I've i have to pass atleast 3 diiferant helliarc welds by friday. But i only have till thursday to learn it. I already through a big fit over it but Stu (shop teacher) already said it is going to be something that i would be gald that he forced on me.

Well anyways Do you metal working guys have any tips on helliarc'ing. Is there anything special that i need to know about it. How much gas or how hard will i have to push on the pedal?

I have lots of welding history before this and i am pretty good as gas welding but this kind of weld seem pretty tough.

What material are you welding? You can weld all kinds of metals using the (GTAW)process.Aluminum is the metal the Heliarc term is associated with. Helium shielding gas is the norm,however you can use a mixture of gases such as 50%Helium 50%Argon.I usually use the 50/50 mixture for Aluminum and have the gas flow rate around 20-25 CFH.Your amperage depends on the thickness of your material.Your welding polarity is AC.Use pure tungsten(green band on end).You'll need to form a(ball shape) on the other end when using Alternating Current. You can preheat the metal and that helps the weldability quite abit.
Cleanliness is very important with all metals you plan to weld no matter what process you use.
You said 3 different welds. That could mean 3 positions such as Flat ,Vertical, Overhead or Horizontal,each requiring slightly different Torch Angles.Could also be different joints such as Butt,Corner,Tee,Lap.
As to how hard to push the pedal, You need to watch the metal as your pushing the pedal down and notice when the metal starts to become a liquid.That is your melting point and you don't need to push the pedal much farther if any.
Keep your hands steady by resting them on the table or some kind of fixturing.Feed your filler wire the same as you do when Oxy-Fuel(Gas)welding.
As you can see theres a lot to learn in the Welding field and we haven't even scratched the surface here.
Good luck in your test and read your textbook and get as much hands on experience as you can.

It is a bit hard to teach you how to weld if we don't know what material, what position, what joints, or the capability of the machine you are going to use... Give us some more clues and we may be able to help you bluff your way through the exam...

You could try the www.lincolnelectric.com site for a bit of info... look for the info on the TIG (another name for Heliarc) machines and processes... If you are welding Stainless, or CrMo, you will use DC...

David

I will be showing the insrtucter Butt Welds, Lap Welds, and a out side corner. After that is up to me to learn the other positions.

I will be welding horizintially (spelling) With Aluminum that will be anywhere from 10 guage to 1/2" for now. As for the machine I will be using a Miller that is capable of welding up 3/4".

Practice, practice, practice. It's extremely difficult to get any good at welding without practice. If you only have until Thursday, that makes me believe you weren't practicing.

I have to laugh, "a lot of welding history". How much welding history can a 15 yr old have?

I have to admit, I don't weld too good myself, but I don't do it often enough to keep my skills up.

If I were you, I'd seek help from your teacher.

Oh, by the way, spell sponsors correctly.

Well i started welding when i was 10 so i got a little head start on everyone else. Yeah i know i should have been practicing but i spent alot of time doing other stuff in the "sticker room" as we call it making stickers and not doing the stuff i should have been doing. Then midterms snuck up on me and i had to get atleast 10 cuts and welds. Just to pass. Well now things are starting to get coaugt up to me and now i am starting to fall behind.

I have been getting help from my teacher but i keep appleing to much gas or to little, burning holes, getting TERRIBLE looking beads because of the air hitting the weld (From not enough gas) and everything else that can go wrong.

Hey i'm even getting spelling lessons I have always spelt sponsors sponsErs.

If you choose the right electrode, the right cup and the right gas flow, you should not have any problems with contamination of the weld. The only potential contamination can come from starting the arc (don't scratch start, if the machine has a HF arc start), finishing the weld run (look to increase the post flow) or not having clean material to work with. Aluminium is a cow to work because it oxidises so quickly... the material should be cleaned right before you are going to weld, not a half hour before... only use stainless wire brushes on the aluminium, and if your electrode is sticking out too far, or your angle you're holding the torch at is too shallow, then you may get a gas coverage problem... move the electrode back in the holder a bit, use a smaller cup, and hold the torch a bit more perpendicular to the work... reposition yourself to see the weld, not roll the torch away to see the pool... remember also that aluminium does not show it's temperature easily, but if you have sufficient current in the arc, then the penetration should be good, and the filler rod should flow nicely... add the filler only into the weld pool, and only when you need to... don't hold the rod in or near the weld pool, or you may disturb the gas flow...

