General question about "hot legs"

[Spazmelda]

Let me share what I've learned....First off, a "hot leg" refers only to a leg that glows red. I'm not going to get into the causes of hot legs at this point. Let's focus on your grommets....this should help.

Silicone grommets (in rba's made with them) will burn even of you don't have a hot leg. Even though your resistance wire legs might not be glowing red, there is plenty enough resistance in your legs to make them extremely hot. Long legs made of resistance wire will get hot enough to scorch silicon grommets and will create a foul taste (can't be very heathy for you either). Most folks make legs made of non-resistance wire when the long legs pass thru a silicon grommets. Non-resistance wire allows the electricity to pass thru it with relatively no resistance. The lack of resistance produces very little heat; therefore silicone grommets won't scorch or burn.

I hope this helps...

It does, thanks. I have some stuff to try making low resistance legs. I tried with some silver crimp beads. It sort of worked, meaning I got the wires to stay together and got the coil made, but the base still seemed to get rather hot, and I had some popping in the coil that irritated me. They seemed to glow evenly, but still was popping. I'm not sure about the low r wire I was using. It was some 30 gauge silver wire from hobby lobby and there was no information on exact wire composition. I've since ordered some nickel wire to try, but it hasn't come in yet.

ETA: oh, actually I did get the nickle wire. I forgot that package arrived. Lol.

I'm not getting the burned silicone taste from the protanks at the moment, even with r legs. The base does get kind of hot with chain vaping, but not hot enough to burn me. I will try the low r wire again when I get a chance.

Thanks!

 

[pizza2me]

Can you tell me how you are using them? I got some and tried and they don't work for me (on the protank heads). First, they are a little large and hard to shove in the hole. I can get them in, but then something about them cuts off the air flow when I screw the head onto the battery. Air flow is fine through the head before I screw it into the base, and it's fine when I screw it onto the protank base, but when I put it on the battery there is no air flow at all. Are they too tall? Do I need to trim them off somewhere? I can't figure out how exactly they are cutting off the airflow.

It's been a few weeks since I did it. But, I think they were just about the same as what came with the protank except they didn't have the lip on top. (You're not trying to put the lip end inside are you?) Actually, I think I got them in easier than the orignal because it didn't have the lip. (There's a lot of "I think"s in here because it was proably on a weekend and I was having some beverages while tinkering. )

If you want, PM me your address and I can send you a couple if you can't get yours to work. Maybe they are different. But, I ordered exactly what is in the link above.

 

[Spazmelda]

The kidney puncher ones are the ones I ordered. Maybe I need to be drunk when I instal them. Lol.

Here's a picture I posted to another thread about these insulators. One is with the original insulator (top) and one is with the replacement (bottom).


I had tried them as is, and then I also tried cutting them down (reducing diameter by cutting a small wedge out of them). The arrow in the bottom pic points to the area i sliced out of the insulator to make it smaller. Either using them as they came or with a slice cut out, I get no air flow once they are on the bat. I did not put the fat end into the head assembly. The coils give a good ohm reading (~2.2 with 6 wraps of 32 gauge), so I think the coil is okay.

 

[cedric212]

The kidney puncher ones are the ones I ordered. Maybe I need to be drunk when I instal them. Lol.

Here's a picture I posted to another thread about these insulators. One is with the original insulator (top) and one is with the replacement (bottom).
View attachment 234234

I had tried them as is, and then I also tried cutting them down (reducing diameter by cutting a small wedge out of them). The arrow in the bottom pic points to the area i sliced out of the insulator to make it smaller. Either using them as they came or with a slice cut out, I get no air flow once they are on the bat. I did not put the fat end into the head assembly. The coils give a good ohm reading (~2.2 with 6 wraps of 32 gauge), so I think the coil is okay.

I'm using a similar insulator (bought mine on Ebay) for my Protank/Puritank head and encountered the same problem you're having. From my understanding, the blockage of air flow is due to the center pin of the device pressing on the positive pin of the head causing the base of the insulator to expand and creating a seal. This can be easily remedied if you have an adjustable center pin device (mostly in mechs) by adjusting it to make contact with the head without compressing the insulator. However, for all other devices, I had to cut off a big chuck off the side of the insulator so that air can pass through when compressed.



As for the issue with "hot legs," a NR-R-NR coil isn't needed if you're rebuilding the head above 1.5+ohms range. You can shorten the insulator by slicing off the top to prevent it from being scorched.

Lastly, NR-R-NR coils are PITA to make (pricking yourself, short, etc.), so make sure that you've exhausted all other options (adjust amount of wicking material used, lower resistance/volt/watt, etc.) before deciding to go that route.

 

[Randy C]

It does, thanks. I have some stuff to try making low resistance legs. I tried with some silver crimp beads. It sort of worked, meaning I got the wires to stay together and got the coil made, but the base still seemed to get rather hot, and I had some popping in the coil that irritated me. They seemed to glow evenly, but still was popping. I'm not sure about the low r wire I was using. It was some 30 gauge silver wire from hobby lobby and there was no information on exact wire composition. I've since ordered some nickel wire to try, but it hasn't come in yet.

