Silicon Bronze Welding

[Richard Taylor]

I currently do a lot of aluminum welding and want to get into working with silicon bronze sheets. Does anyone have any advice for me - such as - need for ventilation or respirator / tig welder settings / type of filler rod / glass # for welder's glass / etc.

Also, has anyone out there used an english wheel with silicon bronze .125"? What has your experience been as far as workability or malleability? Do you know of a good source for e-wheels? I want to be able to work the metal into compound curves and assume the english wheel is the best approach to take.

Maybe I met some of you at the conference in New Orleans...

Thanks!

Richard

[warren01]

Sorry cannot help you on the welding part; I have only gas-welded bronze. What I have heard it is very easy compared to aluminum with tig.

On ewheels go to this site and may help you find a vendor; try Imperial, very nice wheels and I have played with them. (I just came back from the Metalmeet they had in Robinson, Ill, very interesting.)
http://www.metalmeet.com/index.htm

I have used an ewheels on some copper (.043 in) but that is thickest so far. With bronze it will work harden sooner then copper. Bronze works easier when hot, a dull red.

As far as compound curves, an ewheel will make a one directional curve depending on the lower anvil, very slow process. You will still need to stretch and shrink the metal first, using a tucking tool, or hammer methods, or some other shrinking and stretching tool first before using an ewheel. Once one curve is made then you can work on the other curve.

If you know how to work the metal ………….. “shaping”……… then an ewheel would be a good investment.

warren

[Richard Taylor]

Thanks, Warren... I checked out the Metalmeet site and wish I had learned of it before the recent meet in Illinois. There appear to be many varieties of e wheels and I have some homework to do before choosing one. It also appears that more than this one tool is necessary to curve metal in a compund way. I will begin the journey...

[Ries]

I have welded a fair amount of silicon bronze, as well as naval bronze, brass, and straight copper. Tig works very well for all of these. Silly bronze filler rod is easily available, for a decent color match. I use DC, straight argon. I use my standard auto darkening helmet, no problem. No special ventilation is needed with silicon bronze- but since there are hundreds of alloys of coppers and bronzes, you should know what you are really using- some do have lead in them, and some have more zinc or other nasties.
Regular silicon bronze is C655, which is 97% copper, 3% Tin, so it is not bad to weld.
As far as shaping it with an english wheel- well, it should work. I have done stainless steel, mild steel, copper and aluminum on my english wheel, and all have shaped just fine. Work hardening may be a consideration, and you will probably want to anneal the material before working, and periodically as you go.
I suspect .125, or 1/8" material, is going to be really pushing it for most english wheels. They are usually designed for maybe 14ga aluminum, 18ga steel.
I built my own, using a kit of parts from metalace- I liked the quality of their anvils and adjusting mechanism, and building your own frame would allow you to stiffen it more if you wanted, for 1/8" material.
It is quite possible to make compound curves with just the english wheel- as long as they are not too radical. Depends on what you want, and the material you are using. I have seen bowls made with just an english wheel in thin aluminum.
If you are serious about learning about 3d shaping of sheet metal, there are some resources you should check out.
First, I recommend you buy "Metal Fabricators Handbook" by Ron Fournier. He is the king of 3d shaping, mostly in the automotive realm, but the principles all cross over to what you want to do. This book is around 20 bucks from HP books- probably you can find it used at Abebooks.com.
Its great. I actually took a workshop from Ron, at his shop near Detroit, and cant recommend it highly enough. He is the man.
You should also check out the metalshapers.org website, and look at some of the many albums of members work posted there. Again, mostly auto and aero, but it all directly translates to sculpture. Many of the guys there are using power planishing hammers to form sheet in 3d- either old pullmaxes, or newer homebuilt jobs.
Another site to check is Anthony Howe- he makes his sculptures from relatively thick stainless, using a pullmax. http://www.howeart.net/
If this is at all similar to what you want to do, then you may want to consider a machine like a pullmax.

[sculptorsam]

Have you ever tried welding silicon bronze with MIG, Ries? I'm assuming it can be done based on my inspection of the sculptures of Richard Hunt, but I haven't looked into it myself yet.

And I'd love to take a class from Ron. I haven't even had the chance to use an English Wheel yet, but am looking forward to it.

