Cast iron fix help

artmelem - Thursday, November 15, 2007 - 7:09pm

So I got a new torch and I want to try my hand at brazing (I have only MIG welded everything). I have an old ornamental piece from the top of a chimney that I have displayed in my living room. During the removal it broke in several places. I would like to try brazing to put it back together. I thought I could do this just on the back. How do I have to clean it? Do I need to grind any rust or just brush it and clean with something.What kind of brazing rod do I use? Any helpful tips would be very helpful.

SORRY, this is a repeat entry.

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brazing

visitor - Thursday, November 15, 2007 - 9:34pm

depending on how thick your work is probably about 1/4 or 3/16, i would use a #1 TIP WITH OX&ACT SET AT 2 AND 2.A NICE SLOW FLOW.heat your material to cherry red touch your rod to it let it flow then flow it out.Clean with wire brush prior to brazing,use 3/32 or 1/8 rod prefluxed or silibronze u still need flux.always wear a resperator and shade #4 lens when brazing and do not overheat.when your material gets red move in with your stick u will get a feel for if u can already weld. hope that helped ya.

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Thanks a bunch, any

artmelem - Friday, November 16, 2007 - 10:11am

Thanks a bunch, any information is good. I hate sounding completely dumb when I walk into my welding supply store. I think I might find a scrap piece of cast iron first, I would hate to ruin the antique that I have. I sure am glad I found this site, my husband is tired of hearing about it. Now I can get my fill here.
Thanks, Mele

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welding cast iron

bpfink - Saturday, November 17, 2007 - 12:48pm

I have actually welded cast iron (not brazed ) and you use a cast iron rod to do it. It takes a flux and is a gas torch system. Welding rods are available at welding shops and they can give you more details. It is a bit tricky but much of the key is in using reflective heat shields around the piece and taking the whole of the unit slowly up in temperaure ... doing the weld with the rod and then very slowly letting it go back down in temperature. For a small piece I used glass building insulation under it, and old fire bricks to support the sections together while heating up and letting it go back down again.

I should think some hands on words from your local welding shop would be very valuable especially if you can take the item in and ask for better detailing about it. Don't be shy about asking... Good luck bpfink

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