MG Chemicals 421A-500ML Liquid Tin, 475ml Bottle, Case of 4
MG Chemicals 421A-500ML Liquid Tin, 475ml Bottle, Case of 4
MG Chemicals 421A is a clear yellow electroless (immersion) tin solution that deposits a thick, pure tin layer onto copper traces, pads, and solder deposits on printed circuit boards. The tin coating protects copper from oxidation and corrosion, restores solderability on aged boards, and extends the working life of circuits without requiring electroplating equipment. 421A requires no dilution, leaves rinsable residues, and produces a bright, active tin surface that accepts solder readily.
Sold in cases of 4 × 475ml (16 oz) bottles.
Specifications
| Catalog Number | 421A-500ML |
| Volume per Bottle | 475 mL (16 oz) |
| Case Quantity | 4 bottles/case |
| Form | Liquid solution |
| Color | Clear yellow |
| Deposit Type | Pure tin (electroless/immersion) |
| Dilution Required | No |
| Residues | Rinsable |
| Application | PCB copper trace tinning, pad restoration, solderability improvement, corrosion protection |
| Manufacturer | MG Chemicals |
Technical Data Sheet (PDF) | Safety Data Sheet (PDF)
California Proposition 65 Warning: This product can expose you to chemicals including thiourea, which is known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.
Frequently Asked Questions
What does MG Chemicals 421A do to a PCB?
421A deposits a thin, pure tin layer onto exposed copper surfaces through an electroless (immersion) chemical reaction — no electrical current or plating equipment required. The tin coating prevents copper oxidation, restores solderability on boards that have been stored or aged, and protects solder deposits by making their surfaces bright and active. It is commonly used in PCB rework, prototype board preparation, and production line maintenance.
Does 421A need to be diluted before use?
No — 421A is a ready-to-use solution that requires no dilution. Apply it directly to the copper surface, allow the immersion tin reaction to occur, then rinse thoroughly with water. Refer to the Technical Data Sheet for recommended dwell times and process parameters.
Is 421A compatible with lead-free and leaded solder?
Yes — the pure tin deposit produced by 421A is compatible with both lead-free and leaded solder alloys. The bright, active tin surface accepts solder readily and provides good adhesion for standard wave, reflow, and hand soldering processes.
How should 421A be stored and handled safely?
421A contains thiourea, which is a California Proposition 65 listed chemical. Use in a well-ventilated area, wear appropriate PPE including chemical-resistant gloves and eye protection, and avoid skin and eye contact. Store in a cool, dry location away from incompatible materials. Refer to the Safety Data Sheet for full handling, storage, and disposal requirements.
