Getting ready to toss my new welder in trash

Date 08-30-2007 06:03

Dan

Thats a pretty nice machine don't beat it with a hammer just yet!

Forgive me if I ask a few questions but the answers will help me help you. Are you experienced with GTAW welding, what kind of argon I.E. what mix or is it pure 100%, what size gas cup are your using 4,6,8,10 , what diameter filler rod do you have, what is the display showing for your starting current, what grade of Aluminum is it, Have you laid a resonable looking bead flat on this material?

Answer those and I can help you narrow down whats going wrong.

Regards
Tommy

By Lawrence (*****)

Date 08-30-2007 06:03 Edited 08-30-2007 06:06

Dan

The good news is that you don't have to throw your welder away.

The bad news is that it is probably all your fault ! :)

Aluminum Filler wire curling up is generally a sign of improper torch angle... If you keep your tungsten electrode pointed as close as possible to perpindicular to the work (straight up and down) and only about one electrode diameter above the work, your welding wire will dab into the leading edge of the puddle and leave perfect little slices at the end of your filler... almost like cutting a salami.

With GTAW the heat goes exactly where you point the tungsten... so if you lean it forward (a push angle) that heat makes an oblong puddle that does not penetrate too well and a good portion of your amperage simply blows forward... If your filler rod is in the forward area (where it ought to be) it will ball up every time.

Secondly you want to add your filler at about a 20 degree angle from the work... This means lay your hand on the work, and feed the wire as close to flat as your hand allows... If you add the wire from high above it gets too close to that radiant heat I mentioned and again things ball up..

Torch angle... wire angle

Now put down the hammer and try it again with an extra effort to keep your torch straight up and down... Tell us what happens.

By ssbn727 (*****)

Date 08-30-2007 07:00

Hi Dan!

What Lawrence mentioned makes sense, and I just want to elaborate further by stating that when larry mentioned "Torch angle" he's really referring to your travel angle being too steep whereby your torch is leaning too much away from being perpendicular to the joint, and as he mentioned: "too much of a push angle."

So if you're welding a tee joint, depositing a fillet weld, the best way to control your penetration and puddle shape is to control both your work and travel angles of your torch in relation to the seam of the joint. "split the right angle on the Tee... In other words, a 45 degree work angle for the torch, then a ninety degree travel angle with a 5 degree maximum tolerance away from the direction of travel.

Make sure that you see a complete puddle first before you add any filler. ;) Place your head at an angle so that you can clearly see the puddle form, and can clearly see the end of your filler deposit into the puddle... In other words, slightly ahead of the location where your torch is, so that your field of vision is'nt being blocked by your hand or torch. :) :) :) Hope this helps!

Respectfully,
Henry

By Fredspoppy (**)

Date 08-30-2007 11:23

Dan,
One question not asked is "what amperage are you using"? For 1/8" aluminum, T joint fillet, you will need a pretty high level of amperage. If your amperage is too low, you will have to "hang around" generating enough heat to melt the base metal. Crank up the amperage, so that the base metal melts quickly, and then move along rapidly also. The slower you are to get moving, the more heat gets tranfered into the surrounding base metal (due to the thermal conductivity of aluminum) and also may affect the ease with which the filler melts off cleanly into the puddle.

Add this to the other comments here and you should start seeing better results.

By DanS Date 08-31-2007 01:47

Thanks for all the replies. I have tried using amperage of anywhere from 85 to 125. I am not sure what the cup size is but but the inside diamater is 3/8 inch. I forgot what cup size that would be. I have taken a couple of classes in welding at the local junior college, but I am pretty much a newby.
I have noticed I spend a lot of time trying to develop the puddle with the lower amps. At 125 amps the metal heats up quick but I am not sure I am steady enough yet to move along that quick. BTW approximately how long should it take to to the fillet weld on a piece approximately 5 inches long? I am going to give it another try this weekend and really pay more attention to the torch angle. Thanks again for the support.

