Stainless Steel and Oak

[Forbsie]

Am I going mad or do I remember correctly someone saying that the acids in oak reacted with stainless screws to corrode or rot the wood? I've tried searching but cannot find the quote.

 

[ccscott49]

You may be right, not sure with good stainless, steel screws leave black marks on the oak and corrode like blazes. Bronze is fine though.

 

[Spuddy]

Certainly happens with galvanised or mild steel cos of the wotsit acid (tannic ?) in the oak. Interested to hear if stainless doesn't cause it

 

[tcm]

i have a house with tons of extrnal oak and stainless hinges - no stains. BUT as others say, any non-stainlss steel (eg tacks,pins) leaves black marks. So i think you'd be ok with stainless. Unless it rusted a bit, inwhich it would have been better to do what cccscott said, again.

 

[Peterduck]

Your house does not, I hope, live in a saltwater environment. This is what makes all the difference. The saltwater increases the activity between the tannic acid in the oak and the iron in the steel.
Peter.

 

[Forbsie]

Thanks guys, I've now re-assured my pontoon neighbour that I was only talking half-b0llux. I'm sure he'll return to fitting a new hog with stainless once he recovers from cutting his leg off with a grinder. /forums/images/graemlins/crazy.gif

 

[jhughes]

I know you are not supposed to use stainless under water as it needs the presence of oxygen to form an invisible protective layer!

 

[Roach1948]

I have never found this to be a problem as there is plenty of oxygen in water. I think its best not to encapsulate screws in something like epoxy though.

 

[castaway]

I was of the opinion that the tannic acid prevents corrosion to iron and mild steel.

In fact there is a synthesised product called Fertan which which I have used on a few occasions and I understand simulates the same effect.

Regards Nick.

 

[huldah]

Can't remember where I saw the article, but it said that stainless screws have the same life in oak as steel screws. Fresh water may be different to salt of course.

Last time Pendragon was lifted out, there was insuffent time to source a bronze screw for the cutlass bearing, so I has to make do with a stainless screw intended for oak framed buildings. I have some worries about it, especially as the metals are different. She is in fresh water.

The original screw had corroded away immediately behind the bearing, and was sound where it was in the oak. I don't know if it was stainless.

Philip