Kester K100LD 24-9574-1402 Lead-Free Rosin Solder 1 lb
- 0.031 inch (0.80 mm) wire, 1 lb spool
- Sn99.3/Cu0.7 lead-free alloy, 66 core
- 48 activated rosin flux, 3.3 percent, ROM1 per J-STD-004
- Melting range 227 to 229 C (441 to 444 F)
- Shelf life 1095 days
Last refreshed Sep 28, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A lead-free rosin-core wire with an activated flux classified ROM1, aimed at the common metals. The residue resists IPA, so cleaning needs a dedicated agent.
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ASIN: B00FGHTZFIModel: K100LDCategory: Solder
Overview
Kester pairs a lead-free tin and copper alloy with an activated rosin flux in this cored wire, developed to solder most common metals. The description positions it as a successor to an earlier Kester rosin flux.
The flux is built for fast wetting, and cleaning is usually unnecessary because of how benign the leftover is. The limitation is the cleaning route when it is needed, since IPA fails, and the halogen content field is unclear.
Who it's for
Technicians moving from leaded to lead-free work who want an active rosin flux get a wire matched to that job. Those who clean boards with isopropyl alcohol should expect the residue to stay put.
Pros and cons
- Activated rosin flux
- Lead-free tin-copper alloy
- Long stated shelf life
- IPA does not remove residue
- Halogen content field ambiguous
- Spec table lists little
Performance notes
The activated rosin flux is described as enabling soldering of most common metals with fast wetting. Residues are non-corrosive and non-conductive, so they generally stay on the board without harm.
Specifications
| Brand | Kester |
|---|---|
| Model | K100LD |
| Dimensions & fit | |
| Wire diameter | 0.031 inches (0.80 mm) |
| Core size | 66 |
| Spool size | Spool, 1 lb |
| Item weight | 1.1 pounds |
| Capacity & performance | |
| Melting range | 227 to 229 C (441 to 444 F) |
| Construction & materials | |
| Material | Sn99.3/Cu0.7, lead-free eutectic (K100LD) |
| Other details | |
| Certification | ROM1 per J-STD-004 |
| Flux content | 3.3 percent |
| Recommended uses | 1095 days |
| Flux type | 48 activated rosin core |
| Liquidus | 229 C (444 F) |
Frequently asked questions
How do I clean flux residue from Kester 48 wire?
The residues are non-corrosive and non-conductive and need no removal in most uses. IPA will not remove them, so use a saponifier or a cleaning agent designed for no-clean flux.
Is the Kester K100LD 48 wire lead-free?
Yes. The title and description both say lead-free.
What is the alloy?
The description gives 99.3 percent tin and 0.7 percent copper.
How long does it last on the shelf?
The description lists a shelf life of 1095 days.