metal core, wooden exterior

[Chris_belgium]

Hello,

as some of you might have noticed I am in the process of building a sliding driveway gate, the gate is made out of hardwood (aphselia doussie), the posts for the gate will be a metal pipe as a core wich will be cladded (correct term?) with aphselia planks on the outside.

https://www.ukworkshop.co.uk/forums/viewtopic.php?t=34019


Question now is how to do this?

This is a previous gate that I made, I just glued the planks to the metal and glued the edge joint between the planks. Offcourse no 2 years later, the planks have moved a bit leaving me with gaps between the planks.

Offcours i want to prevent this this time round.

my ideas:

easiest would be to route a tongue/groove on the planks and don't glue them up but just slide them into each other. I don't really like this look, so only want to do this if there is no other option

second idead, glue up 4 boards, one for each side of the post, glue them to the metal and join them at the corner with the plank sliding into a dado, wich will allow for some movement.

Last idea and the one I prefer, make a square box, a couple of mm oversize than the square metal pile. Weld a small lip on the bottom of the pile and just slide the entire wooden box over the metal pile.

All advice is more than welcome!

piles in question 25 x 25 x 200, 8mm thick.

 

[Chris_belgium]

Nobody has any tips/remarks? I'm kinda at a loss here, really want to avoid problems this time round.

Or is it my explanations that don't make any sense

 

[jasonB]

I'd go with the last option, that way the wood can move independantly of the steel.

Jason

 

[laird]

Given the temperature drop and condensation caused by the steel I think I'd put a barrier between the two materials. Either an air space , or DPM, or something of that ilk. So it would be your last idea for me, with lots of preservative inside the wood box.

 

[dickm]

I'd go with the last one too, though possibly a bigger air gap than 2mm, as that would be sure to bridge with the amount of movement likely to occur. Something more like 5mm all round would be my preference.
Presumably the wood is not taking any load?

 

[Chris_belgium]

Thanks for the advice, the box it will be then.

Wich leads me to more questions offcourse , the boards I'm using are 19cm in width, the widest panel I'll have to make will be 65cm in width, so at 165cm long that will be a rather large panel.

Do I need to rip the 19cm boards to smaller pieces and alternate the grow rings to avoid cupping or will this be ok, planning on using biscuits and epoxy glue for the joint.

And then there is the question of how to attach the wooden box to the metal pile, I'm wondering if some kind of french cleat (spelling) system would work, the weight of the box wood keep it down and secure, but then there wouldn't be any room for movement, any toughts/tips?

Christof.

 

[Chris_belgium]

I'd go with the last one too, though possibly a bigger air gap than 2mm, as that would be sure to bridge with the amount of movement likely to occur. Something more like 5mm all round would be my preference.
Presumably the wood is not taking any load?

The wood is only to "hide" the metal pile wich will take all of the load.