Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Stainless or Outdoor Green Corrosive Resistant fixing for oak?

373 views
Skip to first unread message

John

unread,
Mar 17, 2009, 8:22:04 AM3/17/09
to
I want to join some chunky pieces of green oak together to form a bench.
Looking at the Screwfix range of Coach Screws the options are either
"Stainless Steel" or "Outdoor Green Corrosive Resistant". I want to
avoid marking the oak so would normally have gone for stainless steel,
but would the green corrosive resistant ones be any better?

Thanks for any advice,
John

Andy Dingley

unread,
Mar 17, 2009, 10:05:11 AM3/17/09
to
On 17 Mar, 12:22, John <j...@yahoo.co.uk> wrote:

>I want to avoid marking the oak

Treenails, not steel at all.

> but would the green corrosive resistant ones be any better?

No, Even stainless isn't brilliant (depends on the grade - if you can
make screws out of it, don't trust it)

If you want nails, pay for bronze ones, or else use cheap copper
roofing nails in drilled holes and rivet them at the back

RubberBiker

unread,
Mar 17, 2009, 10:07:08 AM3/17/09
to
I think "outdoor green" means "zinc plated" - in which case go for
stainless. IME green oak is very capable of attacking plating.

If you want to be a bit more ambitious, google using the draw-dowel
method of using oak pegs - the traditional solution of jointing green
oak, and the joints can be tightened up as the beams shrink.

John

unread,
Mar 19, 2009, 7:39:53 AM3/19/09
to

Thanks for that. I'll done a bit of reading up and will give the oak
pegs a go. I also need to need to fix the oak to some masonary so will
stick to the stainless steel for that.

Andy Dingley

unread,
Mar 19, 2009, 8:45:56 AM3/19/09
to
On 19 Mar, 11:39, John <j...@yahoo.co.uk> wrote:

> I also need to need to fix the oak to some masonary so will
> stick to the stainless steel for that.

One nice way to do that is with steel tenons poking from the wall
(strip welded to a plate, or just buy ready-made staples) and then
hiding them inside a mortice cut from the back of the oak. Peg through
the sides and through the loop.

Steve Firth

unread,
Mar 19, 2009, 9:17:22 AM3/19/09
to
John <jo...@yahoo.co.uk> wrote:

My experience with stainless steel and oak is that the acids in the oak
attack the steel rapidly. Stainless steel relies upon a coat of oxide
for corrosion resistance and if you exclude air (as happens when the
screw is inserted into wood) and provide an acid environment that
coating is dissolved and cannot reform. On wooden boats this is familiar
and leads to crevice corrosion with consequential failing of the
stainless fastening.

The green coach screws sound better, but if you want longevity the
coating on these screws is rather thin and will fail eventually.

The solution on boats is to use either bronze coach screws (expensive)
or heavily galvanised screws, usually sold as "hot dipped". The latter
are available at farmer's merchants such as SCATS because they are
commonly used on farm gates.

0 new messages