key-holing

[BrokenBiker]

just watched jody's latest vid about vert up with 6011 root and 7018 fill and cap.

3/32 gap and root face, 75 amps with what i assumed was a 2.5mm rod.

anyway, when i have heard the term key hole before i always thought it meant just letting the front of the puddle start to melt through, then push on a bit.

after watching his video he has some pretty decent arc shots that show him whipping forwards, and burning the inner edges of the plate away, then whipping back and filling the puddle, and so on.

is there any reason for what appears to be quite an aggressive technique. if i get to the point where the edges of the material are melting away in front of the puddle i turn the set down a bit as i thought i was running too hot. ive never had any noticeable problem with lack of penetration on any of my stick welds where full penetration is required.

am i not doing it right? or does it not really matter as long as im getting good penetration?

 

[wheresmejumper]

You are able to see exactly how much you are penetrating as you progress with a keyhole.if you dont have a keyhole you are just going by feel, which is grand if you have a consistent root gap and landing edge.if someone else has prepped your plate or pipe they mightnt have been so thorough.having a keyhole and using a whip and pause technique lets you alter progression easier.with pipe aswell penetration will vary from the bottom to the top due to gravity and a build up of heat, so just pushing the rod into the bevel and letting it burn might work on the bottom but chances are youll need to whip on top to keep the pool under control and not fall away into the pipe.

 

[Maker]

I thought he was deliberately running too hot and almost burning through to show what to do when you do mess up but I might be mistaken, it was late when I watched it.

 

[BrokenBiker]

I think he was only referring to what to do if it goes wrong when he ground the stop/start back.

cheers wheresmejumper, explains why he was doing it, will give it a go and see what happens. the majority of stuff I butt weld I have easy access to both sides so not really an issue but seems a good idea to pratice when I get another welder

 

[Kent]

That said most of us do stuff without doing it consciously we are just reacting to what we see as the weld progresses, its sort of like asking a great shot exactly how and what he did to break that impossible looking clay, he might tell you but its mainly fiction as he /she never thought about it, just a learned response to what they saw. Do you ever do a difficult weld look at it think "that was neat, wonder what I actually did there?" Heck I know I do and I bet sometimes we all do if we don't get chance to review the footage and talk about it LOL. Or do I just have a poor short term memory?

 

[wheresmejumper]

Didnt see jodys channel for a few months, just my take on it.

 

[backpurge]

Basically what you are doing is melting away the parent material at the edges of the weld prep and replacing it with weld metal, it's the only way to ensure full joint penetration on a single sided butt joint. It is a technique suitable for all processes

 

[haywire]

can you post a link to the channel? :-)

 

[Maker]

https://www.youtube.com/channel/UCqq70AnPkj4-UApS_m_6mPw

 

[haywire]

thanks :-)