# Do you even weld?!



## icanhaschzbrgr (Aug 24, 2021)

Hello there!

It's been a year or so since I visited KKF and done any knife related work. But these day I managed to scrap some time and learn welding basics. While I feel myself pretty confident welding garage doors or workbenches, I'm most interested in welding tangs. I tried to do my homework and read Larrin's "knife engineering" book to get an idea of what happens during MMA welding, but I'm a poor scholar.

So after reading old welding thread on bladesmithsforum, I decided to just give it try.

Starting conditions:
- n690 hardened knife blank with ~40mm tang
- gas torch
- mma inverter with esab ok 61.30 electrodes


As a first step I ground tang to have V shape at the end. I took a heat treated piece of n690 steel to be used to extend tang and ground V shaped groove. I also rounded hard edges (as it was suggested somewhere on bladesmithsforum). The idea was to maximise contact zone.

Started a torch and tried to heat that piece to dark red colour. Either I'm not patient enough or my torch isn't powerful enough, but there wasn't any red color to speak of. But I think I ruined heat treatment on that piece anyways. I never felt file hardness tests to be of any use, so haven't checked hardness.

Then turned inverter on and welded tang.

Waited few minutes and then used gas torch to heat up steel around welding zone. Forum experts suggested this step to relieve metal stress. My own stress level only increased at this point.

Ended up with a pretty ugly looking piece of metal.





But after a little bit of grinding things started looking better.








I haven't done destructive tests so no idea how brittle this thing is. I believe with WA handle this joint won't have much stress in a day to day usage so should be fine as is. But I want to understand what really happens in the metal during MMA welding. How many errors have I done? What can be improved? How does one choose electrodes for different types of steels? Should laminated steel need any different treatment? I know it's lots of questions, but let's start a dialog and see where we can get.


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## coxhaus (Aug 24, 2021)

It really is what it looks like after grinding is what is important. There are welding books on the composition of electrodes and which ones should be used based on the metals being welded. I know nothing about welding knives, I have just had a few welding classes at my community college. It is more of a hobby for me.


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## icanhaschzbrgr (Sep 5, 2021)

I've welded two more tangs, this time it was Niolox and 440c.

This was my setup:





I should confess it suck. Not only cause it fiddly to clamp both blade and tang in a straight line, but also cause welding burns wood. A metal piece instead of wooden block should be way better. I was thinking of making a small anvil from railroad. One day.

After cleanup and before I start hand sanding blade.





And another one. Rex121 core with stainless cladding. Tang is mostly stainless still, cause core steel ends somewhere in the middle of the tang. Welding tang wasn't necessary here, but I wanted some practice.


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## coxhaus (Sep 5, 2021)

You really need a welding table not wood. I guess you could lay some plate steel on wood. Grate works. You can buy it or make. If you are going to use a torch then grate is better than plate. You can cut down a slot and not cut through your table. Miller makes a nice small welding table. You can build one. The home-built ones tend to be heavy not portable like the Miller. I have a tractor supply small welding table not as nice as a Miller. A lot of things I weld on are big and don't require a table.

Stainless takes a different gas and wire or rod depending on how you plan to weld it. How are you welding your stainless?

That last one looks like a good weld.

A small anvil from railroad track would last forever. Not sure you could pick up one that was big enough to hold a kitchen knife. Maybe if the knife hung over enough.

PS
I just followed the electrode and it looks like it runs DC+ or AC and depending on the size on how many amps. It has a coating so it does not need gas.


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## inferno (Sep 11, 2021)

when i weld hardened steel i preheat and postheat.

also check out 309L ans 312ss grades as rods. you can weld anything with these. i like the elga cromarod myself.

to avoid ruining the temper of the blade you can wrap it in a wet blanket or something.


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## inferno (Sep 24, 2021)

so yeah i would just like to add a thing or 2 here. 

about elga and esab electrodes. elga electrodes can lay out in the air for months but the esabs usually turn to **** in a week or 2 out in the air. 
talking the exact same chemistry. 309L. the elgas usually start and weld like butter even if left out for a few months. but the esabs might not even start. and if they do they sputter like crazy and then suddenly burn a hole in some ****. so these basically have to be kept in a heating cabinet at 50-60C. and even then they wont weld as good as the elgas anyway.

and also another thing. if you accidentally weld the electrode stuck to the work and try to rip/twist it off fast as soon as you see it happen. the elgas will usually just release but the esabs will crack their flux coating off for maybe 5-7cm. and then you can basically throw that **** in the bin.

and it works the same with pretty much all esabs unfortunately. they usually crack the flux coating if getting stuck. unlike most elgas.
i also prefer oerlikon (swiss) to esabs. talking stick electrodes. now the welding machines esab makes are very very good. but i prefer kemppi here. they just seem to be designed more durable. but i think fronius out of austria is the absolute best ****. they are at least 1-2 gens ahead of kemppi and esab. and its usually twice as expensive. its probably worth it though.


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## icanhaschzbrgr (Dec 16, 2021)

I did some destruction test a while ago and here's a brief report.

Those were offcuts of laminated steel with carbon core and stainless wrapping.





Here's a welded piece that was on the left on above photo. I burned a bit on the right side.




After that I did some grinding to check for visible defects. There were non on this piece.


Then took pliers and broke off that piece. Turn off sound or ignore my mumbling


That super hard to break, but I had a pretty long lever so applied force was well beyond anything that a knife can see in a day to day usage.
I would mention that I wasn't able to break a solid piece of steel with same amount of force, so I won't claim that my weld is as good as solid piece.

Here it is broken. Not the weld itself failed, but the steel around.





Since welding line is on the tang that would be inside the handle — I find it nearly impossible to replicate this breakage with a finished knife.
You are welcome to interpret results as you like.


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