Stainless steel rivets in aluminum gunnels?

[C. O. Rhodes]

I want to bag out a canoe with aluminum gunnels and I am thinking of using
marine grade stainless steel rivets. I have some hazy memories form school
that different metals, next to each other can cause corrosion, especially if
there is salt water about. Does anyone know whether it is OK to use steel
rivets in aluminum?

C.

[Brian Nystrom]

It probably depends on the type of stainless in the rivets. If you're
talking about off the shelf pop rivets, I would expect there to be a
corrosion problem.

[Kayak Bill]

Stainless and aluminum are very similar metals, neither contain more
than trace amounts of carbon, and they won't encourage corrosion when
mated together. There are two groups of stainless steels, 313 series
and 400 series, and any rivets you purchase that state "Stainless"
should work fine. Just don't use plated carbon-based rivets. Even
chrome plating will deteriorate under salt water attack.

btw, I'm new here. Name's Bill, and I'm pleased to meet you.

[John Fereira]

Kayak Bill <kaya...@bellysouth.net> wrote in
news:y6Toe.98887$J25....@bignews6.bellsouth.net:

Welcome to the group Bill. Good first contribution.

[qrk]

Stainless against aluminum can cause corrosion of the aluminum to
varying degrees (almost none to icky). Results will vary depending on
alloy choices and environment. Don't depend on anodized aluminum
preventing corrosion problems. The rivet can easily ding the
anodization coating during installation. The corrosion potential
between stainless and aluminum is around 0.2 V to 0.5 V depending on
the grades of stainless and aluminum used. Marine grade stainless is
generally 316 which will cause the most corrosion of the various
stainless families to aluminum.

Have you considered using 5000-series aluminum rivets with aluminum
mandrels? 5000-series aluminum has excellent corrosion resistance as
compared to other aluminum alloys. It will also have a corrosion
potential very close to the aluminum gunnels.

Another information resource may be a canoe manufacturer like Winonah.
Winonah uses rivets on aluminum tubing for attaching their seat
structures. Email them for their suggestion.

The above info can be found in standard corrosion potential (galvanic
series) tables for flowing sea water.
http://www.corrosionsource.com/handbook/galv_series.htm
You want the corrosion potentials to be close to each other to reduce
corrosion problems due to galvanic corrosion.

Some people mistakenly use the emf series tables which gives a very
different picture of metal compatibilities.

---
Mark