Ohm is good...but still a hot vape! A7 RBA...arrgh!!

[fourthrok]

I REALLY want the RBA thing to work out for me. The ol' bank account is suffering and a series of unfortunate events have made me aware I really really need to cut back on my vaping costs. With that in mind..I invested in a A7 rebuildable atomizer from MVS because it was intended for a bottom feed device and the price was something I could live with. I researched and looked at a lot of videos and read a lot of tips (some dealing with other brand RBAs however...so unsure how appropriate some tips were).

Here's my thing. I am getting the ohms metered about right...about 2.3 to 2.5, more or less. That is acceptable to me (actually, I'm aiming 2.2 ohm which is what my Cisco Specs and Pro Spec slant coil atomizers are) I STRONGLY dislike a very warm vape and harsh TH. Just been doing this RBA thing a couple of days so I've had a little struggle keeping the ohms down there where I want them. That should iron out with practice, I think. I watch to be sure the "legs"..the wires coming off the coil..are as close to the same length as these aged eyes can determine. I am careful that the coils are the correct amount (4/5) and spaced so they are neat and not touching. They are not wrapped too tightly. I check the ohms after wrapping and before trimming..and after. The bits of ends of the wire, after trimming, I fold against the posts. I am using 32g kanthal with the standard silica wicking stuff sold at most vendors. My juice is 85PG/15VG clear menthol. 3.5mg. nicotine.

My bottom feeder that I want to use with the A7 is a standard BF Bogger Box. I use AW IMR 18650 batteries.

Here's the thing: No matter how hard I tryhms are acceptable. I test fire and watch carefully and I can NOT see any "hot spots" glowing on the coils or legs. I am careful to soak the wick and give things a chance to just sit and soak and "think about it" for a bit before trying to vape for real...yet the vape is STILL HOTTER THAN IT SHOULD BE! I mean really? 2.5 ohm is a pretty mild ohm to vape at 3.7...yet this thing is uncomfortably hot much if not most of the time. What's up with that...and is there ANY thing I can do to try to remedy this? A different wicking material? Can anyone out there help me figure this out so I can use my A7? And please don't tell me to "pony up" and get a reomizer or some other $40 and up sort of thing. I am NOT going to sink any more money into this project with the RBA than I already have ...other than kanthal and wicking stuff...until I can at least get the basics down with the A7. Appreciate any help!

 

[Jimi D.]

Are you getting good air flow?

 

[fourthrok]

Yes...it seems to be fine. And last night it actually was vaping quite good...I was ecstatic! But this morning...I don't know what happened but it is a hot TH/taste again. In fact...it's so hot I can hardly taste my menthol at all. I put on my Cisco Spec...and voila! All is well. Put the A7 (same coil as yesterday) and UGH. Giving me a sore throat!

 

[Crash Moses]

The A7 is known to get a tad warm but I'm vaping a 1.0 ohm coil right now and while the A7 does get quite warm the vape is just fine.

You may have a hidden hot spot on one of the legs but if that were true I think you'd get a nasty burnt taste rather than it just being too hot.

Another possibility is that part of the coil is too near or even touching the side wall or possibly one the posts (although if it was touching it should short out). I had the same problem with one of my IGO-L builds and moving the coil as far away from the side of the atty as practical fixed the problem.

 

[Jimi D.]

Maybe it's flooded, or the coils could be too loose.

 

[Statistic]

Sheesh, rba's are great but it sure can be frustrating building and rebuilding and rebuilding some more and not getting the great vape you know they can produce. Sometimes I just have to set it all down and vape a clearo for a little while then come back to it later.

As the dudes above pointed out you may have a small section of wire that is not actually touching the wick, although (based on my experiences) I would think this would cause a pretty nasty taste in addition to a hot vape.

This may sound counterintuitive but I am going to suggest you get some bigger wire. 2.5 ohms is 2.5 ohms whether it's with 32g or 28g.
32g heats up so fast, a thicker wire will heat slower and may not create quite as much searing heat in the span of a draw as 32g does. Just my Good Luck with it!

 

[notawoman]

The a7 to me never gave me enough wicking, check out junkyrock13s rebuild of the a7 that build made it work really nicely for me.

Hope you get it working bud

 

[Cjax]

You don't want the wick to be too tight, but it's worse for it to be too loose. That's when you get that burning th. Hard to tell cause it may not glow like a traditional hotspot, and the flavor might not be affected much either. You just don't want the coil cutting into the wick, but make sure there's no gaps between the wick and coil. A happy medium of nice and snug. I usually wrap my coil around a drill bit and space the coils, then install. Then thread my wick unil it starts to tug on the coil and back off just a bit.

 

[CloudZ]

Is your coil positioned directly above the air inlet hole in the center? If this isn't the problem, just add another wrap or two for more resistance and a cooler vape.

 

[st0nedpenguin]

If you dislike throat hit, 85% PG might not be the best idea either.

 

[fourthrok]

Just an update. Many of the suggestions and tips were very helpful, and I thank you! I will consider getting maybe the 28 or 30 gauge wire, but it figures I'd just put in a pretty fair size order for the 32 before I posted here. Ah well. Meanwhile...watching for things the good folks here at ECF have shared tips about...I got my coil right (at last!) at 2 to 2.2 ohm which is where I like it best on a mechanical. And if I do say so..my last two were rather pretty. I'm still struggling with getting the wick into the well, but that's just something I'll work out with practice. No hot spots. No tight coils on the wire (or too loose either). Even legs. All is good...and no signs of a burned taste. BUT...despite all that...the TH was still too harsh. I was going to throw in the towel when a little bulb went on. My juice.

