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White brush-cap jar of water-soluble soldering paste

La-Co

La-Co Water Soluble All Weather Flux 4 oz Soldering Paste

SKU CH-A4R1-EA6R9

Water-soluble organic soldering paste for lead-free and tin/lead joints on copper, brass and listed metals, meeting ASTM B813, MIL-F-4995 Type II and NSF 61 standards with water cleanup

  • Product typeWater Soluble Paste
  • Main materialOrganic
  • Water-soluble paste cleans up with plain water
  • Organic formula meets ASTM B813 and MIL-F-4995 Type II standards
  • NSF 61 certified for potable-water system safety
  • Works with lead-free and tin/lead solders up to 840 °F
  • Brush-cap jar applies flux neatly on copper, brass and listed metals

Water Soluble Soldering Paste

La-Co water soluble soldering paste comes in a 4 oz brush cap jar for convenient application. The organic formula is designed for joining copper to copper and copper to brass with lead free or tin/lead solders. It meets ASTM B813, MIL-F-4995 Type II, NSF 61 and UPC standards. This flux suits plumbers and HVAC technicians needing reliable joints on approved metals.

Capacity and Temperature Headroom

The 4 oz container provides enough flux for multiple small to medium piping jobs. Active performance is rated up to 840 degrees F, covering typical soft soldering ranges. Beyond that temperature the flux may degrade and lose effectiveness. Users working with high temperature brazing alloys will need a different flux formulation.

Clean Up and Residue Management

Water soluble residue rinses away with plain water after soldering, eliminating the need for chemical cleaners. This simplifies the workflow and reduces the risk of long term corrosion from leftover flux. The organic paste stays workable in varied weather conditions during application. Excess paste should be wiped off before it dries to ensure easy removal.

How it compares

Measured against everything we stock in Soldering Irons & Stations, at today’s prices. Recalculated every night.

Price $5.99
Cheaper than about 95% of the 802 comparable items (median $25.99).

Specifications

Product
Brand nameLA-CO
Product typeWater Soluble Paste
Size & build
Main materialOrganic

Questions about this item

Will this flux work with the copper and brass fittings I already have in stock?

Yes, it is formulated for joining copper to copper and copper to brass, and also suits galvanised iron, mild steel, nickel, silver, terne plate, tin, zinc, lead and malleable iron.

How can I confirm the paste is still active after I open the jar?

The flux remains active up to 840 °F; if it flows and cleans the joint at your working temperature it is performing as intended.

Does the 4 oz brush-cap jar include a brush, or must I buy one separately?

The container type is a brush-cap jar, so the applicator brush is built into the cap and no separate brush is required.

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