[lesliepatrick]

Migs are great for silicone bronze

[sculptorsam]

Thanks, Leslie.

Anybody have any good US suppliers for bronze sheets and MIG wire?

Sam

[oddist]

http://www.brassmetals.com

sources all over

I know of http://www.hillmanbrass.com/

oddist

[warren01]

Sam,

For sheet bronze you might want to look at Atlas Metals in Denver. http://www.atlasmetal.com/

They have the silicon bronze and you can get from them whole sheets in different thicknesses. I have not bought from them but heard they are pretty good supplier.

I am looking too for a supplier and they are hard to find, most just sell small pieces.

warren

[gregmueller]

Hi
Silicon Bronze is easy to TIG weld, Yes Atlas Metals in Denver is a major supplier of plate bronze--email Jerry from their web site-he can answer anything. Milwaukee has a supplier as well which I cannot think of the name off hand but i will look it up---also understand what you order. Their are differing alloys of bronze plate--for example "Muntz metal" which is a Navy Brass--can give you welders' fever/ night sweats-- if you do not use a respirator and ventilation. some of those alloys contain some nasty quantities of zinc. Stay with the silicon bronze--
good luck

Greg Mueller

[sculptorsam]

Thanks for the warning Greg. Atlas looks like they have the goods. Even .035 MIG wire in 30 pound spools. And they do have 4x8 foot sheets of plate down to 1/8 inch with narrower sheets in lighter guage. Now the question is just how insanely expensive would it be to make a large sculpture in this stuff?

[Steven Haas]

You will find silicon bronze tig rod at any good supplier. I use the tig on the ac setting and there is no need for flux. On -dc I found flux helps but a little goes a long way.
Have you you had any news concerning the GB project? I called my alderman in support and have found the city council to be just a little short sighted.

[jsimms]

I've run hundreds of pounds of silicon bronze with my mig and love it? It also Tigs beautifully. Prices usually run from $3 to $8/lb depending on size. I buy from http://www.alaskancopper.com/ , though I used to buy from Atlas and still do to save freight if I'm in Denver with a trailer. It's very hard to find pipe or tube, and sheet and plate come in odd sizes at varying prices. Structually, silicon bronze (alloy CDA 655) is about 5% heavier than steel, and almost as strong. I also use some phosphor bronze, which is pretty stiff and not available in a range of sizes.

I LOVE IT!

John

[Mordachai]

yep , have to agree, MIG is great for silicon bronze.

This heron was done with Silicon scrap, wire, and a MIG set to a/c with no shielding gas.

[iron ant]

Curtis Patterson,Sculptor teacher from Atlanta College of art mig welded a big silicon bronze sculpture for the airport years ago.The wire is expensive and so are the sheets,but if you can afford it ,definetly worth it.There is a big dealer in Colorado.As far as tig goes,it is like butter,and machines down so easy you have to have a light touch.Bronze dust floats too,so grind it outside or use a fan.

[Jay Long]

have you ever heard of zinc poisoning? most welders have, and base there attitudes of hazards on this condition. However I have welded stainless for years with no protection, I did not feel any ill effects from welding stainless, aluminum, bronzes, coppers, mild steels. but I did educate myself about these metals, and their fumes, and I am very self aware of these poisons, I try to always wear a fume mask, especially when grinding, Just because we dont feel a ill affect now, doesnt mean it wont bite us later. enough said with that.
I used to work in Alaska as a Port Engineer(sounds important) or boat mechanic if you will. My boss found that my skills as a welder were limitless in rural Alaska, And I found that with a TIG welder and a bottle of argon, you could weld almost anything. One of the things that I found was a common problem was a broken stuffing block.(the rear cast block that held the prop shaft, on the bottom of the boat, it had a wax nylon seal in it, and you could compress this seal within the block around the shaft to form a seal)
This block as far as I could tell was a form of cast copper, I took regular house wiring and striped the insulation off the wire, and tried to use it as TIG wire, however when it cooled, the weld would always crack,( one metal cooling faster then the other) I finally ended up finding a broken block from another boat, cutting it up in strips and using this parent metal as a filler, suffice to say it worked great, I still had no Idea what I was welding, It turned out later to be called cast red bronze. During this adventure I ordered silicon bronze TIG rod, and used this stuff for everything, I welded rusted fuel injector lines, galvanize sheet metals, It seemed to weld to about anything, or solder to. I have welded silicon bronze to alloys that I could not Identify,
If welding with the parent metal didnt work, The silicon bronze usually did.
Jay

[Mordachai]

Jay that's great to know, because I have access to so much Si Bronze scrap and wire ( every time the mig snags, you're left with 10' of the wire you were running,= we got a lot of scrap wire!)
We do use it when filling with the tig, but only bronze to bronze.


