some questions on working with green oak outside please

[happyhero]

Hi I ordered a load of green Oak to use outside and I am making what I think you call gallows something like this

http://www.periodoak.co.uk/default.asp?id=870&mainid=809

to support a overhanging roof coming off of a shed,

The uprights are made out of 6"x6" and the diagonal is in 4"x4" and the horizontal is just over 6" wide.

Simple questions really,

What size dowels/pegs would you use with this size timber to get a nice look, would 1/2" be ok?

Are the pegs normally made out of the same stuff, ie oak, or is there something better?

As it is green Oak, what would you do about them getting wet and weather beaten, ie would you treat them with anything and if so what?

I would like to keep them looking the lovely light Oak colour they currently are but I am sure they will go grey like Teak furniture does over time or do you know a way to prevent this?

Any help/advice appreciated.

 

[bodfish]

Those are substantial pieces of oak - you'll have lots of fun / exercise shaping and jointing them. Fortunately green oak is fairly easy to work.

Pegs: I'd use 12mm as a minimum, maybe 14 would look good. Are these brackets going to be structural? If so you'll need to consider how to make the right-angle joint effectively to resist tension. The other joints will be in compression, so the pegging is really just to hold everything together during assembly. Dowels are easy to make using a dowel plate, but I tend to use dried oak rather than green to avoid later shrinkage.

Best to let the timber go naturally grey than be constantly trying to keep it coated with anything - just let it do it's own thing.