Short answer: The GTT Kobuki and GTT Delta Mag are both three-stage Triple Mix bench torches from Glass Torch Technologies, built for production and large borosilicate work rather than everyday beadmaking. The Kobuki ($3,550) puts a Phantom-size flame on a bigger heat base for faster melt-ins; the Delta Mag ($4,250) goes furnace-scale, with roughly double the jets and oxygen appetite. Step up to the Delta Mag only when the glass mass you heat every day outgrows what the Kobuki can hold molten, and only if your oxygen supply can feed it: both sit well beyond a single concentrator, and the Delta Mag in particular calls for banked concentrators, a large booster, or bulk/tank oxygen. For the great majority of makers, neither is the torch you need; the smaller Triple Mix ladder covers that ground.
If you are still mapping the wider decision, the complete glass torch buyer’s guide frames the whole range; this article zooms in on the two smallest members of GTT’s production line.
The two torches side by side
Both are surface-mix, three-stage bench torches in the pro price band. Here is what the catalog carries, drawn from GTT’s own product and flow-rate pages.
| Spec | GTT Kobuki | GTT Delta Mag |
|---|---|---|
| Price | $3,550 | $4,250 |
| Stages | 3 | 3 |
| Jets | 49 | 88 |
| Oxygen (estimate) | ~33 LPM | ~54 LPM |
| Mix type | Surface mix | Surface mix |
| Mount | Bench | Bench |
Editor’s note: the oxygen figures are estimates, not hard specs. They come from GTT’s published flow-rate table at the largest usable flame on propane (the Kobuki around 70 CFH, the Delta Mag around 115 CFH), converted to LPM. GTT notes natural-gas consumption runs higher, on the order of two and a half times. Treat these as planning numbers and confirm the current figures with GTT before you commit to a supply.
What Triple Mix actually is: surface mix, not premix
Both torches use GTT’s patented Triple Mix, and it is worth being precise about what that means, because it is easy to assume anything this powerful must be a premix design. It is not. In Triple Mix, the torch surrounds the fuel with oxygen and injects additional oxygen down the fuel stream, but the fuel and oxygen do not actually combine until they reach the face of the torch. That makes it a surface-mix architecture, the same family as the rest of GTT’s high-end line, not a premix burner that mixes the gases inside the head. The center, middle, and outer fires, along with their oxygen streams, are independently controllable, so you can dial a fine center flame inside a large soft outer envelope. Source: GTT Triple Mix. For a fuller treatment, see how GTT Triple Mix works.
The practical upshot is the reason GTT builds its whole top line this way: a surface-mix flame stays quieter, gentler, and kinder to colors even at high output than a comparable premix flame would. Every trade-off below happens inside that character.
GTT Kobuki: a Phantom-size flame with production heat behind it
The Kobuki is a three-stage torch built around a 7-jet Lynx center, a 15-jet Phantom middle, and a 27-jet outer ring, 49 jets in total. GTT’s stated design intent is specific: it is for makers who love the Phantom-size flame but need more heat behind it for fast melt-ins and rapid heating in production work. In other words, the flame footprint feels familiar to anyone who has run a Phantom, but there is a much larger heat base underneath it. Source: GTT Kobuki.
GTT also frames the Kobuki as a flexible single torch that can imitate several others. The company states it is capable of imitating no less than four other torches plus a flame type all its own: the Lynx, the Phantom, the Mirage, the Delta Elite, and a wider Kobuki flame. Read that as range rather than a claim to replace four separate torches; the value is that one bench torch covers detail work through substantial bulk heat without a swap.
GTT Delta Mag: Phantom or Mirage middle and a furnace-scale outer fire
The Delta Mag is the next real step up, and it is configurable in a way the Kobuki is not. It keeps the 7-jet Lynx center, but the middle fire is offered as either a Phantom (15-jet) or a Mirage (33-jet) stage, and the outer fire scales with it: 66 outer jets with the Phantom middle or 50 outer jets with the Mirage middle. That works out to 88 jets total with the Phantom middle and 90 with the Mirage middle. GTT states the maximum flame size is the same on both configurations, so the choice is about how the heat is distributed, not how big the flame gets. Source: GTT Delta Mag.
GTT describes the Delta Mag flame as hot and penetrating for borosilicate up to three inches of solid glass, and soft and clean for delicate soft-glass colors. That span, heavy boro on one end and gentle color work on the other, is what the extra stage and outer fire buy you: reserve heat you can call on for large mass without giving up the controllable center.
The real decision point: heat base and glass mass, not price alone
The gap between these two is not primarily $3,550 versus $4,250. It is the size of the work you feed the torch every day. The Kobuki gives you a Phantom-size working flame with enough reserve heat to melt in and move glass quickly in a production setting. The Delta Mag exists for the point where that reserve runs out: larger borosilicate, thicker sections, heavier repetitive melt-ins where the Kobuki would leave you waiting on the glass.
A useful way to read it: stay with the Kobuki if your bottleneck is your hands, not the torch. Step to the Delta Mag only when you are genuinely running out of heat on real work, when the glass mass is the thing slowing you down. Buying the bigger torch to feel covered is a mistake here, because the larger flame also brings more radiant heat at the bench and a materially larger oxygen bill. If you are weighing the smaller high-end torches instead, GTT Mirage vs Delta Elite covers the tier just below these two, and the best torches for borosilicate walks the boro-specific choice.
The oxygen supply gap: what can actually feed these
This is the constraint most likely to catch a buyer out, so plan it before you plan the torch. Oxygen concentrators, the units many lampworkers run, are typically 5 and 10 LPM machines. A single concentrator will not feed a large boro torch, and it comes nowhere near either of these. The Kobuki estimate is ~33 LPM and the Delta Mag estimate is ~54 LPM, so both sit far above what one household-style concentrator delivers.
For torches at this scale the practical oxygen sources are banked concentrators, a large booster, or bulk and tank oxygen. Which of those makes sense depends on your run time, your local oxygen prices, and how much noise and space you can live with, and community write-ups describe those capacities in detail; see oxygen concentrators vs tanks for lampworking for the general comparison. The one firm rule is that a single small concentrator is not a supply plan for either of these torches. Source: Ars Brevis oxygen guide.
On the fittings and flashback side, follow the flashback protection your torch and gas supply call for rather than any blanket rule, and treat GTT’s own manual as the final word on pressures and setup; do not substitute figures from a forum or from this page for what the manufacturer publishes for your exact configuration. Both torches also offer a compressed-air option as a separately priced configuration, which changes the supply math again.
Who these are for, and the honest case that most makers never need one
It is worth saying plainly: these are furnace-scale, shop-and-production torches, and most makers never need one. The Kobuki and Delta Mag are the two smallest members of GTT’s three-stage line. The larger siblings, the Ninja, Samurai, Cobra, and Viper, run to $5,500 and beyond, which puts the whole three-stage family in perspective: it is built for high-volume production and large sculptural boro, not for the bench where most people work.
The odd-numbered smaller Triple Mix ladder is what the majority of serious makers actually settle on. The Lynx at $525, the Phantom at $1,425, the Mirage at $1,975, and the Delta Elite at $2,575 cover detail work through heavy boro for a career. If a Kobuki or Delta Mag is genuinely on your list, it is usually because you already know why: you are running production hours or moving glass mass that a career torch cannot keep up with. If you are not sure you need one, that uncertainty is itself the answer, and the smaller line is where to look. When you do buy, confirm the current specs, pricing, and configuration options with GTT directly.
Related guides
- How GTT Triple Mix works
- GTT Mirage vs Delta Elite
- The best torches for borosilicate
- Oxygen concentrators vs tanks for lampworking