By aevald

Date 08-31-2007 03:25

Hello DanS, prior to your listing of the cup size that you are using and the rough amperage range that your at, there wasn't much for the folks to go on with regard to helping you. My first suggestion having heard that the opening on the cup is 3/8" is to suggest that you opt for a larger cup, say with about a 5/8" opening and possibly even switch to a gas lens set-up. The gas lens aren't a necessity, however if you have an opportunity to use one and compare the results to a conventional cup set-up you'll notice the difference.
   The difference with the cup sizes has to do with complete gas coverage of the weld puddle and also with turbulence that can be caused from flowrates that are high enough to create a venturi effect into the weld puddle or disruption of the coverage of the puddle due to the turbulence from too high of a flow rate. Back to cup sizes, with a given flowrate of say 20 CFH, by simply just changing the cup size you can increase and decrease the velocity of the shielding gas through the cup, a smaller cup yields higher velocities, a larger cup yields reduced velocities(based upon a particular flowmeter setting). So as you use various sizes of cups you need to be aware of the flowrates that you are using.
   Tungsten stick-out can be pretty important as well with regard to the type of weld that you are trying to attempt, a fillet weld will generally require an increased stick-out over a weld on a flat joint or a lap joint. Fillets are able to trap gas around the puddle so you can increase the stick-out. Flat welds and laps don't have this natural way to contain the gases so they require the tungsten stick-out to be reduced. I generally run up to 9/16" stick-out on fillets and probably no more than 1/4" stick-out on flats and laps. You will also generally have the best control of the puddle by keeping the end of the tungsten as close to the puddle as you can without actually touching it into the pool, this can also guide your stick-out choice when you are doing fillets, as stick-out generally should be adjusted further out as you increase the cup size. A trick for setting this distance is to select the size of cup you plan on using, set the stick-out where you think it will work and then position the torch as if you will be welding, then note how far the end of the tungsten would be located from the face of the weld that you would be laying in, if the tip of the tungsten could touch the weld face and still leave about a 1/16" of space to the edges of the cup on both the top and bottom pieces of the fillet joint you are probably set-up fairly well.
   Consider that a fillet joint is comprised of two basic components a flat surface and an edge. The flat surface will require slightly more heat to melt it and allow it to become part of the weld in an equal distribution. The edge on the other hand doesn't require as much energy to melt and make it become an equal part of the fillet. This is where torch angle and position of the point of the tungsten can come into play, angling the torch more toward the flat surface will direct more heat there and allow for the correct proportion of heating to occur so that equal distribution of the weld metal will occur. Positioning the tip of the tungsten relative to the centerline of the weld joint will ensure an equal distribution of the weld metal as well. Practice is where you will develope the skills to make this happen consistently, don't expect to immediately be capable of stacked- dime type welds that you have probably seen done on certain aluminum products.
   Since you have a very fine machine it also has some capabilities that many others don't, I am mainly referring to the balance control options and I believe also the variable hertz capabilities. Take a close look at the owners manual with regard to these controls and their adjustments and what they affect with regard to machine performance. The hertz control will affect the focus of the arc, depth and width of weld pool. The balance control will have an affect on the cleaning action that is occuring in the weld pool, I might suggest staying towards the neutral or middle position with this setting until you get the hang of what it does, this also means that you will need to do your welding on "clean" metal. Acetone is a good prep for aluminum and if you're brushing it to clean it, use a dedicated stainless steel brush. With any of the cleaners that you might use keep in mind that most are flammable and care should be used to keep them away from the welding and not to start welding with any visible solvents or soaked rags and such in the vicinity of the welding.
   You've already gotten some terrific suggestions from the other posters on this thread, I hope that some of what I've included here will help also. Regard, aevald

By swsweld (****)

Date 08-31-2007 02:44

Along with the above good points, make sure that the metal is clean or you will have nothing but trouble.
Use a disc that has not been used on other type metals. They make disc especially for aluminum. After mechanical cleaning you should chemically clean with alcohol, MEK or acetone. The aluminum oxide is very difficult to penetrate without removing it first. Preheating the metal might help also.

By Tommyjoking (****)

Date 08-31-2007 08:24 Edited 08-31-2007 10:30

Dan

You did not quite answer all my questions but thats ok ..I will put in my $.02 anyway

