[rahtreelimbs]

I asked this on another forum and I guess it was too stupid a question for one member.

[delraydella]

it's where you touch the electrode to the material to start the arc. Once the arc starts, you lift the electrode to maintain it.

[rahtreelimbs]

What arwe the advantages over a normal pedal push start?

[Otto Nobedder]

The advantage is to be able to use it in the field , on a construction site, a long way from your machine. Lift-arc is for when you don't have a remote & HF start available.

A disadvantage is the possibility of leaving a tungsten inclusion in the weld.

There is also "scratch-start", which allows you to TIG with any DC machine, starting your arc with a scratching motion like stick welding.

Steve

[capozzoli]

The machine has to have lift start capabilities.

What it does is the current wont start until you litf the tungsten away from the metal. For example; you touch the tungsten to the work piece and hit the current. The machine will not deliver power until you lift the tungsten away and then the arc will start. This will make it far less likely to leave a tungsten inclusion as compared to scratch starting.

It works well but HF jump start is of coarse the only way to be sure of a good clean start.

[fairmont1998]

My DC machine is lift TIG.
It works quite well. Touch the tungsten where you want to start the weld, hit the trigger then lift the torch slightly. A small faint spark jumps the gap, ionizing it and then the current flows.

[Ultralow787]

I was shown a slight variation of "scratch start" last summer. The fellow just did a very light sweep of the filler wire across the tungsten (which was already very close to the work) to make contact with the pipe. The arc tarted nicely and I believe the chance of a tungsten inclusion were reduced.

[cornmuse]

On my thermal arc pro wave 185, in lift tig mode, you step on the pedal, touch where you want to start weld, and when you lift, the arc starts. When you touch, the machine recognizes this, apparently there is a very small current passing, (not too technical of an explanation eh?) it works tho, , , -corn-

[Greg From K/W]

Maybe that is what I am doing and didn't realize it. I put the gun close to the work and hit the peddle. The arc starts bang. I usually don't have to strike the metal to start a weld.

That being said I did have a few times a couple weeks ago that it would not start and I had to scratch it to start. Not really sure why though. I find the cleaner the tungsten the better it will start with out scratching it.

[Otto Nobedder]

Greg, if you don't have to make contact to start your arc, it sounds like you have high-frequency start, which is common on machines that are capable of HFAC. If you're finding the arc sometimes doesn't start without making contact, it could simply be high humidity (I've had this problem), or it could be time to clean and adjust the spark-gap. (Transformer machines get HF start, and the high-freq. in HFAC from a "Tesla coil" circuit which uses a pair of electrodes with a narrow (usu. .008-.015) gap. I'm not sure if this applies to inverter machines, but I doubt it.)

Your user manual will have details on how to set the gap, and if you don't have the manual, most are available to view for free online. The best way I've found to clean them, (they are usually short round rods about 3/8" dia.) is to chuck them into a drill press and run them into a sanding block w/ 240 grit.

Your mileage may vary...

Steve

[Greg From K/W]

Ok well I will have to check into it and see. Its a Lincoln 225 precision tig. Im running it at about 49 amps 90% of the time. THough I did find the stupid ground clamp came loose from the machine once so that might be whats going on too. It hasn't happens since so who knows. I am sure the machine will need a good blow out with air in a few weeks. Its only about 2 months old right now.

[Otto Nobedder]

Yup,

The Precision TIG 275 is a transformer based squarewave machine with HF start and HFAC.

Current manual here:

http://www.lincolnelectric.com/assets/s ... /im908.pdf

Steve

[Greg From K/W]

No its a 225 I am sure they have the manual at work. Its a new machine I can't see them not keeping it. I will ask for it. Don't know why it isn't kept with the machine. Oh wait someone would use it for toilet paper lol.

[capozzoli]

It has AC. Same machine just a little less power.

The HF start machines work great for stick too. You can use the Ac, and hot start for stick welding too. No need to strike the arc. Just get the rod close and you are welding.

Do the lift start machines work with stick?

[Otto Nobedder]

It has AC. Same machine just a little less power.

The HF start machines work great for stick too. You can use the Ac, and hot start for stick welding too. No need to strike the arc. Just get the rod close and you are welding.

