Mechanical Parts – How to Roaring Kitten (Portable Version)

To build the vaporiser we can start from the mechanical parts. Let's gather first our ingredients.

Main Features

  • Portability using 2x 18650 Li-Ion batteries. They usually last for an hour of continuous usage.
  • USB chargable.
  • Easy indicator. The test tube turns red when too cold, and green when it reaches the set temperature.
  • Low battery checking. Returns error message (blinking red) when battery is too low. Prevents battery death.
  • Small form factor 15cm x 13cm x 5cm.
  • Heat-up time of around 6min and 30sec from 20-200C (30W heating element) or 5min 20sec (40W heating element).
  • Precise Temperature control through a microcontroller. Takes the guessing out of the equation.
  • 3 Selectable temperatures with potentiometer (Low-Med-High).
  • Wide temperature range up to 260C (tested), and higher (untested).
  • Natural materials.

 

Design Limitations

  • Cannot charge while on. This is due to the fact that the batteries charge in parallel but are used in series
  • The wood piece gets warm (40C) where the heatsink is after prolonged usage
  • Heat-up time will be higher if battery is nearly empty.

 

The Ingredients or BOM

  • A piece of wood (we used 28x68mm which is a standard size you can find in the market so you only have to cut a 105mm piece).
  • Glass Test tubes (we used 100mm long ones with inner diameter of at least 13mm and outer at around 15,5mm-16mm) Your milage may vary as the glass test tubes are not so exact in measurements. Get a few of them as it is possible that you break some 🙂
  • A piece of round aluminum rod. We used 12mm diameter one. cut at 53mm pieces.
  • One reprap heating element. We used the 20mm long ones, the 30W variety. If you want quicker response and heat-up times you can try the 40W variety, but make sure that your batteries can take 2A current draw.
  • A piece of white pure cotton cloth. As insulation/reflector for the LED light. Dont use mixed fabric garments as plastic tends to melt and our aim is to go the most natural way we can.
  • A pure wool string. This is also for insulation purposes. Your milage can vary we are still testing different approaches. The most lazy one is to use a finger from a woolen glove 🙂
  • A glass vaporizer bowl. Usually they have 9mm outer diameter, we used the ones from vapolution.
  • 7x  3mm x 7-8mm long screws.
  • 2x 3mm x 15mm long wood screws
  • A 3d printed vaporizer housing. 1xdoor, 1xtop border maincase, 1x onoff stop, 1x knob

Our ingredients are a little bit on the marginal side. For alternative designs go here.

The Wood

Step 1 (1hour)

The Heatsink

Step 2 (2-3hours)

Test Tube, Heatsink & Insulation

Step 3 (1-2hours)

Mount Everything & Test Drive

Step 4 (2-3 hours)

Cut the wood to length (105mm).

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Measure and mark the center on both sides of the 28x68mm.

Filet the edges with a router for better appearance (optional).

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Drill a 22mm hole on the one side , 85mm deep. We used a spade bit.

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Drill a 7mm hole on the other side, aprox 15mm deep. The two holes should meet hopefully in the middle 🙂

Drill 2x 6mm hole on the two sides of the 7mm hole, placing the center around 3mm to the left and right of the first hole. (these are for the LEDs. We used 5mm LED. If you have 3mm around just make 2x 4mm holes).

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If everything went according to plan, the 3 bottom holes will all connect with the big top hole.

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Sand everything mildly to get smooth edges and apply 3-4 coats of shellac (we are really interested in keeping things healthy and natural, so if you dont have shellac, dont use other plastic or urethane based finishes. (you could leave the sanding and finishing for a little later when you are sure that everything fits together).

Cut the 12mm aluminum smooth rod to length (53mm). Sand if the cut is uneven.

Mark and punch the center on both sides.

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Finding the center on a 12mm rod is a bitch, but I found on internet an interesting and easy way. I took a 10mm drillbit for wood and I laid the rod and the bit on a flat surface. Now the middle point of the wooden drill bit shows 10mm deep in our rod. mark it by scratching a line on the rod. Turn the rod 180 degrees and mark a second time so you now have to parallel lines with 2mm distance between them. Turn the rod 90 degrees and scratch again. Turn it once more 180 degrees and scratch a fourth line. So now you have a # with a center of 2x2mm. Well now its quite much easier to punch the center.

Apply the same method for the other side of the rod. Punch  both centers so that the drill will not travel away from it.

