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Choose your RustGuard™ bundle
Prices in USD. Free tracked shipping on 3-bottle bundles and above.
Rusted metal in, paint-ready surface out
Brush RustGuard™ over sound rust, let it cure, then paint. Images are illustrative — results depend on surface condition and preparation.
The short answer
One bottle covers roughly 55 sq ft in two thin coats on typical weathered steel. Measure your job in square feet, add 20 to 30 per cent for deep pitting, rough castings or corrugated profiles, then round up to the next pack — the 3-pack ships free and surplus keeps for about two years sealed.
- ≈55 sq ft per bottle at two coats — the planning figure to use
- Add 20–30% for pitting, cast iron, corrugated sheet or spray application
- Count both faces of railings, gates and open frameworks
- Round up: running out mid-job costs far more than a spare bottle
Calculate your quantity
Area
100 sq ft
Bottles needed
3
Recommended bundle
×3 — $42
Based on up to 55 sq ft per bottle on smooth steel, adjusted for surface condition. Estimates only — measure generously.
Coverage by surface type
Adjust your estimate for how thirsty the surface is.
| Surface | Coverage per bottle | Multiplier |
|---|---|---|
| Smooth painted or lightly rusted steel | ~50 sq ft / 4.6 m² | 1.0× |
| Moderately pitted steel | ~40 sq ft / 3.7 m² | 1.25× |
| Heavily scaled and pitted steel | ~30 sq ft / 2.8 m² | 1.7× |
| Corrugated roofing (profile allowance) | ~40 sq ft / 3.7 m² | 1.15× |
| Cast iron (porous) | ~35 sq ft / 3.2 m² | 1.4× |
| Mesh, grating and tube | Varies — measure both faces | 1.5× |
Common jobs and quantities
| Job | Bottles |
|---|---|
| One wheel arch | 1 |
| Both rear arches and sills | 2 |
| Small utility trailer frame | 1–2 |
| Pickup ladder frame | 3–5 |
| Pair of driveway gates | 2 |
| Single-garage metal roof | 5 |
| Barn roof section, 450 sq ft | 8 |
| Full 4x4 underside | 5–8 |
How to measure quickly
- Flat panels: length × width, in feet or metres
- Roofs: length × slope width per pitch, then add 15% for the corrugation profile
- Tube and box section: perimeter × length
- Mesh and grating: measure the flat area, then multiply by 1.5
- Add a bottle if you plan a second coat on deep pitting — most heavy jobs need it
Calculate your quantity
Area
100 sq ft
Bottles needed
3
Recommended bundle
×3 — $42
Based on up to 55 sq ft per bottle on smooth steel, adjusted for surface condition. Estimates only — measure generously.
Coverage by surface type
All figures are two-coat coverage per bottle, which is the honest planning number for weathered steel.
| Surface | Coverage per bottle | Allowance |
|---|---|---|
| Smooth panel steel, light rust | 65–70 sq ft | None |
| Typical weathered steel | ≈55 sq ft | Baseline figure |
| Deeply pitted or salted steel | 40–45 sq ft | Add 25% |
| Cast iron and rough castings | 40–45 sq ft | Add 25% |
| Corrugated roof sheet | 45–50 sq ft | Add 15% for rib area |
| Open frameworks, brushed | ≈50 sq ft | Add 10% |
| Spray application | 35–45 sq ft | Add 20–40% for overspray |
How to measure quickly and accurately
- 01
Flat panels: length × height
Straightforward. Do it in feet and keep the numbers written down rather than in your head.
- 02
Railings and gates: count both faces
Measure the overall panel area, double it for two faces, then take off roughly 40 per cent for the gaps between pickets.
- 03
Round tube and pipe: circumference × length
Circumference is diameter × 3.14. A 2-inch pipe is about 0.52 sq ft per foot of run.
- 04
Frames and box section: perimeter × length
Add up all four faces of the section, then multiply by the run length.
- 05
Corrugated sheet: flat area plus 15%
The ribs add real surface area that a flat measurement misses.
- 06
Vehicle undersides: use the job table
Measuring an underbody is impractical. Use the typical-job figures instead — they are derived from real orders.
Common jobs and quantities
| Job | Approximate area | Bottles |
|---|---|---|
| Both rear wheel arches | ≈25 sq ft | 1 |
| Car sills and rockers | ≈60 sq ft | 2 |
| Full car underside | 150–250 sq ft | 3–5 |
| Light truck chassis | 200–275 sq ft | 5 |
| Single-axle trailer | ≈90 sq ft | 2 |
| Pair of driveway gates | ≈60 sq ft | 1–2 |
| 40 ft of railing | ≈120 sq ft | 3 |
| Garage roof, 20×10 ft | ≈220 sq ft | 4–5 |
| Agricultural roof, 30×40 ft | ≈1,300 sq ft | 3 × 8-pack |
| Workshop tool round | ≈50 sq ft | 1 |
Why two coats is the right planning assumption
Single-coat coverage figures look better on a label and are broadly achievable on smooth steel with light surface rust. On anything pitted, salted or weathered — which is most real jobs — a single coat leaves the deepest parts of the pitting under-wetted, and that is exactly where the corrosion will restart.
Two thin coats also cure harder than one heavy coat of the same total volume, because each layer can dry properly rather than skinning over a wet interior. So the second coat is not just more product; it is a better film.
The practical consequence is to plan at 55 sq ft per bottle and treat anything better than that as a bonus. Ordering to a single-coat figure is the most common reason people run short halfway through a Saturday.
