How to build a dry herb vaporizer - Vumo v0

Vumo

Active Member
When I first became interested in building a dry herb vape, I had no idea how a vape actually worked and had to do a lot of reading in this forum. This post is meant to serve as an introduction to building your own regulated portable vape.
Disclaimer: Don’t trust me, do your own research.
Every dry herb vaporizer consists of three basic components:
  • Heat source
  • Somewhere to place your herbs (herb interface)
  • A component from which you can inhale the vapor
Electronic vaporizers add a power source
Regulated electronic vaporizers also have power control

I like regulated electronic vaporizers, because you don’t need butane. Unregulated electronic vaporizers don't have a component that controls the power to the heating element. If you want to build one, you should know what you are doing, because unregulated devices can be dangerous if not built properly. That's why I won't go into this in detail. Examples of unregulated devices are the Milaana or Nomad.
The power source for portable vaporizers are most commonly 18650 batteries. Read the safety thread here: https://fuckcombustion.com/threads/18650-battery-safety.18527/

The Mighty is a good example for a regulated vape:
Storz & Bickel made a nice video that shows how the Mighty works [Link].
Now let’s look at some vape components in detail:

Power control
The electronic regulation on portable diy devices is frequently adopted from 510 nicotine vapes. Nicotine vapes (box mods) provide a solid base for a dry herb vape, since they already have the regulation as well as a battery in a case and don't cost much. Ideal would be a board that allows you to configure the device specifically to your heating element. Temperature control requires a mod with TCR mode (the board approximates the temperature of the heating element by measuring the change in resistance as it heats up). Another option is to load customized firmware on your mod: Arctic Fox, surmyevic and others provide a lot of customization as well as unique features, but only for a number of compatible vapes. While the software still exists, the forum for artic fox mods has been closed, so the instructions for installing custom firmware on vapes are hard to find. The discord for the Divine Tribe Vaporizers might be a good source, since they still use the firmware for their devices.
The premium option for power control are DNA mods: they provide very good temperature control, and their settings can be customized out of the box with their escribe software. The DNA boards are also sold standalone (just the board), which is a plus if you intend to build an all-in-one unit. However, they are a bit expensive.

Heat source
There are various kinds of electronic heating elements. Popular examples are wire, ceramic heating elements, halogen bulbs or resistors. Wire is the most flexible approach, since you can buy it in different materials, shapes and sizes. Stainless steel wire or mesh is a popular choice, since its very durable, and can be controlled in wattage mode as well as TCR mode. However, SS316 is not the best choice for TCR mode (see explanation here).
The combination of your heating element and your herb interface determines if you are building a convection, conduction or hybrid device.
Simplified: With convection devices, the herb is only heated by hot air passing through it, while conduction devices are cooking your herb, similar to an oven. Hybrid devices provide a mix of the too. Convection (or hybrid heating) is currently popular, since it’s supposed to provide the best flavor.
While a standard coil like the one in nicotine vapes can be used, ideally you would want a heater with a very big surface, for more even and efficient heating. Here are some examples of coil shapes:
Herb interface
The herb interface is the connection between your heating element and your herbs. This could be a chamber, a stem or just a WPA adapter in the case of an injection vaporizer.
Choose an option that matches accessories you already have, or accessories that are available to you. For example, there are many glass stems available with the dimensions of the tinymight stem (16mm OD). You might also think about whether you intend to use capsules or not.
For this component, you should also consider a way to cool the vapor before inhaling, as it can be harsh otherwise. In vapes with stems, many people insert steel or glass balls into the stem to provide additional thermal mass and slow down the vapor so it has more time to cool down. The Tinymight comes with custom cooling units, which are made from washers and nuts in a shell. I have my own unconvential solution...
In my next post, I’ll show you the vape I built.

Here are some good threads with inspiration:

Desktop Vapes
Portable Vaporizers
 

Vumo

Active Member
This is the vaporizer I built for myself. I was inspired by the Nomad and Milaana, and went for a wood case. The bottom plate is made from brass, the buttons and some internals are 3D-printed. The heating element is a stainless steel mesh in a glass tube. It is powered by an 18650 battery and the Evolv DNA 100C.

I’m planning to do a closer look and a build tutorial later when I have more time.
Meanwhile, here are two ideas that might help you with your own project:

A big issue with a wire mesh heating element is a loose connection, that leads to changing resistance when the wire heats up. When using TCR mode, your resistance should be rock solid. Otherwise, the heater can’t approximate the temperature. Other vapes have used different approaches to combat this, for example Alans iHeat and the Timber Elite use butt splice connectors that are filled with solder. I use a portable spot welder, the kind that is used for making 18650 battery packs. They are inexpensive, easy to use and provide a very solid weld. They can be used with nickel foil or stainless steel foil. I use stainless steel foil to connect the wire mesh to the actual wire. On the bottom I use a washer, on the top only steel foil. Here are some pictures from a prototype showing how my heating element is made:

The other idea is a way to cool the vapor in a stem. While thinking about the Mad Heaters Revolve stem, I saw this reddit post and combined the two concepts for a very simple cooling solution:
The cooling provided is less then with steel balls, but the noodle is way cheaper and less hassle to clean (because you just replace it). You might even cook it for some THC-rich pasta, but I’m not sure how food safe that is. You can combine the noodle with Alans Paper roasting tubes for some very cheap cooled stems.
 

DeadRabb1t

Well-Known Member
Company Rep
I'm going to bed with the words "stem, reclaim and pasta" bouncing around my head and I'm not sure how I feel about that.

How long do you think it would take to build up sufficient noodles to be able to create a decent sized bowl of pasta?

Sorry excellent and informative post btw really enjoyed it until ...

Yeah I'm really not sure on the pasta recipe, would you go for a tomato based or cheese bases sauce do you think?
 

Hippie Dickie

The Herbal Cube
Manufacturer
A big issue with a wire mesh heating element is a loose connection
i found this is also true for my heating element - 1/8" wide nichrome80 ribbon. i finally settled on a physical connection - sheet metal screw holds the end of the ribbon against a flat copper post. thermal expansion / contraction has not loosened it over several years.

i opted for a k-type thermocouple connected to a MAX6675 for temperature control which a PIC 12F683 reads 3 times per second to adjust the duty cycle (on time) for the heater. the PIC has a built-in PWM which makes controlling the MOSFET very straight forward with such a simple controller.
 

highvaper

Well-Known Member
I started off from a different angle and ended up with something very similar to @Hippie Dickie

I messed about with TCR and found stainless steel a hard one to a get the true temp with a mod - i also went with the max6675 and a mircocontroller to handle the pid/pwm and other control - been my daily driver for a while now - the all glass brings out flavours a steel heater seems to kill for me.
 
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