Now start by drilling a 3mm on both sides around 19-20mm deep. Try to stay in the center.

Continue by widening the holes, drilling a 6mm on both sides (again 20mm deep). As you can see things get easier if you have pre-drilled.

Use some sunflower oil as a lubricant.

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Now the tricky part.

Compare the two holes you made. Probably the one is more to the center than the other. Choose the one which is closer to the center. And on this drill a 9.5mm hole 23mm deep. Go slow and hopefully you wont deform your heatsink 🙂

Use a brush from the rotary tool to polish your 9.5mm hole, clean everything very thoroughly form the scrap aluminum and the oil. We used earbuds for cleaning the hole.

Congratulations! It tooks us some hours to get one right with our cheap shitty drill press, but after you get the idea it gets somewhat easier. The good news are that the aluminum rods are cheap to get. Dont aim for perfection, unless you have really good quality tools and/or a lathe. A professional machinist tried to make a heatsink on our shitty drill press and in the end she used something that in her shop would be destined for the garbage bin. But nevertheless it worked 🙂

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Now the next step is to attach the heating element to the heatsink. Fortunately reprap heating elements are exactly 6mm wide so it should be a snag fit. If it's too loose, use some aluminum foil around the heating element. The idea is to get the snaggiest fit possible. It should look something like that.

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 The red cable of the heating element will help you manipulate the heatsink on the following steps.

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Measure 25mm from the top big hole and draw a line. Do the same measuring 20mm from the bottom of the heatsink. Actually the space between those two lines is the safe area where you can drill the 2 small holes for the mounting screw and the thermistor. But dont go ahead and drill them yet. Its easier to start with the glass tube.

Drill a bigger than 6mm hole at the bottom of the test tube. As always with glass go reeeally slow and drop some water. Did I mention how slow you have to go? if you go too fast chances are that you will break the glass. In our example we went for a 8mm hole at the bottom. Using bits for glasses make your life so much easier.

Now clean the glass from the muddy dust with some water and place it inside the wood. Hold the glass steady at the bottom of the wood and check that it doesnt protrude too much at the top. This is not a real problem, but a protruding test tube can break easier if you drop the vaporizer.

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Place the heatsink inside the tube and pull it from its cable. Leave a space of 10-20mm from the bottom hole of the glass test tube. And now mark 2 dots on the glass (one opposite the other) between the two safe lines you can see on the heatsink.

We had the best chances of drilling them by using a diamond bit on a rotary tool. Try a fast speed but as with every glassware, go really slow and dont apply too much pressure. Preferably do it in a water bucket. The hole should be a little bit over 3mm wide, 4mm could be quite ok. Do the same thing on the other side of the glass. The one will be the thermistor hole. The other the mounting hole.

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Place the heatsink again inside the glass tube. Use the heating element cable to adjust the height. try to hold it steady and mark on the heatsink with a pen two dots where the 2 small glass holes are. Make sure those two dots are inside your safe area and make also sure not to move the heatsink as you try to fit the pen inside the glass holes.

Take the heatsink out and drill a 1.5mm-2mm hole (2mm deep) on the one mark (the one where the thermistor should go) and a 2.5mm hole (2-6mm deep) on the other mark (the back were the mounting screw will come).

Tap a 3mm screw on the 2.5mm hole. If you dont have such a tool, just take a screw and try to screw it in place. Aluminum is soft and the screw will make nice grooves on the walls of the hole. Remove the screw, place the heatsink again  inside the test tube and check if the 2 holes from each side (glass, heatsink) align themselves. If yes congrats you are ready to actually go for the insulation.

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If you fucked up a bit this is the time for corrections. Actually you can widen a bit the glass holes to accommodate for mistakes 🙂

Now for the insulation we used the following (slow process see quick below if you are bored). A small piece of white cotton fabric (actually from an old t-shirt). Threads of wool (from old gloves). Needle and thread to sew the cotton fabric.

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Screw the heatsink and the glass test tube using a 7-8mm long 3mm wide screw. Try to screw as close to the glass without braking it. The cotton fabric acts both as an insulator and as a reflector for the led lights. Sew it together as you see in the pictures. Then with the woolen thread start kneading from bottom to top. When you reach the top, hold it 🙂

Find the thermistor holes and cut a small opening so you can have access to the holes. Put some heatsink glue (glue not paste) on both the thermistor hole on the heatsink (you may need to unmount first) and the thermistor and dip the thermistor head inside the hole.

