The Magic-Flight Box

[OF]

Think a lot of that is way more then what you need to know with mflb.

tcr between boxes would be all the same between boxes. Only issue is if they changed materials for screen and rails. (notices every box hits the same?) and if can get tcr would be able to tell accurate temp with a mod.

Think what you want. That's my opinion (and long experience) and why. I once made mere money teaching this good stuff......

No, TCR is not necessary. You've missed the point, basic Circuit Analysis explains how TCR aids MF with the box design? TCR is not just a technique used to gauge temperature, it's in play all around you (like with light bulbs. "Self limiting"?

"This, TCR, is a key to the success of the box. Since the resistance rises in use, current is automatically throttled back allowing faster heat up without the danger of going too hot." You need not understand the concepts to enjoy the box (of course) but if you want to Engineer around it, it's a handy//useful part of that?

OF

 

[TommyDee]

@scy123 - @OF has filled in a lot of the blanks for me in these discussions. Seeing how I am coming at this from a mechanical background, I am more than grateful to @OF for his timely and expansive insight. Let's just say that cell technology was a missing piece of my long sorted wanderings into the world of electrical engineering.

@scy123 - Wouldn't the TCR for the LB be the same as the MD with a correction factor? I have no way to getting that information.

 

[scy123]

@scy123 - Wouldn't the TCR for the LB be the same as the MD with a correction factor? I have no way to getting that information.

The TCR should be the same between maud dib and regular mflb.

If know accurate tcr. You can acually tell what the temp of the screen is at. Imagine this. You like your herbs vaped at 450f. you set your mod to 450f and it will boost to 450f and hold.

 

[OF]

@scy123 - Wouldn't the TCR for the LB be the same as the MD with a correction factor? I have no way to getting that information.

It absolutely should be (provided the same SS material is used). The total R is higher (smaller cross section), and therefore current driven from the same source is just less. More or less, since there are also fixed resistance in series (rails, contact resistance, and so on) with don't change. This makes TCR a factor in the total, what you measure is actually less (think Thevenin again).

FWIW, TCR is classically listed in 'parts per million', that is 10,000 times percent.. To make it even more fun the TCR value you enter is typically multiplied by 100,000 so numbers can be in the (3 digits) hundreds range

Thanks for the kind words, glad to help when I can (or at least try to). I strive to 'back up' what I spout off with and generally stand ready to defend my lame ideas.

Thanks for 'listening' with an open mind. I feel you're making useful progress.

OF

 

[scy123]

Shit, sorry, if I hurt you. I actually kind of thought you had a grudge or something.

Non of my ideas are made up though. And numbers all backed by either calculations or hardware test.

Edit: Also I would find tcr with the herb temp, not screen temp. Herb temp would be lower then screen.

 

[TommyDee]

Oh, TCR of herb could be problematic. The zone of interest is under all that other duff. But technically yes, the screen temp is the herb temp in conduction vapes.

 

[scy123]

Was actually thinking about measuring temp of herb just above screen. since that will be the area that will be highest temp.

Could actually do multiple profiles. For whatever. Jut need to know the temp of spot in relation to ohms reported.

 

[TommyDee]

Considering we are drawing in cool air, the temp above the herb only gets to a saturated state after some significant warm-up time and no drawing if the screen was set to a specific temp. It is this drawing that pulls herb down to the heat source. This is the good, the bad, and the ugly in the LB. Long live the ugly! Basically I consider the chamber a stash while the herb at work is sitting on the screen.

Convection vapes, from what I understand, can very carefully control the compounds releases by controlling the precise temperature of the heating element. And in that case, the LB is uniquely qualified for stepping your compound temps through the full range in a session. It is that algo that would be something new. Something where you can program a session profile on the computer and upload it to the vape. Maybe a button push advances the temp to the next compound. Besides, if I knew the screen was never hotter than say 450C, would that not prevent combustion? We will have to deal with hot spots and cold spots.

 

[scy123]

Mods will measure and adjust wattage throughout pull. So temp of screen should not vary more then a few degrees. With ecigs this is like 5f.

