Kester 44 24-6040-0039 Rosin Core Solder 0.040 in
- Sn60Pb40 leaded alloy
- 0.040 in (1.00 mm) wire diameter
- 3.3% flux content, activated rosin
- 1 pound spool
- Contains halogen
Last refreshed Sep 11, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A leaded activated rosin core solder with fast-spreading flux for general work on medium to large wires and components. It contains lead and halogen, so ventilation and handwashing matter.
As an Amazon Associate I earn from qualifying purchases. ProductDome earns a commission when you buy through links on this page.
ASIN: B0032US6QKModel: 44Category: Solder
Overview
Activated rosin flux runs through the core of this Kester solder wire, a leaded tin-lead alloy wound on a one pound spool. The flux spreads fast and wets joints quickly, which suits general soldering on medium and larger wires and parts.
Kester's activated rosin flux has a long track record for quick, reliable wetting. The thicker wire is less suited to fine electronics, and the leaded alloy rules out lead-free work.
Who it's for
Repair benches and hobby builders working on wiring and through-hole parts get a well-known leaded solder. Anyone bound by lead-free rules needs a different alloy.
Pros and cons
- Fast-spreading activated rosin flux
- Leaded alloy flows easily
- Full one pound spool
- Suited to general purpose work
- Thick for fine pitch work
Performance notes
Activated rosin cleans oxide from the metal as it melts, so the alloy wets and spreads across the joint quickly. The thicker wire feeds more solder per second, which helps on larger joints and slows fine work.
Specifications
| Brand | Kester |
|---|---|
| Model | 44 |
| Dimensions & fit | |
| Wire diameter | 0.040 in (1.00 mm) |
| Item weight | 1.06 pounds |
| Product dimensions | 2.5 x 2.5 x 2.25 inches |
| Construction & materials | |
| Material | Sn60Pb40, leaded |
| Other details | |
| Item model number | 24-6040-0039 |
| Flux content | 3.3% |
| Flux type | Activated rosin, 44 series |
| Halogen | Contains halogen |
Frequently asked questions
Is this Kester solder thin enough for small surface mount parts?
Kester describes it for general purpose soldering and medium to large wires and components. Fine pitch parts usually call for a thinner wire.
Is this Kester solder lead-free?
No. It is leaded Sn60Pb40.
Does this Kester solder need separate flux?
It has a rosin flux core at 3.3% flux content. The listing gives no guidance on adding extra flux.
Is this Kester solder halogen-free?
No. The listing states the product contains halogen.