National 3B-B: the premix blowpipe hand torch with B-size fittings

The National 3B-B is a single-stage premix hand torch in National’s classic blowpipe lineage — the kind of compact, hand-held burner long common in scientific glasswork and entry-level torching. National positions it as having the same quality and features as the 3A-B, with the addition of 9/16-18 ‘B’-size threaded hose fittings and a leak-proof O-ring union that lets the tip and elbow rotate to suit the piece.

What the premix flame gives you

The 3B-B is a premix torch: fuel and oxygen mix inside the body before reaching the flame. Premix burners are simple to light, stable, and predictable, and the flame is easy to read — part of why National blowpipes became such common teaching and laboratory tools. A premix flame also runs hot, which National notes makes the 3B-B well suited to hard glass like boro and Pyrex, while still handling soft glass. For how premix compares to surface-mix designs, see surface mix vs premix torches.

Who the 3B-B is for

As a hand torch, the 3B-B is held and maneuvered rather than mounted on the bench, which makes it well suited to assembly, spot heating, and mobile flame work — the kind of localized heating scientific glass often demands. It suits beginners through intermediates who want a simple, portable premix flame. The bench vs hand torch guide walks through when a hand torch is the right tool and when you’d want a bench burner instead.

Fittings, fuel, and oxygen

National’s materials give a concrete picture of how the 3B-B is plumbed: it runs low-pressure fuel gas (around 0.25 psig) with air or oxygen at 20+ psig, and uses National OX, HTM, HT, and HTC-3 series tips. Those are line pressures, not flow rates — they don’t tell you how many LPM the torch draws, so an oxygen supply still has to be matched to the work you actually do. It burns propane or natural gas; the propane vs natural gas guide covers that choice, and how many LPM does my torch need helps with oxygen sizing. National doesn’t publish the 3B-B’s jet count or exact oxygen flow (LPM), so confirm those before you buy.

Before you buy

Budget for the whole system, not just the torch: oxygen or compressed air, the correct propane or natural-gas regulator, flashback arrestors on both lines, the right National tip, didymium eyewear, and ventilation. New to plumbing a torch? Start with the fittings, hoses & connectors guide and the glass torch safety setup guide.

Editor’s note: spec details reflect National’s own product materials and dealer listings, including the fuel/oxygen pressures and tip series above (which are line pressures, not flow rates). National doesn’t publish the 3B-B’s jet count, exact oxygen flow (LPM), or current pricing, so confirm those specifics with National or your dealer before purchasing.