A local office building upgraded the old human operated elevator to a new fangled push button operator. I got a bagful of these obsolete open faced graphite electrical contacts that were used to slap against a powersource and apparently, make the car go up and down. I put one in the gas forge one day to see what would happen. After 2 hours, it was happy as could be, with no degradation. I started researching a bit, and found the melting point of this stuff could be as high as 3850C..  

 Last week, a guy came into the shop with a cast iron wood stove door. Grandpa had stumbled while opening the door, and ripped the upper hinge pocket off the poorly designed door. It had a bunch of curves and radii and would have been problematic to locate the bore once I built up the broken piece. The door still had part of the hole remaining. I took one of these graphite contacts and lathed it down to what size the hole needed to be, and stuck it in the broken half a hole. I preheated the cast iron a bit, and TIG'ed around the graphite blank with 316SS rod. It was amazing to see the weld bead just lay there on top of the carbon negative.  I filled a good lump of rod in the broken spot, post heated a while, and drilled out the graphite with a drill bit..The guy called back a couple days later, happy and warm. 

You WELDED graphite to cast iron? Those brushes couldn't've been straight graphite or it wouldn't've even looked like it stuck let alone welded.

 

Of course I'd be a multiple PHD if I learned enough from all my mistakes, being wrong is a way of life for me. I'll be reading to see what's going on.

 

Frosty The Lucky.

Frosty, I used graphite as a 'negative' and welded around it, leaving a precise hole.

I've seen that done to do build up around damaged bolt holes in alum in the past as well, or as a backing to fill in holes that needed to be closed up.

Interesting and nice figurative way of using what was at hand.  :D  always a joy to see someone fix a problem.

Hey Mike ;  Cool how that stuff works aint it ? ..How's things, I;m workin again WOO HOO !!  :D

Frosty, I used graphite as a 'negative' and welded around it, leaving a precise hole.

 

That makes sense. Like a resist etching or a chill plate  to control weld bead. Excellent a new trick to add to my old mental tool kit. Thank you.

 

Frosty The Lucky.

Good Morning,

 

I use the same process to repair woodruff key slots in crankshafts. I make the blanks out of generator - carbon brushes.

 

If you don't build the box, it doesn't get in your vision!!

 

Neil

I used to do the same thing to fix old cast iron gearboxes when I worked as the welder in a factory that both produced DOM aluminum tubing and aluminum extrusions. Worked well using nickel rod for the cast as well as 309 stainless for dissimilar metals. We had large plates of graphite laying around the extrusion presses. They used them as guides for the shapes as the aluminum came out of the dies.

Swedefiddel  never thought about that kind of a fix for a keyed shaft way COOL Idea !!

 

Steve's Welding & Fab

I used it for keyways too, but now I use copper mostly as I have more of it. I have also backed up other welds with brass, and aluminum depending on what I am doing.

VERY interesting about the graphite!!! I've used aluminum, brass, and copper on numerous occasions but have never heard of using graphite before. Thanks again!

 

-Hillbilly

Hmm I need to see if I still have some of that large graphite electrode around, 14" diameter IIRC, the 3 phase arc furnace drew kiloamps running them...

Took a tour of a steel plant last year. Suddenly realized the paper wrapped 'telephone poles' underfoot on the gantry were the graphite rods for the crucible.   :blink: