Learning a Mug Sublimation Workflow in a Single Day

Today wasn’t about producing a finished order. It was about producing a sample for a client and getting familiar with the mug heat press itself. What I thought would be a quick test run turned into a full day of learning—about printing, cutting, heat distribution, workflow, ventilation, and even the realities of shipping ceramics across the world.

Like most maker projects, progress came through a series of small mistakes, observations, and adjustments.

A Very Early Morning Test Run

The day technically started before sunrise.

Sometime between 4:00 AM and 7:00 AM, I ran my first sublimation tests for the Apple Valley Shrine Club. It was a quiet time to experiment, and I wanted to get a feel for how the press behaved before working on another client’s order later in the day.

At the time, the smell from the sublimation process didn’t seem especially strong. When you’re standing near the equipment, working and focusing on the process, it’s easy to get used to it.

After finishing those tests, I went to sleep.

Waking Up to the Smell

When I woke up and walked into the kitchen later, the smell was unmistakable.

The room had that familiar warm sublimation scent—a slightly sweet, plasticky smell from heated dyes and the polymer coating on the mugs. The smell was much stronger than I had noticed earlier while working.

That’s when I realized how easily your nose adjusts while you’re in the middle of the process.

Once I stepped away and came back hours later, the lingering odor became much more noticeable.

That moment also helped me better understand something I’ve heard from library staff in the makerspace. Even during small sublimation runs, they sometimes notice the smell outside the room where the equipment is located.

After experiencing it in my own kitchen, I finally understood what they were describing.

Thinking About Ventilation (and My Dogs)

Ventilation quickly moved to the top of the improvement list.

Fortunately, the weather has started warming up, which makes airflow much easier to manage. My plan is to create simple cross-ventilation using fans:

• A box fan in the door bringing fresh air in
• Another fan in the kitchen window pushing air out

That should keep the air moving across the workspace instead of letting fumes linger.

One additional consideration is my dogs. I have a corgi and a pit-lab rescue who would happily wander outside if I simply opened the door.

The likely solution will be putting a child gate on the porch, allowing airflow while keeping the dogs safely inside, or letting them watch over the neighborhood from the porch.

I also spent some time looking into whether sublimation fumes pose any particular risk to dogs. I wasn’t able to find any clear information suggesting the odor itself is dangerous to them. Most sources simply point out that dogs have a far more sensitive sense of smell, which means they may notice the odor long before humans do. Even so, good ventilation seems like a sensible precaution for everyone in the house—two-legged and four-legged alike.

Maker projects always seem to intersect with everyday life in small ways like that.

Starting the Real Work After Some Rest

After that early morning session, I went back to sleep for a few hours. When I woke up again later, I felt much more rested and ready to focus on the other client’s mugs.

The goal for the day was simple: produce a few high-quality samples so the client could review them and choose which design to move forward with.

That meant learning the press quickly and carefully.

Preparing the Artwork

The artwork for the mugs arrived in several formats.

One logo was already a PNG file. Another was provided in multiple formats including PNG, JPG, and Adobe Illustrator (AI).

Since Illustrator files are vector graphics, they can be exported at extremely high resolution. I opened the AI file in GIMP, rasterized it at high resolution, cropped the content, and adjusted the canvas so the final design was a 1:1 square.

Because sublimation requires mirrored artwork, I flipped the image horizontally and exported it with a helpful prefix:

“inv-” for inverted.

That naming convention makes it easy to identify the correct version when preparing prints.

The second design required a slightly different approach. It had intentional spacing around the artwork, so cropping too tightly would have altered the design balance. Instead, I carefully adjusted the canvas size while preserving the original composition.

Building a Reusable Template

Rather than building a page layout from scratch, I copied the document I had used with the first run and turned it into a reusable template.

This made it easy to:

• replace images quickly
• maintain consistent spacing
• preserve alignment for each mug

Google Docs includes a Replace Image option that allows artwork to be swapped without disturbing the layout. That saved a surprising amount of time.

For each printed sheet I alternated the front and back logos so both sides of a mug could be transferred using a single sheet.

Discovering the Printer’s Paper Profiles

Another small but important discovery came from the printer settings.

