tig welding beginner

[colmmc]

hi all just some questions in relation to tig welding.
i recently bought an inverter tig/stick/plasma cutter welder.
the tig torch came with tips and shrouds but no electrodes.
are all tungsten electrodes the same length?
what thickness electrode do i need for welding say s/steel at 150 amps?
also how long will a disposable bottle of argon last as its an inverter i'd prefer to make the unit as portable as possible instead of hooking it up to a big bottle.
3 different shrouds came with the welder with the numbers 4, 5, and 6 on each of them, is this to do with the thickness electrode i use?
cheers
colmmc

 

[GrahamGKD]

Hi Colmmc,
As far as I know all the tungstens start out the same length (all the ones I have are the same) but there are different types for different materials. There is a very good TIG handbook you can download from the miller site.

http://www.millerwelds.com/resources/improving-your-skills/tig/

Only problem is that tables etc. are given in imperial units. Just looking in the handbook again, it does mention that you can get tungstens in different lengths!

I have a handy table which suggests welding current, tungsten type and filler rod size for different materials and different joint types - I could email it to you if you were to PM me your email address. The table suggests a 2.4 tungsten for 150A. That current would be good for 5mm stainless. I have used a normal red tip thoriated tungsten quite successfully for stainless.

I can't see disposable Argon bottles being that practical for TIG - I even gave up with the rent free Adams gas ones in favour of a proper BOC contract as I was getting through the Adams bottles too quickly.

TIG is a great process - you will love it - good luck.

Graham.

 

[GrahamGKD]

... oh, and somewhere in the TIG handbook it mentions that the inside diameter of the ceramic should be at least three times the diameter of the tungsten. Graham.

 

[shenion]

The Miller site also has a TIG calculator. It will give the recommended tungsten size, gas flow and ceramic size.

 

[rkde]

There is also a nice little guide on the r-tech website. r-tech guide

I have yet to work out which tips to use, which tungsten, and what size filler to use... Lots of reading will get me there

 

[GrahamGKD]

The Miller site also has a TIG calculator. It will give the recommended tungsten size, gas flow and ceramic size.

Personally I've not found the calculator to be that useful, I can't remember my exact complaint with it, I think it may be that it over eggs the current needed? Maybe I'm not using it right? Graham.

 

[shenion]

No, you are using it right. The Miller calculators are set for pro welders where they want to work as fast as possible for the most productivity.

I take the values as the high limit for current.

 

[Alfaman]

The Miller calculators are set for pro welders where they want to work as fast as possible for the most productivity.

Definitely agree, Shenion. Correct size/current/flowrate for professionals. Especially flow rate, when they're not paying for their own Argon

 

[colmmc]

thanks for all the replies.
i know that the disposable bottles might not last long but sure they wont rob the nation in trying them out anyways!.
i got a packet of 2.4 thoriated electrodes and 2.4mm s/steel rods so i'm all geared up just need to get a bit of stainless.
i see on the pack of electrodes that thorium is mildly radioactive are there any long term health risks with using these electrodes?
the way my welder will be set up for the start anyways is disposable argon bottle connected to regulator on the welder, (this is also used to regulate the air for the plasma cutter).
because i dont have a flow meter on either the regulator on the bottle or the one on the welder, would anyone be able to hazard a guess as to what pressure i could set the argon at, or is it just a case of fiddling around with it?
also what shade on the helmet do i need to weld in tig?

 

[shenion]

I use thoriated here for both steel and aluminum. They work well. On aluminum it should be plain tungsten, but the thoriated handle heat better (on an old transformer beast, supposedly they may crack on inverters.)

Yes, they are mildy radioactive, helps keep the arc going and handle heat. Suppsedly about ad radioactive as those old watches with luminous hands. Main safy issue is breathing dust when grinding.

Get a pea shooter to measure the flow. Really only way to measure accurately.

I use a shade 9 or 10 on TIG.

 

[GeorgeB]

because i dont have a flow meter on either the regulator on the bottle or the one on the welder, would anyone be able to hazard a guess as to what pressure i could set the argon at,
also what shade on the helmet do i need to weld in or is it just a case of fiddling around with it?

I was told that the pressure on the disposable cylinders is so low that you need to have them full on (at least there's no need for a meter!) to stand any chance and, even then, the pressure isn't as good as from a proper gas cylinder. If true, one could question whether they are even fit for purpose.

 

[colmmc]

another thing i was wondering is how far should the tungsten electrode be sticking out of the shroud on the torch?
cheers
colmmc

 

[Shox Dr]

1.5x the Dia. To be anal. However anywhere between -1mm to + 25mm+ all depending not CFM of gas, shroud and type of joint.



So if you are just starting out, go with 2mm. do learn from there