Advice Needed With Tig

[Medium Dave]

Hey guys, I am fairly new to this TIG welding so my apologies for the rubbish terminology, but I am trying to weld a subframe which is 2mm mild steel to a 3mm thick plate on the back of my clubman and it is going well for the most part, but there is a section thet is a T intersection where the weld puddle is bubbling, and the bubbles are going through the weld. I have tried grinding away all the bad weld and cleaning it with the wire wheels, resharpening the tungsten and trying again, but it happend again! it is happening over about 2inches and either side I can weld ok, I am using a pretty simple welder set at about 100amps. Any ideas how to clean that weld off and get it welded properly? thnaks in advance

[QWK32]

100 amps thats too high for 2mm and 3mm plate

and what do you mean by bubbling? like spitting at you?

[Craved]

are you wiping the material down with anything first?

i have used metho, and allowed alot of flash time. but i found acetone works better with lower flashing time between cleaning it and welding.

What gas are you using also?

[QWK32]

and have you got the leads set up right? earth lead into positive and torch lead into negative. also what size tungsten tip are you using?

Edited October 9, 2007 by QWK32

[Medium Dave]

Whoops, got busted indoors and immediatly handed a vaccum cleaner

I say 100A but I do admit it is a pretty cheap setup, so its probably imperial amps, but I am usually getting a nice clean weld, but this one is like when you blow bubbles in milk through a straw (on reflection a picture would be handy) not spitting tho,

I have not tried cleaning it, I will grind & clean it out again and have a go with some metho I have handy. Using pure argon.

Leads are set up ok, and 1.6mm tungsten, most of the space frame is 1.5mm rhs, I have done some welding with the 2-3mm plate which has come up ok, its just over about 5cm

Thanks guys

[ylwgtr2]

whats the flow rate setting of the gas?

[Medium Dave]

I have been setting it on about 6-7 **cant remember the measurement** - might need a little more? - Actually come to think of it, there is a bit of a gap, and I can hear it whistle in the gap, might be worth cranking it up a but eh'

[QWK32]

6 will be fine. i tig weld pretty much all day anything from as small as 1mm up to plate as thick as 15mm and use a flow rate of around 8 L/m to 5 l/m.

amps are the same not mater where you are in the world. no such thing as imperial amps. they are all the same. and for that size plate i wouldn't go over 60. you don't happen to know the duty cycle of the welder?

whats on the back of what you are welding? and any rust in that area?

[Medium Dave]

Sorry, I probably should have put in a smiley with the imperial amps comment, I just thought it was that rediculous that it wouldnt be taken seriously - I was just taking the piss out of my rubbish chinese copy welder*, what I should say is at the 100 mark I get a nice weld pool on both surfaces, the 60 mark does not even make a dent

there might be a little bit of surface rust, cant quite remember - although I dont really want to take it all off - last resort! it took ages to get lined up and I have already taken apart the jig I think the duty cycle is about 60% but I could be wrong (and I might have completely the wrong figure)

* To answer the "you should have bought a decent welder" question; I would love to throw a bunch of money at this project, but that is just not an option at the moment - Its most important job is keeping me sane, which it has been doing quite well for cheap gear

Update: I got it! grided out the rubbish weld, wire wheel, metho, upped the gas flow and bam! nice clean weld Thanks for your help guys

Edited October 11, 2007 by Medium Dave