Do the lift start machines work with stick?

If they are designed for stick in the first place, then yes.
Just remember, electrode positive for stick.

Steve

[Greg From K/W]

It has micro start but i noticed that one problem was the Tungsten wore down and thats when I started having problems with it starting the arc. I didn't realize having the tungsten wear off would cause any problems.

[capozzoli]

Not sure what you mean when you say 'wear down''?

If you are sharpening a point and after a short time of welding the point is gone you are most likely pulling contamination from somewhere. Could be you are too close to the steel and the tungsten is pulling up some steel. Or there is not enough shielding gas. Possibly the joint being welded still has mill scale on it. It could even be that there is a loose joint or leak in the gas line that is pulling air. If the tungsten is getting shorter then you are including tungsten into the weld.

[Greg From K/W]

I keep the tungsten about 3/16th or so. Maybe a bit more. I sharpen them to a point and maybe the taper is about 1/2" I have it stick out of the gun about 1/2" or so. It wears down to about 1/8th depending what I am doing. I was tig welding 12 gauge stainless and it wore down and I started welding thinner material and it wouldn't start the arc. I stuck it out more and it started right up bang.

The Tungsten does wear down right? It rounds off even if you dip your wick as Jody says? I know it does. Other wise you would not have to resharpen it at all.

[capozzoli]

They refer to tungsten as "semi consumable". Meaning yes it does become consumed, but very slowly.

When I weld stainless steel I get a point to last a long time, sometimes even a whole day of welding if I don't accidentally dunk it.

Half inch sounds a bit far. Are you reaching? If it is out too far it may not be getting enough shielding.

What size cup are you using?

Also you will want to change the protrusion of the tungsten depending on the type of joint. As an example the tungsten should stick out farther for an inside corner and not stick out so much for an outside corner.

[weldin mike 27]

Hi there,

Stainless steel tig is very clean thats why the electrode stays clean and sharp. Mild steel has more crap in it. Also alot of people dont have the settings exactly perfect so that can be a factor in the electrode "wearing down" Make sure the post flow is adequate so it keeps going while the electrode is hot.

I love it when the tungsten stays sharp for a long time. We normally use the Tig for repairing welds so there is some times a bit of crap around. Sometimes I can only get a weld or two before resharpening.

Mick

[Greg From K/W]

Ok cup is a size 6. I think they should be buying at least a size 9 for this. I hit the puddle once in a while but I am getting better at it. I have the post flo at about 15 sec. Gas is at 15 and ya maybe it is a bit far out. I am only welding outside corners. So I maybe have to shove it in a bit. I am getting better and better at it. Would this be why my welds turn gray on me? Not that it matters. They are ground off any way lol. Just wondering.

[capozzoli]

Sounds like you are not getting enough shielding at the weld pool. The weld may be crystallizing.

Try sticking the tungsten out only a small amount past the cup. Maybe 3/16. Do it by loosening the collet and resting the cup and tungsten on a hard surface. Then lean the cup over untill you get it where you want it, then tighten. (Its hard to do it with your finger.)

For outside corners it shouldn't stick out very far at all. If you are worried about comfortably seeing the weld pool you can get a clear glass cup. Also try turning the gas up too, maybe even 20 or 25.

Are you using a gas lens? They work great for welding SS.

I cant remember the cup sizes but I use a small one for outside corners, It tapers down to maybe 3/8" opening.

Here is a good word, have you ever tried welding the outside corners autogenously?

[Greg From K/W]

Gas lens um no lol. I will give that a try and see what happens. I was using the gas at about 25 before but i was told it was too much cause it can cause turbulence so I turned it down. I knew I should have shot that guy. Oh well up it will go.

[Otto Nobedder]

I prefer an autogenous weld when it's possible. It's much easier to get a smooth consistent bead. For one thing, both hands are free to control the torch.

If you're not using a gas lens, turbulence is possible. You'll know it when you see it. You'll see "sparkling" around the puddle while welding, the tungsten will dull quickly and blacken, and the weld will have a dark surface.

Steve

[Greg From K/W]

Ya thats whats going on alright. I will talk to them about a gas lens then. See what happens. Thanks for the help. I appreciate it.