Welding fine stainless steel mesh

[GrahamGKD]

Hi Folks,
I've been trying to TIG some fine stainless steel mesh (20 holes per linear inch; wires are 0.35mm in diameter; apertures are 0.92mm) to some 3mm 304L rod, the purpose being to provide a kind of translucent skin to metal sculpture insect wings. The rod forms the perimeter of the wing. I quickly found that welding from the top was a complete non-starter as the mesh burned back instantly, so I tried wrapping the mesh around the rod and then welding from the underside. This worked after a fashion but I was right on the threshold of melting the rod (the rod drooping and loosing its form) before getting the wire to fuse. Also, the rod was getting quite grey with oxidization (too much heat?). I was working with the wing laid mesh down on a copper plate.

I also found that, where the wire did not fuse on the first run, it was (for me in any case) not possible to go back and repair the non-fused section, meaning that any faulty section in my wing meant writing off the whole thing. I fiddled with all kinds of settings (I'm no TIG expert) but in the end I was running my Lorch with a 1mm tungsten, about 7 lpm, 35A/12A pulse at 2.2 Hz. In the end I gave up and simply fitted the mesh by wrapping around the rod with a pliers - this works better than you would think; saves all kinds of costs in gas, power etc. but does seem like a bit of a cheat and has the disadvantage that it is hard to get rid of all of the sharp ends of wire.

Looking back at my ebay purchase, I don't seem to have a spec for the mesh - maybe it's not a suitable welding grade of stainless - I will try to find out.

My questions is - for those who have had the tenacity to read this far (Thanks) - should I be able to weld this, or am I asking too much of myself? If I should be able to do it, where should I focus my next experimental session?

I will be away from the forum for a while so if I don't respond to questions or suggestions please don't interpret this as rudeness.

Cheers,

 

[Shox Dr]

Welding mesh that size is never going to be fun.

Does the Lorch have a Mirco tack function, use that and lift start, you'll need an ultra sharp tungsten as well.

if not set amps to 20 (as a starter) in lift start and just zap it.

 

[chunkolini]

Might be worth trying to Mig rather than Tig it.
You might get more filler than you need going on but you can grind it off.
I was happily welding up a spiders web using 3mm bar and 0.8mm filler.
Wrap it right round and do a series of tiny spots onto the bar from the bottom just flicking the trigger, probably for longer than you might think. I found more power than I expected and a quicker weld worked best. more penetration, less bulk to the weld but easy to mess up. Work fast. Sounds like a PITA to get the hang of. Put up some photo's.
Last thought, might the kind of 'mesh' made of punched holes work better than a woven mesh.

 

[GrahamGKD]

Might be worth trying to Mig rather than Tig it.
You might get more filler than you need going on but you can grind it off.
I was happily welding up a spiders web using 3mm bar and 0.8mm filler.
Wrap it right round and do a series of tiny spots onto the bar from the bottom just flicking the trigger, probably for longer than you might think. I found more power than I expected and a quicker weld worked best. more penetration, less bulk to the weld but easy to mess up. Work fast. Sounds like a PITA to get the hang of. Put up some photo's.
Last thought, might the kind of 'mesh' made of punched holes work better than a woven mesh.

Thanks for coming back Chunko - yes, I guess tacking with the MIG might work - like you, I have used the MIG to successfully join the 3mm rod (both SS and mild) together in the past. To be honest, just the cold wrap method works securely enough but a seam around with the TIG would be neat if I could do it. Will find out the spec of the mesh I have used and maybe look at different types - this is my first experimentation with this approach.

 

[matt1978]

Graham, you could try it in Spot mode.

Have the current set really high, (Start at 220 amps and work down) and the spot time on for 0.05 seconds.

Obviously the figures I have given are just a guide, but you can try and see if its worth experimenting further

 

[GrahamGKD]

Graham, you could try it in Spot mode.

Have the current set really high, (Start at 220 amps and work down) and the spot time on for 0.05 seconds.

Obviously the figures I have given are just a guide, but you can try and see if its worth experimenting further

Hi Matt, Do I have that mode one my HT220 - I was pouring over the manual the other day and I don't remember seeing it?

 

[Drains]

Graham, on the T220 it's a setting available in the 2/4 stroke/pulse selection group, if that helps.
I imagine it'll be on the HT too, just harder to find.

I'd not noticed it before now - but it would have been extremely useful a number of times in the recent past!

