Tigging thin steel to thicker steel

[Shox Dr]

Just normal MIG wire?

I hadn't thought of that. I shall get some from the mig welder that is sat next to the Tig !

Thanks!

Yes, standard MIG wire is A18, it wets out a bit better than A15 so should help as well.

You need a keep an eye on torch angle as well

 

[hotrodder]

From the pics i'd say your arc length is waaaay too long at the moment. Read this thread... http://www.mig-welding.co.uk/forum/showthread.php?t=7862 and look here too... http://www.mig-welding.co.uk/tig-fillet-weld.htm. As said torch angle can have a large effect- when working with tube the angles of attack are constantly changing as the weld progresses. Lose the angle and the arc length increases

Without wishing to sound rude i'm thinking you're trying to run before you can walk. You'll progress much faster if you forget about thick-thin fillets on small dia tube for the moment and go back to basics... get the technique nailed with flat sheet in the 2-3mm range and then progress to thinner sheet and then tube. Lack of fusion (LOF) at the root is a common flaw with fillets, fig 4 here... http://www.millerwelds.com/resources/articles/common-TIG-GTAW-welding-problems-visual-guide-graphic. While it's less of an issue with thin material burn through becomes a bigger deal where the back of the joint is melted in an uncontrolled manner

There's a section on weld testing here... http://www.mig-welding.co.uk/wiki/Weld_Testing, macro etching and nick breaks are the most applicable to fillet welds. You can get a crude macro result using a drop of acid from a car battery

ey that'n stop er'n dowrs using it

That'd stop the missus from using it? Are you calling me a girl?

 

[Shox Dr]

Are you calling me a girl?

If the Coil fits...

 

[serepton]

From the pics i'd say your arc length is waaaay too long at the moment.

I don't think it is, I am fighting not touching the metal with the electrode. What makes you think it is too far away?

As said torch angle can have a large effect- when working with tube the angles of attack are constantly changing as the weld progresses. Lose the angle and the arc length increases

I will hold my hands up, this is something that I know I need to pay more attention to.

Without wishing to sound rude i'm thinking you're trying to run before you can walk. You'll progress much faster if you forget about thick-thin fillets on small dia tube for the moment and go back to basics...

It isn't rude, just demoralising but I can handle that! You haven't seen me walk though?!

I just ran a quick fillet which I don't think is too bad considering that I have only been doing this for four months.

I prefer to find something that I can't do and then practice it until I can. Bearing in mind that at this time yesterday I was blowing holes left,right and centre and after three attempts with a bit of helpful advice from some people on here I haven't done too bad.

Imagine how good I might be in another month of practicing.

Ultimately, I am going to build my bike so I need to learn how to do it!

Thanks for all of your advice.

Sheridan

 

[Shox Dr]

As HR says. You are either holding the tungsten too far away and or not keeping a correct torch angle.

 

[backpurge]

You may struggle with ordinary MIG wire as it is not triple de-oxidised like TIG specific filler, this can lead to porosity in your welds

Keep at it, you have made good progress, as has been said you need to keep your arc really tight to help keep the weld size down and put a lot less filler in as in Citizen Kanes welds. With practice you will find you hardly have to weave at all, it's all about where you point your tungsten and travel speed.

 

[serepton]

Thank you Backpurge, I am going to get some more practice in today.

I'll post my progress later!

 

[hotrodder]

I don't think it is, I am fighting not touching the metal with the electrode. What makes you think it is too far away?

To be blunt everything about 'em is screaming it. The welds are huge for the material thickness, more so for welds done at 42A with 1.0mm wire. We've all been there while learning, that's why both TigPaul and myself purposely demonstrated the effect that arc length has (first two links in my last post). Another thread on the subject... http://www.mig-welding.co.uk/forum/showthread.php?t=23592&highlight=arc+length

I just ran a quick fillet which I don't think is too bad considering that I have only been doing this for four months.

Yeah, that's coming along nicely for a newbie. Again, just being blunt, it's one i'd be practicing until nailed. First welding downhand (flat/horizontal) and then vertical before switching to tube. There's nothing to judge scale with but the toes (edges) are poorly tied in, possibly with some coldlap and some undercutting (millscale can cause/exagerate that)

I prefer to find something that I can't do and then practice it until I can. Bearing in mind that at this time yesterday I was blowing holes left,right and centre and after three attempts with a bit of helpful advice from some people on here I haven't done too bad.

Imagine how good I might be in another month of practicing.

Ultimately, I am going to build my bike so I need to learn how to do it!

Thanks for all of your advice.

Sheridan

Noone's saying you are doing badly but you came here for advice not praise right? If you follow the advice layed out in the tutorial i promise you you'll progress faster*, it'll be a less frustrating journey and you'll be a better welder at the end of it. The guy that did the TIG tutorial has been doing this for years and like most of us giving you advice actually earns a living as a welder/fabricator


* If for no other reason than the fact that a sheet/plate fillet weld is faster to set up than coped/mitred tube i.e. you spend more time practicing welding and less making weld coupons. Once arc length/weldpool control become more natural then the switch to tube will just be about the muscle memory needed for torch manipulation as the weld progresses

 

[serepton]

I am taking it all on board.

I appreciate you taking the time to post and yes, it is advice I am after rather than praise.

I will practice the straight fillets and get them nailed first.

Thanks once again,

Sheridan

 

[jakecouling]

I am pulling my hair out here!

I have a cycle bottom bracket shell which has a thickness of 3mm. I am trying to weld the rear chain stays to it and they have a thickness of .9mm.

I can't get a puddle going without blowing through the chain stays. If I wait until there is just enough heat to start the puddle then as soon as I add filler rod to the puddle it cools it too much and the puddle solidifies.

Is there a technique to doing this so it wont blow through?

Thank you

Sheridan

i would suggest using a foot peddle to control the heat going into the metal, start it up getting a puddle and as the puddle forms take your foot off the pedal

 

[langy]

i would suggest using a foot peddle to control the heat going into the metal, start it up getting a puddle and as the puddle forms take your foot off the pedal

Very contradictory to your other reply !!!

Quote:
Originally Posted by seanc
How vital is a foot pedal when tig welding ?
Im looking at the 160amp r-tech unit im only ever going to use it for thin stainless so i dont require ac or high amperage but this machine doesnt have the option of adding a pedal and the next machine up that can use a pedal is an extra £300

foot pedal is only really useful for ali i find as ali takes in heat faster but gets rid of it fast to and using the pedal you can control your puddle

 

[Shox Dr]

doh!