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02-09-2012, 05:00 PM #1
Tig Welding Thin Wall SS Spheres Together?
I have to tig weld a series of 7" or 10" diameter stainless steel spheres to each other. The wall thickness is .047".
How would you guys suggest doing this? How would you get close enough, since they are making point contact to each other? What size electrode, amps, rod, etc..
Any help would be appreciated,
02-09-2012, 05:24 PM #2
02-09-2012, 05:34 PM #3
I can not get inside the sheres, since they are full spheres.
I just realized that I could use my Mig welder with SS wire. Do you think this would be better than using Tig, since I could get in closer by using a longer stick out?
02-09-2012, 05:42 PM #4
I did this last year.
Stainless warps big time when you weld it, just the nature of the beast.
I recommend a lot of tack welds, evenly spaced.
What I didnt do, and probably should have, is drill holes, and make some kind of removable clamp system- maybe Cleco based.
As it was, I ended up tacking, prying up low spots, pounding down high spots, and then grinding, filling, grinding, filling, sanding, filling, and so on. Repeat as needed.
I was lucky that, in the end, I could needle scale the whole thing, for a slight texture, so you couldnt see that they werent perfect. If it had to be polished, it would have been even more work.
These spheres are something like 12" in diameter, as I recall. The upside down bell shape is bigger, around 22", but its aluminum, and was a lot easier. The upper picture actually makes the seam stand out more than it really does - the light hits it just right.
I used a pretty small tungsten, 3/32, mostly. 1/16" filler rod. Let it cool a lot and move around a lot- it warps when it gets hot, so you want to keep it from getting too hot. No long beads.
02-09-2012, 06:03 PM #5
It sounds horrible what you had to do! My situation is worse since I have to weld the spheres to each other.
I'm thinking now, maybe forget welding and trying to find some industrial adhesive that would stand up to outside weather conditions and the sun? Do they make such an adhesive?
02-09-2012, 07:03 PM #6
I've seen smaller ones for fighter planes. They were electron beam welded.
02-09-2012, 07:28 PM #7
I wouldnt trust a glue edge to edge.
It might be possible to cut a backing strip, and then use the fancy 3M doublesided foam tape- they use it to put the skin on buses and subway cars, it really sticks.
But in the end, welding is probably the best.
One trick people do sometimes is put the piece in a tub of water, with only the part you are welding sticking out- keeps it cool and keeps it from warping as badly.
Mine actually turned out okay in the end- and they are about 20 feet up, so people dont look too closely.
02-09-2012, 08:25 PM #8
How about Silver Brazing with some 45%? Much lower temp should keep the material from warping. depending on how they need to connect you could even drill holes and use some rod to create some kind of bridge that the filler would like even more than just the two spheres touching each other. That would be hella strong.
02-09-2012, 08:43 PM #9
What is the aplication? Do the welds get ground and polished for sanitary use? How close are the tolerences? If its an art project, it should be very simple for you. If demensions matter then you better have your act together. Mig welding it will be very tough, Especially if the gaps are not perfect. How many of these do you have to do?
02-09-2012, 08:47 PM #10
Would it be possible to make a hole in each one and then weld a little strip inside that has a nut welded to it? Then, you could put a piece of threaded rod between them and thread them together. It sounds like the two just need to be held together and aren't anything structural. Threading them together might not be too noticeable.
02-09-2012, 09:00 PM #11
02-09-2012, 09:03 PM #12
Weld a nut to one and a bolt to the other.
Than screw together.
You can cut the nut into the one and the head of the bolt on the other.
I can see that i type to slow
02-09-2012, 09:05 PM #13
Can you drill a small hole in them, fill them with water, weld together, drain and patch the holes. Shouldn't warp as the h2o will carry heat away.
Maybe drill one, weld a cap nut in the hole, drill the other, weld a stud in it. torque them together with permanent locktight.
You too Heavey Metal, you beat me.
02-09-2012, 09:23 PM #14
Can't remember the name but I think they are called nut serts?
Its basically a threaded rivet, uses a tool similar to a rivet gun, doesn't leave much of a hight....
Drill, nutsert, all thread with red loctite?
02-09-2012, 09:26 PM #15
02-09-2012, 09:33 PM #16
The sphere shape should be more resistant to warping, no?
Maybe tig without the nozzle with two inches of stickout and two argon hoses flooding the area (or weld in a glovebox)
You're going to have to 'bridge' the gap no matter but you could get a uniform bead I would think.
02-09-2012, 09:41 PM #17
If applicable, you could also cut a short length of pipe to go between the spheres to increase the welding surface as well as get that surface closer to the nozzle.
02-09-2012, 09:42 PM #18
Originally Posted by jamie76x
"What is the aplication? Do the welds get ground and polished for sanitary use? How close are the tolerences? If its an art project, it should be very simple for you. If demensions matter then you better have your act together. Mig welding it will be very tough, Especially if the gaps are not perfect. How many of these do you have to do?"
This is for an art sculpture consisting of about 60 spheres, each one touching one or two others. My concern, aside from the warping due to the heat, is how do I get the end of the Tig torch in close enough to the point of contact between the spheres? Why do you say Mig welding will be very tough?
The ideas of bolting the spheres together will be tough because the 60 spheres are in closed loops and are unsupported except for each other.
Thanks to everyone for the interesting ideas,
02-09-2012, 09:44 PM #19
02-09-2012, 10:09 PM #20
Now to deal with the warping problem. Do you think the sphere shape will resist the warping? I guess if I'm very careful and do small tack welds, this will help.
These spheres are expensive, so I do not want buy them and then find out that it's not going to work.