Welding a nut

I need to weld a 5/16" nut to the bottom of some 1.5" tube. My question is what kind of nut would weld best with my MIG running .030 wire and C25 gas? Zinc plated, Grade 5, Grade 8? Does it make a difference?

Jim

Reply to
Jim Meyer
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use a zinc plated, but grind the coating off. You can do them with the coating inplace, but stay away from the fumes...very hazardous.

Reply to
James Arnold

Use regular black hardware to avoid fumes. Cadmium oxide fumes are particularly dangerous. In some situations you can select a square nut or an extra heavy in order to increase the wall thickness and avoid burning through. Randy

Reply to
Randy Zimmerman

Reply to
RoyJ

Get black iron square nuts. They are MUCH better for welding. Make sure to screw a bolt into the nut before welding, and smear high temp anti-sieze on the threads, or just assume you will be chasing the threads. after welding, with a tap.

Reply to
Ernie Leimkuhler

I like make my own from plate. Center punch, drill & tap, cut or punch out slug. You end up with a flat washer shape with treads & thick metal edge for welding. It sits nice and flat on ends of tube or pipe.

Reply to
Lance

Thanks for the advice Guys. I didn't see the black iron nuts at my local hardware store, but will keep trying.

Jim

Reply to
Jim Meyer

Hmm -- I read with interest all of the replies to this question, as I have made several projects which required welded nuts. I'm a little confused, though, about the zinc issue. When I go to the local hardware store, there seem to be two very different sorts of "zinc plated" nuts (and bolts). If I understand correctly (a dangerous assumption, of course!), the comon, inexpensive nuts and bolts do have a thin, bright coating of zinc; this provides some resistance to rust, but not enough to stand up to outdoor use. Then there are the nuts and bolts that I would call "galvanized," with a heavy, dull-looking coating, which are intended for outdoor use.

I would certainly be concerned about removing the zinc from the latter category, but I've welded quite a few of the common variety without worrying about removing the zinc. I've never noticed any difficulty getting a good weld, nor any unusual fumes, nor have I gotten sick ... have I just been lucky? Or am I confused about the common variety of nuts & bolts having a thin zinc plating? (I've been using stick exclusively, if that makes a difference; usually I weld nuts with 6011, tacking them on three of the six sides.)

Like Jim, I have never seen "black iron" nuts, either at the big box stores--no great surprise there--or even at the local hardware store, which seems to have one of everything anybody ever thought of ... some of the stock appears to have been there 30 years or more!

Reply to
Andrew H. Wakefield

Electro and hot dip. Hot dip galvanising is thicker, so it works better outdoors. It's also thick enough to make a mess of threads, so a garden gate latch is often hot-dipped, but the nuts and bolts to attach it are just electrolytically galvanised.

Be wary of plating with a golden, yellow or greenish tint - that might be cadmium plating, and you really don't want to be burning that.

I haven't seen black iron nuts in years. Generally I use galv and weld right through them - it's a poor weld though, don't do this if it's going to be stressed.

Reply to
Andy Dingley

Virtually any hardware you get from a hardware store will have some form of zinc plating. When this welded you'll see a stream of white smoke appear when the plating first burns off. This is bad stuff and you don't want to breath it in, so its best not to weld on zinc plated metal if you can find a way around it.

If I have a big piece to weld on I'll dunk it in muriatic acid first. This is cheap and available from most hardware stores however this is nasty stuff also, requiring gloves and a face shield during use. Also you can't really leave any of it around your shop as its fumes are extremely corrosive. If you're considering using it definitely search the web on "muriatic acid" to get some ideas on how to handle it safely.

When you dunk something with zinc plating in the acid it bubbles like hell at first while the plating gets eaten away. When the bubbling stops its down to the steel part and its time to get it out as the acid is now attacking the steel. Carefully rinse it well in very hot water and then dry it with compressed air and you're ready to weld.

However, if I just need to weld on nut on something, I'll usually use a stainless steel nut, also generally available from most hardware stores and you don't have to worry about this plating issue. The only downside of a stainless nut is that its not as strong or durable as a regular steel nut. However any nut you weld on like this is not going to be a strong as an unwelded nut due to the loss of heat treating, so I don't use welded nuts for anything that is highly stressed, or if I have to I would use an oversized nut for the job.

By the way if you're doing a lot of these, unplated grade 5 nuts (a better solution that a stainless nut) are available from industrial suppliers such as

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but you'll have to buy a box of them.

Good luck-

Paul T.

Reply to
Paul T.

What is readily available (at least mail order) is unplated nuts. I know MSC has them, I'd think McMaster-Carr and Grainger would too.

Steve

Andrew H. Wakefield wrote:

Reply to
Steve Smith

You can avoid the muriatic acid with electrolysis. Qt. of water 2tbls of salt and 12volts DC stainless anode work is cathode, this will strip most conductive coatings. If you really feel creative mask the metal with nonconductive coating and etch designs into the surface of the work.

Reply to
geoffrey gangel

I was just wondering... are there any metals that you _can't_ cut with a plasma cutter? if so, why not?

-sean

Reply to
Sean J Kelly

My guess is very conductive very low temp materials that might be hard to control. e.g. some of the melt in hot water type. But who would want to do that anyway. Or Indium...

Naturally there are Nasty stuff - Cadmium or Mercury ... or the stuff that a Plasma torch uses as the current source :-)

But for the most part, all metal that we normally work with can be cut.

Martin

Reply to
Martin H. Eastburn

All the non-exotic metals can be plasma cut.

Titanium produces BRIGHT white light when plasma cut.

Tungsten carbide cuts as easily as copper.

The more conductive a metal is, the higher the amperage it takes to cut in.

Reply to
Ernie Leimkuhler

"geoffrey gangel" wrote: (clip) If you really feel creative mask the metal with

Sounds like fun. It could be used for decorating tool handle ferrules, for nameplates, and countless other things. I can hardly wait to try it. My woodlathe tools will never look the same.

Reply to
Leo Lichtman

Probably - but Ti cuts pretty easily. We tried hacking up an inch cube of it, mainly to see how much the fire hazard was. No big deal at all - not even particularly bright. Whilst grinding it though, I've had (small) Ti dust fires.

There's a couple of feet of 4" Ti H-girder in the stockpile that would be useful forging stock, if only we could slice it up.

Plasma has problems with thermally conductive metals, so mere aluminium is surprisingly hard work. Maybe there's an exotic out there it would have trouble with.

Reply to
Andy Dingley

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Reply to
Andy Dingley

The former are indeed electrolytically plated with a *thin* zinc layer. The latter are "hot dip" galvanized with a thick layer of zinc.

Even the plated nuts fume, just not as much.

Auto parts store. Plated or galvanized nuts and bolts are the exception rather than the rule for automotive uses.

Gary

Reply to
Gary Coffman

I like to run a few nuts through a bead blaster.. Takes coatings off nuts quite well, especially in the threaded center.

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Reply to
Barry S.

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