I'll have to give it a shot!

|M|

[JAZ]

Very helpful thread. Based on everyone's input I bought one 2'x10' sheet of 655 silicon bronze .125 and one 10' x 3/4" solid rod from Alaskan Copper. I had them cut both in half because I would have anyway. Including the shipping charge of $75.21 (UPS from Seattle to Massachusetts) the total price came to $714.21. I also checked the prices at Atlas Metals and they were almost the same.
I found the .035 silicon wire in stock at the regular welding shop across the street and I think it was about $70 for a ten pound spool, though I'm not 100% sure exactly because I also bought new tips, grinding and sanding discs, steel brush, etc. so as not to contaminate the bronze, since I usually use steel. I cleaned the studio before opening the package.
After Jsimms' comments about not needing a respirator for this type of bronze I'm using my regular two exhaust fans with hoses more or less directed at the work, and a particulate dust mask (the better ones). The studio air seems cleaner than with welding steel and I feel cleaner too. The residue on the floor looks kind of like fairy dust or something (I'm used to true dirt!) and the plasma splatters are like golden stars. The plasma cutter works fine with it.
I'm using my MIG on 1 or 2 - the lowest settings - and straight argon. It takes less effort to grind than mild steel.
It is beautiful stuff. Too bad it's so costly. Really scary to cut it.
JAZ

[Araich]

What's the spatter like JAZ?

[Mordachai]

I know this wasn't directed to me, but.....
well, from my experiences, the spatter is pretty wide-spread, but again, we don't use shielding gas, cause it's gonan be ground down , and we don't care if the welds don't look pretty right away. but we grind and sand them all till they dissappear anyways. It'd just be more money to spend, and if it's not needed, why do it? ( we do use argon when tig on Stainless steel)

BTW- the Artist I do all this work for can be found here:

www.collinsstudios.com/
some of the pictures aren't that great, but it'll give you an idea.

|M|

[JAZ]

What's the spatter like JAZ?

There is some spatter in spite of the straight argon. I've been laying down a piece of aluminum flashing as a shield to catch what I can, but of course that doesn't work everywhere. The good news is, it certainly doesn't take much to remove whatever there is.
Obviously it would be better to TIG weld it, but when you don't have the machine, the MIG works fine.
Today I went to Mark Tabor's studio - ExNihilo. He showed me a bronze bust and a small figure he's cast himself. The figure has one small hole at the throat (he calls it a tracheotomy) which I may be able to fill for him. So, fixing casts may be another fringe benefit.
I'm not looking forward to putting a finish on this one, though. I'd say that's my weakest point. I'd like to leave this one light in color, but I don't think there's a practical way (for the long term) to do that since it will be an outdoor piece. So, I'll probably end up with liver of sulphur by default just for the longevity.
Hey, Araich, what happened with your paired sculptures?
JAZ

[JAZ]

By the way, one of the drawbacks of fabricating in bronze is that you can't use magnets to hold things in prep for welding like you can with mild steel. Aggravating on odd shapes that are hard to clamp.