The above posts with regards to technique are all sound advice..Keep your torch pointed perpindicular to the weld joint. Aluminum is very forgiving of your distance you hold your torch away from the weld....tight is better once you are practiced but for now you could hold your tungsten a good 1/8 to 3/16 away from the top of your bead and its ok. If you have a synchrowave with the digital readout display it will show your starting amperage when idle....if you have a foot control. This should be between 75-80 if you have the foot control. To get a good puddle going you will probably be about 60% to 90% all the way down on the pedal for proper "wetting" I.E. wetting means that the aluminum has turned liquid and will have a chrome shiny appearence. If you are not getting a good wetted area under your torch then you will not get a good weld. If this ends up not being enough (I have only used synchrowave 250's the ranges might be different...go up in ten amp increments on your starting current setting and you should be able to manage it with a pedal. You should have a "balance" control on that machine...it should be set between 6-7 1/2 for all intents and purposes on what your doing. This contols has a unique ability to fan you arc out or narrow its focus for deeper penetration...when its set incorrectly it can make the machine seem like its not doing its job. Your tungsten size is correct for that thickness....one thing you may try is to sharpen your tungsten get a thick piece of steel or a thin piece of copper and turn your welder to DC + strike an arc against the material and gently step on your pedal for a moment.....what this does is take your sharp tungsten and melt the tip this will create a small rounded area on the end of the tungsten which is perfect for running A/C (aluminum/magnisum). IF you do this and you ball gets bigger than the tungsten diameter its a bit of overkill and you should try again (grind it start over). What your looking for is a little shiny rounded place at the tip of your tungsten ....for 1/8 material it should be about 1/32 to 1/16 max. A sharp point on tungsten with A/C will always degrade into a misshapen lump which will adversely affect your arc and your control of the puddle.

Aluminum is different then all other metals really...it takes to high heat and fast travel speed best. A five inch joint on 1/8 should take you maybe about about a minute with tig. The key here is getting both sides of your base metal to wet really well (maybe a1/4-5/16 area overall) then add your filler and move your torch along in front of that deposited metal then do it again. You will get a feel for how often to add your rod according to how hard you are stepping on that pedal with time...it takes practice. But with aluminum the faster you weld it the better results you get for the most part. Now if you are using 1/16 filler you will almost have to shove it into the arc/puddle to fill it up....with 3/32 you will have to add filler at a regular pace...with 1/8 filler you will add it slowly (good pauses inbetween dabs).

For doing fillets and to get good at it ...pay attention to the crack/joint inbetween the two pieces.....you want to see that get wet and flow'''''''join together before adding filler....basically try to keep your two base metals melting together in front of where you added filler at all times.....thats the difference between sticking it together and making a sound serious weld. When you are running at proper temperature the sides of your fillet will simply flow right into your parent metal with no bumps and no notches. If it weld ever looks like its piled on top of the metal you are adding rod to quick or you simply are not runnning HOT enough. It should look like it was made together with an interesting row of coins laid on top of each other somehow impressed inbetween the two pieces. IF it looks like sand trapped in your weld you are: Not moving fast enough, not adding filler quick enough, running too hot.

CLEANING: Aluminum is probably the most particular metal when it comes to cleanliness: no oil, no wax, no glue, no tape no nothing. Brush your joint with a stainless steel brush (321 ss toothbrush is fine) wipe it down with acetone. Acetone leaves no residue at all ....great cleaner....but the fumes are bad for your brain ....hold your breath or wear a respirator. Avoid oil based cleaners whatsoever.

If you cup size measures 3/8 at the opening you are using a #6 usually its printed on the cup itself....that is adequate for this job with about 20cfm a bigger cup (10) would not hurt but is not absolutely neccessary. Now as long as we are on the subject of gas...you should be running 98% argon or 100% argon.....you can get away with a 92% mix but this will cause you problems and be a handicap an aluminum. I know its a pain paying to get that gas bottle filled up for the sake of practice but since you here now maybe we can make the next bottle much more productive for you. The best welders on the planet frequent this forum so you are in good hands here.

Oh I almost forgot....run your tungsten about 1/8 beyond your cup....yep that means you will touch off easier but it also means you will have better control over your arc instead of your gas dictating its shape. If there is any misunderstanding or you have questions on anything I have said please post them here and I will try my best to elaborate....sometimes I talk to fast.

Best regards
I hope that helps out
Tommy

By DanS Date 09-01-2007 22:43

Thanks for all your help guys. It seems many of you are very experienced with TIG. I got a chance to practice last night and this morning some. I am really paying attention to my torch angle and my welding has improved. At least I now know what the main cause was. I was leaning the torch away from 90degrees too much making the radiant heat melt the filler rod. I had a few beautiful welds, very consistent. One of my main problems seems to be keeping the angle consistent as I move along and keeping my hand steady so the tungsten remains close to the puddle without touching it. Do most of you keep a couple of fingers on the bench as you move your torch along or do you totally keep your hand and arm off the bench. I keep my second to the last finger on my work bench as a guide as I move along but sometimes my gloves seems to stick on the table and then I contaiminate my tungsten. Any tricks to keeping your hands steady as you move your torch and your filler rod?

