Copper Dome Head Open End Rivets with Steel Mandrel
What are copper rivets with steel mandrels? These are open end blind rivets with a copper body and a steel mandrel, in the standard dome head profile. The copper body gives you the appearance, conductivity, and material compatibility that copper work requires, while the steel mandrel lowers cost and often sets more cleanly than a softer brass one. The tradeoff is that a small piece of steel remains inside the rivet after setting, so this pairing suits dry and interior work better than exposed weathering installations. AlbanyCountyFasteners.com stocks these in 1/8 inch.
Rivet Number, Diameter:
Steel mandrel or brass mandrel in a copper rivet?
It comes down to where the joint lives. Both give you a copper face, so appearance at installation is the same. The difference is what happens to the mandrel remnant sealed inside the body. A steel mandrel is stronger, breaks more predictably, and costs less, which makes it a sensible choice for interior work, dry assemblies, and anything that will not see weather. Put the same rivet on an exposed copper roof and that steel will eventually rust, and because it sits at the center of the head the staining bleeds outward across the copper exactly where it is most visible. For exterior copper, the brass mandrel is worth the difference.
Why choose copper with a steel mandrel
- Copper body for appearance, conductivity, and compatibility with copper sheet
- Steel mandrel breaks cleanly and predictably during setting
- Lower cost than a fully matched copper and brass pairing
- Stronger set than a softer brass mandrel provides
- Well suited to interior, dry, and non weathering copper work
Where to use this pairing
- Interior decorative copper work and fixtures
- Dry assemblies where the mandrel will never see moisture
- Craft, hobby, and instrument fabrication
- Electrical joints in enclosed or protected locations
- Cost sensitive copper work where exposure is not a factor
- Not recommended for exterior copper roofing, gutters, or flashing
For exposed exterior copper, use copper rivets with brass mandrels instead, since nothing inside the fastener will rust. General background on head style and sizing is on our dome head rivets page.
Related Categories
- Dome Head Open End Rivets
- Copper Dome Head Rivets, Brass Mandrel
- Open End Rivets
- Rivet Tools
- Rivet Products
Copper Rivet with Steel Mandrel FAQs
Will the steel mandrel rust?
If the joint gets wet, yes. The mandrel head is sealed inside the copper body but not sealed against moisture, and an open end rivet is hollow through the middle. In exposed service that steel will corrode and stain outward through the head. Indoors and dry, it is not an issue.
Can I use these on a copper roof?
We would not recommend it. Exterior copper roofing, gutters, and flashing see constant moisture, and rust staining on copper is both unsightly and difficult to reverse. Use the brass mandrel version for anything exposed to weather.
Are these stronger than copper with brass mandrels?
The set is somewhat stronger, since steel is harder than brass and pulls the body up more firmly. The difference matters less than the corrosion consideration in most applications, so let the environment decide rather than the strength.
Do they still conduct well?
The copper body conducts as well as any copper rivet, and the body is what forms the joint. The steel mandrel remnant sits inside and does not carry the primary current path, so conductivity is essentially unaffected.
Will these match existing copper hardware?
The visible head is copper and will patina like any copper rivet. Over time the mandrel break at the center may darken or stain if moisture reaches it, which is the visual difference between this and the brass mandrel version.
What sizes are available?
Stocked in 1/8 inch across a range of grip lengths. For other diameters or for exterior work, contact us and we can advise on the brass mandrel version or alternatives.