so is it better to coarse grind or fine grind?
Speculation about how vapour clouds form
- Thread starter pakalolo
- Start date
so is it better to coarse grind or fine grind?
That's a hard question I think because it is somewhat device dependent. A course grind has less surface area but a Lower pressure drop. The higher surface area is beneficial but the high pressure drop might reduce the flow rate such that the heat cove grates on the upstream side of the load potentially causing charring. I believe the grind should be as fine as possible provided it doesn't provide too much flow restriction. As you add heat to the load it tends to settle and reduce in volume and increase in pressure drop which is another reason to stir.
However, if a device has a low pressure drop, sufficient high quality heat, and uniform heating it can handle course grind or no grind with favorable results.
I did some test this weekend that suggested that a change of 1/2" in the length of a mouthpiece impacted the quality of the vapor significantly. Very small changes to a convection system will have big changes in vapor quality.
However, if a device has a low pressure drop, sufficient high quality heat, and uniform heating it can handle course grind or no grind with favorable results.
I did some test this weekend that suggested that a change of 1/2" in the length of a mouthpiece impacted the quality of the vapor significantly. Very small changes to a convection system will have big changes in vapor quality.
nosmoking
Just so Dab HAppy!
Material is going to be the number 1 culprit when it comes to finding consistent results. Let's say you do all this testing over with another strain next weekend. How different do you think your results will be?
I am getting a new strain every week or two and I notice that each strain gives me varying results in my vaporizers. The Daisy and Firewood 3 seem to have the most consistent results between varying strains, however the ESV is very particular in response to each strain I feel. Some strains will produce much better results and require no stirring in the ESV. Another may not produce much vapor without constant stirring after each hit. For this reason I believe the question of "is it better to coarse grind or fine grind?" is dependent not only to device but even more so to strain possibly.
I do find it interesting that the mouthpiece length has much affect. I would expect it to change the temperature of the vapor but not the actual profile or flavor of the vapor. I would be interested in hearing more about this.
RUDE BOY
Space is the Place
I don't understand all the 'science' put forth in some of the posts here but from my experience with my Underdogs and EV2 the length of the stem does only affect the heat of the vapor. I have many stems for the UDs from the length of about 3 inches to 10 inches and don't notice a difference in taste or vapor production from stem to stem if they have the same type of bowl. With the EV2 i have 4 different length direct draw stems that all perform the same as far as I can tell. regardless of being from 5 inches to 12 inches long.
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like RastaBuddhaTao says, it depends on the design of the vaporizer. i have a longish bowl (1/2" diameter by 1 3/8" long), and so i like to distribute the herb along the bowl, rather than in a clump at the bottom. i break off pieces of herb with tweezers and drop them into the vial. This way, the hot air is exposed to more trichomes coming through the vial, and the trichomes are exposed to radiant heat from the heater coil. i need to stir to break up the melted plant waxes that coat the remaining thc goo. much larger cloud after a good stir.
Shit Snacks
Milaana. Lana. LANA. LANAAAA! (TM2/TP80/BAK/FW9)
I don't understand all the 'science' put forth in some of the posts here but from my experience with my Underdogs and EV2 the length of the stem does only affect the heat of the vapor. I have many stems for the UDs from the length of about 3 inches to 10 inches and don't notice a difference in taste or vapor production from stem to stem if they have the same type of bowl. With the EV2 i have 4 different length direct draw stems that all perform the same as far as I can tell. regardless of being from 5 inches to 12 inches long.
For me though, it can be tough to draw with as much lung power on a long stem, as I can on a short stem. Though it is hotter the vapor itself can be thicker and stronger bc I can pull better air through the load more evenly with a strong draw more quickly, than with a long stem which requires a longer slower draw for me
Hashtag46&2
Trichome Technician
Couldn't agree more here...pretty much the same exact routine.
If it's late at night, I'll use my fingernails to speed up the process, but gently using tweezers to expose those Trichomes is part of the Vaping ritual that I enjoy so much.
Especially since I grew the Trichomes, the Vaporization routine is so sacred to me.... So being able to visually see the Glands in my load is very important to me as well.
To someday create my own Vaporizer will complete the circle of Life.
