DIY Starbucks 16oz Tumbler Induction Heater Notes and References

I used 18 awg stranded copper wire for everything. I went with 18 awg because I was told it's the perfect size to hold the amount of heat that the IH generates. It was a little bit bigger and a little harder to work with compared to 20 or 22 awg, but I made it work.

uxcell 2.1mmx5.5mm DC Power Jack Female DC 30V Panel Mount Connector Socket 5pcs

I need a hole that allows the glass slide to poke through it a little bit. 17mm inner diameter + 4mm thickness x 2 = 25mm. The hole is 25mm. Cut it out with the DIY hot knife.

Momentary push button switch
2mm thickness x 2 plus the inner diameter.
Make a 12mm mounting hole
I need a 12mm drill bit

Mini DC voltmeter:
Length: 22mm or 22.5mm
Width: 10mm
Height: 6mm

Tactile Switch
Length: 6mm
Width: 6mm
Height: 5mm

DPDT 3 position slide switch
Length: 22mm
Width: 12mm
Height: 8mm

DC Power Jack 1a 30v
Panel Hole Diameter: 7.60mm
For the DC input jack, it is 7.6mm. So get a uxcell 7.6mm drill bit. May need to use a step drill bit before using the 7.6mm piece.

Plastic Barrier for Battery Pack and Coils
Piece 1: 50mm x 22mm
Piece 2: 56mm x 4mm
Xacto Knife. Rectangular bottom part is 10mm. Thickness is exactly 1mm.
Glass slide and coil. All together, 4mm. So the distance between that and the switch, button, ect., needs to be at least 4mm or more. 15mm spaces apart should be more than enough room.

Dremel EZ406-02 EZ Lock Cutting Wheel is 1.1mm thick. Perfect for the blade.

I used 6 awg solid soft drawn copper wire and bought 25 ft. Also used a light duty workshop vise. You’ll need to get a cheap 30 watt lightweight soldering iron. I cut part of the wire off just long enough to insert into the DIY hot knife. Clamp the soldering iron tip. Cut off the top part of the soldering iron tip with a hacksaw or Dremel. I prefer the hacksaw because it’s a little more delicate. Take it out. Then put the copper wire piece into the vise and cut a slith/notch 10mm long right in the middle to allow the Xacto blade in. The soldering iron tip must be completely still and stable, or else it will be extremely difficult to cut or the cut will be slanting. Be mindful of the copper point. Then insert the blade into the slith/notch. Drill out 1mm holes with a power drill across the copper wire and blade. The holes need to be lined up perfectly where you’ll put a 1mm screw to secure the blade in place. The hole needs to be placed somewhere close to the bottom of the rectangular part of the blade and also where you’ll be able to screw it into the soldering iron. After you’ve screwed the copper wire and blade into the soldering iron, plug in the soldering iron and test it out with some plastic. You may need to use an infrared thermometer gun to check the temperature on the blade itself. It should take about 20-30 seconds for it to reach the operating temperature. The soldering iron I got is rated up to 735F degrees, but with the copper wire and blade you’ve made, you may only get about 100-120F degrees out of it, which isn’t really that hot, but as long as it’s 100F degrees and up, that’s good enough to cut plastic cleanly. Make sure the blade is not slipping out of the copper wire. But as long as it’s secured in place with the screw, it should be good. The hot part of the blade will be more towards the bottom of the blade, not so much at the top. Because you’ll only get 100-120F degrees out of it, it’ll be a little slow and difficult to cut the plastic. You’ll have to move it up and down to get it going, but if you push the soldering iron down more, the blade cuts the plastic better and cleaner.

For the glass slide, momentary push button switch, DPDT slide switch, and voltmeter, use the DIY hot knife to cut the holes.

For the tumbler cap, I designed it in a way in which the DPDT switch and the momentary push button switch were at least 10-15mm away from the glass slide because I had concerns about the coil getting hot and potentially melting/destroying the wires.