At first, I was simply printing using the operating system’s print dialog and selecting a paper type like Photo Paper Matte. The prints looked acceptable, but something about them felt slightly soft. The lines were there, the colors were there, but the prints didn’t look quite as crisp as I saw at the Library.

Then I noticed something I had overlooked.

The printer itself also had its own paper profile settings, separate from the operating system’s settings. In addition to selecting the paper type in the print dialog, the printer driver included options such as Premium Matte, Presentation Matte, and other paper profiles designed to control how the printer lays down ink.

Once I set the printer’s internal paper type to Premium Matte to match the operating system setting, the difference was noticeable.

The prints suddenly looked sharper and more saturated. The lettering filled in more completely, and the edges of the graphics looked cleaner and more defined.

The earlier prints weren’t exactly wrong, but the new settings clearly produced a higher-quality transfer.

It was a good reminder that printers often have multiple layers of configuration, and getting the best results sometimes means making sure those settings match on both sides.

In this case, simply matching the printer’s paper profile to the operating system’s paper type made the output noticeably better.

Fixing the Cutting Process

Early in the process I noticed that cutting the transfers was taking far too long.

I was lining up sheets by eye on the guillotine cutter, which led to small inconsistencies and extra effort. I also tried lining up a pre-cut paper over the edge as a template to align the paper, but that also took time.

The solution was adding cutting guides directly to the template.

I added tiny trim marks at about 5% black along the edges of the page and matching marks at the top and bottom of each strip.

The difference was immediate.

Instead of guessing where to cut, I simply aligned the marks with the cutter’s edge and made the cut. Every strip came out identical, and the transfers wrapped around the mugs much more predictably. I didn’t even see the top and bottom marks.

I also discovered that my document originally had one-inch margins enabled. Removing them revealed that the layout was already using the full 8.5-inch page width.

The printer still leaves about a 2 millimeter margin, but seeing the true page size made planning the layout much easier.

The marks eventually became a problem. One of the prints had a small black smear in the corner. I’m still working out exactly what happened. One possibility is that the guillotine blade cut through one of the trim marks, causing ink to smear or concentrate along the paper edge. Even at 5% black, that could leave enough dye at the edge of the transfer sheet to show up during pressing.

Learning the Heat Press

With the transfers prepared, it was time to learn the heat press.

My first attempt used 390°F, but the results were disappointing. The colors were muted, and the transfer looked incomplete.

Even stranger, the temperature display didn’t drop when I inserted a mug. I expected the ceramic to absorb heat, but the display remained fixed at 390°F.

That suggested the thermistor (temperature sensor) was located in a specific part of the heating element.

To test that idea, I moved the mug closer to the side where the power cable connects.

Immediately the temperature reading dropped to about 340°F, then slowly climbed back to the set temperature over the next three minutes.

That confirmed it: the press heats unevenly, and the sensor is located closer to one side.

Stabilizing the Heat

From that point on, I changed the workflow slightly:

• Place a blank mug in the other side slot
• Wait for the temperature to recover fully
• Then start the timer

Adding the second mug helped distribute the heat load more evenly across the heating element.

Finding the Right Temperature

Through several test mugs I gradually adjusted the temperature downward:

• 390°F produced dull colors
• 380°F improved the results
• 375°F produced vibrant transfers without scorching

The final timing settled at 180 seconds after temperature recovery.

Part of the improvement likely came from correcting the printer’s paper profile settings earlier in the day. Once the printer was configured to use the proper Premium Matte profile instead of the default settings, the printed transfers themselves appeared sharper and more saturated, which carried through into the final sublimation results.

Even with these settings, I noticed that black areas sometimes looked slightly brown when viewed at an angle. Viewed straight on, however, the color appeared perfectly black.

That’s a common optical effect caused by how sublimation dyes interact with the glossy ceramic coating.

The Yellow Tape Problem

Another issue appeared during the early runs: a faint yellow mark left by the heat tape.

In some cases the mark would fade or wash off, but on one mug the yellow discoloration remained visible.