Reasons to round up rather than down
- Pitting hides real surface area that no tape measure catches
- Running out mid-coat means a patchy film and a second prep session
- The 3-pack ships free, so the third bottle often costs less than the shipping on two
- Sealed bottles keep about two years, so surplus is not waste
- Almost nobody has exactly one rusty thing to fix
- Unopened bottles can be returned within 30 days if you genuinely over-ordered
Where these figures do not apply
- Bare, non-rusted steel, which should be primed conventionally instead
- Aluminium, stainless, copper or bright galvanised surfaces
- Immersion service or permanently wet surfaces
- Surfaces above roughly 400°F
- Specified industrial systems with a required dry film thickness
- Perforated metal, where the real requirement is welding
What buyers say
Rated by people who hate sanding
Saved my truck bed
Wire-brushed the loose scale, brushed a coat on and left it overnight. Next morning it was a flat black surface that took primer without fighting me.
Dale R. · Tucson, AZ
No more grinding for hours
I restore gates and railings. This cut my prep time in half on pitted sections where the grinder just polishes the rust around.
Marcus H. · Leeds, UK
Held up through the wet season
Treated the shed roof sheets and topcoated them. Two seasons of rain later the treated panels still look the way I left them.
Janine K. · Brisbane, AU
Trailer frame looks new
Frame rails were surface-rusted everywhere. Two bottles covered the whole thing with enough left over for the tongue and jack.
Tom V. · Hamilton, ON
Simple to use
Shake, brush, wait. No mixing, no strong acid smell like the jelly products I used before.
Ricardo M. · Houston, TX
Bought the 5-pack, no regrets
Fence posts, patio furniture and a mower deck off one bundle. Ordering the workshop pack was cheaper than buying singles twice.
Ellen S. · Portland, OR
Reviews shown are illustrative sample copy while we collect verified customer feedback.
Buy with confidence
Nothing to lose but the rust
Worldwide shipping
Tracked delivery to the US, UK, Canada, Australia, EU and more. Free on 3-bottle bundles and above.
Encrypted payment
Card details are captured on a secure, encrypted checkout page. We never see or store your card number.
30-day guarantee
If RustGuard™ is not right for your project, contact support within 30 days for a refund of the product price.
No grinder needed
Brush-on chemistry designed for pitted, hard-to-reach rust where abrasives cannot get a bite.
Secure checkout
Order your RustGuard™ bundle
Pick a bundle, tap checkout — that's it. No account, no forms to fight. Your delivery address and payment are collected on the secure checkout page.
Step 1 — Choose your bundle
One bottle covers about 55 sq ft. Treating a whole vehicle, trailer or roof section? Most people need 3 or more.
Free tracked shipping unlocked
Most projects use more than they expect — the ×8 pack drops you to $9.00/bottle (you pay $11.00 now).
Step 2 — Checkout securely
Apple Pay, Google Pay and all major cards are accepted on the secure Shopify checkout — address, payment and confirmation, all in one place.
- 1Tap checkoutYour bundle is reserved in a secure cart.
- 2Pay your wayCard, Apple Pay or Google Pay — under a minute.
- 3Tracked dispatchConfirmation email instantly, packed in 1 business day.
“Ordered the 5-pack, treated the whole trailer frame and still had a bottle spare.”
Tom V. · Hamilton, ON
“Arrived tracked in five days and the brush kit saved me a trip to the store.”
Dale R. · Tucson, AZ
Reviews are illustrative while verified feedback is collected.
Frequently asked questions
Does one bottle really cover 50 sq ft?
On smooth, lightly rusted steel, yes. Deep pitting has far more actual surface area than its footprint suggests, so plan for less.
Should I budget for two coats?
On heavy rust, yes. Light surface rust usually needs one.
What if I order too much?
Sealed bottles keep for about two years, and rust jobs have a way of finding you. The larger bundles are also much cheaper per bottle.
What if I run short mid-job?
Finish the section you are on rather than stopping mid-panel, and order more before starting the next. Bundles ship worldwide.
How much rust converter do I need?
About 55 sq ft per bottle in two thin coats. Measure your area in square feet, add 20 to 30 per cent for pitting or rough surfaces, then round up to the next pack size.
How much does one bottle cover?
Roughly 55 sq ft at two coats on typical weathered steel, or 65 to 70 sq ft on smooth steel with light surface rust.
Do I need one coat or two?
Two on pitted, salted or heavily weathered steel. One is enough on light surface rust on a smooth panel.
How do I measure railings?
Measure the overall panel area, double it for both faces, then deduct roughly 40 per cent for the gaps between pickets.
Does spraying use more?
Yes — typically 20 to 40 per cent more on open frameworks because of overspray and atomisation loss.
What if I buy too much?
Sealed bottles keep about two years, and unopened bottles can be returned within 30 days of delivery.
How much for a whole car?
Three bottles for a small car underside, three to five for a saloon or estate, five to eight for a 4x4, van or pickup.
Keep reading
- Rust converter for iron and steel that leaves a paint-ready surfaceBrush RustGuard™ onto rusted iron or steel, convert the corrosion and topcoat in 24 hours. Bundles from $24, free shipping on 3+.
- How to use rust converter, step by stepThe full method for applying a rust converter: preparation, degreasing, coats, cure time and topcoating. Written for RustGuard™ but valid for any converter.
- Rust converter for metal roofsTreat rusting corrugated roofing, gutters and flashing with RustGuard™. Coverage figures, safe access and topcoat guidance.
- Rust converter for carsTreat surface rust on car sills, wheel arches, floor pans and subframes with RustGuard™ — convert, prime and repaint without blasting.
- Rust converter in gallon-scale quantitiesNeed gallon-scale rust converter coverage? RustGuard™ multi-bottle bundles cover the same area with less waste. 8-pack from $72, worldwide shipping.
Last step
Ready to stop the rust?
Ships from our US fulfilment partner, typically 3–7 business days. 30-day money-back guarantee.