[Mordachai]

Very helpful thread. ..............................
After Jsimms' comments about not needing a respirator for this type of bronze I'm using my regular two exhaust fans with hoses more or less directed at the work, and a particulate dust mask (the better ones). The studio air seems cleaner than with welding steel and I feel cleaner too. The residue on the floor looks kind of like fairy dust or something (I'm used to true dirt!) and the plasma splatters are like golden stars. The plasma cutter works fine with it.
.....
It is beautiful stuff. Too bad it's so costly. Really scary to cut it.
JAZ

well, I would strongly disagree with doing any work on any kind of bronze with that plasma torch without a respirator. Maybe just grinding would be ok, welding really is not ok to use a dust mask, and Plasma is bad news. Especially with the plasma torch. Especially that Plasma torch. Don't forget the Plasma torch. It is the most dangerous tool in a metalworkers shop. REALLY!... More dangerous than any pressbrake, mill or anything. More dangerous than Elec. or gas welding. More dangerous simply because of the health risks. It is a really nasty tool. And I am NOT talking about the spray, or cutting yourself with the torch(which would be pretty hard to do)

The nature off the plasma torch, is that it makes plasma. Plasma is defined (in this use) as = A gas of charged particles, meaning it's using that arc(like a arc welder) and compressed air to blast the metal out of the way. IT is sending microscopic bits of every single atom through the air.
Define Plasma: A low-density gas in which the individual atoms are charged, even though the total number of positive and negative charges is equal, maintaining an overall electrical neutrality..

It uses this overall electical charge to keep the cutting point in one area, and give a somewhat clean cut.

You might think it's looks better, and you might think you feel better, but you really should take some precautions. Read on why.....

I have met two people( that I have met so far) who have had thier health affected for the rest of thier lives. One is a Man who used to work in a foundry. He was the guy who would chip the investment off of the casting. He worked outside about 20' or more from the shop door. He said he only worked there for 2 years before he felt sick. Inside the shop door, a guy used a plasma torch to cut the gates and sprues off of the castings, to be melted down again. He changed his line of work, and got a blood test, and he had so many heavy metals, his doctors could not believe he had the feeling and control of his bodily movement. In the next year he developed some type of nerve degeneration/damage, and now he spends his days in an electric wheel chair(oddly enough, selling art in a gallery out west). When I told him what I did with sculpture, then metal, etc, he really made it a point to let me know why he was in that chair. All the while that he was talking, half his body was twitching, his face, his arm, everything. It was scary enough that whenever I use the torch I make sure NOBODY else is in the shop, and if someone else is using it, I stay far away.


After I already knew of the dangers I learned about this other fella. The other guy worked in ornamental bronze, copper, brass and steels. Very much like what my Mentor does,and you and me and half the people on this board want to do or are doing already.The only thing is he never wore face masks of anykind, and insisted that the work was ok. Now he's dead, he died from complications of lung cancer (black lung) and never smoked a day in his life. Unfortunatly he never got a chance to really get his art out there, and still and forever will remain an Unnamed artist.

I'm just saying we(as society) need more talented artists, and not to lose the ones we have. Please do some of your own research of the materials you are working on, and not take other's advice. IT's is your life, and your health, most important to only YOU!

Every bit of metal sheet, rod, wire anything has a MSDS (Material Safety Data Sheet) avail to you from the person who sells it. Legally I think it must be included with every sale of such an item, although some companies state you have to request it on thier sales order. Read the MSDS for what you are working with, and then decide if the heath ricks are worth not wearing a mask.

OK my rant is over, I think.
Just play it safe
|M|

[Araich]

I've been TIG welding 12mm bronze (copper-tin) cast plate together lately with silicon bronze filler rod and come up against a problem. Hot cracking in the root welds and then when under stress, cracking along the weld surface. In particular on fillet welds (angled joints).
Any suggestions?
Do these cracks represent a complete failure of the weld?

[RuBert]

Hi Araich,

I was wondering what gas you are using and what the welder is set on?

Sounds like it could be stress related to the material moving as the weld is still molten, but cooling.

A few more tacks then a quick clean weld might solve the problem.

[Araich]

Hi Russ, I'm running with pure argon and have my little TIG at max, 150amps, to ensure good heat saturation and slowest cool down.
Part of the problem is that on T-Joints to a base plate, the base plate's deformation is limited and hence intense stress is caused as the weld shrinks. I also think now that my efforts to enlarge the weld - bevelled edges and gaps - has made things worse as the area of shrinkage is increased.
Cracks are appearing later when the joint is stressed and my worry is that these cracks sink all the way to the parent metal. I'm going in early this morning to run some tests and load a joint to failure in an effort to answer that.
Could large welds like these be better done with MIG? If so, what pattern?
Frankly, this is a nightmare.