 

[pedrobedro]

I'd run a bead of glue round the sharp edges to cover them and help secure it as well.

 

[GrahamGKD]

I'd run a bead of glue round the sharp edges to cover them and help secure it as well.

Pedrobedro, This is a 'welders' forum No, seriously, I like that suggestion, I might just do that - thanks.

Drains, Just had the book out again and can find no reference to spot mode – if I do have it that would be useful to me as well, for things like welding tentacles on. Hopefully Matt will confirm.

 

[mike os]

braze?

silver solder?

 

[GrahamGKD]

braze?

silver solder?

I don't know Mike - I've done quite a bit of brazing with the TIG using the SIF Bronze N0 8 rods - it still needs to be quite hot and I guess I was hoping for the simplicity of a heterogeneous weld. If I had a decent gas set up I'd give the silver solder a go but I'm not sure that can be done with a TIG set - if anyone knows different I'm all ears!

 

[Paul.]

I've used a lot of this woven mesh in the food industry stuff I do, its used for strainers in wash down systems, usually we clamp it, obviously not suitable for your application though, resistance spot welding works fairly well, on the occasions I have tig welded it I fold the edge over 2 or 3 times and flatten it to make a thickened hem, continuous welding is going to be a real challenge though,

 

[GrahamGKD]

I've used a lot of this woven mesh in the food industry stuff I do, its used for strainers in wash down systems, usually we clamp it, obviously not suitable for your application though, resistance spot welding works fairly well, on the occasions I have tig welded it I fold the edge over 2 or 3 times and flatten it to make a thickened hem, continuous welding is going to be a real challenge though,

Hmm, I hadn't thought of folding over 2 or 3 times - would be a bit of a fiddle on my curved pieces though. Something to experiment with. I did try sandwiching the mesh between two 3mm rods and then seeming the rods together with the mesh caught up in the join - that worked better but the appearance of the finished article is not as good with a rod top and bottom - I just really want one rod at the bottom with the mesh curved over it.

I've been thinking about using something like a carpenter’s pinchers to neatly crimp the cut edge of the mesh around the rod and kind of tuck it under for the non-welded approach.

Thanks for confirming the welding approach is expected to be a challenge - I was hoping it wasn’t entirely my poor technique!!

 

[outofthefire]

I saw a tip on an american site for welding fine mesh onto frames to make fly screens they suggested clamping the mesh between the frame and a washer then welding up the hole in the washer, I presume that the mesh will get trapped and partially welded under the edge of the washer. Probably not too useful in this instance unless you could split some drilled tube and use it in a similar way on the back of the wing.

 

[hotrodder]

I did try sandwiching the mesh between two 3mm rods and then seeming the rods together with the mesh caught up in the join - that worked better but the appearance of the finished article is not as good with a rod top and bottom - I just really want one rod at the bottom with the mesh curved over it.

Just throwing ideas out there... what about sandwiching the mesh between some 1.6 filler wire? Be a lot less bulky than the 3mm rod although obviously still not 'hidden' on the underside of the wings. Other than that pretty much all been said... 'kin difficult, you'll only get one shot at welding i.e. make a mistake and start again. Higher amps and shorter weld times are the way forward. High pulse frequencies (> 100Hz) will work better than low as they constrict and stiffen the arc resulting in better focus and stability

 

[langy]

I saw a tip on an american site for welding fine mesh onto frames to make fly screens they suggested clamping the mesh between the frame and a washer then welding up the hole in the washer, I presume that the mesh will get trapped and partially welded under the edge of the washer. Probably not too useful in this instance unless you could split some drilled tube and use it in a similar way on the back of the wing.

Thats what i do when making mesh grilles, works good.

 

[Tiggy_dorset]

I had to do a similar job some time back, welding thin stainless mesh to some 12mm bar. The technique I used at the time was to heat the bar, build up some filler then flick it/bridge it across to the mesh whilst its still hot. Admittedly it wasnt easy and not every weld came out as pretty as i would have hoped. I am liking the washer idea though (keeping that one in the memory banks).

 

[mike 109444]

Why not go the "spot weld" (resistance spot) route. Search youtube for home made spot welders prob knock one up in less time than re doing one wing ?

 

[dannyp]

micro tig ?

 

[GrahamGKD]

Thanks for all of the suggestions - I just got organised to have another experiment but my Argon has run out so I will have to put it off for a while as I am otherwise engaged for a couple of weeks.

I will report back in due course.