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Corrosive, and says so

GALLUNOPTIMAL Corrosive soldering grease F-SW 12 for copper and copper alloys, 20 g

A 20 g tin of soldering grease from GALLUNOPTIMAL, made by FELDER in Germany, classed corrosive to F-SW 12, for soft soldering copper, brass, bronze and copper alloys in installation, repair and model work, with thorough cleaning of joints required.

FELDER Lötfett 20 g tin with a corrosive hazard pictogram, the word Gefahr and a zinc chloride content line

GALLUNOPTIMAL Corrosive soldering grease F-SW 12 for copper and copper alloys, 20 g

A 20 g tin of soldering grease from GALLUNOPTIMAL, made by FELDER in Germany, classed corrosive to F-SW 12, for soft soldering copper, brass, bronze and copper alloys in installation, repair and model work, with thorough cleaning of joints required.

Form
Grease, title
Chemistry
Active flux components, classed F-SW 12, second bullet; the tin in the product photograph states zinc chloride and DIN EN 29454.1, 3.1.1.C
Residue and cleaning
Corrosive; thorough cleaning of the joints required, second bullet
Activity level
Corrosive active flux, F-SW 12, title and second bullet
Volume
20 g, title and fourth bullet
Dispensing
Tin, fourth bullet
Handling guidance
Absent from the listing text — the tin in the product photograph carries a corrosive pictogram, the signal word Gefahr, a warning of serious eye damage and instructions to wear protective gloves, clothing and eye protection
Amazon reference
B0DZPL52G4 (same reference on 6 Amazon marketplaces)
EAN
4250078327714
  • A flux class given: F-SW 12, corrosive
  • Cleaning requirement stated plainly
  • Corrosive: residues must be cleaned off

Best for: A model maker or repairer soft-soldering copper and brass who will clean every joint afterwards.

≈ 6 €
Check price on Amazon

Specifications

Form
Grease, title
Chemistry
Active flux components, classed F-SW 12, second bullet; the tin in the product photograph states zinc chloride and DIN EN 29454.1, 3.1.1.C
Residue and cleaning
Corrosive; thorough cleaning of the joints required, second bullet
Activity level
Corrosive active flux, F-SW 12, title and second bullet
Volume
20 g, title and fourth bullet
Dispensing
Tin, fourth bullet
Handling guidance
Absent from the listing text — the tin in the product photograph carries a corrosive pictogram, the signal word Gefahr, a warning of serious eye damage and instructions to wear protective gloves, clothing and eye protection
Amazon reference
B0DZPL52G4 (same reference on 6 Amazon marketplaces)
EAN
4250078327714

The GALLUNOPTIMAL grease listing, bullet by bullet

Five bullets: soft soldering on copper, brass, bronze and copper alloys, removing oxide layers for installations, repairs and model making; corrosive to F-SW 12 with active components, requiring thorough cleaning; industrial quality; a 20 g tin; and manufacture for GALLUNOPTIMAL by FELDER GmbH in Oberhausen.

GALLUNOPTIMAL names the class

F-SW 12, corrosive. The second bullet states the classification and its consequence: joints must be cleaned. That is the difference from the no-clean rosin pastes in this family.

Where GALLUNOPTIMAL grease belongs

Copper, brass and bronze, for installation and model work. The listing does not name electronics, where corrosive residue on a board is the thing to avoid.

The hazard label on the GALLUNOPTIMAL tin

The maker’s label says what the listing does not. The FELDER tin in the product photograph carries a corrosive pictogram and the signal word Gefahr, lists zinc chloride, warns of serious eye damage and tells the user to wear protective gloves, protective clothing and eye protection. That label, not this page, is the handling reference.

Availability

At the last look-up, the German Amazon store was asking roughly 6 €.

The American, British, French, Italian and Spanish Amazon catalogues list the product, yet no seller was offering it.

Every figure here is Keepa’s reading on the date this page was last updated. Stock and prices can change at any time.

Prices quoted in this text were read on 15 September 2026. The live price is at the top of the page.

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