From seed to Vapor all self-sustained... Winning!
nosmoking
Just so Dab HAppy!
I am just being curious here but I may be on to something too...what are you testing with? I recall reading that you vape botanicals and I was wondering if your testing with them or with the more common herb that many of us buy vaporizers for? If you are using botanicals in your testing, have you been able to compare them to herbs and what are you findings between the two?
I guess I'm just wondering if botanicals have more consistency between strains or just less strains so less inconsistencies and I'm also wondering if botanicals would be better for testing or not.
Yeh I found it very counter intuitive as well. It was just one quick uncontrolled test so I need to do more work for sure. I am thinking it might have something to with pressure drop ornot adequate cooling time? Mostly it was hot but definitely not as dense. I was fontina the to do the seed to vapor bit this year so only limited botanical use... But yeh the stain piece of the equation is a big influencer.
Another 'not so sure on all the science' here. I get some of it. Which just makes it worse for me.
@RastaBuddhaTao, I think I can see how stem length could make a difference. Would the extra length influence the speed of the vapor due to different time for it to accelerate to it's final velocity. Which in turn would influence pressure drop?
I have more knowledge of motorcycle exhaust design which involves pulse lengths and back pressure. Cylinder head gas flowing where the inlet ports are shaped to aid 'swirling' of the fuel/air mixture. Hence my post in the Zion thread about a baffle or 'swirl' to help with the high center temps.
Totally agree on strain differences, cultivation techniques etc., etc.
Curiosity got the better of me and will do again. I weighed out one gram and vaped it. There was 0.4g difference. I know this would be a mixture of trich's and the plant materials initial moisture content.
Tickled me how I had actually only vaped 0.4g and enjoyed the shit out of it.
@RastaBuddhaTao, I think I can see how stem length could make a difference. Would the extra length influence the speed of the vapor due to different time for it to accelerate to it's final velocity. Which in turn would influence pressure drop?
I have more knowledge of motorcycle exhaust design which involves pulse lengths and back pressure. Cylinder head gas flowing where the inlet ports are shaped to aid 'swirling' of the fuel/air mixture. Hence my post in the Zion thread about a baffle or 'swirl' to help with the high center temps.
Totally agree on strain differences, cultivation techniques etc., etc.
Curiosity got the better of me and will do again. I weighed out one gram and vaped it. There was 0.4g difference. I know this would be a mixture of trich's and the plant materials initial moisture content.
Tickled me how I had actually only vaped 0.4g and enjoyed the shit out of it.
Velocity is more effected by cross sectional area rather than distance. There is an increase in deal pressure with length but it's really small. I was really surprised by the result. I think it has something to do with pressure drop or residence time. It is a gradual progression ad the stem gets shorter the condition seems to get worse. I will resume the studies early next year when I have more time. I also have some ideas on eliminating the hot spot in the center. Damn laminar flow effects 
stickstones
Vapor concierge
How many times have you run this test with the shorter tube, @RastaBuddhaTao ? Is it repeatable? Since the reason for your results doesn't jump out at us, I wonder if it was a one time thing...
Yeh could be. The first time was at the. Bottom of a battery discharge. Then I put fresh batteries in and I was able to reproduce it and turn it on and off with the longer stem. I even transferred the same load between stems and saw a change with variation in stem length. Basically quick uncontrolled test. Point being, small changes may have a big impact on vapor.
nosmoking
Just so Dab HAppy!
Come to think of it, I do believe you are on to something here @RastaBuddhaTao Now a lot of this is still way over my head but take a look at the ElevapeSmart schematics sometime. I have discussed some with the manufacturer about the great deal of thought that went into the design of the vapor path. I don't want to elaborate much but Joe mentioned some things about their patented design that reflected on the R&D that went into making the vapor path.Velocity is more effected by cross sectional area rather than distance. There is an increase in deal pressure with length but it's really small. I was really surprised by the result. I think it has something to do with pressure drop or residence time. It is a gradual progression ad the stem gets shorter the condition seems to get worse. I will resume the studies early next year when I have more time. I also have some ideas on eliminating the hot spot in the center. Damn laminar flow effects
So how about the Hopper very short path and tiny hole to draw thru?
