TIG technique

[Scotland90]

wats the views on laying ur filler rod in the joint as opposed to dipping?

 

[Richard.]

Very widely used technique the "lay wire" method. It's predominantly a method used while walking or weaving up a thick butt joint. Pipe boys hammer in the filling passes using the lay wire technique on all weld metal GTAW pipe joints. It's not a popular fabrication method with single passes as filling is generally done by dabbing in this case as a form of more control over the amount of fill used.

 

[Scotland90]

yea this is very good, on flat butt joints i tend to dip but its almost like laying the wire, i let it burn into a blob on my filler wire then id almost have the blob drop into my pool itself so i wondered if its a good idea for laps and fillets

 

[Richard.]

Well there should never be a blob because the wire should remain in the pool all the time and you weave the arc straight over it.
With dabbing you shouldn't get a blob either. If you do this means your melting the filler across the arc rather than letting the molten pool melt it. Arc length been too long or current too low are usual culprits if the filler is melting before its home.

 

[Scotland90]

no like before dipping ill let my wire burn back a little because im welding on carbon steel and the wire doesnt melt as fast as id like it too.

 

[Richard.]

Even on steel mate if the pool isn't taking the fill before the arc melts it the method is incorrect. If the wire isn't melting in the pool as you would like then your lacking power. There is no case scenario where you should be letting the arc melt the wire.

 

[Scotland90]

well the heat off the arc burns it back a little, its something i do to get a good amount of filler and its really easy to add to ur pool. i cant explain exactly wat i mean need a drawing or something

 

[Tigman]

Scotland90 have you had a look at weldingtipsandtricks.com ? Jody has some nice videos of all the techniques and how not to do it aswell ! worth a look !

 

[Richard.]

Good call.
Here's one
http://www.weldingtipsandtricks.com/how-to-tig-weld-lay-wire.html

 

[Tigman]

Its much easier to learn by sight !

 

[Richard.]

Its much easier to learn by sight !

Dead right.
Even easier when you pick up the torch and have a crack at it.

 

[Scotland90]

guys iv been tig welding for over a year, welding to at least bs.4872 and destructive testing im no a newbie i know how to tig (ish). i appreciate the comments but im gonna give u a demo ill make a video or something or take pictures. i learned how to tig by watching good tradesman im just after tips to better my techniques, i mostly do freehand

 

[Tigman]

Scotland90 trust me Jodys videos will help , Ive done a fair bit of tig myself and I learnt quite a bit from watching his Vids

 

[Tigman]

Would like to see what you do aswell !

 

[Scotland90]

yea hes good loads of vids

 

[hotrodder]

On most* materials laywire doesn't make sense if it's a thinwall butt etc. Makes lots more sense on heavy wall stuff with a root gap whether freehanding or walking the cup. Especially if the weldpool is being fed 'from behind' i.e. feeding the wire through the rootgap

Fillets are a bit of a curveball IMO... makes it relatively easy to produce a pretty weld (especially if walking the cup) with LOF and cold lap problems (although the latter will never be pretty) as you can't see the edges melting. If the bits being welding are thinnish then pretty much guarenteed to increase heat input and result in a larger weld than necessary too

* TIG brazing and Ti are two exceptions that come to mind, the former as it's way faster and the wire won't out if too cold/too fast and the later as with Ti the wire has a tendancy to 'stick' to the weld pool (or the parent material if you miss the pool/catch it's edges). Using pulse and laywire can make life a bit easier/faster but need to watch out for LOF and incomplete penetration. With aluminium laywire has never made sense to me personally

 

[Richard.]

Especially if the weldpool is being fed 'from behind' i.e. feeding the wire through the rootgap

Done quite a lot of pipe roots like this with GTAW but the lay wire meathod isn't the best for feeding behind through the gap IMO. Dabbing in the root has always been my preferred way and lay wire on the filling passes with the wire firmly in the leading edge.

 

[hotrodder]

Yeah i can see the advantages of maintaining the key hole and dabbing. More visual clues as to what's going on etc. Heavy stuff isn't really my world but when feeding wire through gaps etc for access reasons or whatever i've always prefered the ease of constant feed

 

[henry Kadzielski]

Good morning gents
I do lay wire for root and caps, this is what I have gotten used to. Compared to others that do the root I have always used higher current and then higher travel speed and penetration is still very good. So it is up to the individual as the saying goes 'what works for you', however that must be determined by the individual through practice and patience over time

 

[Richard.]

On an open root joint you don't need lots of current to get fusion and penetration on the back side. Its an open root so as long as your root faces on both sides open up a small key your through it. I usually gap them at 3mm which allows me to get a 2.4 filler right through it for the underside filling.
I like a bit of clearance because it will close up a bit and I've had them nip the rod in the past.
100-120 amps on the root is more than plenty IMO.