hole drilled in tubular frame-WHY!

[colesy]

Could anybody tell me why the odd hole is drilled in tube sections of a wrought iron fence/gate.Making some at the moment and would really appreciate a reason,maybe a galvanising reason! i dunno-HELP

 

[Welderpaul]

They are vent holes - must be drilled through any closed section of steel -box section, pipe etc - it stops the gases inside expanding during galvanising and possibly exploding or tearing the box section apart - also allows the zinc to coat the inside of the piece.

 

[Tigman]

you`ll find that the tubular fence has been galvanised the holes are to release the traped air as the fence is hot dipped and or to drain the zinc from the tube as it is brought out of the dipping process

 

[Paul.]

Vent holes for galvanising, stops the tube exploding in the hot dip tank, and allows molten zinc inside.

 

[Wozzaaah]

Vent hole for galvanising most likely .
The hole is normally at the end of a hollow section to allow air to escape and the molten zinc to fully flow throughout then the excess zinc to drain out afterwards.

Edit: Just like buses, all at once!

 

[Tigman]

Ha Ha Snap

 

[reno]

Hi,

As far as I can remember: its normally required for when gates/railing sections are hot dip galvanised. It allows the gases that can build up inside the hollow sections to escape. I'm not sure whether you need to do this if you are having them powder coated.

Usually an 8mm hole should be sufficient for each individual hollow section.

Hope that helps!

Cheers, reno

 

[reno]

Beaten to it! Maybe I should just learn to type faster...

 

[colesy]

powder coated

Cheers fella`s.The fence is being powder coated so maybe holes arent necessary.What do you rekon

 

[Paul.]

Venting box section isn't required for powder coating, had loads of it done, never any problems.

 

[Welderpaul]

Something like that would normally be galvanised and then powdercoated. Powdercoating doesnt take too well to bare steel. Plus if its outside, powdercoating offers little corrosion protection.

 

[chunkolini]

OI heard it was so that the evil spirits could escape before they was permanentely galvinized in there.
Chunko'.

 

[Paul.]

If you don't want to galv it, have it blasted, hot zinc sprayed then powder coated,

 

[Welderpaul]

If you don't want to galv it, have it blasted, hot zinc sprayed then powder coated,

Cheaper just to galvanise first?

 

[Normsthename]

I have had bare steel powdercoated for many years, no problems.
Just find a good powdercoater, its how they degrease and clean the steel before coating that makes the difference.
I have had some shocking powdercoating jobs done over the years :

Andy

 

[gavuk]

We used to have our panels blasted then powder coated,never had a problem either......inside jobs though ...Gav

 

[Paul.]

Cheaper just to galvanise first?

Guess it depends on what local facilities you have, and how big a job it is, galvanisers usually have minimum charges, and if not local, transport will need to be factored in, most decent commercial painters can blast and metal spray, at least round here they do, no distortion with zinc metal spraying either,