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Phosphoric Acid Flux for Stainless Steel Soldering

Phosphoric Acid for Stainless Steel

Phosphoric Acid for Stainless Steel

MPN: F051

Trying to solder stainless steel and having problems? Use the correct flux, Phosphoric Acid flux, and get excellent solder joints.

Note: Currently not available for delivery to N.Scotland, N.Ireland, Scottish Isles, Isle of Wight, Isle of Man, Scilly Isles, Europe Zone 3, Europe Zone 4, Europe Zone 5, Europe Zone 6, Guernsey, Jersey and Australia, Brazil, Canada, Hong Kong, Malaysia, Mexico, New Zealand & USA.

$46.35 ex VAT($40.74 inc VAT)
In Stock
Phosphoric Acid

Delivery Options

Product Description

A 75% Phosphoric Acid flux available from Somerset Solders designed to aid soldering of metals such as Stainless Steel and Nickel Chromium where tough oxide layers are present. Phosphoric Acid, recommended by the British Stainless Steel Association, allows wetting of the metal surfaces where Zinc Chloride and Rosin based fluxes would be ineffective. 

Link to the British Stainless Steel Association

For Stainless Steel and Nickel Chromium soldering

Promotes excellent wetting

Supplied in a 500ml  bottle

Easy residue removal in warm soapy water


Customer Reviews

By on
"Very good flux for soft soldering stainless steal, would definitely recommend it."
Star Rating 5
By on
"Excellent service, product first class."
Star Rating 5
Staff response...
"Thank you so much for your kind review. The AIM Phosphoric Acid promotes great wetting for stainless steel soldering."
By on
"works well on stainless steel roofing sheet and cheaper than my usual supplier"
Star Rating 5
By on
"Very pleased, fast delivery, will use again"
Star Rating 5
By on
"Excellent product & service"
Star Rating 4


When soldering stainless steel which solder can be used?
Conventional Tin Lead solders can be used for soldering of stainless steel, as well as a high Tin solder such as the Lead Free 99C alloy. It is recommended that the Tin content is greater than 50% to give good bond strength.

What solders are
We stock a 60% Tin 40% Lead blowpipe solder (grade K). Blowpipe are thin sticks of solder approximately 5mm in diameter and 500mm in length. We also stock the Summit Solder range from AIM Solders and the 99C Lead Free on 250g and 500g reels would be suitable and give a good colour match.

Should the flux residues be removed and if so how?
Yes removing of the residues is important. As the flux is acid based removal will prevent discolouration of the metal and any further corrosion. Warm soapy water does the trick. 


Safety Data Sheet CLP

Safety data sheet for phosphoric acid

Somerset Solders

Leading stockist of lead free and leaded solder wires, pastes and bar. Liquid fluxes and flux gels stocked.

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Phosphoric Acid Flux for Stainless Steel Soldering