For the green and blue LEDs and DC input jacks, you'll need to make pilot holes using a hand drill. Then carefully size up the holes until you get to the drill bit that you need for the holes. For the DC input jacks, insert them, then screw the nuts and you may need to bend the terminals a bit with some pliers. They should be at least 7mm apart from each other to make sure the terminals or wires don't touch each other. The DC input jacks should be small enough to where the terminals don't touch the bulging part of the cap underneath. You should be able to easily solder wires to them.

For the tactile switch, use a hand drill, use a 1mm bit. Drill two holes and mount the switch in place. Then use hot glue underneath and around and also use epoxy to secure it in place.

Use a compass and pencil to draw the diagrams for the glass slide, momentary push button switch, tactile switch, DPDT slide switch, DC input jacks, voltmeter, and the plastic barrier that'll be put underneath the custom plastic container. You'll need to use JB PlasticWeld to make the barrier. Scan the papers and upload them to the computer, then print them out. Use scissors to cut them out and using your best judgment, place them where they need to go and apply Scotch tape to keep them in place until you're ready to cut or drill out the holes. Using the Scotch tape and trying to keep them where they need to go is a delicate process, so be patient.

To make the plastic barrier, cut out the two pieces from other plastic fruit cup lids, mark them with a black Sharpie and carefully Dremel them out. It needs to be precise, so be patient but more importantly be careful when using the Dremel. Once you've gotten that done, use the JB Plastic Weld and wooden craft sticks to make the barrier. Typically it takes about 4 hours to be somewhat dry, 12-15 hours to be mostly dry, and 24 hours to be completely dry. If after it's completely dried and you're still not satisfied with the results, repeat the process until it comes out with better strength and looks good. Once it's completely dried and you're satisfied, apply the plastic barrier to the bottom of the custom fruit cup container using the JB PlasticWeld and wooden sticks. Once that's done, check and inspect it to make sure it's all good. Then using a dremel, you may need to cut out some notches on the plastic barrier to allow it to sit more comfortably on the wires of the battery pack. On the 18650 battery pack, the top and bottom soldered ends need to be covered up with electrical tape to protect them from abrasion and accidental short circuiting. After that, the entire fruit cup container should click in and sit perfectly inside the case and also so the container and battery pack don't move around too much, it should be pretty stable. If the notched ends on the plastic container aren't welded on the plastic piece very well, like if they don't stand up straight, they're slanting, or are not stable, it may be okay to just take off those notched ends and just leave the flat plastic piece instead, which is what ended up happening to me. I left it like that and didn't have any issues with the wires. But I still made sure the container clicked in the middle well and the top part of the battery pack was hitting the barrier, keeping it stable.

For the fruit cup container and IH board. Drill a hole sitting to the left side of the IH board that sits underneath the lid. The hole needs to be large enough, but not too large, to allow all the wires from the cap to go through it. Drill it to the very left of the lid. The wires need to feed through the container, preferably to the left of the IH board and somehow go through the container and out of the hole where the plastic barrier also sits below the container, while making sure the wires don’t get too close to the coils. It will probably be a little messy and they might end up being a little too long, but it’s best to figure out how long you want the wires to be beforehand. The mosfet will also be sitting suspended in the air inside the container, so with the wires going to the mosfet, the IH board, and the battery pack, it’s gonna be a little messy and a tight fit. The mosfet also needs to be covered up with electrical tape so the terminals or wires don’t touch other components like from the battery pack.

The IH board needs to be custom fitted for the fruit cup container. You’ll need to dremel out the corners of the silver surface pads on the output side. This side doesn’t have a lot of circuits that go to the mosfets of the IH board, so dremel this side mostly, take your time with it and be careful, it’ll take a while. You’ll also need to dremel out the black corners on the input side, but only do a little bit on this side because the circuits that go to the mosfets are closer to the corners, so please be careful when dremeling out this side. Otherwise if you cut into a circuit, the board will become useless. You want to dremel out the silver side just enough so it can go down the container far enough towards the middle and also so it leaves room and an air gap for the IH coil, The black side needs to be dremeled out just enough so the IH board has a snug fit and stops somewhere in the middle. The IH board with the coils needs to be facing downward perfectly leveled in the middle of the container.

