304 Stainless Steel Rivet Washers
What are 304 stainless rivet washers? These are backup washers in 304 stainless that sit on the blind side of a riveted joint, giving the rivet a hard, wide surface to form against instead of soft or thin material. Because a backup washer is buried behind the panel where it can never be inspected or replaced, material choice matters more than it might seem: a corroding washer weakens the joint invisibly. Stainless removes that risk. AlbanyCountyFasteners.com stocks these in 1/8, 5/32, 3/16, and 1/4 inch at 0.058 inch thick.
Nominal Size:
Why stainless for a washer nobody will ever see?
Precisely because nobody will ever see it. A backup washer sits behind the panel, and once the rivet is set there is no way to inspect it, clean it, or swap it without drilling the rivet out and starting over. If moisture reaches that cavity, and on a boat hull or an exterior panel it will, a plated steel washer corrodes where you cannot watch it happening. The joint gradually loses the bearing surface that was the entire reason for adding a washer, and the first sign of trouble is usually the rivet pulling through. Stainless costs a little more per piece and eliminates the problem, which is a good trade on a component you are sealing in permanently.
Why choose stainless rivet washers
- Corrosion resistance in a location that cannot be inspected or serviced
- Pairs correctly with stainless rivets, keeping the joint galvanically consistent
- Prevents pull-through in fiberglass, plastic, wood, and thin sheet
- Spreads clamping load across a much wider area on the blind side
- Suits marine, outdoor, and washdown service where steel washers fail
Sizes stocked
- 1/8 inch, 0.133 inch inner diameter and 0.375 inch outer diameter
- 5/32 inch, 0.165 inch inner diameter and 0.437 inch outer diameter
- 3/16 inch, 0.197 inch inner diameter and 0.500 inch outer diameter
- 1/4 inch, 0.263 inch inner diameter and 0.562 inch outer diameter
- All 0.058 inch thick, which counts toward your rivet grip range
Common applications
- Boat hulls, marine hardware, and dock equipment
- Fiberglass and composite panels in exterior service
- Outdoor signage and architectural panels
- Food processing and washdown equipment
- Trailer and RV panel repair over enlarged holes
- Any joint where a corroding washer would fail unseen
Pair these with stainless rivets such as our closed end rivets for a fully corrosion resistant sealed joint. For head side load spreading instead, large flange rivets solve the same problem from the front.
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Stainless Rivet Washer FAQs
What size washer do I need?
Match the washer to the rivet diameter, not to a bolt size. A 3/16 inch rivet takes a 3/16 inch rivet washer, whose 0.197 inch inner diameter is sized to slip over the rivet body with minimal clearance.
Does the washer count toward grip range?
Yes, always. At 0.058 inch these add meaningfully to your material stack, and forgetting them is a common way to end up outside the rivet's grip range without realizing it.
Should I match the washer to the rivet material?
Wherever the joint may get wet, yes. A steel washer against a stainless or aluminum rivet in a damp cavity sets up galvanic corrosion at exactly the point you were reinforcing. Stainless washer with stainless rivet is the consistent pairing.
Which side does the washer go on?
The blind side, behind the material, so the rivet body forms against it. That means you need enough access to place the washer over the protruding body before setting the rivet.
Can I use a standard flat washer instead?
Not ideally. Rivet washers have inner diameters matched to rivet body sizes and a thickness chosen to work within typical grip ranges. A standard flat washer usually has a looser hole, letting the rivet form unevenly.
Are these magnetic?
They may show slight magnetic response from the cold working involved in stamping. 304 is nominally non-magnetic, and a magnet sticking does not indicate the wrong material.