EDIT: might be able to adjust it to herb temp with pull taken into consideration. Only problem I see is maybe herbs get burnt.

EDIT: DNA 250C does have a save pull feature. Which might be what you want. You set max watts and pull and then adjust watts/pull strength to what you like your pull to be. When you have a good pull you set it to save pull. Then it will regulate the pulls for you. (this is also temp regulation not just watts)

Edit: also anyone can make and adjust tcr profiles.... you don't even really need to know what you're doing if you like to tinker.

Edit: also, here is an example of the tcr I use on my vape.https://i.imgur.com/WNNbgBS.png. (the exact one actually)
Basically just enter a few resistance values measured at that temp and you have a tcr profile.

 

[TommyDee]

I'd love to have a mod with all the analysis tools but alas, I cannot justify one in any sense of wish list justification. I suspect you will find the mod to be quite responsive to the LB if you set the screen temp. Shaking the LB is what presents new herb to the screen for roasting.

 

[scy123]

I actually need testers. I would likely go a head with this. Just a matter of how long. Since you been so responsive and interested level high. I could send you a few to test along with an old dna75c to keep.

Edit: dna75c same as 250c but max 75w or something. Not gonna find better mods. Dunno how you can resist hehe

Edit: also all testing products will be end user products. Just to see if any weakness. Don't see why their would be.

 

[TommyDee]

I am all up on beta testing for you. And I'd be happy to provide feedback and data based on the 2 LB's and 2 MD's I have. One LB is still new as that is the backup spare in case something happens to my DD. But I can certainly get data from it based on a new screen and compare that to see if it changes over time.

Let's do this!

 

[scy123]

Honestly, funds are only thing holding me back from this project. I don't see this happening for 4+months I can start printing.

Edit: most of the funds will be on a printer capable of printing ULTEM 9085.

 

[TommyDee]

What temp does Ultem 9085 require? I got a hacked CubePro filament printer sitting here

Just as an aside, I ran my cell plugs using PLA and ABS. The only thermals I was worried about was junction temperature. I found that with the 20A fuse junction, it got very hot, indeed, something like Ultem would be good. Without the fuse, no heat. Copper on stainless doesn't seem to produce a noticeable temperature rise. And of course, the copper is a great heat sink. And even then, if the donut is in place, it is a sealed off zone. The braid is 15 awg equivalent and plated copper on the negative end; again, no thermals to even consider. However, I will default to PLA over ABS in the fact that is not as nasty if it ever did get hot. The air path is over the negative loop which means the body of the device is in the vicinity of the air path. However, other than the noted exceptions, there is no thermals happening other than maybe adding the resistance of the stainless rails which is what... 5F max in a session?

I am in no hurry to add things to my plate but this definitely has a way to get placed on the priority list when you're up for it.

 

[scy123]

360c plus. Problem not so much printing temp, but you need chamber temp around 90c plus to prevent warping. Might be able to get away with a lot cause print would be close to bed which would need to be around 130c depending on bed material.

Edit: fun fact Stratasys has a patent on heated chambers, that's why ones that can print Ultem cost so much. It is set to expire soon.... https://patents.google.com/patent/US6722872B1/en

 

[OF]

Was actually thinking about measuring temp of herb just above screen. since that will be the area that will be highest temp.

No, that's not how Thermodynaamics (flow of heat) works. The hottest spot is the source (screen), next the herb touching it, then the herb touching that and so on. Sensing that temperature is not easy, since any sensor used is going to alter the local temperature. We went round and round with this on Solo, Thermo Couples gave false readings (lower in that case) due to heat being conducted away locally by the sensor, the finer the wire used, the less the effect.

In the LB the only active area is the layer touching the screen, which is why shaking (renewing this layer) is so important. It's also why it works so well with such a low level of power. The bulk of the load is basically insulation, not active.

As with electricity you have to consider the heat flow......interestingly enough both 'schools' follow the same basic rules (with different names) regarding that flow. Magnetics is similar, but has some twists.

