dissimilar metals

[nickk]

does any one know the durability of brass screws holding a galvanized bracket to green oak,i can seperate the screw head from the bracket with an insulating washer of course.

 

[TechnicAl]

I believe you should only use stainless steel for joining green oak. I know the "sap" is very acidic

 

[brightspark]

I believe you should only use stainless steel for joining green oak. I know the "sap" is very acidic

l second that all this lot was bolted together with stainless bolts

 

[pedrobedro]

It's the tannin in oak which causes problems. It reacts with iron and steel to cause blue inky staining but I don't know if galvanising or brass will react.

 

[the artfull-codger]

Brass & galvanising don't go together well the zink will corrode,but only if they're exposed to an electrolyte ie water if as you say put an insulating washer between them & cover the screw then it'll be fine, brass of course has been traditionally used in oak for years & is o-k steel screws should never be used in oak due to the acid in oak

 

[nickk]

actually the zinc can be eaten by the tannin but the customer didnt want shiny s/steel & failed to tell me they were touching oak until after i had them galved!so i will suggest a seperation layer between the 2.i thought bronze screws might be best,i find s/s ones can shear.