By aevald

Date 09-02-2007 00:00

Hello again DanS, there are really many ways to support the torch as you are welding, you will need to experiment with them to see what works best for you and your situation. Myself, sometimes I freehand the torch as I weld, try not to though and only do this when the situation calls for it. Other times I will almost drag the cup along on the lower piece when I am doing a fillet, although sometimes it will hang up and as you found out, you will end up dabbing the tungsten into the puddle or hitting the filler rod with it. Consider this, it is not necessarily etched in stone that you have to weld any certain distance before repositioning yourself, so don't get stuck on that. When you find that resting your fingers or palm or any other part of your body won't work without ending up jerking and hitting the puddle or something, then simply stop, reposition yourself and start out again. This will also help you to learn to blend your starts and stops to where with some practice you will barely notice where you have started and stopped. One thing that I try to do consistently when I am getting ready to make a weld is to give it a dry run without having the arc on or my hood down, if I can do this in this manner it is likely that I can also do it when I am actually welding. It sounds as though you have made some good progress in getting this figured out, continue to practice and try different things to hone your skills. Just remember that as you try something new that you should limit the changes to a single item so as to weed out the bad and figure out the good. Good luck and regards, aevald

By 803056

Date 09-03-2007 03:23

It seems everyone has hit upon the various aspect of obtaining better welds in aluminum, but I would like to boil it down to a couple of basic steps:

1) Use Alternating Current (AC) with the balance set to about 45% to 55% as a starting point.
2) Use zirconiated tungsten electrode (it has a brown band around one end to identify it) with a balled end. The tungsten will form a hemispherical or balled end when you try to increase the amperage high enough to weld the aluminum. Hold the tungsten perfectly vertical while forming the balled end or it will be lop-sided.
3) Clean the aluminum with a stainless steel wire brush. Clean the filler metal with stainless steel wool (from a marine supplier). Wire brush by pushing the brush toward the weld groove. Do not push and pull the wire brush.
4) Use a large gas nozzle (cup). A number 8 should do for a start. Set the argon flow rate at 20 to 25 cfh on the flow meter.
5) Extend the tungsten out beyond the end of the gas nozzle about 1/4 inch (1/2 the cup diameter).
6) The arc length should be about one electrode diameter in length.
7) Lean the torch into the direction of travel about 10 to 15 degrees. Less torch angle will result in increased joint penetration.
8) Feed the filler rod into the puddle as you move the torch forward. DO NOT DIP the rod in and out of the puddle.

You should see an improvement in your weld very quickly.

Good luck - Al

By aevald

Date 09-03-2007 04:07

Hello Al, point #8 of your post did remind me of something that I hadn't included in any of my posts and didn't remember seeing in any of the other posts. When I dip the rod in and out of the puddle, differing slightly from your suggestion, I make sure that I don't take it out of the gas envelope as this will cause the end of the rod to become contaminated and then will in turn contaminate the weld pool as the dabbing takes place. Thanks for reminding me of that. Regards, Allan

By 803056

Date 09-03-2007 14:25

Hello Allen;

I teach "brush-up" welding classes for several of my aerospace clients that do a lot of manual GTAW. I always get a wide-eyed response from those individuals when they hear of the method I propose for feeding the filler metal for the first time. Then I ask the question, "Have any of you operated a mechanized or automated GTAW system?"

Usually, one or two in the group will reply that they have. At that point I ask the question, "Does the automatic wire feed mechanism dab the filler metal or does it feed into the puddle at a set speed?"

To which the reply is usually, "It is a set speed."

Then I ask, "If the mechanized system utilizes a fixed, steady feed into the puddle, why do you dab it in and out when welding manually?"

The answer is always the same, "Because that's how I was taught."

The problem, as you point out, is that there is an inherent risk that the hot end of the filler metal will be exposed to the atmosphere when withdrawing it from the protective envelop of shielding gas. The oxidized filler metal is then reintroduced into the molten weld puddle. Depending on the base metal being welded, the result varies from "big deal." to "Oh, Sh@t!"

I was told the method I use is called the "lay wire" technique by a pipefitter that taught it to me. I liked it and I use it for nearly all GTAW. It minimizes the opportunity to introduce oxidized filler metal into the weld puddle.

The individuals that are most prone to pulling the hot end of the filler metal out of the protective envelop of shielding gas are those welders that have or are used to welding titanium in a bag or chamber. I call them my "Big Band Leaders" swinging their maestro's baton to and fro with the beat of the music. That usually gets their attention.