For the IH board, you’ll need to dremel out holes on part of the lid and part of the container, like a square cut on the container. Needs to be big enough, but not too big to allow the heating coil to sit comfortably from the glass slide and the coil should sit comfortably on the lid and allow the ends of the coil through the hole. The glass slide needs to be placed somewhere on the middle of the lid or wherever the glass slide hole is. This part was a little tricky and difficult because I had to do this while the container was still in the case and I had to guess where the center of the hole was. After looking at the hole and lining it up with the glass slide, I placed the glass slide on the lid where I thought the center of the glass slide and hole met and then marked around the glass slide with a black Sharpie on the lid. Alternatively, you can leave the glass slide in there, then take a #2 pencil and black Sharpie, insert it through and then try to mark where you think the center of the glass slide/hole is. Take the glass slide, put it on the lid where the center is, then delicately trace around it with the black Sharpie. You need to use your best judgment and hope that's where the glass slide needs to be. This won't work if you try to take the cap and container out of the case because you’ll be doing a lot of guessing and it won't be completely accurate. You have to do this while the container is already in the case. The glass slide or coil needs to be sitting up completely straight and not bent or on an angle. If it is, it means you’re either pushing the glass slide or coil down against the lid too much or the coil isn't long enough and you're trying to force the coil down, which will make the glass slide not go through the hole.

The coil should go on the bottom of the glass slide. It should be 17mm apart. Then past that, 26mm apart. It'll allow you to put the glass slide through the hole, but it's probably gonna overshoot/poke out of the hole by 7-8 millimeters, which is fine. The gap will be far enough apart where you won't melt the plastic on the cap or harm the wiring of the blue LED.

Straighten up the capacitors and line up the capacitors in place on the lid. The IH board needs to be sitting somewhat in the middle of the lid and the coils need to be able to bend a little bit over the edge of the hole on the lid and go straight down through the hole and over the air gap on the IH board. Be very patient with this process. Once you’re satisfied where they need to be, use a black Sharpie and trace around the capacitors, the area where they need to sit and be glued underneath the lid. Carefully place the capacitors where they need to be and put a lot of hot glue underneath and around the capacitors and on the lid and very quickly hold them in place for a couple minutes. You’ll need to be quick with the hot glue and use paper towels if necessary. If you’re not quick enough or the hot glue is not in the right places or you didn't hold them long enough, you won’t get a good hold, the hot glue will be too cold/fall apart, and the capacitors won’t hold very well underneath the lid. You may need to repeat this process to get it right. The IH board, terminals, and silver surface pads should be hanging underneath. Cut a hole near the input side of the IH board on the container just big enough to allow the wires to get into the terminals and have them screwed into place.

The coil needs to be long enough, but not too long, to bend it to shape and solder them to the silver surface pads. For the coil, you’ll need to cut off part of another coil and solder it to the other coil so it’ll be long enough to bend and solder. This part will be very difficult and may take a few tries, but be patient with the process and make sure the pieces are all good and have a good solder connection. There should be about 7-9 wraps around the glass slide.

Separate the cap with the glass slide from the fruit cup container and IH board for a bit and take them out of the case temporarily. Take the lid off the container and work with the coils and the IH board. Make sure the holes on the lid and container have been cut. Place the coil underneath the glass slide, take the ends of the coil and play around with them for a bit to see if they’re long enough and can go through the holes and if you can bend them just enough to solder them. The IH board needs to be sitting somewhat in the middle of the lid and the coils need to be able to bend a little bit over the edge of the hole on the lid and go straight down through the hole. When the IH board is upside down and it’s been hot glued and the lid is snapped to the container, it should be positioned somewhat in the middle of the square hole on the container. The coils need to be able to go through the container and there needs to be a little air gap that allows them to go over the board, and then bent so they can be soldered. Bend the coils straight down and bend them again so they touch the silver surface pads. Solder the coils to the silver surface pads. Make sure the coils are completely soldered to the pads and have a good connection. If they’re not, that will cause a problem and potentially cause the IH board to short circuit.

Put a piece of cork underneath the glass slide just enough where it’s a little bit below the coil and also so it won’t get burnt/cooked while using the IH. Then secure it in place with electrical tape.