ETA: oh, actually I did get the nickle wire. I forgot that package arrived. Lol.

I'm not getting the burned silicone taste from the protanks at the moment, even with r legs. The base does get kind of hot with chain vaping, but not hot enough to burn me. I will try the low r wire again when I get a chance.

Thanks!

Oops, I forgot something... I have at times run two lengths of resistance wire (twisted together) for each leg. This doubles the ohms per leg and it greatly reduces leg heat. It's a great work-around if you've got no NR wire hanging around

 

[Spazmelda]

I was going to try that eventually too. But, do you mean it halves the ohms, or am I totally misunderstanding ohms?

 

[Randy C]

I was going to try that eventually too. But, do you mean it halves the ohms, or am I totally misunderstanding ohms?

Look at this Ohms formula below to see how ohms comes into play- in this case, doubled legs make one thicker leg; measuring more ohms... We don't often talk about Watts, but watts is POWER and it produces heat

(Volts X Volts) / Ohms = Watts

Lets say you're running 4 volts at 1 ohm- 4X4=16. 16/1=16 Watts- More power/more heat
Now lets say your running 4 volts at 2 ohms- 4X4=16. 16/2= 8 Watts- Less power/less heat

So... Less ohms creates more heat. Make sense?

 

[Spazmelda]

I'm using a similar insulator (bought mine on Ebay) for my Protank/Puritank head and encountered the same problem you're having. From my understanding, the blockage of air flow is due to the center pin of the device pressing on the positive pin of the head causing the base of the insulator to expand and creating a seal. This can be easily remedied if you have an adjustable center pin device (mostly in mechs) by adjusting it to make contact with the head without compressing the insulator. However, for all other devices, I had to cut off a big chuck off the side of the insulator so that air can pass through when compressed.

View attachment 234246

As for the issue with "hot legs," a NR-R-NR coil isn't needed if you're rebuilding the head above 1.5+ohms range. You can shorten the insulator by slicing off the top to prevent it from being scorched.

Lastly, NR-R-NR coils are PITA to make (pricking yourself, short, etc.), so make sure that you've exhausted all other options (adjust amount of wicking material used, lower resistance/volt/watt, etc.) before deciding to go that route.

I forgot to respond to this yesterday. Thanks, I will try that. Obviously they can work with some tinkering.

 

[TheSystemHasFailed]

Yes, you need NR wire. Period. Well, I mean, if you don't want to get fumes from the rubber that WILL heat up.
You notice how you, yourself said that you noticed scorch marks on the grommet.
Kanthal wire resists the current, producing heat, NR does not. I've rewired an EVOD with ribbon/NR wire. It is far from impossible.

I'm telling you, get that heat away from sources that can't handle being pressed up against them.
Peace of mind is priceless.

 

[Spazmelda]

Look at this Ohms formula below to see how ohms comes into play- in this case with doubled legs to make one thicker leg measuring more ohms... We don't often talk about Watts, but watts is POWER and it produces heat

(Volts X Volts) / Ohms = Watts

Lets say you're running 4 volts at 1 ohm- 4X4=16. 16/1=16 Watts- More power/more heat
Now lets say your running 4 volts at 2 ohms- 4X4=16. 16/2= 8 Watts- Less power/less heat

So... Less ohms creates more heat. Make sense?

I'm still pondering this. I was under the impression that twisting the wire was basically like using a thicker wire (lower gauge) and that thicker wire has less resistance because there are more paths for the electrons to go through. Oh well, I know that there is some scientific rationale for twisting the wire to make it less hot, even if I don't understand why it works, lol.

 

[Spazmelda]

Yes, you need NR wire. Period. Well, I mean, if you don't want to get fumes from the rubber that WILL heat up.
You notice how you, yourself said that you noticed scorch marks on the grommet.
Kanthal wire resists the current, producing heat, NR does not. I've rewired an EVOD with ribbon/NR wire. It is far from impossible.

I'm telling you, get that heat away from sources that can't handle being pressed up against them.
Peace of mind is priceless.

It's interesting that the grommet doesn't always scorch. I'm working on the low r. Next time I make a coil I will try the low r with the nickel wire that I now have and see if that works better than the unknown hobby lobby wire I tried last time.

 

[TheSystemHasFailed]

Nickel shall set the true vape free.

 

[xwarp]

they way coils work is that the leads are were the power is coming from. so the positive side and the negative side meet in the middle causing heat to be made. thats why the middle of the coil should in theory glow first followed shortly by the outer coils. the legs could get hot if you kept the power going but not in the timespan of a drag on an ecig i could be wrong but i think thats somewhat right. when shorts occur thats when the two powers meet in an unexpected spot (the rubber seal) and usually sparks ensue due to the uncontrolled environment like all metal touching it causing it to ground out and heat up and potentially pop a wire. hope that helps

Are you serious?