Hold it there steady and start knitting around the woolen thread from top to bottom again. The woolen thread will actually cover the thermistor and its cables and envelop it in an insulated area. Keep knitting up and down until you reach the thickest possible insulation, before its really hard for it to fit inside the wooden hole. Try not to move the thermistor too much as the thermoconductive glue isnt dry yet 🙂

What you actually have as an end result, is a glass test tube covered in woolen thread and 4 cables coming out from the bottom (in the picture below you can see the mounting screw. Actually this was a mistake). If the whole thing is too thick to fit in the wood you can wet the woolen thread with some hot water so that it will tighten and shrink a bit. But before doing and fitting try, wait for 12hours until the thermoconductive glue is set.

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The quick or lazy method.

Just take and an old pair of wooden gloves. Cut the small finger and place the test tube inside it like a pouch. Open a small hole on the bottom so that the cable can come out. It offers quite good insulation but you dont have a fabric acting as a reflector for the LEDs. Also it can be a bitch to open a hole big enough for the led light to come through.

P.S. If you want to learn how to prepare your thermistor, please go here.

Mount the insulated test tube inside the wooden part. bring the 4 cables of the insulated test tube to the bottom hole. Take the electronics board before you solder the arduino mini (refer to the electronics section if you havent done that yet) and fit the two led lights inside the 2 holes on the wood. Try placing the board as close to the wood as possible. When the led lights are inside the hole, put some hotglue in the 2 small holes in order to fix them. Now take the 2 thermistor cables cut them shorter and solder them to the thermistor holes on the board (polarity is unimportant as the thermistor is actually a resistor). Do the same for the two red cables of the heating element (also polarity is unimportant). Try to keep cables short.

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Now its time to mount and solder the arduino. Be careful to place it on the correct side (the serial port pins should be on the side of the big capacitor). Actually the correct side to solder is the one that has the VCC GND A0 A1 A2 and 10 11 12 pins. When done it's actually time to check if you have done everything correctly. Because actually now your vaporizer is functional. Place some power (anything between 6,5V and 12V is ok) on the Vin (check polarity first) of the board´s and check if everything behaves as it should. The red light should turn on and the vaporizer should start getting hotter. You can also check the serial monitor on arduino IDE. It outputs voltage, low-med-high setting and temperature. Let the vaporizer heat enough so that the light turns green. Then let the vaporizer burn for 10-15 minutes. You may see a little bit of smoke on the first run, as small threads of the t-shirt can burn around the mounting screw.

When you have completed the first test, let everything cool down and then try to determine where to screw the wood piece on the front door of the case. Test by placing the wood in the case. Mark the two middle holes and place 2 wood screws 15-20mm deep.

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Now its time you place the 4 nuts (3mm) on the 3D printed case. The two top nuts fit from the inside, the two bottom nuts fir from the outside. If the nut holes are not big enough do the following trick. place the nut on a nice big screw. Heat up the nut using a lighter. Sink the nut in the nut hole. The surplus plastic will melt to make way for the nut. Allow to cool without moving the screw or the nut. It should now have a snag fit. If its loose, just put some instant glue between the plastic and the nut, or ABS smudge (actually 30% ABS melted in 70% aceton). The 4 nuts are there to help keep the vaporizer door closed. Don't worry! The top cover keeps everything mostly in place. The screws are just an added security.

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Well mechanically speaking you are mostly through. Now you only need to make all the electrical connection between the vaporizer the batteries, the battery charger and the 3PDT switch. Part which will be covered in step 3 of the electronic how to.

The wood of the vaporizer tends to get 45-50C hot around the place where the heatsink is. In order to insulate some more and also to make things more appealing (if thats your style) you can fit of knit something to cover the whole apparatus. If you are not into knitting, you can cut some old leggings and dress the vaporizer with a piece of them.

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4 Comments

  1. Hey there 🙂
    I’m wondering where to get some of the parts listed:

    -glass vaporizer bowl
    -reprap heating element

    Thanks in advance!

  2. Hey thanks for the answers, looks like the vaporiser bowl isn’t really an option unless i pay a lot for shipping, do you have any idea on how to make one out of chemical tubes?

    • we just made one. We have to make it better but actually it doesnt seem so difficult. Just heat up the tube slowly and then with a blunt needle (like knitting needles) you push the side until it reaches the other side. It needs practicing probably but nothing unfeasible.

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