Discontinued MistVape Touch

[mistvaporizer]

Mist was the first vaporizer I did. That gradually evolved into a session convection unit, MistVape. Most recently the MistVape Touch was created, an on demand convection unit. It is the result of many experiments and input from members of the FC community. Many thanks to @paytonpenn for recognizing the potential of the early MistVape and his many helpful suggestions. Also thanks to @Shit Snacks, @PPN, @KeroZen, @Stu and @Pipes for input, testing and interest in this project. We are moving posts about MistVape Touch from the original "Mist Herbal Vaporizer" thread to here. Thanks for looking.

 

[mistvaporizer]

I'm looking at 18650 batteries and the possibility of doing an on demand type of vape at the lowest possible cost. I have a 3.7V 3200 mAh battery but seems that is not the most common. So questions for all what is the favorite 18650 battery in terms of mAh rating. Is protected or unprotected preferred?
thanks
Here's an update, with the 3200 mAh battery I am able to get temps of up to 600 F. Within three seconds it goes to 375 to 400 F. Haven't tried this rig with any herb just running temp checks with the thermocouple.

 

[Shit Snacks]

I'm looking at 18650 batteries and the possibility of doing an on demand type of vape at the lowest possible cost. I have a 3.7V 3200 mAh battery but seems that is not the most common. So questions for all what is the favorite 18650 battery in terms of mAh rating. Is protected or unprotected preferred?
thanks
Here's an update, with the 3200 mAh battery I am able to get temps of up to 600 F. Within three seconds it goes to 375 to 400 F. Haven't tried this rig with any herb just running temp checks with the thermocouple.

@KeroZen knows a lot about batteries, as do some other members who I don't think I've seen in this thread much if at all... I know the Samsung 25R are pretty commonly recommended as are the Sony vtc, those are high drain high amp unprotected I believe

 

[KeroZen]

You need to know your load resistance before you chose your cell, not the other way around. This will give you the continuous discharge rate that you need and you add a safety margin on top of that (+5A at least)

But any battery that is not from LG, Samsung or Sony (and Panasonic but those aren't high discharge) is likely to have false numbers on their wrapping. For instance 3200mAh 30A doesn't exist...

 

[mistvaporizer]

The 18650 25R arrived and it is great. Results with nichrome and SS mesh have been promising. I like the nichrome better from a manufacturing perspective, just my preference. Easy to get temps in the 500 F range, biggest problem has been combustion. The coil can get really hot very quickly. I'll adjust things and do some test vaping later today.
The oil cup is working great, just settling on a design for the testers at this point. I have several models that I have tested and need to determine which is the best for vapor production.

Here is some abv

Vaped with a test rig. Nichrome heater, 18650 25R battery, estimated 6A and about 25 watts
This load is definitely charred some but a decent result for such an early test.
Well medicated after this load, Kosher Kush
The test rig is just a battery holder, a push button switch and the heater all wired together.
Started work on a prototype of the on demand vape I think I will be ready to ask testers to take a look
within a month or two.
thanks to @KeroZen for great advice

 

[mistvaporizer]

Tried a new coil today, calculates at 10A 42W. Temps of 600 F are possible. Easy to maintain vaping temps. I'm getting great effects but not seeing dense clouds. Two to three medium density clouds per load.

 

[PPN]

The Mist is definitly a beast and the perfect tool for micro-dosing. I like how the manufacturer is sharing with us without opacity, definitly an honnest, humble and smart guy!

Sadly I was sick enough and stopped to use my vapes (Mist included) until my throat feels better, before to get my daughter in school I was never sick (or rarely)... I think she carries everything to my home!.......or maybe am I less strong than before...
But I'm feeling a lot better today and some Mist'hits are in order!

 

[mistvaporizer]

1Tested a pancake coil on a suggestion from @paytonpenn. Same 10A/42W coil as my previous post just a new coil configuration.
It kicks butt. Increased vapor production, less charring same wonderful effect.
Here is a pic of the testing setup

The chimney is a 14/23 female joint and sits on over of the coil. The load is in the male end of a 14/23 joint. This is a little clumsy to load, the screen wants to move around. It is doable and as the stem gets sticky it is easier.
In this pic the male stem is fitted with a thermocouple to measure inhaled air, it hooks up to a bubbler so I can simulate vaping and not bake my lungs.
I can swap out the coils easily so I can investigate best coil configuration, resistance etc.

 

[paytonpenn]

How many seconds to get vapor based on your few tests so far?