 

[cowboy6591]

Oh so many pioneers lead to so many choices.
If you have a Genny style tank;
Well If you want a quick and lazy way to eliminate hot-legs [sorry Rod Stewart}, Watch a Lazy fat guy like me.
I went to Radio Shack and bought some sub D-Shell connectors. And low and behold the push pin male and female tin shells came on a tin strip. Now both these items can be used. In case you’re a novice at techno babble if you remember ever seeing the audio plug that connects cd rom audio channels to a sound card in an older computer, this is the same material. It’s cheap tin sheet metal but thicker and less mushy then tinfoil from a grocery store, though I was tempted to use that. YOU CAN USE PLAIN SCISSORS.
Just cut off and fabricate [work with your creative hands] and bend the tiny strip to a “C” shape, now you’re making a crimp connector for your legs. Put that between the Positive post and your wick sort getting ready to wrap it around the leg, but just crimp it with needle nose pliers instead.
You have done 2 things , you have re-routed the current to your wick directly by-passing the resistance wire on the leg, 2, If that fails the crimp will act as a “Heat-sink” preventing the leg glowing hot.
NOT THE BEST WAY but the Lazy way , a time saver it is.
Better then nonresistance twisting wire and fooling with open circuits as a result.
Oh ya, don't bother with the bottom leg, unless you have to.
If you have a "Pro-Tank" style then you will have to stock up on "Micro-Tubing" which Digi-Key Inc. does have.
You slip it over the legs and crimp it on each end , wala!! instant NR-leg. Various inner diameters as small as 40 awg.

 

[TheSystemHasFailed]

Fighting "hot-legs" on a genesis is only masking the problem.
Learn to properly oxidize.

 

[Randy C]

I'm still pondering this. I was under the impression that twisting the wire was basically like using a thicker wire (lower gauge) and that thicker wire has less resistance because there are more paths for the electrons to go through. Oh well, I know that there is some scientific rationale for twisting the wire to make it less hot, even if I don't understand why it works, lol.

Sorry to steer you in the wrong direction.... I was totally wrong. I was overthinking this one

 

[xwarp]

You've almost got this!

Here is where you are going wrong: "thicker wire has less resistance"
No, thicker wire has more resistance (higher ohms). Electricity passing through a greater mass faces more resistance. Two legs twisted together, making one thicker leg, has more resistance (higher ohms). [/B]
[/I]

Your statement is absolutely INCORRECT.

 

[Spazmelda]

Okay, well confused as heck now. I thought that thinner wire (assuming the wire compositions are the same) has more resistance because there are less paths for the electrons to travel. Iow, a thinner wire resists the flow of electrons. The analogy I seem to remember is that it's kind of like a water hose. A bigger/wider water hose allows more water to travel through, less resistance to the flow of water molecules.

V=IR, which would mean that R is indirectly proportional to I. As current increases resistance decreases. Looking at the formula up there V*V/R=P, and I don't think I understand the relationship between power and heat in the situation we are discussing. Does more power make more heat, or is it more resistance that makes the heat (or a combination of both)?

A 28 gauge coil will give me an ohms reading of less than 1, whereas a 32 gauge gauge coil will give me a reading of ~2.2 ohms. The 28 gauge wire is thicker and provides less resistance.

Then, the thing with using low resistance wire for the legs, it was my understanding that nickel and silver are examples of low resistance wire. They do not resist the flow of electrons as much because of the physical properties of the metal, they are better conductors. So these would be appropriate for the parts of wire that are not supposed to heat up. Then, twisting the r wires for the legs would be better than just using the r wire untwisted, because it would be like doubling the gauge of the wire, creating less resistance > less heat.

Now... I still don't understand why the coil part of the kanthal wire is the only part that glows. And the glow starts in the middle of the coil. The side coils do heat up pretty quickly and glow but they heat up a smidge later than the center of the coil. I read some posts on here and elsewhere that attribute this to inductance (which I don't understand in the slightest, something about the reversal of current flow?) and then others say inductance can't be occurring here because we are using DC power and DC power doesn't allow/cause (?) inductance across a coiled resistor element. I don't think I ever found anyone posting who had a good physical answer for why this happens (at least not one that i understood). I know this isn't really an important question, curiosity about it is just what spurred my original post.

I took baby physics in college (the kind without calculus) so my understanding of things is probably very simplified compared to what many of you here know. And, that was oh... About 20 years ago. I guess it's not really important. I seem to be able to make a coil for the protank that is working very well, and I'm sure I can find tutorials on the aga when I get around to messing with that. I don't really need to know how it works, I just like to have a basic understanding.

 

[The Dingo]

Thicker wire does, in fact, offer LOWER resistance.

Although it is probably very rudimentary compared to the knowledge of most people on this forum, one way I like to remember it is to compare electrical wire to plumbing pipes:

Larger pipes = lower resistance to the water flowing through them...same thing for electrical wire.
Smaller diameter pipes = higher resistance to the water flowing through them...again, same thing for electrical wire.

Not sure why, but it's easier for me to visualize water than it is for me to visualize electrons.

 

[cowboy6591]

I was going to try that eventually too. But, do you mean it halves the ohms, or am I totally misunderstanding ohms?

Your only doubling the wire mass of the legs not the whole coil, expect a 0.2 ohm drop doing that. If you were doubling the wire for the whole coil then you would be cutting the resistance in half but you’re not doing this. You are only cutting the resistance of the legs not the coil.