Duly noted retired! We need to maintain our safe spaces. Here is my amended reply.
The coil is quenched to harden it. This makes the metal more resistant to working; to make it harder and less easy to deform plastically. It will hold shape better when you are threading it. When heated to a higher temperature, some common metals will experience change in the crystalline grain structure. This occurs due to precipitation in the metal "solution" of different crystalline forms of the metal. I only really know about high iron content steels. Kanthal and SS metals would come under this broad definition.
The crystalline structure of iron changes as it gets heated up. Once it reaches melting, there are no crystals left in the "solid solution". The rate of cooling, eg time taken and liquid used (water vs oil) has a major effect on the crystal structure of the cooled metal solution. Over quenching and then not annealing leads to hard, but very brittle metal tools. However, the tiny diameter of the wire used here shouldnt have any issues with rapid quench cooling without annealing.
If you like to read, this is a better source about quench hardening of solid solutions.
What is the Difference between Heat Treatment, Annealing, and Tempering?(link)
Think of this like concrete without aggregate vs concrete with just sand. Aggregate has a much wider particle size, from small COPYRIGHTDMCA down to tiny sub mm diameter quartz. Having a range of different sized aggregate particles in the cement increases strength and toughness of the concrete or cement or whatever the proper name is
Some metals, eg titanium, do not quench harden. They quench soften, through a similar but opposite process to steel.
When metal working, e.g making a knife from steel stock, quench hardening is accomplished using oil. This slows the cooling rate as oils have a much lower specific heat capacity than water and will not flash evaporate. Furthermore, quenching in water will not prevent formation of oxides.
What happens when you get a red hot metal and dip it in water? The hot surface allows greater diffusion and reaction between the metal and the water. The hot metal, if steel or iron, will reduce water to oxide ions and/or hydrogen gas (traces). This forms metal oxides.
IF you want to reduce oxide layer formation, you should quench in diesel or a very light oil (Diesel??? just rinse it off afterwards with acetone you baby). Baby oil/mineral oil or cooking oil would reduce the formation of the oxide layer (you wont prevent it)
As the metal is heated more the thickness of the oxide layer increases. Btw this is irrelevant just wanted to let you know I earned my degree
If you heat the coil to yellow or white hot and quench, you may find you get a very brittle coil. Stress it too much and it will crack or snap when handling.
This brings me to the most important part of the post. Dry firing coils produces thick oxide layers on teh surface of the coils. This in turn provides a porous oxide ceramic film on top of the metal, even if the metal doesnt look like its covered in thick white oxide. Chrome and nickel can oxides possess significant catalytic properties. Not only that, but the high surface area microscopic "pitted" oxide layer will increase the rate of fouling of the coil and decomposition of the
juice.
How to deal with this??? Pickle the coils in HCl 30% or a mix of nitric acid and HCl. Metal picking relies on the reaction between acidic species and basic oxide layers. These will react with and dissolve the oxide layer on the coil and smooth the surface. An immersion of the coil for a few seconds in teh acid followed by rinse and repeat until the coil is shin again. Can then polish it if you can really be bothered (only for aesthetics, the smoothness wouldnt have much performance gain.
You can also "pickle" the metal to remove oxide layers by placing the coils in an ultrasonic bath with an abrasive slurry, eg alumina or zirconia. This is called eco pickling.
Once out in the air again, the shiny metal will form a very fine oxide layer. This will be much thinner and smoother than the one produced during high heating a water quenching and should be a good balance between a porous coil surface and shielding the juice from catalytic properties of metals in the alloy (eg Ni and Cr).
The nickel and chrome metals have great catalytic activity and the oxide layer shields them. But, a thicker porous oxide layer will hinder mass transfer of juice and heat transfer, resulting in more microscopic hot spots on teh coil surface. Oxides have a milder catalytic ability than the metal, hence we want a minimal layer thickness.
Your experimental data looks arbitrary and meaningless btw. You would be best running coils of similar resistances and using pulsing them for a set amount of time with wet cotton. You could weigh them before and after and see what mass of juice was vapourized. Breathing in for a set amount of time at a set power rating is ridiculously imprecise.
Ridiculously imprecise
You could then adjust the numbers for coil resistance and output or whatever if you wanted to get fancy.
These radiator coils are interesting. The temp of the vapour getting into your lungs will be dependent on many factors, eg the velocity of air being sucked through the RDA and how you hold your mouth. Compression of gasses through flow streams will result in heating of that surrounding pipe or tube. Compresion and sudden expansion will allow heat to be dissapated from a hotter source, the compressed air, and then sudden cooling as the gas expands into a larger diameter opening. My tsunami RDA has a similar feature to it. Expansion of diameter as it gets closer to your mouth.
Just keep doing your science. I will build a radiator coil at some stage. These coils may have benefits to claptons in rate of decomposition of juice as it is vapourized. Claptosn freature a lot of tight spaces, great for stagnation and overheating of fluids. But this may increase the wicking capacity of the clapton as well as juice will be attracted to -OH groups on the oxide layer of the metal and claptons probably have more surface area as the narrower wire exterior doesnt carry current and acts solely as a heat spreader.
Radiators will reduce the number of lower diffusive flux regions on the coil, at the price of running current through all the wires instead of the core.
Reporting my comments isnt going to save you from being called out.