 

[mistvaporizer]

I start to see vapor within twenty seconds. Definitely vaping nicely within one minute. I pulse it on for a ten count then start taking mini hits and pulsing for about three seconds on and a couple off. Then as I sense hotter vapor (not using a bubbler here) I would hit harder just after I let up on the switch.
As I get a feel for how this works I am getting less charring and nicer looking abv

 

[mistvaporizer]

Thanks again to @KeroZen he pointed me to some threads I haven't seen and there is great info. Ordered some SS wire 22 and 24 gauge so I'll try that also. With the test rig I can test coil designs as fast as I can make them.
Did a little oil cup testing today and it looked like this

Still getting more splatter than I like, maybe a cap with a high temp o ring? Going to work on other options first before I look at o rings.
So this load was two dabs of an oil from the dispensary, 70% THC
MistVape set at just under 5
Let the oil cup heat sink for a few minutes then loaded the oil and let it heat sink a couple more minutes. I took three big hits and then I stopped, I'm pretty sure there are two or three more hits at least.
Just got three more hits and I think there is more, last hit was pretty dense.

 

[mistvaporizer]

Got a prototype body ready to go. All the parts are pretty much done. I'll post some pics tomorrow. It is just a block of wood 1.2 " thick x 4" long with two holes drilled to depth. The door is the on/off switch it has brass on one side and wood on the other. Brass side towards the battery and power is on, flip the door over and the wood side is towards the battery and the power is cut. Then of course a push button to pulse the coil.
@paytonpenn agreed to test some coil builds for me and I will be sending him a test rig tomorrow.
Should be some interesting things to report.

 

[Crussell27]

Bad ass. Hard to make a decision on the next vaporizer.

 

[mistvaporizer]

Here are the prototype pics. I am mainly posting them so people can see where this is going and I'm open to suggestions on looks, button placement etc. Part of the frame on the heater side could be removed and then it would have an h shape.

This is the front with a recessed spot for the push button.
Haven't done any finishing or clean up yet.

Looking down from the top, the bottom hole is the heater chamber, upper large hole is for the battery. At the base of the battery chamber is a spring loaded brass bolt for the negative connection.
The two small holes are I didn't like where those holes were so I moved them
The little bar is a piece of wire that goes from the top to the bottom for the positive connection, it is also spring loaded.

Here is the door being inserted. Note the wire, it hits the brass face of the door which is in contact with positive end of the battery. The wire routes the current to the bottom of the unit where it is connected to the coil.

If you flip the door over then the wood surface contacts the wire and battery and the vape is off, unless you soak the wood in salt water first

Here is the bottom view, The brass nut is the negative connection for the battery, the switch sits on top of that. The hole is where the heater coil goes. The white wire is the positive battery connection.
So I have everything to make this work except the switch, waiting on an order so hopefully early next week I'll have that and I can assemble this one. There are some alterations I need to make as far as hole placement, spacing that sort of thing. All the basic ideas I came in with seem to work so no major surgery at this point.
The coil will be surrounded by a glass fitting, hopefully a 14/23 female joint like in the test rig.
Speaking of the test rig I cleaned mine up some it looks like this now

Sitting in the middle is 24 gauge, 0.42 ohm 316L SS wire. I made it into a pancake coil, works very nice.

In the container some kosher kush, bottom abv. On the right you can see the charring but on the left, from the bottom of the cup screen, a pretty nice brown. This was the first test with the SS coil
After I assemble the proto I will be in a position to start making beta versions and tweaking (assuming no issues crop up). This coil puts out a lot of heat and the battery seems to last, I haven't really tested battery life but it just seems good to me. still looking at all coil options.
If this works I think it can be offered for under $100, no promises though.

 

[Shit Snacks]

Nice!

You mean lower case h? I think that could be cool, more unique and less wood, smaller too? Could make it more rounded too... maybe even sideways or angled oven so it could be held more HammerVape style like I did with the old early convection prototype box Mist?!

So itd be glass on glass style as opposed to the current system? Was expecting the wood stem system here but 14mm makes sense too... If it's the wooden stem though, maybe turn the h back into a black with a glass stem encased in wood? You twist it on and get a long concealed vapor path the same length as the battery

So it's fixed temp fully manual? The battery door system is neat, good luck with the button!

 

[mistvaporizer]

Fully manual, when you push the button the coil is on.
Just tested a coil, 0.62 ohm SS 24 gauge wire.

