DIY Wireless 14mm Injector (for 16mm Coils)

MrGrumpyMcGrumpster · September 30, 2026, 1:04am

A while ago, I got impatient waiting for a wireless ZX to be released, so I wondered if maybe I could cobble together a home brew amazon special until one did come out. It’ll be cheap, dirt cheap, but still aiming for a peaky flavour blast with small < .15g loads. Here’s the basic haul of parts:

Amazon hexagonal concrete ashtray I bought quite a while back.
A 3D Printed Ashtray and Coil Holder specifically for that Ashtray (step file linked below)
16mm barrel coil I had laying around
5.5 grams of 3mm corundum balls for a nice spiky heat curve
2 concentrate pads (I’m using S&B ones)
m2 threaded rod and nuts and a small handle

I also looked for the roundest 304 Stainless tubing I could find, 14mm/13mm OD/ID, and 16mm/14mm OD/ID. Stuff from ‘METERXITY’ on Amazon seems to work well. I bought 2 feet of each diameter for $40 CAD total , and I have enough for another 10-15 housings. Access to a dremel tool, and heavy duty pipe cutters (the kind you spin around the pipe) is a must.

Base and Coil Clamp for Concrete Ashtray.step (114.8 KB)

Ignore the scratches. They are well used! 27mm length for the 16mm OD tube, and 37mm for the other will be perfect for 5.5g of rubies. A spinning pipe cutter creates a perfect round outer edge with a small inner lip. Leave the lip on the bottom of each tube, but dremel smooth the tops. The bottom lip on the large tube keeps the smaller tube from slipping through, and the bottom lip of the smaller tube keeps the concentrate pad in place.

A bit of emery cloth and buffing with the dremel will allow them to slide freely. Smooth and burr free openings are the key or the injector will constantly ‘catch’ and drive you crazy. You should get it now. Drill a hole for the m2 rod. Be careful you don’t hulk out on the drill and squish the pipe out of round.

The concentrate pad should fit in with a little bit of persuasion. Fill with the 5.5g of 3mm ruby balls, then top off with another concentrate pad. The concentrate pad on the bottom is awesome. Completely evens out the flow.

Rig up a handle by bending a threaded rod 90 degrees and securing with nuts. Again, careful not to go hulk and tighten the tube out of round. A vertical handle is best. A DIY tube vape without a mirror finish will catch horribly with a perpendicular offset handle.

For a bowl, I just use any 14mm Female fitting with a 19mm screen pushed in (a 13mm diameter rod is perfect screen tool). I happen to have a bunch of 14F18M adapters that are perfect with hookah grommets.

Nice and even cook throughout with the concentrate pad! I run mine at 250c, and it has a nice peaky heat curve with a flavour extraction to match! If you don’t mind stainless in your air path and have a few parts laying around or within an easy click, chip in with a few friends and make a bunch of your own. It’s so satisfying! Satisfaction even doubles when you get through it baked and with your digits intact.

MrGrumpyMcGrumpster · October 6, 2026, 4:00am

Update:

The hardest part of this is the 16mm tube cutting, and polishing the inside for things to slide smoothly. Can be completely replaced with an off the shelf M14x16x20mm stainless spacer. So the only tube cutting will be for the 14mm injector tube.

And here’s a rough parts list with cost (Canadian Dollars) and links:

M14x16x20mm Stainless Spacer - $2.72 per piece

14mm Stainless Tube - Roughly $1.50 a piece after cutting

Concentrate Pads - Roughly $5.50 for 2

3mm Ruby Corundum - Roughly $20 for 100, about 5.6 grams

16mm Heater Coil - Roughly $21 per coil (type 2)

Type 2 PID - Roughly $31 (type 2)

m2 Nut and bolt set - $14 for a large assorted set, lets say a conservative $1 per

Works out to about $83, so lets round up to about $100 for a small one hit 14mm injector, with controller and coil, geared towards flavour and a completely even cook. Other bits and bobs like ashtray, 3d printed parts, tools, etc… are up to you.

jackrod · October 6, 2026, 4:45am

Love the DIY stuff. I will have to make one of these.

I use a lot of that uxcell / METERIXITY ss tubing to make my logs. It’s nice stuff, definitely rounder than the K&S stuff they have at the hardware store. They also have 316, but not in as many sizes. Not that I think there is anything wrong with 304.

I used to cut it with a pipe cutter. It works, of course, and the lip can be useful. But it leaves a pretty nasty burr. Those cutters are really designed for soft metal tubing. SS on the other hand is hard to begin with and work hardens like crazy, resulting in the burrs. But you probably know this already.

Anyway, I switched to using a small abrasive chop saw to cut the log tubing pieces. The one I have is kind of shit and can only do up to 12mm. I should get something at least a little bigger. This will leave some burr still of course but it is much narrower, and less hard, so not as hard to remove with one of those swiveling blade deburr tools (get plenty of blades with them, ss wears them out fast).

The concentrate pad is interesting! Have you tried it with just a normal basket screen? Wonder if it would be worth it for the airflow.

Good finds on the cheap PIDs and coils.

Since you’re comfortable with the ss tubing and stuff already, I’d highly recommend a log build too! I have a guide for how to make a halogen one posted in my thread here:

I can also help out with any advice or some parts. You could even make a combination of this and a log if you used a heater cartridge from a 3D printer.

Other ideas:

Try a “diffuser” arrangement as well, with the bowl fitting into the heater, instead of the heater into the bowl
Use 14mm or 18mm male/female ground glass joint blanks to make bowls/stems that can go into your water pipe either directly or with a male-male adapter