I have been able to study a few vaporizers in detail but not the EV. As an engineer I am very impressed with the cool technology so I have been meaning to take a closer look.
I did a retest last night and the results where not as noticeable. Definately noticeably hotter but I believe less dense and not as rich of flavor. With much of this being subjective it could just be me. Either way I know I have a limit on how short a stem I want to use in the future.
I really think t acts as a system so small units can function as good as larger ones if the entire system functions well together. Large load and a small flow path might not work but small load and slightly larger flow path might be perfect. I hope to instrument units and do some studies next year and maybe eventually some CFD.
I did a retest last night and the results where not as noticeable. Definately noticeably hotter but I believe less dense and not as rich of flavor. With much of this being subjective it could just be me. Either way I know I have a limit on how short a stem I want to use in the future.
I really think t acts as a system so small units can function as good as larger ones if the entire system functions well together. Large load and a small flow path might not work but small load and slightly larger flow path might be perfect. I hope to instrument units and do some studies next year and maybe eventually some CFD.
nosmoking
Just so Dab HAppy!
The ESV was built by a team of engineers that build medical devices so I think in a way it's right up your alley. What is coming next from them may blow our minds completely...just like Zion tech has with the Beta team and will with the Zion 100 or whatever it is we have now.
I agree with this. If you look at the miVape and Firewood 3 for instance they have very short vapor paths and the vapor is often warm which can create a harsher vaping experience (subjective). The ESV, Zion and MiniVap all have a longer/larger vapor path than the former mentioned and are claimed to taste the best and coolest.
Shit Snacks
Milaana. Lana. LANA. LANAAAA! (TM2/TP80/BAK/FW9)
Maybe once things are settled down next year I can send you my Elevape to test for yourself, by then I'll be in Zion country and should even have their sequel too I would hope...
I am starting to believe that a slower draw gives more vapor. Lower velocity means less delta in temperature from the center of the load to the OD. More residence time and less drag effects at the side walls makes for a more consistent heating and therefore liberation. Higher velocity forces more heat past the load into the vapor steam. A lower velocity allows more of the heat to saturate the load. At least this is my initial observations with limited scientific understanding.
stickstones
Vapor concierge
We've been referencing this effect for a long time but attributed it to the faster draws overwhelming the heater and reducing the heat. But if you are using a heater that doesn't get overwhelmed by faster draws and you're still seeing this effect, we might have a new reason!
If you google laminar / turbulent flow, boundary layer, fully developed flow... You can see that the velocity at the wall is always zero and increases as you approach the center of the flow front. So as you increase velocity the center gets more heat while the walls still are close to zero flow. This occurs not only in laminar flow but also in turbulent flow to a lesser degree. The missing element is the heat transfer rate due to residence time. The longer you keep your hand on the stove the more severe the burn. Really a complex problem.
grokit
well-worn member
How could you have an ssv tucked away and not know this before; it's ssv 101 (?!)
I posted this in the Zion thread but this is more appropriate location .
This just slips into the end of the stem in front of the load.
EverythingsHazy
Well-Known Member
I think it's a lot simpler than what a lot of people are making it out to be. Of course, it involves a bunch of different things, but for the most part, if you want convection to produce clouds, try using a very fine grind (almost like sand), and a slow draw. That way, all the air that enters your piece, will have touched a particle of bud, and created vapor. If you have bigger pieces of bud, more fresh air can get sucked into the piece, and dilute the vapor. Also, drawing more slowly allows the air to touch the heater for a longer period of time, which raises it's temperature, allowing it to be useful in boiling off the cannabinoids and such.
If you put 5 grams of salt in a glass stem on a metal screen, and used a dropper to drip water through it, would it dissolve take more water to dissolve it if you used 5 individual gram pieces of salt, or if you ground it into a powder? With the 5 individual chunks of salt, a lot of water would drip through the screen before ever touching any salt, and that final solution at the end would have a higher water:salt ratio than it would have, had you used powdered salt. Similar concept but with heat evaporating what it touches, and water dissolving what it touches.
I know the thought of such intense grinding probably makes a bunch of you shiver, but don't knock it until you've tried it yourself at least once.
