Thanks, could you please tell me what kind of current do you use? AC / DC ?. Otherwise thanks for the tip, and I'll try it out as soon as possible, but first I need to cast something at home.

I'm using phosphor bronze (RG5), because it's the only thing that's available in Slovenia, or at least in the capital city where I live :(...

Thanks for the info.

Heres what I do: DCEN (ground clamp is positive) 2% tungsten, not pure, sharpen tungsten, argon sheilding gas, preheat to 300-400F, weld in spite of outgassing, preferably with silicon bronze rod. Don't let it get too hot. You may have to let it cool down. Clean w/stainless wire brush. Weld more. Realize that tungsten and gas cups are consumable and need to be replaced/ cleaned or sharpened more often than when welding other metals. John Christiansen

Actaully, AC would be problematic with bronze welding. You'd be begging for problems when the current reversed and both cooked the tungsten and tried to plate it with outgassing elements from the bronze. Cleaning is only required with aluminum, not bronze. Stick with DC.

High frequency start is always handy with TIG, but for silicon bronze it is not needed while running. Some other bronzes it might be handy, but I can't personally say from experience.

TIG works fine as a heat source for brazing almost any metal. After all, it is fundamentally nothing more than a heat source developed from an arc as opposed to a flame, and has the added benefit of a shielding gas to inhibit oxidation, a function performed by the excess carbon in acetylene.

Thanks, for all the replies, I've learn how to weld bronze. That saved me some money, since I was seriously thinking of selling my DC TIG, and buy AC/DC or even oxy-acetylene burner.

Thanks !

This link will give you a lot of instruction on how to do it yourself.
http://www.backyardmetalcasting.com/

can you help.i have been asked to repair a small casting,i have argon tig and oxy acet what to do and how to identify metal type,its a quarter inch thick horses hock

Since you don't know what the metal is, I'd definitely recommend that you try to remove a tiny bit of it from a hidden location and do a melt test on it. If it melts at a temperature higher than aluminum, then ou may be able to do an autologous TIG weld for the repair. Again, remove a few small bits of the parent stock and use it as filler to make the TIG weld. If you can't remove that much stock inconspicuously, then you'll have to find a filler rod that is a near color match. Silicon bronze, naval bronze, architectural bronze, phosphorous bronze - something should be close enough to work.

The starting point is learning what the melting point of the metal is and whether it has alloying ingredients that may boil off during welding. Best way to test this is to melt some.

Hi,
I did a little TIG welding on silicon bronze at school, and now am setting up a small foundry to cast my own work. Have been trying to weld with an inexpensive chinese inverter machine which really puts out the heat! But, it's a little different from the big Lincoln I used. My welds have black residue, and are sort of bubbly or pebbly. I can't get the machine to continue shielding after I am done welding. When I stop the heat, the gas stops too.I don't remeber having residue when I used the Lincoln. I use DC, and straight argon. The psi is around 8, and the ball is at 3.Any suggestions? (I think my welds should be cleaner)
Thanks- katt

Katt,

If you're welding silicon bronze and not some other alloy, your welds should come out pretty clean.

It sounds as though you have the argon set too low. I use at least 7 and up to 12 lpm argon flow, using a 3/32" tungsten and a medium cup. If you can get one for your torch, a gas lens will help with even dispersion of the shielding gas, but it should work okay without it. Grind your tungsten to a sharp point about three diameters long and with the scratch lines running parallel to the length, not across it. I hold the tungsten in a battery-operated drill and spin it while holding it against a belt sander to get the proper grind lines. Quick and easy this way.

You need to use high amperage at the start, just to get the metal heated, then you back off the heat to the point where you can maintain a controlled puddle and not much more. A foot pedal is pretty much a necessity for doing this easily, though it can be managed with a just a finger switch and some dexterity.

Cleanliness is of course necessary for clean welds. Sand everything clean and shiny and then wipe it down with acetone before welding - the same with your filler rod.

If you're welder doesn't have post-flow on the shield gas, you can knock the ground connection loose as you finish welding and that will stop the arc while you continue to hold the switch for a few seconds of shield gas. Alternately, you can run a second line from your argon flowmeter and use that for additional purging and post flow.

Hope this helps.

Rich

Hi all, completely new to this site -stumbled across it looking for info on using an inverter to weld bronze.

I don't know much about welding, I have a done a bit of all types and currently have a small mains powered arc welder which was cheap and does the job on steel nicely.
I've been paying through the nose for welding touchups on bronze at foundries so far and would like to do it myself.

So firstly, what i've gleaned from this thread is

a) it IS possible to weld bronze using an Inverter (something many people have told me is not worth the trouble)

b) the best current is DC

c) the best bronze is silicon as it produces the best colour match etc

d) there is a lot more to learn!

So, for someone looking to get started with an Inverter/Tig setup for around £300, where on earth should I start?

What do I need? Basic components? Can it run off mains?

Sorry if these questions are all elementary, I am pretty much a beginner and any help is appreciated!

Welcome to ArtMetal.

I'm not sure if you're going to be able to find a decent inverter TIG within your budget. To weld bronze, or any copper alloy for that matter, takes plenty of current. You'll need a machine capable of a minimum of 200 amps DC. That will take more than your "mains" if I understand that to mean the same household current you run your TV off of. A 200 amp tig welder will take 220 volts at about 35 amps.

You might check Ebay or similar venues for a used machine.

Rich

hi rich thanks for your reply.

I've been looking around and was liking the prices of the giant machines on ebay for a while, til I read how crap they are and how often they go wrong!

I'm currently considering the clarke range from my local machine mart as this is where I got my arc from and i'm very pleased with it so far.

Yes I do mean the same current that I use for my tv, hi fi etc.

So you don't think that a 150-155 amp machine would have the grunt?

this is the one I'm looking at now..

http://www.machinemart.co.uk/shop/product/details/clarke-at150-150amp-arc-tig-inverter-welder

Not sure of all the specs, I've extended my budget to £400-450 to accomodate the accessories kit etc

Also, someone told me I can weld bronze with arc rods, is this possible? Where abouts could I get them from in london?

Thanks for your help,

The short answer is no, I don't think that little machine will do the job on bronze. It just doesn't have the ampacity to get bronze hot enough to weld, at least not on anything more than a few millimeters thick. Generally speaking, when a TIG welder boasts that you can weld with minute amounts of current very accurately, they're telling you that the machine simply cannot deliver heavy current - and you need heavy current for bronze welding.

Copper alloys conduct heat well, so you need a big machine to overcome that loss. The laws of physics aren't just "suggestions", they're laws - you ignore them at your peril. Your foundry charges a lot for welding bronze because they've probably got a 350 amp TIG welder that cost several thousand pounds and is operated by a very experienced weldor who also costs them several thousand pounds. They have to charge for that in order to stay in business.

Little DIY welders are for doing body work on your classic Renault, not for doing touch-ups on your Rodin. :-)

Rich

Very well put my friend,

Yes, phosphorous bronze is a pain to deal with, particularly if you've ever worked with silicon bronze, which is wonderful to work with. Generally, I recommend just brazing phos bronze if possible, and not try to weld it. I suppose if I had more experience with the phos bronze I might change my opinion, but I stick with silicon bronze.

Rich