One other point, use a sharp electrode, but make sure you sharpen them toward the point, don't put them on the grinder and just spin the electrode to make a point, have them in the same plane as the grinding wheel direction...

Practice... it is all in the wrist... little circles... just like in Oxy welding... make sure one bit of material doesn't go cold... once you get the arc established, you may want to drop the power a bit to keep it stable...

Good luck...

David

What do you mean when you say "scratch Start"?

How will i know how much gas to apply? Do i just put the filler rod in as needed and make a puddle then push it along?

Is it ok to make side to side patterns? The is the pattern i have always used. Or make a puddle and push it.

Here are a couple of links to articles on tig welding. I have reviewed each of them and I think the second link may serve you best. http://www.lincolnel...ent/tigalum.asp, http://www.millerwel...rt/Tigalum.html

A quote from the Miller article,

"Learning GTAW

There is good news and bad news about GTAW of aluminum. The good news is that it is very difficult make a bad GTAW weld. If the welder melts the base metal and gets the filler rod into the weld puddle, a sound weld is most likely to result.

The bad news is that learning to make pretty weld beads, as well as coordinating the hands, feet and eyes, takes patience and practice. However, when a welder becomes proficient, the results are very satisfying."

Ok i'm starting to understand it but i still don't understand how to use the pedal.

Scratch start... In any electric welding process, you need to get an arc between the work material, and the electrode... this is what provides the heat to melt the material and/or the filler material... In TIG, esp. DC welding, you strike (or scratch) the electrode on the material to be welded to initiate the arc... you then pull the electrode away a small amount and maintain the arc, and you are now officially welding... On some higher spec machines, esp. those that do Ave an AC circuit, you have an option to initiate the arc by a momentary surge of voltage, rather than having to physically strike the arc - this HF start is great, because you cannot contaminate the electrode or the work piece... in TOG welding, the electrode should never touch the work...

Your teacher should have gone through it or supplied you tables or a textbook to calculate gas flow rates, electrode selection, cup sizing, current ranges etc...

The best pattern is a small circular one, esp. with Aluminium... then you are going ahead to preheat the metal, going back to keep the bead fluid, and catching the sides to make sure both bits of material are being heated and included in the weld pool... For aluminium, it will cool so much faster, and conduct away heat from the weld pool to the surrounding metal... so you need to keep the heat up in the whole perimeter of the weld pool...

As for filler, heat the base material, add the filler into the weld pool, and let it flow... you should be able to include the filler rod in your circle so it melts, without interrupting the arc... you cannot really push the material with the filler rod or the electrode... it just has to flow, as long as the weld pool is hot enough, it will...

The pedal regulates the current and therefore the weld depth and the bead appearance... once the arc is established, and the material is flowing nicely, you don't need to add more power, in fact, work a bit slower with the same power and you will get much better bead appearance. don't let the bead get too wide, or let the arc wander...

David

Thanks yamaha.dude!!! I started practising it today and it VERY COMPLICATED but i am starting to get the hang of it.

I have not gotten a chart or anything to choose the right cup sizes etc... do you know where i can print one out off of the net?

i'm worken at it.

If you can't get a textbook, then look at the welding machine manufacturer sites mentioned above - Miller and Lincoln Electric, or just call their support numbers, and tell hem you need help selecting an electrode, cup and gasflow rates for a particular job you have not done before... tell them you are new to alumnium... even the packs of electrodes may have charts or recommendations on them...

There are a few sizes of cups, but it is more important to get the correct electrode and have it sharpened right than to be one cup size wrong, or have to much gasflow... it is only wasteful to use too much gas, but it won't adversely affect the weld, unlike too little gasflow...

Good luck,

David

I can't thank you guys enough. ALL of it has really helped out alot. I have read all of the links that have been posted and espeacally yamaha.dude's posts.

I sat around think about the articles and thinking about what i have been told and put it together with what my insrtucter has taught me nad things are startting to come together.

THANK YOU