Then there are those welders that "snap" the torch away from the molten weld puddle when they terminate the arc. I flunked a welder the other day for doing that on his pipe test. I asked him what was the proper way to terminate the welding arc and I asked him what the dangers were if he did it incorrectly.

His reply was to, "Reduce the amperage, extinguish the arc and hold the torch over the puddle until it was cooled so that the molten puddle wasn't exposed to air." I told him twice during the test that he was snapping the torch away from the puddle. The third time I simply stopped the test.

I guarantee you that he will be very careful of how he extinguishes the arc when he takes his next test.

Happy Labor Day!

Best regards - Al

By aevald

Date 09-03-2007 18:08

Hello Al, I certainly follow the reasoning that you have used to explain the technique that you propose for adding the filler wire in this case. I will also agree that the "dab" method is one that has been proposed by many who have learned to tig weld from various individuals over the years. DONE CORRECTLY, this method will yield very high quality and consistent welds. In a previous post, there was a comment that Tommyjoking made that I base support for the dab method on. I believe he stated to watch for complete fusion to the corner of the two materials in the puddle before adding additional filler metal, or a statement similar to that. I would make one further comment in support of the dab method, the cleaning actions that take place in an AC welding arc promote cleaning ahead of and around the weld pool as the welding is taking place, laying the rod ahead of the pool in this case "could" possibly block this action from taking place, so unless the materials are absolutely clean this could be an issue. Laying rod differs in this sense than having an automatic wire feed as the wire in a system such as that is generally fed into the center of the pool, I believe. To me it is easier to gage this when the dab method is employed. I also use this logic due to the nature of aluminum, it and magnesium are a whole different breed of cat in regards to their welding characteristics and their intricasies.
The "lay" method is one that has been used for a number of years, mainly I believe by pipe welders. I generally employ this method whenever I do any pipe welding on any materials other than aluminum. I am definitely aware of the benefits of the lay method of rod addition on the root passes in pipe and also filler passes as they are run in while walking the cup. It would be next to impossible to have any sort of consistency trying to dab in this case, IMO. I believe I am correct when I also say that the lay method of rod addition can be greatly influenced by the diameter of filler wire that is used in any particular situation, it requires proper sizing to aid in the ease with which it can be done(I know that is possibly an arguable point).
I maintain that I am here on the forum to learn as well as to share, so you can trust that I will certainly give the lay method a try in the manner which you suggest in your post. I have enjoyed the information, the logic, and the reasoning, thanks Al and best regards, Allan

By Tommyjoking (****)

Date 09-03-2007 19:46

Al and Allen

Both methods work fine I use both...it depends on my position and what I am welding. I use a constant feed typically more on steels then aluminum. You both mentioned the fact that pulling a hot filler out from under your gas sheild can happen....I certainly should have mentioned it because it is extremely common especially when somone is learning.

Feeding into the puddle directly requires a bit more heat then dabbing, travel speed and feed must be very consistent. If you do it wrong you get a lof and a piece of rod showing in a root an aluminum...or cracks forming from not enough filler being added. There is nothing wrong with the technique but like everything else it takes practice to do it consistently and well. On Aluminum 95% of the time I will just dab it in as its needed letting it flow in and freeze behind the torch while keeping the front of the puddle flowing and hot this allows me to also juggle the heat of my weld with the filler as well as my foot....that seems to be what produces the best results for me. On many steel welds (especially fillets) a constant feed produces a fantastic well tied in weld that looks like it was done with the worlds smallest smaw rod....in a lot of cases this method is much preferable. Like Allen said they are different cats with regards to thier charecteristics and how they respond to technique.

My measily $.02
Best Regards
Tommy

By swsweld (****)

Date 09-03-2007 22:01

Interesting to read discussion about different techniques. I have one to share but it was SS not aluminum. I was taught the "lay wire" method for all GTAW welding except for aluminum. In 1991 we were in England at a nuclear plant under construction and had to test on site. (no pressure there) We tested mechanized and manual GTAW SS open butt. The Brits were very impressed with our lay wire method on the manual root pass.

They fit their pipe using bridge tacks on compatible ss plates. Never disturbing the bevels. Then they use very small diameter filler wire maybe 1/16" or smaller and a steady feed and occilating pattern. Gap was much larger than the wire maybe 5/32" gap. When they came to the bridge plate they stopped and removed it and proceeded with the root pass.

