Tech & Gadgets · Head-to-head
Kester 44 Flux-Cored Wire (Sn63Pb37) vs MG Chemicals 4880-4888 Sn63/Pb37 RA Solder Wire
Which should you buy? Our verdict on both, pulled from our full The Best Solder Wire for Electronics: 4 Compared (and One to Skip) comparison.
Kester 44 wins on range and on documented behaviour: one flux chemistry, seven alloys, diameters from .010 in to .125 in, and three flux loadings by weight. MG Chemicals 4880-4888 delivers the same eutectic alloy and the same ROM1 rosin classification in a shorter list of sizes, including an 18 g pocket pack that suits an occasional repair kit.

Kester 44 Flux-Cored Wire (Sn63Pb37)
Buy itThe reference activated-rosin wire, in a eutectic leaded alloy and just about any diameter you could want.
- Kester classifies the 44 flux as ROM1 under J-STD-004, a rosin base with moderate activity that wets fast on tarnished copper and old component leads.
- In Sn63Pb37 the alloy is eutectic, so it melts and solidifies at 183 °C with no plastic range for a joint to be disturbed in.
- Kester lists Sn63Pb37 in diameters from .010 in through .125 in and in three flux loadings by weight, 1.1, 2.2 and 3.3 percent.
- It contains lead, so it is not suitable for equipment you intend to place on a RoHS-regulated market.
- Kester lists every 44 variant as containing halogen, and halide-bearing residues raise the ionic contamination potential of a board.
- Moderate activity means the amber residue is worth removing on anything you care about long term, which is an extra step and an extra product.

MG Chemicals 4880-4888 Sn63/Pb37 RA Solder Wire
Buy itThe same eutectic alloy and the same ROM1 rosin classification, with a data sheet that publishes real numbers and a pocket pack for small jobs.
- The data sheet gives the flux classification as ROM1 RA to J-STD-004B, activity moderate, acid number 150 to 160 mgKOH/g and halides 0.5 to 2.0 percent by weight.
- MG states the alloy is eutectic, exceeds J-STD-006C purity requirements and meets ASTM B 32, and lists a 10 year shelf life.
- It comes in an 18 g pocket pack plus 227 g and 454 g spools across .025 in, .032 in, .040 in, .050 in and .062 in.
- The technical data sheet does not publish the flux content as a percentage by weight, which the Kester tables do.
- There is nothing finer than .025 in, so very fine-pitch surface-mount rework needs a different spool.
- MG lists it as unavailable in the EU and UK, so buyers there need a different source.
Side by side
| Kester 44 Flux-Cored Wire (Sn63Pb37) | MG Chemicals 4880-4888 Sn63/Pb37 RA Solder Wire | |
|---|---|---|
| Our verdict | Buy | Buy |
| Best for | Anyone repairing or building through-hole and mixed-technology boards by hand who wants one wire that handles almost every joint size. | Hobbyists and repair benches who want a fully specified leaded rosin wire without committing to a full pound of it. |
| Price tier | $$ · mid-range | $ · budget |
The bottom line
Our overall pick is the Kester 44 Flux-Cored Wire (Sn63Pb37) - The reference activated-rosin wire, in a eutectic leaded alloy and just about any diameter you could want. Choose the MG Chemicals 4880-4888 Sn63/Pb37 RA Solder Wire instead if hobbyists and repair benches who want a fully specified leaded rosin wire without committing to a full pound of it.
Want the full picture, including the other options we compared and the popular one we'd skip? Read the complete The Best Solder Wire for Electronics: 4 Compared (and One to Skip).