[JAZ]

Wow. Scary story. I had not noticed any similar problem with the piece that I MIG welded, but now you've made me think I should examine it more closely, just to be sure. Right now it's in a show in Bar Harbor, a six hour drive away.
And becasue you posted this, I just reread Mordecai's warnings about hazards. I hope you did too, Araich.
Hey, I met an Australian guy who knows you. His name is Andrew David Logan. He was at my studio picking up a sculpture by Bob Emser that I had stored there after a show I organized came down and while I helped him load it onto his truck we got to talking. He's a nice guy. The sculptures of his I've seen are stylized figurative. He has some things cast in bronze and I showed him the picture of the one I'd fabricated. Then he was picking my brain about where to get the plate, etc, so I gave him the link to this info we're now adding to. Funny how these things work. Anyway, maybe you know him or maybe not.
JAZ

[Araich]

Yeah I know Andrew, I think we met at another sculptors studio here in Sydney. Remember me to him.

Well, I went in to the studio early and did some tests. The TIG welds look lovely to the eye but have marginal strength at best. It is nothing to do with weld shape or penetration, it is a failing in the weld metal itself. It is brittle.

I made an equal weld test with the MIG - silicon 1.2mm wire with pure argon gas - and the weld strength was radically greater. On the order of +10 times as strong. In fact I could not break it or even get a fracture, the 12mm cast plate bent with no deformation in the weld.

This is very sobering news for me, because it means that a 220kg bronze I installed 24hrs ago now has to be removed to the studio and have all the welds cut out and redone. 4 days patination out the window and the added problem now of wax removal.

In a illustration of the value of a dealer/agent, mine has taken the news without blinking, spent more time concerned about the stress that I am under than the problems with the client, and assured me that all I need to do is to work to the highest standard and stand by my judgements. They will sort out the rest.

This is a public work and the implications and complications are immense.

Right now I feel 100% better than this morning. Simply because I have a solution, all be it costly, and because I know that I am doing the right thing. What doesn't kill you...

[JAZ]

Araich,
I feel so badly for what you have been through over this. As if the work on the sculpture itself isn't toil enough, to have to deinstall, grind away, re-patina and all....what a nightmare.
It is so good that you posted this story. I'm in no danger of having your TIG problem since I can't afford a TIG machine, but it's so good to be forewarned.
In order to distract you from the difficulties you face, could I ask what kind of patina you settled on? If you have already posted an image of the piece on your website I will find it there, but if not, could you post it here?
I fully admire your values and work ethic and it's really a shame that you have this problem to deal with.
JAZ

[RuBert]

Araich, it sounds as though you have found a solution. The mig will lay down the metal faster and that is good in this situation.

Another thing to consider is pre-heating the sculpture to reduce the amount of movement the weld is causing.

Compared to steel, copper based alloys have some characteristics that are undesirable to welding. Let me digress a bit about copper and perhaps get to the root of what is causing your problem.

Copper has a thermal conductivity of about five time that of steel. Copper melts at 1980 F and steel about 2775 F. The surface of a thick plate of steel can be melted very quickly with an electric arc. But a thick section of copper will suck the heat away almost as fast as it is put in the metal.

Not until the entire block has been well pre-heated will the surface melt and weld. This means preheating is necessary for most welding. My practice of tacking closely is a way of preheating the metal, but my tig may also have higher amp output than yours does - and the lack of amperage may be a reason you are having problems in this situation.

Also, Copper absorbs carbon monoxide and hydrogen readily. These gases are released as the metal solidifies. To prevent porosity (and brittleness) cooling needs to be from the bottom up to the surface. It is possible to manipulate the torch to allow the surface to freeze last.

Copper expands and contracts during welding more than steel does. In addition, the tensile strength of copper decreases very rapidly at above 500 F. The high contraction of the metal coupled with the low hot strength greatly increases the possibility of weld cracking.

My last tip is related to total tensile strength.

The base metal probably has a tensile strength of around 50,000 psi. Even a good weld that has recrystalliszed would have a tensile strength only around that of annealed copper - 30,000 psi. Cold hammering can be used - depending on the situation - to increase the strength of the weld. The ductility of the weld is increased by hammering the weld while it is hot then reheating. This breaks the film of copper oxide that is causing brittleness at a granular level, and reheating relieves the strains and raises the ductility.

