Edging

[Welderpaul]

Have a little conundrum.

I need to form some infill panels from punched sheet. The sheet is pre galv, with the holes punched through after the galvanising process. I need to cut the sheets down, and so to hide the cut edge i was planning to tack a 10 x 3 flat along the edge. Its up a building from ground level to 20M up. Galvanising after fabrication isnt an option as the holes will fill with galv and the sheets will no doubt twist to ******y. They are to be powdercoated.

Even if i spray galv the 10 x 3 strip, i have concerns that rust will start to seep through from it all after a while.

Had the idea of spraying it all with a decent enamel paint instead of powdercoat to give a better level of corrosion protection.

Any thoughts?

 

[Hitch]

Id have thought a decent bit of powder would be sufficent? Let them do it, rather than doing it over cold galv. I assume the mesh has staggered holes? so you couldn't just cut to one side of a row...?

 

[Welderpaul]

The holes in the sheet are staggered so you will always cut through holes when its sheared. I've had stuff powdercoated only before (Stuff going inside) and there has been small bits of rust in crevices if its been left outside for a few days.

 

[^neo^]

if the holes are punched post galv, then you'll get rusting round the holes too.
Thicker sheet shouldn't distort too much from galvanising.......... only from the monkeys loading it into the tank and the forklift drivers sticking it on the lorry.
What size holes are you on about?

 

[Welderpaul]

if the holes are punched post galv, then you'll get rusting round the holes too.

Yeah. And it's a long way up to do anything about. The holes are only 6mm dia. Aparently the holes need to be 10mm+ to avoid the galv bridging the holes. They need to be smaller holes. I think a couple of coats of decent enamel are in order, although that wont sort the problem of the 10mm welded to the face of the sheet.

 

[Robotstar5]

A powder coater I've used applied a "chromate primer" before powder coating, he said it prevented rust?

 

[Delgado]

On a slightly different note, when you weld it together make sure that you grind off the galvi coating around where you are going to be welding, and wear a mask whilst you are welding. In case you didn't already know, when you weld galvi It gives off a highly poisonous white powdery substance that floats around in the smoke.

 

[Welderpaul]

On a slightly different note, when you weld it together make sure that you grind off the galvi coating around where you are going to be welding and wear a mask whilst you are welding. In case you didn't already know, when you weld galvi It gives off a highly poisonous white powdery substance that floats around in the smoke.

I know

 

[^neo^]

depends on how long it needs to be in the tank. Most vent holes are 8mm. Have had 3mm perforated sheet galved before (probably around 8mm holes) with no problems.
Got a bit of light coating over some of the holes but a brush off with a wire brush fixed that as it was only like tin foil in the holes

 

[tomb]

My powder coater hot zinc sprays before powder coating. I was told it offers a thicker level of coverage than dipped galvo apart from hollow section and with no distortion .

 

[Jay]

thought for ya then, we usually get a thin channel, more of a u shape than a channel that we slot over the sheets. Think it comers from Brundles. We have always put a couple of holes in the bottom for the bit of water that will get in inevitably, always 45 the corners and weld it up, but if corrosion's an issue grab some in stainless and tig the corners. I knw stricly speaking you'll get a reaction from the stainless to the galv, but once its powdercoated should be ok.