Welding Sil-bronze

Discussion in 'Castings, finishing/ repair/ and patina's' started by Jason, Jan 3, 2018.

  1. Jason

    Jason Silver Banner Member

    Silicon bronze doesn't weld like steel. It doesn't weld like aluminium either. To say it welds like chewing gum is probably more accurate. It has a nasty habit of going from rock hard to a gooey mess quickly. Sadly there isn't much stuff on the net for welding cast bronze and I'm not sure why that is.... I've figured out it's easiest to weld on DC-EN with a 2% lanthanated tungsten or thoriated tungstens when using an inverter machine. I've tried green tungstens and grey tungstens and both produced erratic arcs that simply didn't work. As with any welding, heat control is critical and that means a careful touch with the foot pedal. Welding thick to thin is always a challenge and the normal dab technique is a farce with this. When you attempt to get the filler rod near the operation, it will ball up from the heat of the torch so you have to be quick to pull back the torch, get your dab on and get the heat back in there. The good thing about welding this stuff is it's really easy to grind it into shape due to it's softness. SO I needed a bronze pin that will allow a small piece of metal to swing to hold in a photo, piece of cardboard and a small sheet of glass. Here is the solution. Stacked bronze! The method is get a tiny puddle and dab. Allow a couple of seconds to cool, hit it again and repeat. The growing pin can be leaned by only heating on one side as necessary. If you use too much heat, the tower falls. The trick is to heat enough and control the depth of the puddle on the top of the pin. The oxy/acetylene guys should have learned this lesson years ago as the old farts would make students use bronze and braze up a little tree by stacking material. I essentially do the same process here to create the necessary pin. To lock the tab onto the pin, it's time to superheat the top of the pin and let it fall. Fun stuff, good exercise and can be practiced with just some bronze filler wire. Why do this? Simply because store bought trash from HD and lowes would look outta place on these little frames. ;) Now I get to fill in some of those tiny holes. It never ends.:oops:

    Stacked bronze



    Shortened pin

    Melted the top of the pin.

    Last edited: Jan 3, 2018
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  2. Tobho Mott

    Tobho Mott Silver Banner Member

    I guess it's up to you to make the youtube video that shows us all how to weld bronze castings! :D

    Any reason you couldn't have built in that pin when you were working on the wax? Maybe you could leave a stub from one of your sprue/vents to grind down to size and shape.

    Anyhow, looks like building it up by welding turned out great - you gonna try and sell it, or is this one for keeping?

  3. Jason

    Jason Silver Banner Member

    I totally could have used a piece of wax during casting and it would have made my pin in advance for me.. Trouble is, I wasn't that smart at the time. Learn from others, you wont live long enough to learn everything on your own.;)

    One of these is going up for sale. My wife claimed the other one. I'll toss the mold in the closet never to be seen again.
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  4. OCD

    OCD Silver

    And here I was thinking you were making another BP. :rolleyes:

    Last edited: Jan 4, 2018
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