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Test time

I got the Invar/NiLo CF42 TIG filler today (Thanks Dan !) in the mail , now I need to learn how to use it . I have an old standpipe faucet body that got frozen and cracked a couple of winters back , I plan to attempt to repair it before I work on a piece for a customer . I have a couple of questions - am I looking for a puddle of molten CI like when welding mild steel or aluminum , or do I use the rod more like a brazing rod ? I watched as many welding videos as I could find , none were clear as to what I'm looking for . This stuff is widely praised for it's very very low thermal expansion , with preheat should I still peen the cooling welds and stop every 1/2 inch or so to peen ? The preheat will be to

thermometer) . -- Snag

Reply to
Terry Coombs
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I would thunk you used it more like a brazing rod. Actually more like a ha rd surfacing rod. I think you do not want to have a lot of mixing of the C I and the rod.

I think when you weld cast iron, you peen the weld to expand it. The weld is cooling and the added material is shrinking, so you peen to expand the w eld metal so it does not shrink and cause cracking. So I would think you w ould not peen the weld with Invar. Or if you do, you would not peen it ver y hard as you do not have a lot of shrinking going on.

Dan

Reply to
dcaster

I've just finished stripping down that cracked CI faucet head , will be grinding the crack out and trying this stuff out in the morning . Photos of the repair will be posted in my photobook album and a synopsis here .

Reply to
Terry Coombs

The low CTE of Invar only applies near room temperature. At 500F its CTE is in the range carbon steel's, and continues to increase with increasing temperature. At 1000F Invar's CTE is close to that of other nickel alloys like Inconel.

Reply to
Ned Simmons

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