Welding 5083 ally

[yorkie_chris]

Hello folks,

Have got a bit of a project on with my mates boat.

We want to take 2 loops from the console, up and over back to the A frame.


We reckon 5083 will be most suitable for corrosion resistance, and we can get it, and it should cold form ok because we need to put a bend in it.


Joints to make will be

1 butting the tube against flat plates (at a slight angle, maybe 75 degrees) to make some feet to bolt it down.

2 Teeing two tubes together (tubes are just structure, not holding anything inside)

3 Some plug welds to hold the tubes to some clamps which will slide up inside the tubes.

4 some strips of flat bar maybe 4mmx10 or 15mm butted against the side of the tubing, this will then get drilled to bolt a windscreen and roof cover to.

The tube material is 5083 1.5inch nominal bore schedule 40.

The stuff for (1) will probably be 4mm plate, I'd like to use as thick as possible in the hope that it will stay flat but on the other hand thicker will need more heat.
Any recommendations on this score?

What filler wire should I use?

I've got a 200A AC chinese TIG set, is this going to have enough poke or am I better off prepping and tacking everything and taking it somewhere to have it done by someone with a bigger machine?


And last of all if it's not too cheeky, does anyone deal with this material and could I have some offcuts/scraps to have a practice on before we spend the cash on ordering the full lot?

Many Thanks
Chris

 

[Rrunnach]

When I use to manu ROV's for SubSea Offshore, now SS7, 5083 was material spec, so yes, very good corrosion resistance. Very strong after welding, working beyond 1000 MSW.

5183 recommended filler, if you feel you will struggle with tig unit you have, pre-heat the alloy prior to welding, if forming, I recall the 6mm thick plate would crack when forming along matl grain, no probs forming against grain.....

 

[hotrodder]

In a perfect world you'd use 5183 as it's the matching filler wire for 5083. 5356 will also work, there's several others too but 5356 tends to be a commonly kept flavour. Having said that 5183 ain't expensive to buy or hard to find

As the bits of plate are smallish mounting feet/narrowish strips a 200A machine should have enough poke to handle 10+ mm i.e. mass plays a big role due to the thermal conductivity of ally

Flat bar tends to be only (or at least most commonly) a 6xxx series extrusion. Aluminiumwarehouse.co.uk sell plate cut to size including 5083 (only O temper = annealed as the pipe probably will be) and the site will price it for you once you've stuck the dimensions in. Unlike the majority of offcut/cut to size online places their prices are generally very close to proper stockholders but check the carriage on largish bits of plate- might be OK but full sheets used to be VERY expensive. As Runnach said, watch the grain direction if you have to bend plate

 

[yorkie_chris]

I'm not forming the flat plates, they'll just be 2 sort of 150x100 flat "feet" which will get bolted to the console so we should be alright there.

Aluminiumwarehouse doesn't do the tube but I have found a place that does, they do the rest of the bits though for pretty reasonable cost.