If you put 5 grams of salt in a glass stem on a metal screen, and used a dropper to drip water through it, would it dissolve take more water to dissolve it if you used 5 individual gram pieces of salt, or if you ground it into a powder? With the 5 individual chunks of salt, a lot of water would drip through the screen before ever touching any salt, and that final solution at the end would have a higher water:salt ratio than it would have, had you used powdered salt. Similar concept but with heat evaporating what it touches, and water dissolving what it touches.
Whoever has access to an electric coffee grinder should at least once, try a bit of super fine (almost powder but not quite there) very dry bud in a Nano GonG. *edit* Only if you use a bubbler. *end edit* IMO it creates far denser vapor than a handheld grinder's coarseness.
If you try it, share your experiences here and tag/quote me
*edit*
On second thought I remembered the particles that get into the stem and these would probably be significantly worse. I'd avoid such a fine grind without percolated water filtration.
I know the thought of such intense grinding probably makes a bunch of you shiver, but don't knock it until you've tried it yourself at least once.
Such a cool thread!
There are so many ways to skin a cat. I've been tinkering with a homemade vape for a bit. I am not an engineer... i just like vaping.
I'd like to point out that some convection vapes use a large mass to maintain temps and others are using high temps on a small heater. The GH has a spiral inside a heater and uses that for a temp controlled stream of hot air. The volcano heats a large aluminum block. Some portables use coils and small ID tubes. Some desktops use light bulbs. A vape like the evo has you drawing off a large mass of glass (bamboo). There are tradeoffs for sure and it is so interesting to see how many ways people can heat herb to vaping temps.
I'd rather hit a vape I cannot overwhelm and have the least restrictive draw possible. So my preference is to hit off something big and hot. I heat a few hundred beads inside a 24mm dia. tube with a 3" 200w heater down the middle of it. What is nice is that I can add and remove beads to change the amount of surface/mass I draw off of. When the vape is maxed out, most of the flavor and dense vapor is in the first hit. The next few hits are sorta boring and a shadow of the first.
So I know that convection can make clouds on the first hit, but if taken too far I think some might not like the session. It took me some time to get used to only getting strong flavor on the first hit. It can be a good thing that a convection vape takes a few hits to warm up because the other end of the spectrum has more flavor in fewer hits.
I have played with pre-warming my bowl (conduction) and vapor flashes so much faster. So a little bowl warming can be a good thing at the expense of making things hot to handle.
My glass vape makes more vapor the faster I hit it if you limit the hit to 4-5 seconds. So it is probably being overwhelmed? Then again I have combusted with slow hits and larger loads. More testing!
There are so many ways to skin a cat. I've been tinkering with a homemade vape for a bit. I am not an engineer... i just like vaping.
I'd like to point out that some convection vapes use a large mass to maintain temps and others are using high temps on a small heater. The GH has a spiral inside a heater and uses that for a temp controlled stream of hot air. The volcano heats a large aluminum block. Some portables use coils and small ID tubes. Some desktops use light bulbs. A vape like the evo has you drawing off a large mass of glass (bamboo). There are tradeoffs for sure and it is so interesting to see how many ways people can heat herb to vaping temps.
I'd rather hit a vape I cannot overwhelm and have the least restrictive draw possible. So my preference is to hit off something big and hot. I heat a few hundred beads inside a 24mm dia. tube with a 3" 200w heater down the middle of it. What is nice is that I can add and remove beads to change the amount of surface/mass I draw off of. When the vape is maxed out, most of the flavor and dense vapor is in the first hit. The next few hits are sorta boring and a shadow of the first.
So I know that convection can make clouds on the first hit, but if taken too far I think some might not like the session. It took me some time to get used to only getting strong flavor on the first hit. It can be a good thing that a convection vape takes a few hits to warm up because the other end of the spectrum has more flavor in fewer hits.
I have played with pre-warming my bowl (conduction) and vapor flashes so much faster. So a little bowl warming can be a good thing at the expense of making things hot to handle.
My glass vape makes more vapor the faster I hit it if you limit the hit to 4-5 seconds. So it is probably being overwhelmed? Then again I have combusted with slow hits and larger loads. More testing!
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