Once all that’s done, carefully put the container and all the wires back into the case, making sure the container sits comfortably on the wires of the battery pack and the container should snap into place. The container should be able to move very much down the middle of the case so it gives more room to put the cap back on the case. The container and battery pack should be stable inside. Later, we find out that we cannot put the cap back on the case, so we’ll have to use two tumbler cases instead.

When I finished everything, I tried to push everything down the tumbler, but there wasn’t enough room in the bottom of the case for the battery pack and the fruit cup container, the fruit cup container wasn’t going down the middle far enough, and I couldn’t snap the cap back on the case. So I decided to cut out the bottom part of another tumbler with the DIY hot knife. After I cut it out, I took the case with everything in it and put it through the one with the bottom cut out and snapped the cap back on. Then I secured everything in place with 3M electrical tape. This way it gives more room for the battery pack, IH board, fruit cup container, and wires because the wires I used were a little too long.

For the LEDs, you have 3mm and 5mm LEDs, so you can use either 7/32 or 3/16 inch drill bits, which I already have. Actually, it's 3/16ths.

Blue and Green LED: 3/16 inch diameter. Snug fit. Use a 3/16 inch drill bit. May need to file it out to help it fit in better. Drill where you want it to go. Make a pilot point.

To make the 18650 battery pack: there’s a couple videos on youtube that show you how to do it.
https://www.youtube.com/watch?v=di7YiCQ_DSY
https://www.youtube.com/watch?v=YPK47xsH1II
But I’ll explain how I made mine.

You’ll wanna use battery cell insulator rings from IMRbatteries or Illumn. You’ll place them on the positive cells of the battery pack. You’ll also need kapton tape, fish paper, double sided tape for mounting the BMS to the battery pack once it’s been put together, hot glue gun, silicone caulk and silicone caulk gun, nickle strips, a portable spot welder, and the 18 awg wire. There’s a diagram on vapoven that shows you how the batteries need to be arranged

You may need to do it outside like on a workbench or in a well-ventilated area. What you’ll wanna do is put the insulator rings on the positive cells. Then you’ll place them in the series shown. Using the hot glue gun, you wanna apply hot glue across the batteries and also apply silicone caulk in between the batteries. You need to be quick with the hot glue. Be careful to not get hot glue all over the place and use paper towels if necessary. The silicone caulk will be more temperature proof. Wait for the hot glue and silicone caulk to cool down/dry for a little bit and until the batteries are secured in place together. Measure out the fish paper to the size that you need. You may need to use a ruler and pencil. Trace it to the size you need and cut it out with scissors. Take the fish paper and wrap it around the battery pack as shown in the video, with one flap over the other. Then take a cut piece of kapton tape and apply it over those two flaps, securing them in place. Take the hot glue again and apply it in between the crevices of the batteries and the fish paper. Make sure to use a lot of hot glue on the crevices and fish paper and very quickly, hold them in place for a couple minutes with your fingers or use like a Sharpie and something heavy to push the Sharpie down in between the crevices while they cool down and hold in place..I had a lot of trouble with this part and the hot glue kept getting cold and the fish paper wasn’t staying secured in place with the crevices. You may need to take out some of the cold glue if it didn’t work out and repeat the process if necessary to make sure they’re all glued together.

Once that part is completed, you’ll need to use the spot welder. Take the nickel strips and spot weld the strips across the cells as shown in the vapoven diagram. It may take a while for the spot welder to reach operating temperature or you may need to start using it a little bit to get it going and up to the operating temperature. After they’re spot welded, now you may start soldering the wires to the nickel strips as shown in the IH design/diagram. Once all the wires are soldered to the nickel strips, apply some electrical tape over the bottom part of the battery pack to protect it from abrasion inside the case.

The fruit cup container has its bottom cut out. The bottom of the container should sit on a fully wrapped 3s 18650 battery pack and shouldn't cause any issues. If you want, you may cut out a portion of the bottom so the container can go down more and sit on the top of the battery pack. Although there is concern they may short each other out. But as long as the battery pack is fully wrapped and as long as everything is stable inside, there shouldn't be any issues.