This appears to be related to a combination of temperature and pressure. When the press temperature was higher, the adhesive from the heat tape could transfer slightly onto the coating during pressing. Lowering the temperature helped reduce this effect, but it was a good reminder that even materials designed for heat transfer can sometimes leave marks under the right conditions.

It’s another reason dialing in the temperature carefully matters.

Alignment Matters

One of the later mugs showed slight browning near the base while the others looked perfect.

The difference turned out to be alignment.

If the mug rim wasn’t positioned exactly at the edge of the heating element, the design shifted into a slightly hotter part of the heating band. Even a quarter-inch difference was enough to affect the result.

Reducing the temperature to 370°F may also address this problem so that alignment with the edge may not have as much impact on the final result.

Pressing mugs turns out to involve a small dance between temperature, pressure, and alignment.

Fading Near the Handle

Another behavior that appeared occasionally was fading near the handle side of the mug.

This seems to happen because the handle area sits slightly outside the most consistent pressure zone of the heating element. The handle itself also acts like a small heat sink, pulling some heat away from the nearby ceramic.

As a result, the edges closest to the handle sometimes receive slightly less heat and pressure than the rest of the mug surface.

Paying extra attention to how the transfer sheet wraps around the handle area helped reduce this effect.

Preventing White Specks

Another issue appeared as tiny white dots in dark areas of the print, where I had ripped the paper upon removal.

At first, I feared incomplete transfer, but after the mug cooled I discovered the dots could be wiped away. They were actually paper fibers stuck to the mug surface.

The solution is straightforward:

• wipe the mug with isopropyl alcohol
• dry it with a microfiber cloth
• avoid touching the print area afterward

I’ll also be purchasing gloves to help keep the surface clean while positioning transfers.

Other random dots were found to be related to high temperature and disappeared as the temperature was lowered in later runs.

Why This Was Different From the Library Makerspace

One thing worth mentioning is that I didn’t encounter nearly this many issues when using the sublimation equipment at the library makerspace.

At first I wondered if I was doing something wrong.

The reality is much simpler: the equipment at the library has already been dialed in through repeated use. The staff and makers who use it have already worked through many of the early problems I encountered during today’s testing.

Settings like temperature, pressure, and timing had already been tuned for their specific press and the mugs typically used there.

Another difference is the heat press itself. Mug presses can vary significantly in how heat is distributed and where the thermistor is placed, which can change how the machine behaves.

Finally, the mugs themselves are different.

The box of 48 mugs I purchased specifically advertises a heavier sublimation coating. According to the packaging, this coating requires longer heating times to achieve proper dye transfer.

However, the instructions were written for sublimation ovens, not mug presses. Oven-based sublimation heats mugs using circulating air rather than direct contact with a heating element, so those settings don’t translate directly to a mug press.

Between the new press, the heavier coating, and the lack of established settings, it’s not surprising that today involved a fair amount of troubleshooting.

Shipping Reality

Before starting the project, I checked the Amazon reviews for the box of mugs I purchased to find information on temperature and timing. Several customers mentioned receiving crushed boxes and broken handles.

When my shipment arrived, it was a box containing individual boxes of mugs. The original box clearly had a long travel history. It appeared to have come all the way from China and looked like it had seen more than one warehouse floor.

Fortunately, most of the mugs themselves were fine. A few packaging corners were crushed, but so far the handles I’ve seen survived intact.

Still, the reviews served as a reminder that shipping ceramics in bulk is never entirely predictable.

Sorting the Results

By the end of the testing session I had produced:

• three good mugs
• three imperfect mugs
• two additional rejects from the Shrine Club test

The good mugs were labeled L and R to indicate handle orientation when viewing the main logo. The imperfect ones were also marked with X and set aside as freebies.

Rather than letting them accumulate, they’ll likely be given away or used as samples.

Looking Ahead

Tonight I’ll bring the samples to the client. Tuesday evenings tend to bring people into town, and there’s a good chance community members will be around when I stop by.

Seeing the mugs in person may even lead to a few early sales.

Once the client selects the preferred design, I’ll order another box of mugs and produce the full 48-mug batch.

Thanks to everything learned today—from cutting templates to heat distribution, ventilation, tape behavior, and mug alignment—the next round should be much smoother.