Tig welding brass

I don't want to use a gas flame and flux. I want to weld it with the tig.

I tried this myself at school last week with no success. Then my welding instructor came into my booth and asked me what I was doing. "Trying to tig weld brass.", I replied. "Can't be done.", he said. So with his knowledge and my direct experience, I would say it can't be done...

The problem is that the zinc bubbles out in ugly little blisters, sort of poison ivy looking nastiness. I have decided to use mechanical fasteners - picked up brass hardware at Home Depot for 88 cents...

Of course, I might be wrong...

Yes, you can TIG weld brass. Use RCuSi filler and DCEN. Be aware that the zinc will fume. You don't want to breath it because the fumes will make you sick as a dog. And it will likely cause some porosity in the weld metal. Keep the arc on the filler metal to avoid burning the base metal. Use stringer beads, don't oscillate.

You can TIG Braze-weld it using silicon bronze or sil-phos-bronze filler, but keep your heat very low or you wil burn the zinc out of the brass. Besides giving off toxic zinc oxide, burning the zinc out will also change the color, making it redder.

The sil-phos melts a little lower so you tend to burn less zinc.

Color match will be OK if polished, and coated. If the surface oxidizes at all, the weld will show up bright as day.

I have AC or DC. I can not reverse the DC electrode current. So do I use AC?

Can I use normal brass as the filler rod?

I tried normal bronse filler rod, using DC tig. The whole thing cought and spluttered and covered everything in light coloured powdery soot. I guess I did something wrong, yes? What?

Wrong filler. You are trying to use Low-Fuming Bronze for gas brazing. You need Silicon Bronze or sil-phos bronze.,

Cheers Enrie, I thought it was the filler that was making it all flair up. Was I right to use DC?

The zinc in the brass filler will fume and caused increased porosity. You can try it. But you will be better off using the silicon bronze recommended previously. And if you are already having trouble with fuming, I don't think you will like the results with brass filler.

You want to use DCEN to put most of the heat on the work because of the thermal conductivity of coppper based alloys. You could use AC. But you will have to use a larger tungsten and higher current.

BTW if what you are welding is much more than about 1/16" thick, you may need to use an argon-helium mix to get adequate penetration and weld pool control.

No. Brass is an alloy of copper and zinc, and zinc has an infamously low boiling point . If you heat brass to anything like the temperature of a TIG torch, you'll lose an awful lot of the zinc as fumes or zinc oxide. Find some silver solder and a cheap low-temperature gas torch and do it that way instead.

There are also questions as to what brass alloy you're using. Some are easier to work with than others.

(I know this is really sublimation not boiling, but you get the point)

AC works, but DCEN works better.

I can set my tig to AC and get 80/20 percent either way. It also had the normal CD for normal CD tig welding... is this DCEN?

Does "DCEN" mean direct current electrode nutral?

So that should mean that the spark jumps from the brass to the tungsten, yes?

UH...electrons are negatively charged...in this universe. If you have positively charged electrons (called positrons or antimatter), then you come from a parallel universe and must have a goatee.

DCEN means the current goes from the tungsten to the base metal.

A long time ago it was commonly thought that electric current flows from "positive +" to "negative -". However, in more recent years it has been proved that electric current actually flows from "negative -" to "positive

+" .

It actually flows in the opposite direction to what is shown on a circuit diagram.

Regardless of how you view current, DCEN means the electrons flow from the electrode to the work, and positive ions flow toward the electrode. Considerable energy is required to make the electrons leave the electrode. This is called the work function. When the electrons hit the work, they give up this energy. What you wind up with is about 70% of the heat on the work and 30% on the electrode. This is what you want when welding copper based alloys.

If you use AC, about half of the heat will be on the work, and half on the electrode.

FWIW both views of current are still in use.

*However* only one view refers to metal current flow. The other is semi-conductor hole flow.

I believe even the electrical trades have long given up + flow they got from Ben Franklin IIRC.

Electricity and Electronics is electron flow that is e- flows to the +. Solid state Electronics inside a crystal allows hole or e+ flow.

We are talking about welding rods and Tig - so the electron e- is king.

Martin