Aluminium or stainless pop rivets for a wet outdoor joint
Updated: 22 October 2026
You are repairing outdoor sheet, a gutter, or something near salt air, and the photograph is black. Black paint is not stainless steel. This page says when an aluminium body with a steel mandrel is the right buy, and when you need body and mandrel both named stainless, as a different product. It uses the cards in the [blind rivets comparison](/hub/screws-and-accessories/blind-rivets). Stars do not certify a metal. There was no corrosion test, and no card publishes a shear load. A qualifying purchase can earn a commission at no extra cost to you.
You are repairing outdoor sheet, a gutter, or something near salt air, and the photograph is black. Black paint is not stainless steel.
You are repairing outdoor sheet, a gutter, or something near salt air, and the photograph is black. Black paint is not stainless steel. This page says when an aluminium body with a steel mandrel is the right buy, and when you need body and mandrel both named stainless, as a different product. It uses the cards in the blind rivets comparison. Stars do not certify a metal. There was no corrosion test, and no card publishes a shear load. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Body and mandrel | Finish | Listing conflict | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  INCLY INCLY 1000-piece countersunk kit | Aluminium rivets. Mandrel not stated. 304 washers | Washers described as 304 stainless | One bullet says stainless steel rivets | 8.2 | about £21.99 | View offer |
| Alternative |  Glarks Glarks 560-piece black kit with washers | Aluminium alloy. Mandrel not stated. 304 washers | Black | Mandrel metal not named | 7.5 | about £10.99 | View offer |
 KLRS KLRStec 500-piece dome assortment | Aluminium body, steel mandrel | Not stated | None on material | 9.0 | about £19.99 | View offer |
On this page
The normal rivet is aluminium with a steel mandrel
The ordinary open pop rivet is an aluminium body with a steel mandrel. ISO 15977:2002 describes that pair for a dome head. ISO 15983:2002 is the different fastener: austenitic stainless body and mandrel, A2 with A2, from 3 mm to 5 mm. Both were confirmed in 2023. Neither certificate is claimed here.
Part of the steel stem stays in the body after the snap, so “aluminium rivet” leaves that stem out. Black and silver are finishes, not a change of standard. KLRStec states aluminium body, steel mandrel and a dome head, with no material conflict. Gutter and trailer uses on that card are the seller’s claims. Head and diameter sit on the how to choose pop rivets page.
Wet metal is the problem, not the paint
Dissimilar metals left wet can corrode. The British Stainless Steel Association says aluminium is anodic to stainless steel. A small aluminium fastener on a large stainless part is the unwise way round, because corrosion concentrates on the small anodic piece. Salt and a missing insulator make pitting more likely. That is not a rule that every mix fails indoors.
JRP names stainless when the job needs a corrosion-resistant rivet. Dry, similar light sheet is the case for an aluminium body and a steel mandrel. A gutter that stays wet, or salt air, is a different case. Paint does not decide it. Cladding guidance from the Metal Cladding and Roofing Manufacturers Association says to use aluminium or stainless fasteners rather than carbon steel, and to isolate dissimilar metals. That is not a script for sealing a gutter. For a household panel: will the joint stay wet, and have you named both metals?
Nothing in this set is a matched stainless rivet
No card here names a stainless body and a stainless mandrel together.
INCLY, B0D44SX4MJ, has a bullet that says stainless rivets. The material line is aluminium, plus 304 washers, and the mandrel is not stated. A washer does not change the rivet alloy. DMJJSD says stainless, then an aluminium head and a steel shank, and also “stud earrings”. Leave both until one metal pair is stated and kept.
Glarks is black aluminium alloy, mandrel not named. TXXATX is a black large flange with an aluminium head and an iron core. Zynthor’s black title sits next to a colour field that says “Sliver”, and a bullet that says an aluminium mandrel. Section 11 of the Consumer Rights Act 2015 says goods must match their description. Do not average two lines into “probably stainless”.
When to buy stainless instead
For dry, similar light sheet, buy an aluminium body and a steel mandrel when the card says both. KLRStec does. For stainless sheet, or a joint that stays wet in salt air, buy a matched stainless rivet separately. ISO 15983 is A2 with A2. Trade sellers offer A4 in salt air. Neither grade is in this comparison. A black assortment, a 304 washer or one stainless bullet is not that purchase.
If you cannot name the alloy on a coastal job, ask a professional. Drill on the how to fit a pop rivet page once the metal is chosen. Stainless does not make these open rivets suitable for brakes, steering, lifting points, gas appliances or designed structural steel.
Common questions
Can I use aluminium rivets on steel sheet outdoors?
On dry, similar light sheet, an aluminium body and a steel mandrel is the normal kit if the card actually says both. Outdoors, where the joint stays wet, dissimilar metals can corrode. A small aluminium fastener on a large stainless part is the combination the British Stainless Steel Association calls unwise. Salt and a missing insulator make that worse. This is not a rule that every mix fails in the dry.
What is left in the joint after the mandrel snaps?
A piece of the mandrel stays inside the set body. If the mandrel was steel, that steel remains in an aluminium body. Calling the finished rivet “aluminium” leaves that stem out of the description. The snapped-off piece you throw away is waste, not the whole mandrel.
Is a 304 washer the same as a stainless rivet?
No. INCLY and Glarks include 304 washers. A washer can back up a worn hole. It does not convert an aluminium rivet into a stainless rivet, and it does not resolve a bullet that says stainless while the material line says aluminium.
What should I buy for salt air or stainless sheet?
Buy a rivet whose body and mandrel are both named stainless, as a separate purchase from these cards. A2 with A2 is the general pattern in ISO 15983. A4 is the further grade UK trade sellers use for marine air. If the sheet alloy is unknown on a coastal job, ask a professional. Do not use a price from outside this folder as if it were one of these listings.
What if the listing contradicts itself?
Treat the metal as unresolved. INCLY says stainless in a bullet and aluminium in the material line. DMJJSD says stainless, then an aluminium head and a steel shank, and also “stud earrings”. Section 11 of the Consumer Rights Act 2015 requires goods to match their description. A contradiction is a reason to skip the card, not a puzzle to solve in your favour.
Related pages
Sources
Public standards and UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the stored amazon.co.uk cards, not a live re-check. No pack is treated as ISO 15977 certified unless the card says so. There is no laboratory test.
- ISO 15977:2002 Open end blind rivets with break pull mandrel and protruding head (aluminium body, steel mandrel) (retrieved October 2026)
- ISO 15977:2002 sample, length and grip (retrieved October 2026)
- Danetre Workshop, blind rivet size chart (retrieved October 2026)
- Leitz UK, Rapid, choosing the right blind rivet (retrieved October 2026)
- bolts.co.uk, pop rivets (retrieved October 2026)
- HSE, using the right type of PPE (retrieved October 2026)
- BlueSpot rivet gun manual (retrieved October 2026)
- Consumer Rights Act 2015, section 11, goods to match the description (retrieved October 2026)