I DIY a pretty strong menthol...which is ALL I vape. I'm very fussy about my menthol, and my juice must taste just so or as they say..."If the juice ain't right...ain't NUTHIN' right!" I'd had to step down my percentage of flavor earlier this year. It's pretty strong stuff, even at 7%. I'd moved it down to 5% aend was pretty happy with it. but decided to try 4% with the RBA.

It worked. No more harsh TH...just nice flavor. I have a wee bit of fine tuning to do with the new mix...but it's 99.9% there. All is well. By Jove...I think I've got it!

 

[vapdivrr]

hopefully it is working good for you now, but maybe in the future you may want to try some thicker wire, it will produce a better flavor and actually is easier to work with. also disperses the heat a little more making for a smoother vape, the only drawback is a slight lag time in heating compared to a thinner wire. 30g is a great wire.

 

[dhomes]

you are vaping at 5.7 watts so the heat problem is strange
you are also using silica which is a cooler vape than SS Mesh

there is something weird with your setup

anyhow, at the same wattage the thicker the wire the less heat it produces (note, WATTAGE, not Volts)
try using 28 kanthal for a cooler vape,

but you still have a problem anyhow

 

[fourthrok]

you are vaping at 5.7 watts so the heat problem is strange
you are also using silica which is a cooler vape than SS Mesh

there is something weird with your setup

anyhow, at the same wattage the thicker the wire the less heat it produces (note, WATTAGE, not Volts)
try using 28 kanthal for a cooler vape,

but you still have a problem anyhow

You are right about that. I thought things were better when I posted...but they are not. By the time I went to bed, my throat was sore again. This morning I tried taking a hit...and the back of my palate hurt like h#ll and so did my throat. I threw in the towel. At least for the immediate future. Packed up those infernal A7 RBAs , the kanthal and the wire and put it all away. Went back to cartos and my one Cisco Spec 306 I can use on my Bogger. It'll be days before my mouth and throat will be better, I'm pretty sure. Ticks me off.

If I get over being p.o-ed..I'll look into the heavier wire. Or else I'll just sell the sorry stuff. lol!!!

 

[CloudZ]

Is your coil positioned directly above the air inlet hole in the center? If this isn't the problem, just add another wrap or two for more resistance and a cooler vape.

Just wondering if you made sure the coil is placed directly over the air inlet. Most of the time, harsh throat hit from an rba is from not having the coil directly in the air stream.

Also make sure you have a gap between the coil and the inlet hole, as the coil can expand slightly while hot and cause a short. This will temporarily reduce resistance and increase vapor temperature.

\*_* Posted from my humanoid robot phone *_*/

 

[fourthrok]

Just wondering if you made sure the coil is placed directly over the air inlet. Most of the time, harsh throat hit from an rba is from not having the coil directly in the air stream.

Also make sure you have a gap between the coil and the inlet hole, as the coil can expand slightly while hot and cause a short. This will temporarily reduce resistance and increase vapor temperature.

\*_* Posted from my humanoid robot phone *_*/

I've checked those things...the coil is over the air hole thingy..and there is room for the coil to expand...but it's not set too high. It looks like the ones I've seen in YouTube vids so it ought to be right. I'm thinking maybe it's that connector screw in the bottom that might be the problem. I have to unscrew it a bit to make connection with the Bogger connector (it's "supposed" to be okay to adjust that screw a bit). But some have said it can cause a short...so maybe that's it?

I've read somewhere on ECF about someone wrapping that little connector screw on the A7 with dental floss to make it more stable and he had success. I was thinking maybe I could try that...only use regular thread (which I do have) and coat it lightly with petroleum jelly before wrapping it. IF I can figure out how to wrap it, of course! (anyone got any tips or photos how that is done??)

 

[xpen]

What I did on mine was to insert a tiny oring (it was from an old carto I think) between the screw and the a7 body.

Fully unscrew the positive screw, insert the oring onto the screw and screw it all back in the a7. In a pinch, some rubber of sorts/silicon washer will do.

Be careful the treading of that damn screw is very weak and lose, don't overtighten it...

That worked for stabilizing the 'ohm dance' on my a7's, due to the screw making bad contact; that may be the cause for your performance roller-coaster by the way.

I've checked those things...the coil is over the air hole thingy..and there is room for the coil to expand...but it's not set too high. It looks like the ones I've seen in YouTube vids so it ought to be right. I'm thinking maybe it's that connector screw in the bottom that might be the problem. I have to unscrew it a bit to make connection with the Bogger connector (it's "supposed" to be okay to adjust that screw a bit). But some have said it can cause a short...so maybe that's it?

I've read somewhere on ECF about someone wrapping that little connector screw on the A7 with dental floss to make it more stable and he had success. I was thinking maybe I could try that...only use regular thread (which I do have) and coat it lightly with petroleum jelly before wrapping it. IF I can figure out how to wrap it, of course! (anyone got any tips or photos how that is done??)