Cthulhumod Zathog review: A 30mm RDA that's somehow better with round wire than claptons!



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Cthulhumod Zathog RDA Review

Hey everyone!

I'm a little late with this one. I've had this for about two months now. I've put several different kinds of builds on it and I'm honestly a little perplexed by the results. More on that below.

If you aren't aware, it's a 29.5mm, dual coil, BF compatible RDA. It's the result of a collaboration between Cthulhumod and Morten Oen, of the airflow analysis fame. The RDA has side and top airflow which you can adjust individually.

It comes in black or stainless steel. I have the black one. At 85 grams it's easily one of the heavier attys you'll come across. Even the airflow adjustment ring is a solid piece at 2.7mm thick, weighing 13 grams. There is absolutely no branding, etching or carving on the atty. It's as minimalistic as they come and I love it!

I've been using my main ADV (85VG) to test this for the sake of consistency. The RDA was sent to me by Cthulhumod to review.

Photos - Album
Building with round wire

It's a very easy, post-less deck to build on. The legs need to be pretty long so clip with room to spare.

The RDA comes with a booklet that lays out the steps to what I presume is the optimum build on this RDA. Two interesting things in there:

  1. It suggests building a cotton wall around the ends of the wicks
  2. It shows round wire being used!
You don't see too many people using round wires for dual coil setups in 2018, let alone a cloudy/flavor RDA officially endorsing them.

I was intrigued so I built one just like the photo using 24g SS316L wire. Since I use regulated mods only I didn't care about wraps or resistance, I just built them to fit as nicely as possible. I didn't bother with the cotton wall at first, but I added them a day later. Made no difference really.

I was very surprised with the result. Smooth and silky draw, and quiet too. The flavor was easily the best I've gotten from round wire, or at least the best I can remember. Generous vapor production without a lot of heat. Every hit was full of flavor that was made only better by the smooth draw.

Building with fused claptons

After my experience with round wire in this RDA, I thought surely it was gonna be better with some claptons!

Unfortunately it wasn't, it was noticeably worse. I can't exactly figure out why, and that's why it took me so long to get this review out.

I have tried all my usual wires: quad 26g/40g SS316L, quad and triple 28G/40G SS316L, dual 28G/32G SS316L. I tried 2mm, 2.5mm, 3mm and 3.5mm inner diameters. Not a single build with fused claptons produced flavor good enough to recommend. It was always muted. Forget the subtle notes, even the base flavor were uninteresting.

The flavor feels more pronounced with round wire. I don't know how that makes sense.

Plenty cloudy though, surprisingly cloudy considering the size of the airflow slits compared to other cloudy RDAs. It's cool to blow so much vapor out but it quickly gets boring because the flavor can't keep up.

Like I said I can't quite figure out why it's performing so poorly with claptons, my best guess would be the side airflow slits are not tall enough to bring in enough air to hit the bigger coils properly.

Squonk Performance

It squonks just fine, although I mostly used this as a dripping atty because of the huge juice wells. The squonk pin has a bore wide enough for juice to get to the well pretty fast. It doesn't suck the excess back as efficiently but that's not usually a problem because it's very hard to oversquonk on this.

Build quality

Build quality is a mixed back with this one. The RDA feels hefty in a good way. The top airflow adjustment ring is just one solid, chunky piece of metal. Everything is machined well and feels very sturdy.

On the flip side the flat head screws are rather bad. Since this is such a big RDA the screws go pretty deep into the deck from the sides. The marking on the screw heads isn't deep enough for the screw driver to get a proper grip on them. They should have used longer hex screws that don't go as deep into the deck.

The ceramic insulator cracked after just a few builds. They anticipated this because the RDA comes with a spare. I also tore one of the o-rings under the top airflow adjustment ring. Can't remember the last time I tore an o-ring.


Excellent flavor from round wire

No branding or superfluous designs. Very minimalistic.

Great vapor production.


Subpar flavor from clapton wires

Build quality is a mixed bag

No barrel lock

~TLDR & Conclusion

There was understandably a lot of hype around this one, unfortunately the flavor doesn't quite live up to it IMO. It's still a very cloudy RDA if you're into that sort of thing.

Sure it makes round wires sing like they've never sung before, but it falls rather short with clapton wires. Besides it's round wire performance is nothing that can't be topped buy a good RDA and a good pair of fused claptons. I love it as a proof of concept but it's not something very useful in 2018.

If $30 doesn't sound like a whole lot and if you've got a lot of round wire leftover from yesteryears, you won't be too disappointed with this one. For everyone else this might be worth a try if you ever find it for around $10.

I have to commend Cthulhumod for putting out one unconventional product after another. Cthulhumod continues to surprise us all in a market where the majority of the attys are just slight variations of each other. I hope they learn from their mistakes and don't stray from their unconventional path. I for one freaking love the freakishly tall AF drip tip on the Hastur MTL Mini.

Meta stuff

I'm on Instagram now as well. I post daily photos of my stuff and gear that are in the review queue. I'd appreciate it if you guys checked it out!

I haven't posted a review in a while because I got a little burnt out from writing. I had a nice little break but my review queue has been getting quite heavy. I've been using a lot of setups and have been taking notes, hopefully I can bang out a few more reviews in the coming days.

  • Height: 44mm (ex. drip tip & 510)
  • Diameter: 30mm officially, 29.5mm in my caliper.
  • Weight: 85g! (ex.coil)
You can buy the RDA on Cthulhumod's website. You can also find it on Heaven Gifts, Health Cabin, Sourcemore or Fasttech among other places. I deal with all four of those companies regularly and I have nothing but great things to say about their customer service.

Where to buy

You can find the Zathog pretty much everywhere. I recommend the following sites because I deal with all of them on a regular basis and I have nothing but great things to say about their customer service.


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