SixStringToker
Naked member
This is my first cut at the full-up Steamroller based on testing that I've been doing with the Steam Engine. Like the SE, it's an 18.5mm diffuser ball vape that uses a 20mm coil. The coil extends partially down over the bowl to add some conduction. I totally fubar'd the threads for the cap on this one. Rather than starting over from scratch, I just lopped off that section and added a screen groove - the testing must go on! The next build will have a cap so that I can further experiment with airflow and change balls more easily; this one will obviously be wide open. I've also left a bit of length below the coil so that I can experiment with extending the coil further down. The final build will very likely be shorter.
My goal with this build is to create a lightweight fairly nimble ballvape that mixes in a bit of conduction and responds quickly to temperature changes while operating at the lowest temps that I can get out of it. Ideally, I'd like to be able to temp-step with the Steamroller. One of my silly sub-goals is to get my typical darkest abv at 420°F; no particular reason other than the fact that I want to vape at 420.
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Most of my work is done with a miniature metal lathe on my kitchen table. It allows me to quickly make and test changes. I can simply run a test by vaping a bowl, dump the balls, quickly modify the part on the lathe, refill the ball chamber and fire it up for further testing. I can retest a modified part within 30 minutes of deciding to modify it. There have been times where I've done 9 or 10 iterations in a single day!
These are some of the things that I will be experimenting with for this build:
Here's a clip of the smaller Steamroller in action (it's a bit further along it its development cycle):
My goal with this build is to create a lightweight fairly nimble ballvape that mixes in a bit of conduction and responds quickly to temperature changes while operating at the lowest temps that I can get out of it. Ideally, I'd like to be able to temp-step with the Steamroller. One of my silly sub-goals is to get my typical darkest abv at 420°F; no particular reason other than the fact that I want to vape at 420.
Wall of Text:
Most of my work is done with a miniature metal lathe on my kitchen table. It allows me to quickly make and test changes. I can simply run a test by vaping a bowl, dump the balls, quickly modify the part on the lathe, refill the ball chamber and fire it up for further testing. I can retest a modified part within 30 minutes of deciding to modify it. There have been times where I've done 9 or 10 iterations in a single day!
These are some of the things that I will be experimenting with for this build:
- The diffuser interface. The seal on most diffusers is created by simply seating the top of the bowl against a surface up inside the vape (usually the bottom diffuser itself). As long as there is good metal-on-metal contact all the way around, there will be a decent seal. However, the slightest tilt of the head will introduce an air gap and break that seal; this is what happens with the majority of the diffusers currently on the market when the user places the head on the bowl and releases the handle. If the user is inhaling with enough force to create a vacuum (easily doable in most heads with 3mm balls), that air gap becomes a new viable air path, allowing cool air to travel up around and down into the bowl, completely bypassing the ball chamber and undoing some of our precious heating. The effects can range from barely detectable in an A/B comparison to VERY detrimental depending upon the head and the draw strength. Adding a taper to the bowl walls and the inside diffuser walls so that the interface is more like a traditional joint with the bowl being male and the head being female has fixed this. It ensures a 100% seal AND significantly increases the surface contact between the head and the bowl, allowing for much better heat transfer.
- How far down past the rim of the bowl the coil extends. This has an effect on the level of conduction in a hit. Extending the coil further down increases the active heating of the bowl. Too far down and the conduction will ramp up high enough that it’s hard for the convection to keep up… and we get brown-ring.
I've spent quite a bit of time playing with the conduction/convection balance with the Steam Engine. 100% conduction is not really viable with this setup (and also not something that I really want), due in part to the 18.5mm bowl diameter. Since the radiant heat is only coming in from the sides, by the time the center of the bowl reaches vaporization temperatures, the outside edges will be charred. 16 to 17mm would probably be better for that.
- The distance from the rim of the bowl to the screen. This has similar effects to changing how far down the coil extends, but there are subtle differences since the proximity of the herb bed to the diffuser is also changing. If the herb bed is too close to the diffuser, the top of the herb bed can end up getting scorched from direct radiant heat.
- Restriction. While I prefer the feel of a more open hit, I’m finding that I prefer the vapor when there’s some restriction in the draw. Not entirely sure what it is… it feels smoother? This particular build is obviously going to be wide open, but I already have a couple of caps made with different hole configurations... I just need to maybe stop f'ing up the threads!
- Ball chamber size (total height). More balls = more calories. But more calories does not necessarily equate to better performance. Most of the ball vapes on the market right now store significantly more calories than the typical user burns through in a bowl. Still... “MOR BALLS!!!” seems to be the approach that a lot of makers are taking. I say “Less Balls, More Engineering!”
- Ball chamber wall thickness (also affects the chamber size). This is the interface between the balls and the heater coil. The thicker the walls, the longer it will take for heat to transfer from the coil to the balls and the less responsive / more lethergic the vape will become. Responsive heads with thin walls will heatsoak much more quickly and can actually recover lost calories DURING a hit. I have a highly responsive head with ~125 3mm balls that can easily plow through 0.5g of herb with no problem; it’d likely do more but that’s all I can comfortably fit into my rtiti bowl. With a responsive enough ball vape, it’s possible to do temp stepping.
- Ball size. In a nutshell, the smaller the balls, the more surface area inside the ball chamber, the more quickly the heat calories get released. The total thermal mass itself doesn’t change that significantly with different ball sizes, but the speed at which the calories get released DOES. A ball vape loaded up with 1.5mm rubies is a scorchy mf’er that’s hard to control because the heat is released so quickly; like vaping with a laser! This is similar to what we see with different ball materials; size-for-size (and “more-or-less”) sic behaves like smaller rubies while zirconia behaves like larger rubies and the effects on the roast profile (and thus the overall flavor) will be similar. Roast profile and flavor is a whole different discussion.
- Ball material / shape. I stick mostly with ruby balls for consistency. The "flavor effects" from the other materials comes mostly from how they hold and release heat, which effectively changes their "roast profile". We can effectively get these same results by mixing in some ruby balls of different sizes. This can also affect the draw resistance, so there ARE some differences there, but I'm still content to stick with rubies. As for round vs gemcut stones... I prefer round, at least over the typical brilliant cut stones. Size-for-size, brilliant-cut stones offer more total surface area in the ball chamber and the potential for better heat transfer but they can also stack irregularly and create areas of uneven airflow within the ball chamber, resulting in uneven extraction; shaking the head will usually rearrange the stones and fix the problem, but 'tis annoying! Now as for faceted rondelle cut stones... THOSE interest me and I plan to do further testing with them.
Here's a clip of the smaller Steamroller in action (it's a bit further along it its development cycle):
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