My first build. Possible help needed.

[mix1983]

So this is my first go at a coil and wick. It is on my Lemo which came in the mail today. It came out to 1.3 ohm which I was hoping for 1.5/1.6. I'm learning that my multimeter doesn't have the accuracy for something like this. The MVP doesn't fire 1.3 very well at all (it's like turbo lag on a vaporizer). I did about 15 (!) wraps in a 1/8" diameter. Honestly not sure what gauge this wire is, no indication is given in the package.


Any tips or advice on the coil or wick? Uniformity, etc? I realize the coil isn't perfect, especially the ends of the wraps, this was the difficult part for me, because of how the coil "mounts". I know it'll be hard to give advice on the resistance without knowing the gauge, that's why I looked everywhere trying to find out.

 

[Lessifer]

Are you sure it was 1/8" ID? That looks like decently thick wire, at least 28g. 28g, 1/8" ID, 1.3ohm should be about 6 wraps, so either that's smaller like 1/16" or the coil is shorting somewhere, either against the deck somewhere or against itself. Did it heat evenly from the inside out when you fired it?

 

[mix1983]

Not at first, it started out at .9 until I heated it and pinched it out a bit. Definitely not shorting on the block, I made very sure of that before I even hit the fire button. I didn't want a firework show. According to the tape measure it's about 1/8". I'll try to find something of larger diameter to use.

 

[Signmaker]

Im with Lessifer, just by eyeball that looks like 28 or 26 gauge wire. 15/0.125 would put you well above 2ohm, which would give a very laggy fire. I'd also like to know when it looked like when you fired it, ie even from the center vs random coils glowing, solid glow in a couple seconds vs 5+ seconds to see orange.

 

[tFOrRESTee]

I tried both 24g and 26g for 15 wraps with my 1/8 drill bit. 26g came out 1.7 ohm and 24g came out about 1.4. I think yours is 24g.

Anyway, I think your coil is too long for the current to pass thru efficiently to generate the heat. Try 9 wraps instead and see if it goes better, and make sure there's no gap in your coil.

 

[Cullin Kin]

That's definitely a lower gauge wire and that definitely doesn't look like ⅛" (3.175mm). Here's a photo for comparison along with a coil I just wrapped on it (26 gauge):



Pro tip: Go to a hardware store and pick up a precision screwdriver set. It's like $5.00 and makes things a lot easier. Also, use steam engine to predict your builds: http://www.steam-engine.org/coil.asp

Steam Engine says that it should take 8.82 wraps of 26 gauge or 13.53 wraps of 24 gauge on a ⅛" mandrel. I'm going to go with tforestee that that is 24 gauge. Unless your using a smaller mandrel, maybe say 2.5mm?

 

[mix1983]

Im with Lessifer, just by eyeball that looks like 28 or 26 gauge wire. 15/0.125 would put you well above 2ohm, which would give a very laggy fire. I'd also like to know when it looked like when you fired it, ie even from the center vs random coils glowing, solid glow in a couple seconds vs 5+ seconds to see orange.

I pinched it out until it glowed evenly from the inside out. I tried to do a ton of research before I got into this, I learned at least that much. Just not sure why my resistance is so off. Could it be quality of wire? It did come with the rta. I'll try another coil with a larger diameter I suppose.

 

[mix1983]

I tried both 24g and 26g for 15 wraps with my 1/8 drill bit. 26g came out 1.7 ohm and 24g came out about 1.4. I think yours is 24g.

Anyway, I think your coil is too long for the current to pass thru efficiently to generate the heat. Try 9 wraps instead and see if it goes better, and make sure there's no gap in your coil.

I just saw something on the "coil guide" that came with the rta about .4mm, I had been looking for gauge and overlooked it. Would that equate to 24g? I do have 28g in the mail so if that's the issue it's no biggie. I just want to make sure I'm not making a mistake somewhere.

 

[mix1983]

Ignore. Double post.

 

[mix1983]

 

[Signmaker]

0.4mm is 26ga. 15/.125" would give you 2.1ohms.

 

[mix1983]

So is my multimeter in fact correct and it's my MVP that is inaccurate?

 

[tFOrRESTee]

Since you have 1m long gauge wire, try 6 wraps, 8, or may be 10 as well, and you will see that the shorter the coil, the faster it will get heat up. Experiment it and play with it.

Anyway, do you have a torch? I bought BernzOmatic torch for around 10 bucks from home depot and it works great, and don't use lighter! I always torch my coil before I put it on my atty. That way I can see if there are any gaps in the coil so I can make it nice and tight before putting it on.

Good luck!

 

[Signmaker]

I'd wager it's somewhere in between. If your multimeter was giving you around 2 ohms, I'd say it's ballpark.

For that wire and a 0.125" mandrel, a 10 wrap would get you close to the 1.5ohm you seek.

 

[Lessifer]

So is my multimeter in fact correct and it's my MVP that is inaccurate?

I think you're not using a 1/8" bit, probably more like 1/16" which would work out with the calculator to be ~15 wraps for 1.3

Try to find something bigger to wrap on, like a nail or something for the time being. If you have a harbor freight nearby, I picked up a set of metric bits for a few bucks, has everything from 0.5mm up to 3mm

Eta: based on 26g wire

 

[Signmaker]

I think you're not using a 1/8" bit, probably more like 1/16" which would work out with the calculator to be ~15 wraps for 1.3

I disagree. If you look in his pics, whatever mandrel was used was not much smaller than the screw heads, which would put it closer to 1/8". It might not be 1/8", this is all speculation.

Unknown wire diameter, wrapped on an unknown mandrel size, for unknown resistance...this is how pipe bombs are built =D
(I know, I know, not on an MVP...just sayin though)

 

[Lessifer]

I disagree. If you look in his pics, whatever mandrel was used was not much smaller than the screw heads, which would put it closer to 1/8". It might not be 1/8", this is all speculation.

Unknown wire diameter, wrapped on an unknown mandrel size, for unknown resistance...this is how pipe bombs are built =D
(I know, I know, not on an MVP...just sayin though)

I was just saying the math worked out with a 1/16" mandrel, hard to gauge the size in the pic because I've never seen a lemo deck in person.

 

[mix1983]

Could be, I never was good at reading measurements. I truly do appreciate all of the help, I'll pick up some bigger round things to work with tomorrow and implement this information.

 

[joesquid]

I'd recommend waiting on your 28ga to arrive and then use Steam Engine to help you figure out what you need to build. I like to keep my coils down around 1/16, no bigger than 5/64. The smaller coils just seem to work best for me.

 

[mix1983]

Yeah I'm just using the freebie wire to get my feet wet. I figured it couldn't hurt to get some help with what I'm working with, it can always be used for future reference.