(Pics added) Frustrating afternoon forge welding cable

[3fifty7]

Failed to get a good weld on a cable billet. In most cases failure is a learning opportunity but I’m not sure where I went wrong here. Maybe it’s still too soon and I’m still frustrated but this one is really bothering me.
A little background: I’ve been making knives for 4-5 years and am only on knife number 22. Often I’ll go 6 months without lighting my forge, between family-work-other hobbies my knife making gets pushed to the end of the line. So it’s almost as if I’m starting from scratch on every knife I make. I’ve successfully made 2 San Mai knives, 2 low layer twist damascus knives and one cable damascus knife(Everything else has been forged from mono steel). I really liked the cable(it was a lift cable from a cane harvester). It was only about 7/8” diameter and unknown steel but it forge welded well and has held a decent edge. I wanted to “do it right this time” so I ordered 1 1/2” high carbon cable. I got 2 10” sections, it was a little greasy and a little gritty so I un twisted it to clean as best as I can( gasoline soak and wire brush). There was a plastic wrap around the center strand which I removed and wrapped the strands back just as they came. I welded a 1” nut to each end to help grab and twist. Tossed it into my forge and waited for it to come up to red/orange removed lightly fluxed returned to forge until orange/yellow removed untwisted slightly fluxed the inner strands twisted to original form back into the forge for full welding heat and a little soak. I pulled the cable out and began to twist maybe 2 rounds, brush flux back in. Back up to welding heat pull and twist, repeat a couple more times then began hammering the cable all the way around fairly lightly but definitely moving it. Heavier hammer strikes seems to be fairly solid but the tone isn’t quite right. I begin to press it and draw it out to 3/8” x 2” x 18ish” working between the press and hammer and anvil I can feel some areas are definitely welded more solid than others.
Ideally I’d like to make 2 blades from this billet so I go to the chop saw and cut into what I believe is the worst part. And man was it bad. The small strands seem to have welded together inside each of the 6 large strands but the 6 large strands didn’t weld together at all in places and other places they are fairly tight but I can still see separation lines after grinding into the billet.

Man that was longer than I thought and I don’t have pics as I left out of frustration. I’ll get some pics tomorrow and add them.

Any idea on how to go about getting a better weld with my next piece ?

 

[A.McPherson]

Work on consolidating your welds first, before you move to the press.
You don't have to do the whole billet all at once. You can work from one end to the other, slowly working your way to a solid bar. Just remember to clean up the oxidization before each round under the hammer.

Do you have squaring dies? If so, if go a few rounds on the squaring dies before I started drawing out.

Just my take on it.

Also, I don't have a press, I've only done billets of cable by hand so I really don't know about the press side of things.

Oh and the tighter you twist it, the easier it'll be to get a good weld, especially if you twist it at welding heat.

 

[3fifty7]

Here is what I bought. 10” of 1 1/2” high carbon cable. The blue and pink is grease which was removed with a gasoline soak and scrub.

I removed this plastic from the inner core.

There could be something useable in here somewhere...maybe.

This is a section of the worst. The strands separated when I cut this piece off in the chop saw.

This is the end about an inch from where I cut the worst section out.

After 6 strikes with a 4lb hammer it opened up this much.


Most of the inner strands seem to have welded together but the larger strands did not weld to one another well. Should I do something different to clean prior to welding ? I’m believe my heat was good when setting the welds. I welded a 1” nut to each end and when up to temp I locked one end in a vise while twisting the other end with a 1 1/2” wrench so I had a lot of leverage to tightly twist it together. I kept things as clean as I could fluxing and brushing scale every heat. I did several welding heats twisting then several welding heats on the hammer and anvil before the press. On the press I only have flat bars to press with.

I’ve ordered a thermocouple and reader but I haven’t installed it yet, but I will before I attempt to weld again.

What should I do next time ?

 

[Stacy E. Apelt - Bladesmith]

Some thoughts:
Work it a lot more before trying to draw it out. Cable takes many welding heats.
Cable tends to get a lot of scale in the twists. Work it hot, brush it off before and after each heat, and continuously twist it tighter.
Allow enough time in heating for the cable to reach full temperature inside as well as outside.
Adjust your forge to have a bit more reducing atmosphere is needed.
Work cable with moderate blows, increasing the force as it gets welded up.
A 4 pound hammer is pretty heavy for welding cable. Try a 1k to 1.5K hammer ( 2.5# to 3#)