So this coil has four winds and two levels, that is each wind has an upper and lower wind.
Anyway this coil takes longer to heat up maybe 20 seconds and doesn't get as hot as the pancake.
It does vape nicely and it is easy to avoid combustion. Great effect but very wispy vapor, amazing flavor. This might be @Shit Snacks coil, I know he likes to ride the flavor.
The numbers work out that this is a 30 watt coil, the pancake was 42 watts. Guess I'll try 35 watts see how that works.

 

[Crussell27]

How about a titanium coil?

 

[Shit Snacks]

Fully manual, when you push the button the coil is on.
Just tested a coil, 0.62 ohm SS 24 gauge wire.

So this coil has four winds and two levels, that is each wind has an upper and lower wind.
Anyway this coil takes longer to heat up maybe 20 seconds and doesn't get as hot as the pancake.
It does vape nicely and it is easy to avoid combustion. Great effect but very wispy vapor, amazing flavor. This might be @Shit Snacks coil, I know he likes to ride the flavor.
The numbers work out that this is a 30 watt coil, the pancake was 42 watts. Guess I'll try 35 watts see how that works.

Does it get hotter the longer you hold the button? How does that work, since you know even riding those low temps I go pretty far just totally heat soaking it I guess... Less combustion risk with this one I bet, I'm sure taste is great, a very slow steady long deep draw could yield large clouds I'd think. Interesting how the different sizes and shapes relate with different wattages, materials too... Do you think wrapping around ceramic could be a good way to go like before? Might be able to make some other high surface area shapes with the wire at various watts?

 

[mistvaporizer]

How about a titanium coil?

I've read mixed reviews about titanium, maybe I'll look at it down the road. With this design I can swap coils so could offer both coil styles if titanium had an advantage or people really wanted it. Do you like titanium coils? better flavor, heating or something else?

I'll try slow stead long draw with this coil, that might be the ticket.
I don't know what temp this maxs out at but after about 20 secs it was getting warm and at vaping temp, around 360 F .
Within about a minute of feathering the button I read 450 F with the thermocouple.
The vapor was wispy but good effect, the herb was browned with no charring, one of the best looking abv I've seen with this proto.
This design has the leads silver soldered to the coil, the leads are 16 gauge and the SS is 24 gauge. These are larger gauge wires than the MistVape so these coils are self supporting and hold their shape well so I can remove the ceramic support.

this is an edit, I tried this approach. Heat sink one minute (timed for a full minute holding down the button and watching the clock). Then over another two minutes (about) keep the button pressed. Got three nice exhale clouds. No charring and it looked like a great extraction on the herb.

 

[KeroZen]

But did I miss something here? I thought your device was unregulated but now you say that you can hold the power for that long without combusting and/or busting the coil?

When I use my custom 510 attys in power mode, there's no protection in the mod. You can get the coil glow bright red, then white and beyond... then pop!

I'm unsure it's a very good idea to use silver solder to attach your coil. Screw terminals are the preferred solution usually (even in the Milaana and the Bud Toaster, but also in all commercial 510 attys)

Talking about glowing red, this is something we try to avoid in fact, and also the reason why I prefer 18ga or 20ga SS wire: you can have them heat to the correct temperature with practically zero glow. But the side effect is that you get more inertia (less responsive)

The brighter the glow the more oxidation and damage, and possibly the more out-gassing you'll get. We might be well under the various metal vaporization points, but I read some very concerning studies about cheap e-cigs where they found Nickel and Chromium particles everywhere...

So if you don't use some kind of closed-loop regulation, I would advise you to try a larger gauge wire to minimize the glow. But some kind of regulation would be even better of course!

Then finally Titanium is very controversial indeed. Apart from the potential but unproven health issues, many people reported getting some bad taste out of it. Note that some SS grades also can have detectable taste for very sensitive people.

 

[mistvaporizer]

@KeroZen I am able to continually power on this latest coil for two minutes without it burning out. It glows a dull red. The 0.4 ohm coil gets very hot, bright red. I may do another version with pwm control but I want to try this unregulated unit first, if it doesn't hold up then I'll abandon it but so far I'm liking it a lot. The MistVape is a silver soldered coil, I've always used that. For beta units I am going to use fine silver leads instead of copper, so I will have 16 ga silver wire that is soldered to the SS coil with silver solder. What is your concern with silver solder?
The taste issue on titanium was what I was concerned with. I can't believe there are any health issues with titanium it is very bio compatible (I have a master's degree in biochemistry btw)
thanks for you input

 

[nondarb]

How about a titanium coil?