I don't know if this somewhat theoretical discussion about material properties helps you at this point, as you just need to get the darn sculpture re-welded and out the door. But I do think the cause of your problem is likely related to one or more of the above characteristics of welding copper based materials.

[Araich]

Thanks guys.

Russ, I think it has to be the exposure to reactive gases during molten or cooling states. Quite possibly I just don't have the current to deposit the weld metal fast enough and the prolonged liquid state is allowing degradation. In contrast the MIG is almost instantaneous.
I had preheated the plates to several hundred degrees prior to welding.
I'll also experiment with a higher sheilding gas flow.

I've spent the last two days helping a friend finish a huge stainless steel water feature and the break from my troubles has been welcome.

Tomorrow I'll de-install and begin the reworking. Here is a snap of the work moments after it was bolted down.

I'm ok with the whole thing. After all, 10 days work will erase the kind of concerns I just don't need, even if I could have gotten away with it.

[JAZ]

It looks as if the piece is indoors, though. Would it still be a problem? I see that it is delicate, which might mean more stress? It is lovely because the form moves the eye around so well. The perforations are nice, too.
JAZ

[airwolfsculpt]

When welding CuSi to mild steel what do people use for filler? I have had great success with silicon rod, but my shopmate swears by stainless(308 i think). I was just trying to get a feel for what other people were using. We are using TIG straight dc with argon.

[Araich]

Just a little update. I re-installed the bronze 5 days ago. All went well.

I'd cut out 70% of the welds and replaced with MIG welds, close to double the size. I also added an extra element to the base and a band along the inside of an area that showed the most flex.

And... I'm sleeping like a baby.

[JAZ]

Araich, you are good.
JAZ

[Chris W]

The input on the plasma tourch is verry helpful. I realized withing the first month that I had to deal with the fumes of the tourch. Even gas tourches create rugged fumes. My answear to the problem was to get a saw dust collector and a 275 gallon oil tank/drum. I cut the drum in 1/2 and turned it on one end. I piped the collector fan onto the side of the drum and rigged a foot switch on the floor right in front. The exaust pipe was then directed out the window. It worked realy well but it was loud. Then I switched to a larger pipe and duct work and slower moter. I think it's pretty good. I use it for welding as well as cutting. I work with silicone bronze all day.

I do have a question, I've got a Torit fume collector mounted on the ceiling of the shop and drop down arms for collecting. The machine has long liters inside that collect the smoke. Does this machine also collect the atoms and gasses that are created from the tig welding process? The bronze is one issue and the tungston also has additives that are poison. Do I need a different type of collector with a carbon filter?

[dtonnesen]

I am pricing some 655 silicon bronze 1/8" plate and find it still quite expensive.

Its currently around $10.95 a pound at Atlas or $1248 per 48x96 sheet, then add $65 crate charge and FOB costs.

Has anyone here used Commercial Bronze alloy 220? Its less than half the price but is composed of 90% copper 10% Zinc. I have heard its MIG weldable but have zero experience with it. I have a commission to build some bar tops in bronze.


thanks

[Ries]

Welding alloys with zinc in them is always somewhat problematic.
There is a difference between "can be welded", and "can be welded in an aesthetically pleasing way".

zinc boils of somewhere south of 1000 degrees, with, as a side affect, nasty toxic fumes. Your finished weld is therefore some OTHER copper based alloy, not 220, or whatever you started with. So it may be porous, or bubbly, or it may be a different color.

People like Silicon Bronze 655 because its mostly copper, with a bit of silicon, so it welds very nicely, forges quite well, casts predictably, and, basically, when you are done, you have the same alloy you started out with.

"bronze" and "brass" are very imprecise terms- there are hundreds of copper alloys- kind of like chocolate chip cookie recipes, similar looking ones can be very different.

Bronze is never cheap, but its a whole lot cheaper to buy it once, and do it right, than to buy it twice.

You should also get quotes from Farmers, Copper and Brass Sales, and Alaskan Copper. These are the biggest dealers in various copper alloys, and each may or may not have your exact alloy/size configuration, but they might.
Since it is basically a commodity, prices wont vary too much, but sometimes there is a significant difference.