be imprinted in the same manner as described above.
The third specialty cup is referred to as a “black” cup (Fig. 10). The entire cup is black except for a white stripe around the outside of the cup. The white band measures 8.25" x 3.375". When making a transfer for this cup, be sure to make the transferable image slightly larger than the white band (I make mine 8.5" x 3.625" realizing that the outermost part of the image won’t be visible). Imprinting of the cup is best done by treating it like you would an edge-to-edge cup. Because the image comes so close to the edges, the same issues that apply for edge-to-edge imprinting also apply to this cup.
11 Ounce Morph Mugs
The morph mug is truly unique in the sublimation world. This mug comes in what appears to be a solid dark color (blue, black, brown, etc.). The sublimation image is transferred directly over the dark color just as if it wasn’t there. When hot coffee or a similar beverage is poured into the cup, the heat causes its special color coating to turn clear and then reveals the sublimated image. This should be seen as a novelty item and although it may be used extensively, it should not be microwaved and I recommend hand washing. Because of the physics involved, it’s not advisable to print an image beyond 3" in height since it typically won’t become visible anyway. Again, this is a novelty item so don’t expect the coating to become perfectly clear resulting in an image like one you could achieve on a white cup. Care should be taken not to overheat morph mugs when imprinting them.
• Recommended Transfer Size: 8.25" x 3"
Sublimating 15 Ounce Cups
Sublimating 15 ounce cups is the same as printing their smaller cousin. Of course, some adjustment may need to be made to the pressure applied by the press and the time for imprinting should be increased to 5 minutes. I don’t see nearly as many quality issues with 15 ounce cups as I do with the 11 ounce cups.
Using the JP 500, I found the ideal method of sublimating 15 ounce cups was to keep the transfer well inside the top and bottom edges of the cup. The biggest variation occurs at the bottom of the cups where there’s considerable “roll-off.” Needless to say, no press I know of is capable of printing beyond the “flat” portion of the cups. I prefer to remove the transfer (optional) and dip the cups in water immediately after removing the cups from the heat press. This will stop any off-gassing that might occur. When cups or steins are permitted to air cool after the transfer has been removed, the natural off-gassing that occurs can cause the ink on the cups to appear as if it has been smeared from bottom to top.
To print 15 ounce cups using the JP 500, the support ring in the bottom of the press must be removed. This is easily done when the press is cold, but a bit tricky when it’s hot. Having a heat resistant glove like the “Ove Glove” sold at Kmart for under $15 is a good investment. Once the support ring is removed, place the cups in the press right side up and press.
• Recommended Transfer Size: 8.5" x .5 "
• Maximum Transfer Size: 8.75" x 4"
Pressing 18 Ounce Fluted Steins
There are actually a couple of designs that fall into this category, but all work the same way (Fig. 12). The imprint area is about the same as on 11 ounce cups. Apply the transfer and insert the steins into the press upside down. These tend to be pretty simple, so little has to be done to insure a good imprint. Any variation that does occur with these steins is usually at the bottom 1/4" of the printable area, so leaving a little extra space toward the bottom may reduce product waste. Print these steins for 5-1/2 minutes at 400°. The recommended size is 3.5" x 8.25". With the 15 ounce cups, I prefer to remove the transfer (optional) and dip the cups in water as soon after removing them from the heat press as possible to prevent off-gassing.
• Recommended Transfer Size: 8.25" x 3.5"
• Maximum Transfer Size: 8.5 x 3.75" (Increase pressure)
Sublimating Stainless Steel Travel Mugs
The super popular stainless steel travel mugs are heat pressed in exactly the same way as the 18 ounce steins (Fig. 13). Insert them into the press upside down and then press for 3-1/2 minutes at 400° F. Like all sublimatable mugs, stainless steel mugs must be specially coated to accept sublimation dyes. Because sublimation dyes are translucent, the silver metal will show through. This will affect the color to some degree, but generally results in a very attractive product. Be sure to remove the plastic top prior to imprinting. Once the imprint is made, immediately dip the cup in water to stop any off-gassing that might occur.
• Recommended Transfer Size: 8.25" x 2.75"
• Maximum Transfer Size: 8.5" x 3"
Sublimating 16 Ounce Flat Bottomed Steins
16 ounce steins are sometimes a challenge to mug presses so, typically, they must be done using a mug wrap and a conventional oven, but the JP 500 press is more than capable of imprinting these steins. Like the 18 ounce steins, these are heated upside down in the press with a recommended imprint size of 3.5" x 8.5". The print time is 5-1/2 minutes at 400° F. In order to accommodate these styles of steins, you’ll need to remove the spacer at the bottom of the heating blanket (Fig. 14). This allows the steins to be inserted further into the blanket.
Although similar in design to the rope steins discussed later, these seem to be more consistent in size and shape and therefore don’t generate nearly as many problems as rope steins. Because there’s a ridge at the top and bottom of the imprint area, this design will require fairly heavy pressure to insure the heating blanket compresses itself into any imperfections in the sides of the steins.
• Recommended Transfer Size: 8.25" x 3.25"
• Maximum Transfer Size: 8.5" x 3.5"
Sublimating Glass Steins
Caring For Your Mug Press
This mug press uses what is referred to as a silicone heating blanket. The advantage of a silicone heating blanket is that it’s thick and very pliable so it conforms to the shape of the cup better than a steel banded heater. The disadvantage is that, if not cared for properly, the replaceable blanket’s heating element can burn out prematurely. There are two things you can do to prevent this:
1. Keep a cup in the blanket at all times. The cup not only helps the blanket hold its shape, it acts like a heat sink to disperse heat away from the blanket. Overheating is what causes premature burn out. The heat press heats up very quickly so turning it off when not in use rather than letting it idle for hours and hours is also a good idea.
2. Always keep the spacer at the bottom of the blanket except when printing steins. This not only helps position smaller cups correctly in the blanket, it also acts as a heat sink to keep the lower part of the blanket from overheating.
If these two steps are followed, the manufacturer says an average blanket will last for about 5,000 imprints. With a replacement cost of about $125, that’s a cost of about 3¢ per cup. Of course, the actual blanket life will vary.
When it does come time to replace the blanket, it’s a simple process that can be done in just a few minutes with nothing more than a screwdriver.
Over the years, I’ve used a lot of mug presses and imprinted a lot of mugs. All in all, I have to say that this is the easiest press I’ve ever used. It accommodates more styles and shapes than any other press I know of without making any adjustments. With the optional plug that allows you to add a satellite press, it can also allow the user to print two cups at once or with the new plate attachment, a cup and a plate at the same time. It’s a little pricier than other presses, but it will do more as well.
As I stated in the beginning, mugs, cups and steins offer a number of sublimation challenges not associated with other items. The increasing diversity in merchandise sizes, shapes and styles, coupled with the challenges of edge-to-edge and handle-to-handle coverage can create a lot of headaches even for the experienced sublimator.
I’ve found that my best sublimation results when printing cups is a combination of the techniques I’ve detailed here, as well as the extensive cup printing capabilities of Johnson Plastics’ JP 500 heat press, which really scales the job down to size.
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