Grade M Solder
Product Overview
DKL Grade M 45/55 is a high-quality, manufacturing-grade tin-lead soft solder alloy engineered with a medium plastic range. It is formulated specifically for industrial metalworking and electrical engineering applications where heat-sensitive components require lower operating temperatures.
This alloy delivers exceptional wetting and reliable capillary flow across a wide variety of base metals. It provides fully traceable, compliant joint integrity under modern international manufacturing standards.
1 kg Solder Bars
Standard bulk weight format optimised for large melting pots, industrial baths, and heavy-duty line production.
Tinmans Sticks
Approx. 250g cast sticks designed for manual metal work, traditional soldering irons, and seam joints.
Blowpipe Strips
Approx. 85g fine strips ideal for precision hand-feeding, torch brazing, and detailed engineering work.
Solid Solder Wire
Continuous solid spooled wire available in various industrial gauges for benchtop hand-soldering configurations.
Technical Specifications
| Property / Standard | Specification Value |
|---|---|
| Chemical Composition | Tin (Sn): 45% | Lead (Pb): 55% (Nominal) |
| Current Industry Standard | ISO 9453:2020(E) Alloy 113 Pb55Sn45 |
| Legacy Classification | BS219 Grade M |
| Solidus Temperature | 183°C |
| Liquidus Temperature | 215°C |
| Ultimate Tensile Strength | 5.67 kg/mm² @ 21°C |
| Shear Strength (Steel) | 4.09 kg/mm² |
| Material Density | 8.94 g/cm³ |
Application Guidelines & Compliance
Metal Compatibility & Substrates +
Grade M is highly versatile and optimised for soldering all common industrial metals. It provides clean structural joints on:
- Mild Steels
- Copper & Copper Alloys
- Brasses
- Bronze Alloys
Flux Selection Requirements +
The correct flux profile depends strictly on your industry application:
- Sheet Metal & Engineering Work: Use in conjunction with DKL Activated Fluxes. Active flux residues must be thoroughly cleaned and removed post-soldering to prevent long-term joint degradation.
- Electrical & Electronic Assemblies: Use an Alcohol Resin paste flux. This variant is entirely non-corrosive and does not require post-solder cleaning or residue washdown.
Heating Methods & Safety +
Due to the material mass, joints should be formed using a large heavy-duty soldering iron or indirect localised flame heating.
Health & Safety: Always wear certified eye and skin protection during handling. Avoid breathing in processing fumes. Workspace extraction systems must be active. Full material safety datasheets (MSDS) are available directly upon request.
Frequently Asked Questions
What is the difference between ISO 9453 Alloy 113 and legacy BS219 Grade M solder? +
There is no functional difference in material composition. ISO 9453:2020 Alloy 113 (Pb55Sn45) is simply the modern international classification that directly replaced the legacy British standard BS219 Grade M. Both specifications designate the exact same high-purity 45% tin and 55% lead industrial soft solder alloy mixture.
Can Grade M 45/55 tin lead solder bars be used for heat sensitive electrical components? +
Yes. Grade M features a solidus point of 183°C and liquidus point of 215°C. This relatively low melting profile and medium plastic range allow it to flow safely at thermal thresholds that protect heat-sensitive electrical joints and delicate components from heat warping or damage during manufacturing.
What type of flux is recommended when soldering mild steel or brass with Grade M? +
Use DKL Activated Fluxes for industrial sheet metal work on mild steel, copper, or brass, ensuring active residues are washed off post-solder. Electrical configurations involving tinned or brass surfaces require a non-corrosive Alcohol Resin paste flux which needs no post-solder cleanup.
Where can I buy bulk Grade M solder bars and blowpipe strips manufactured in the UK? +
You can source Grade M solder directly from DKL Metals Ltd, the UK’s leading independent alloy manufacturer operating from our fully certified ISO 9001 and ISO 14001 fabrication facility in Grangemouth. We supply commercial batches in 1kg bars, 250g tinmans sticks, 85g blowpipe strips, and spooled solid wire.