Consumer advocacy teardown
Rust Remover Gel alternative & active ingredient dupe
Stop paying £8.99 for Jenolite. The bulk active is Phosphoric acid 81% (food / technical) diluted to ~25% — 78% less per working litre than a typical pack.
- Active
- Phosphoric acid
- CAS
- 7664-38-2
- Dupe
- Phosphoric acid 81% (food / technical) diluted to ~25%
- Saving
- 78% / L
Saving is per litre of working-strength mix versus a typical pack price, not versus the DIY kit total. Shop prices move — always check the listing.
The Marketing Claim & The Catch
A typical 500 millilitres pack of Jenolite Rust Remover Gel is about £8.99 in patio & exterior. That is a snapshot, not a live Amazon price — listings, sizes and deals move. The marketing line is that you are buying a finished lifestyle product, not a weighed chemical.
On the pack: Converts rust to a paintable phosphate film; and No sanding on light surface rust.
The catch: This is not oxalic (that is HG masonry rust) and it is not hydrochloric (Mortar Clen). Phosphoric acid etches rust to iron phosphate. Technical 81% phosphoric diluted to about 25% is the same attack without the gel tax. Keep it off limestone.
- “Converts rust to a paintable phosphate film”
- “No sanding on light surface rust”
Proprietary Blend & Dosage Breakdown
The labelled active is Phosphoric acid at 25%. Everything else in the pack is water and a thickener.
At 25% active, most of what you pay for is carrier and packaging. The brand is selling convenience, fragrance and a label — not a uniquely potent molecule.
Branded working strength is whatever comes out of the bottle. The bulk alternative is 81% Phosphoric acid 81% (food / technical) diluted to ~25%, mixed to 1:2.2 (to ~25% w/w working, matching the gel).
- Labelled active
- Phosphoric acid
- 25%
- Carrier
- Water and a thickener
- Retail pack
- 500 millilitres · £8.99
The Active Chemical Alternative (Dupe Stack)
The dupe stack is Phosphoric acid 81% (food / technical) diluted to ~25% at 81% bulk. Indexed as CAS 7664-38-2, formula H3PO4. Buy it as 1 litre for about £12.50 from Amazon UK.
Working strength: 1:2.2 (to ~25% w/w working, matching the gel). Indicative cost £3.90 per diluted litre — 78% below a typical branded pack on a per-litre basis, before you reuse leftover bulk.
Follow the mixing method and the supplier SDS. Wear the listed PPE. Do not mix incompatible oxidisers, acids or ammonia.
- Causes burns. Splash goggles, household gloves, ventilation. Always add acid to water. Never mix with bleach.
- About 1 part 81% phosphoric + 2.2 parts water lands near 25% — the same order of strength as the branded gel.
- Apply to dry rusted steel, dwell 15–30 minutes, rinse, dry, prime. Not for aluminium, zinc, or marble.
- 1 litre of 81% makes about 3.2 litres of 25% liquor. Store in a labelled HDPE bottle.
Mixing desk
Dilution calculator
Switch between filling a sprayer and covering a measured surface. Figures are educational estimates from the listed ratio — always check the SDS.
Formula
Phosphoric acid 81% (food / technical) diluted to ~25%
- Concentrate
- 156 ml
- millilitres of liquid
- Water
- 0.34 L
- carrier volume
- Batch cost
- £1.95
- 0.5 L working solution
- Saved vs retail
- £7.04
- 78% · retail £8.99
Estimated coverage at the listed rate: 4 m².
Side-by-Side Price & Potency Comparison
Head-to-head comparison
| Measure | Retail brandedJenolite | Raw active dupeDupeStack |
|---|---|---|
| Product | Rust Remover GelAmazon UK search — listing, not a confirmed seller | Phosphoric acid 81% (food / technical) diluted to ~25% |
| Pack / unit | 500 millilitres · £8.99 | 1 litre · £12.50 |
| Active | Phosphoric acid at 25%Carrier: Water and a thickener | 81% bulkH3PO4 |
| CAS number | Not disclosed on pack | 7664-38-2 |
| Working strength | Ready-to-use pack | Dilute 1:2.2 (to ~25% w/w working, matching the gel) |
| Cost per litre | £17.98 / L typical pack | £3.90 / L mixed from bulk |
| Headline saving | Baseline | 78% cheaper |
| COSHH / PPE | Follow the branded SDS | Gloves. Chemical-resistant gloves (nitrile or neoprene)Eye protection. Indirect-vent splash goggles — not ordinary spectaclesVentilation. Use outdoors or with mechanical extractionAcid-resistant PPE. Apron and gloves rated for corrosive liquids |
Active ingredient and cheaper alternative — FAQ
What is the active ingredient in Jenolite?
Jenolite Rust Remover Gel is labelled as Phosphoric acid at 25%. The carrier is Water and a thickener. Pack size: 500 millilitres. The bulk equivalent we index is Phosphoric acid 81% (food / technical) diluted to ~25% (CAS 7664-38-2).
Is Phosphoric acid 81% (food / technical) diluted to ~25% safe on paving?
Used at the listed working strength (1:2.2 (to ~25% w/w working, matching the gel)), the dupe is the same chemistry as the branded pack for paving, porcelain and masonry. That is not a blanket all-clear: read the supplier SDS, wear the listed PPE, keep acids away from hypochlorite, and follow UK HSE/COSHH rules. Wellness teardowns are supplements, not medicines.
Is there a cheaper alternative to Jenolite Rust Remover Gel?
Yes. The bulk equivalent is Phosphoric acid 81% (food / technical) diluted to ~25% (CAS 7664-38-2). Indicative saving 78% per working litre versus a typical £8.99 pack. Working strength: 1:2.2 (to ~25% w/w working, matching the gel). Live shop prices move.
How do you mix the Rust Remover Gel dupe stack?
Causes burns. Splash goggles, household gloves, ventilation. Always add acid to water. Never mix with bleach. About 1 part 81% phosphoric + 2.2 parts water lands near 25% — the same order of strength as the branded gel. Apply to dry rusted steel, dwell 15–30 minutes, rinse, dry, prime. Not for aluminium, zinc, or marble. 1 litre of 81% makes about 3.2 litres of 25% liquor. Store in a labelled HDPE bottle.
DupeStack provides chemical concentration data and educational mixing guides. Always review official manufacturer Safety Data Sheets (SDS) and comply with UK Health and Safety Executive (HSE) and COSHH regulations when handling concentrated substances. Some links on this site are affiliate links.
More teardowns
Patio & exterior
Wet & Forget Exterior Surface Cleaner
Wet & Forget
- Retail pack
- £34.005 litres
- Raw active
- Benzalkonium chloride (BAC 50)68424-85-1
A dilute quaternary ammonium biocide sold as a lifestyle patio product. The active is commodity BAC 50; the brand is paying for the trigger bottle and the television advert.
Patio & exterior
Patio Magic!
Patio Magic
- Retail pack
- £24.995 litres
- Raw active
- Benzalkonium chloride (BAC 50)68424-85-1
Another BAC patio biocide in a different coloured bottle. Same quaternary ammonium as Wet & Forget; same bulk drum of BAC 50. You are paying for the brand, not a different molecule.
Patio & exterior
HG Rust Stain Remover
HG
- Retail pack
- £8.50500 millilitres
- Raw active
- Oxalic acid dihydrate6153-56-6
Oxalic acid is the classic rust and tannin bleach for masonry. HG bottles a dilute solution; a kilogram of crystals makes tens of litres of the same chemistry.
DIY stack · 78% / L vs branded
£22.50indicative kit · Amazon cannot add a mixed search kit as one basket