Series of experiments with extemly low resistance

[Alexander Mundy]

Let me start with some background.
I built a VV bottom feeder mod that will safely go from 0.6V to 5.5V up to 20A with two 18650 batteries just to be able to do these experiments.
Attempting this without appropriate electronics would involve currents that are far above what any 18650 or 26650 battery could take.

http://www.e-cigarette-forum.com/forum/battery-mods/507150-20a-vv-bottom-feeder-rises-ashes.html

The 1st experiment was on a previous mod with the same electronics with an RM2 atty and simple rolled up mesh for 0.065 ohm at 1.23V for 19A at the coil.

A+ for vapor.
B+ for throat hit.
B for flavor.( Above protank, below Rene41, and further below Magic )
C for lag time


I finished up prototype #1 special atty for this mod and the results were mixed.
First try was with 6 circles of mesh and no vapor was produced because I couldn't get over .72V without going over 20A.
Second try was with 1 mesh circle and at 1.12V at the module (.97V measured from center tube to base) the current was 20A and the mesh had 0.0485 ohms of resistance.

B- for vapor
F- for throat hit
A+ for flavor ( * At least as good if not better than Magic * )
A for lag time

Due to the excellent flavor this design has potential if throat hit can be increased made to happen.
Unfortunately there was noticeable heating of the whole atty base.
3 watts was dissipated from module to center post and base of the atty so not a huge amount.
Most of the heat however was conducted from the perimeter of the mesh circle to the atty.
The only way I see that this setup would be workable is if the mesh could be thermally isolated from the atty base with ceramic or other high temp low heat conductive material.
Otherwise the atty itself draws too much heat away from the mesh heating element.

Parts from left to right: Drip pan from BT804 / Compression spring from ? / Ring from Hero Hybrid / 1/8" OD SS tubing with feed hole just above mesh / 1/8" stop collar / Circle of 400 SS mesh with hole in center / washer / Compression spring / stop collar / Compression spring / Modified BT804 base / BT804 tank & drip tip topper.

The first compression spring pushes the Hero Hybrid ring up clamping the perimeter of the SS mesh against the base.
The second compression spring clamps the center of the mesh to the SS center tube between the 2 stop collars.
The third compression spring pushes down on the center tube to maintain good connection with the 510 center pin.

The air flow was from below the mesh going through it and the tube to the drip tip


BT804 base with center removed.

I will follow up with other prototypes as time allows me to make them.

 

[Alexander Mundy]

Small update

Made some sleeves out of the next size SS tubing to contact the mesh so as to increase the area of the mesh exposed since the stop collar covered a good portion of the middle.
That did not help.

Another member suggested I put some small holes in the mesh around the circumference.
Started with 5 as suggested and when I brought the voltage up to the point vaporization occurred it did indeed increase vapor production.
However it also created hot spots around the small holes.
Tried adding to the number of holes thinking that would even it out some but that did not help.
Interesting how a few holes did not get hot spots and I am at a loss as to why.

 

[Visus]

The burning of ss mesh creates a highly toxic gas. I say its not rocket science its there already all your trying to do is hurt yourself.
Rethink your experiments
Wiki
hexavalent chromium

 

[Alexander Mundy]

Yes, I am very aware of this, but thanks for your concern.
I did not draw on the mesh that had the holes in it as I tested dry first to see the results with the mesh.
I do not understand "I say it's not rocket science it's there already" however.

 

[onjre]

Yeah I was wondering what that meant too.

What temperature constitutes burning? I would be a bit surprised if stainless did anything at the vaporization temperature of our juice.

 

[Visus]

Yes, I am very aware of this, but thanks for your concern.
I did not draw on the mesh that had the holes in it as I tested dry first to see the results with the mesh.
I do not understand "I say it's not rocket science it's there already" however.

Your mundy coil others, etc. etc. you can only have so much rewarding vapage goin on lol..

 

[pdib]

yet again, . . . . .. . nuppin'

 

[Alexander Mundy]

Yeah I was wondering what that meant too.

What temperature constitutes burning? I would be a bit surprised if stainless did anything at the vaporization temperature of our juice.

The temperature reached locally where the black is was very high when I did the dry test. High enough there were bright red spots and some vapor emitted, so it is possible that CR6+ was created at the ends of the individual wire strands since I did clean and run the mesh through the ultrasonic to remove any residual oils. Wondering if juice might prevent the hot spots due to the energy required for vaporization I did wet it with unflavored and blow through the inlet hole in the base and the resultant vapor in the air had a slight burnt oil component so I ceased. Even if it wouldn't do it with a fresh wet wick, the possibility of drying out and getting to those temperatures makes the hole idea a dead end for me. Maybe if the holes were laser cut where the strands sintered together it wouldn't occur, but that is beyond my ability.