Convection vapes, from what I understand, can very carefully control the compounds releases by controlling the precise temperature of the heating element. And in that case, the LB is uniquely qualified for stepping your compound temps through the full range in a session.

Actually not. Convection carries heat energy into the load, therefore must heat the air a LOT hotter than the target load temperature. The sources are generally incandescent. "Glowing hot" in order to do this. So systems run 'open loop'? ESV controls the heat by the IR emissions ('color') of the heater element, load temperature follows that. To control the load temperature you'd need to accurately sense it, controlling the air temperature will only work at one exact operating point otherwise. Change the flow rate, for instance, and 'everything changes'.

There's a smart fellow around here, @Hippie Dickie, who senses heater temperature in a convection vape he builds but for sure it's a lot hotter there than 400F.

Convection vapes are effective/useful because the super heated air warms the load up to magic temperature slowly. Adding only enough heat to make up for heat used for evaporation and losses. Get a VG and experiment some, you'll see how this works in practice.

Automatically 'stepping up' the temperature like Miqro does is of course possible but very tough to accurately link to load temperature. You should be able to easily ramp up power delivered to the screen although most find a 'sweet spot' (setting on the PA) and stick with it?

Regards.

OF

 

[scy123]

No, that's not how Thermodynaamics (flow of heat) works. The hottest spot is the source (screen), next the herb touching it, then the herb touching that and so on. Sensing that temperature is not easy, since any sensor used is going to alter the local temperature

Most will be interested in herb temp not screen temp. True won't be easy to get exactly, but I figure I can come close. Just need a really high end IR temp device.

Edit: could potentially rig up an ir temp device with custom lens to fit mflb lid and read temp of whole heating area. Including shakes and anything you do.

 

[TommyDee]

360c plus. Problem not so much printing temp, but you need chamber temp around 90c plus to prevent warping. Might be able to get away with a lot cause print would be close to bed which would need to be around 130c depending on bed material.

Edit: fun fact Stratasys has a patent on heated chambers, that's why ones that can print Ultem cost so much. It is set to expire soon.... https://patents.google.com/patent/US6722872B1/en

Funny, the CubePro has a heated chamber and it cooks everything inside to around 70C including the build plate and the material spool. 360C might be a trick though. F/W is cringing.

Crap... got em backwards again. Conduction vapes is what the LB is and that is where the screen temp should be used as the only thing to determine the extraction temp. Of course convection is about herb temp. But in the LB, I suspect that if we maintained a 420C on the screen, you'd have a pretty good session as long as you took the time to eventually make contact with all the herb by shaking. The reason I say this is because the way my first draw always comes out... it is duffy so it forms a trench shape and it is structural at this point. The entire screen's shape is scorched after a complete and cloudy draw. The depth of the 'browning' is maybe a 1/64-1/32" I mean barely penetrated. That which does freely shake from the top exposes a green duffy (keef laced) "bed" of still fresh green herb. This takes a brush or hard knocks to dislodge. This setup produces less and less vapor and a high risk of combustion remains if you do not intervene. Therefore yes, the screen is getting hot enough to combust but the chamber is far too cool (poorly insulated) to extract compounds to any fundamental degree past say the first 1/16" above the screen. Shaking the load is a reality for proper function of the LB. Therefore I feel confident in the setting the screen's temp. There may be a correction factor of course, but that pretty much makes the LB act like a frying pan set to a particular temp for simmering. We're just simmering while consuming.

Now preheat the incoming air... Kidding!

 

[OF]

Most will be interested in herb temp not screen temp. True won't be easy to get exactly, but I figure I can come close. Just need a really high end IR temp device.

Doesn't have to be that high end to play, but the idea has a major flaw. The 'E value' (Emissivity) plays a huge role (literally a 'k factor'). As the color of the surface changes, IR emission changes. Cheap units default to .95 but real world numbers vary a lot. Useful precision this way is not possible. We need temperature regulation to a few degrees?
https://en.wikipedia.org/wiki/Emissivity

This is a common misunderstanding, but generally a fatal flaw in such attempts.

As it says in Ecclesiastes "There is nothing new under the sun".