Ti in this usage adds a metallic taste and seems to degrade/corrode over time. Its strange, the surface of the metal becomes rough and discolored. Can only imagine the implications of this but I for one think Ti is a huge step back from SS having experimented with both. I've tried multiple gauges and grades.

the reason why I prefer 18ga or 20ga SS wire: you can have them heat to the correct temperature with practically zero glow. But the side effect is that you get more inertia (less responsive)

What are you using 18awg in?! I don't glow with 22 on my project or other DIY attys (then again I'm in TC mode) and get plenty of heat, even risks of combustion if I draw too slow!

Agree with your comment on screw terminals.

 

[KeroZen]

Yeah 18ga is surely overkill and it requires a lot of room to pack all that metal you need to get a reasonable resistance value. I only tried it in that fat-ass Cali RDA but I didn't post the results yet. I think I prefer 20ga in the end.

I don't know what gauge came with my Project but it still needs to be very slightly glowing, maybe 22ga is fine indeed? But the prototype above was with 24ga apparently... Anyways whatever works is fine as long as it's not glowing too much. And it's less of an issue with proper regulation.

For the silver leads I planned to experiment with it at some point but then I read how fast silver tarnishes when exposed to oxygen (and heat accelerates the process) so I was concerned about long term properties. And yes, I read people talking about spot welding etc for the assembly and it sounded like a PITA. Didn't think about silver solder... don't know how it will age. The main problem I see is that your coil won't be easily user-serviceable but maybe you didn't intend your product to work this way?

PS: plus with silver you really have bio-compatibility issues... unless you want to end like the Smurf chap

 

[mistvaporizer]

It would take a lot of silver to get like the smurf chap
My leads will be fine silver, 99.9% pure. Tarnished silver is actually the copper alloy in sterling silver tarnishing. Fine silver doesn't tarnish.
Another option would be to use stainless steel bolts for leads, I may try that. Any idea how large of a bolt you would need to make sure you get no resistance in the lead? All the internal wiring (outside the heating chamber) is 16 ga copper. I'm guessing you need at least 0.125" diameter SS. If you look at the test rig pic earlier in this thread you can see how I support the coil on the leads (copper leads in the test rig). This is part of the design I use, I could replace the copper with SS bolts but like I said I'm concerned about creating resistance in the lead and losing power to the coil.
Trying to design this so the end user can replace the coil or switch so SS bolts would be nice.
0.125" diameter SS has 0.002 ohms/inch, 0.125" diameter copper has 0.0005 ohms/inch. That might not be bad, I'll investigate.
This is a good site for getting resistance ratings http://www.hsmwire.com/alum_calc.php
Ordered some 316 SS 6-32 bolts, I'll give those a try and let everyone know how that works.

Tried a 9.5 inch 22 ga SS coil. 0.51 ohms, 34.5 watts (ohms are the reported value for that length of wire and watts are calculated based on voltage and ohms)
Used the stacked coil design

top and side view of coil with 16 ga copper leads silver soldered on

load after vaping

abv

When I measured the temp I was able to get to 450 F within 30 seconds, didn't try to max it out.
For my first try with this coil I heat soaked for 30 seconds and started hitting but kept the button down. As the vapor got harsher I started feathering the button. Several nice exhales. Charred a bit but mostly dark brown abv. The 22 ga wire definitely looks good. Also this is 5 watts more power than the previous post.

 

[mistvaporizer]

Figured out how to use screws to mount the coil. Also here is a pic of a stacked pancake coil, 22 ga SS, .5 ohm. Earlier I posted a coil pic that I called stacked pancake but @nondarb pointed out it was really a coil in coil. This pic is a stacked pancake.

This is using brass uprights. I am trying to find some ss 1/16 x 1/8" and will use those for future coils. The bolts are SS #0-80, tiny suckers.
Fired this one up and it works great, didn't try vaping with this particular coil. Vaped with a similar one with soldered leads and it worked great. 10 second heat soak and pulsing 3 on 2 off was actually a bit too hot. Has potential.
The 14 mm gong female fits over this coil and inserts into the wood base, like the test rig I posted earlier. This will be the coil set up in the new vape. The wood base slides into the frame and the power attaches to the uprights. The uprights extend through the wood base and has a connection screw that isn't visible in this pic.
Also found a nice push button and mounted that in the proto frame. I'll post more in the next few days.