OF

 

[scy123]

Funny, the CubePro has a heated chamber and it cooks everything inside to around 70C including the build plate and the material spool. 360C might be a trick though. F/W is cringing.

70c just might do the trick cause it's small and will get heat from bed. I don't suggest you do it so up to you if you want to, but you might be able to change firmware to put out anything...... Mines is a lot custom and I can set it to go 500c if I wanted.

ULTEM is just for safety and strength. If just making for yourself..... anything non toxic at operating temp should do.

Doesn't have to be that high end to play, but the idea has a major flaw. The 'E value' (Emissivity) plays a huge role (literally a 'k factor'). As the color of the surface changes, IR emission changes. Cheap units default to .95 but real world numbers vary a lot. Useful precision this way is not possible. We need temperature regulation to a few degrees?
https://en.wikipedia.org/wiki/Emissivity

This is a common misunderstanding, but generally a fatal flaw in such attempts.

As it says in Ecclesiastes "There is nothing new under the sun".

OF

Yea, Just recently been getting into temp measuring. So lot to learn. Guess I can spray the herb with something to test temp if it's just the surface color giving mixed results.

Edit: actually I can test the emissivity of the herb. Would be as easy as heating herb to known temp and pointing the ir temp device at it and adjusting values.

Edit: was just reading flirs faq on emissivity and guides to find emissivity. The ir camera I could get would likely have a 2% margin error. Not really so much. Plus will do other test to supplement.

 

[TommyDee]

Crap, now I've gotta learn about emissivity

​

 

[scy123]

Dude... been eyeing a lot of thermal cameras. https://therm-app.com/shop/ and https://www.thermalexpert.eu/english-1/ Sells smartphone connected ir cameras at really nice specs and price. Almost had a brand new Therm-App TH for $600usd (retails $2000) but I fucked up and that deal is over.

BTW therm-app Pro has 300,000 resolution.... that's 300,000 temp readings from image........

 

[TommyDee]

Go ahead, hurt me more

So I went did some research. I loaded a trench with some duffy top shelf green bud. It did exactly as I suspected, just kind of bedded down and fixed itself in place. Just a little loose bits floating around on the top. I top off the trench to the flat, no more. So basically 90% of the plant matter is now fixed after the first most excellent draw. The lose bits made for an entertaining snow globe but the load stayed put on subsequent draws. Not bad on the second draw. Maybe half the first. Continued for 5-6 more draws until clouds waned to whiffs. The 'cast' herb hasn't changed in color or texture. The herb basically ends up in a very narrow heat zone that drops off before it even hits the surface. The draw temperature is based on the peak of the sub-C. I used a good amount of energy. And I have a half trench left to finish - at least. No hint of combustion (very vigilant draws).

 

[OF]

Crap, now I've gotta learn about emissivity

​

Naw, only important if it's important. That is you only need to understand the technology in play if you intend to use it?

Your job is to enjoy the box.

So I went did some research. I loaded a trench with some duffy top shelf green bud. It did exactly as I suspected, just kind of bedded down and fixed itself in place. Just a little loose bits floating around on the top.

If you go back a couple of years you'll find Pioneers experimenting what what was often termed a 'loaf' technique. The goal was to get a block that could be turned to all four sides in turn. The interest died as folks decided that the vast majority wasn't being presented to the screen directly. That's when the 'shake, shake, shake' dogma got traction. Most held the best results came from fresh herb against the screen for each hit.

OTOH, this technique is quite useful in Solo/Air/ArGo in keeping the herb off the bottom of the cup (where it heats faster than through the glass stem). Guys would hold it upside down and hit it a time or two until the trichomes 'glue' the mass in place in the stem as it normally contracts a bit. "Hamster style" since it's like a hamster at his water bottle. After a hit or two you can invert to normal 'stem up' posture and stop worrying about people seeing you hit it and pointing......

OF

 

[TommyDee]

Oh good. I have a great digital thermometer... <<== that thumb digit!

I can see the great debate now - Hobbits sitting around getting higher and higher while arguing about the best way to get even higher.