It took a lot longer than our method. But, the good welders put a very nice bead in and you didn't have to worry about IP or IF no suckback. They keyholed the root. No tacks to tie into. After our return I had the opportunity of observing a couple of Ragin Cajuns on Inconel and that's how they did it too. Only they used 1/8" filler for the root. Same results, heavy root but you didn't have to worry about it.

If done properly by a skilled welder either way will work. After 25+ of welding years I still learn from others on this forum (aluminum, pipeliner downhill, branch test, mig/fcaw tips,etc.) and never have to leave the farm.
Those blokes at Sizewell B were alright.

By aevald

Date 09-04-2007 02:16

Hello swsweld, I do have a question about the method that the Brits used. Was there any concern for having situations arise from tacking these bridges to support the root gap? We have all had exposure to arc strike conversations and I am curious if this type of bridging method could introduce any of the issues that arise from arc strikes as far as leaving residual stresses or introducing any possibilities of fractures. I'm just curious and wonder if you have had any conversation in this regard? Sorry to take this post off track but the question came to me after this post. Regards, aevald

By 803056

Date 09-04-2007 02:43

It's by comparing notes that we find out what works, what doesn't work, and what to try the next time we get the opportunity.

I use the "laywire" technique to demonstrate to the "band leaders" of the group that it isn't always necessary to dab the filler metal into the weld puddle and to get them to try something different, something new.

I don't say that the "laywire" technique is superior to the traditional dabbing method, only that it is a means of reducing the tendency of some welders to pull the hot end out of the filler metal out of shielding gas envelop and hopefully break them of a bad habit or two.

It is amazing to me how many welders will not try something other than what they learn as "youngsters". Welders that learned to weld aluminum using DC with helium refuse to believe welding it with AC and argon is worth considering. Likewise, welders that learned to weld aluminum with AC and argon refuse to even try welding it with DC. I have a few welders that refuse to walk the cup and others that use it exclusively.

Most welder are receptive to new methods if you can show them it will work as good or better than the method they are currently using. I view any new technique as another tool to added to the tool box. The more tools you can use, the better your chances are of completing the difficult job assignments. Knowing how to use and apply all the tools separates the truly good welders from the rod burners. Refusing to consider new methods and ideas only limits our ability to join the ranks of the skilled welders, to meet the quality requirements on a consistent basis, and to get the job done as economically as possible.

I have to ask swsweld to explain the "bridge tack" more completely.

Best regards - Al

By swsweld (****)

Date 09-04-2007 03:54

The bridge tack to the best of my memory (16years ago) consisted of 1/4"thk x 3/4" wide strips. I think about 3 on smaller pipes 8" and below. I'm sure more on larger pipes although I was only in their fab shop a couple times and it caught my eye on their methods. They tacked the temporary attachments to one pipe, placed a gap spacer, then brought the next pipe in made the fit and tacked it off.
They would weld up to the bridge, stop and remove the bridge steel then resume until the next or the top. I am not suggesting all Brits did this as I only worked the one job there but I do think that was their way especially the small wire on the root pass. As far as the arc strikes Allan, I do not remember how particular they were about that for their work. If we ever used temporary attachments or inadvertant ark strikes in the nuclear plants there or here we had prior approval for the temps and had visual and usually NDE upon the removal. We did not weld outside the groove without approval.

Out RT's went well but they killed us with UT. Babcox and Wilcox NDE I think they used 7 different transducers. I didn't pay much attention to the details on the UT back then Just think they were still mad about the revolution and all. I was told B & W bid on the work that we did and maybe didn't like the yanks taking their work. Or maybe we had I. F. Never seen UT that sensitive. We never saw the indications with our eye. Doesn't mean it wasn't there. I prefer the RT. At least I can see the film. I am not UT qualified.

By aevald

Date 09-04-2007 04:50

Hello Al and everyone else, I do agree with you when you state that it is through discussion and comparison that all of us are able to see differing points of view and realize that there is more than one way to skin a cat so to speak. I for one am very appreciative of the ability to have exposure to these differing points of view. I also agree with you Al, if I understood correctly, that in a sense you are saying that not everyone sees things in the same way or is comfortable with doing things in the same manner. In a previous post I made the statement that I have come to appreciate that the end result is the important one with regards to making a particular weld, how it's done isn't so important as to whether it is done correctly and meets the expectation or conforms with the code. I can also identify with those individuals which you speak of, who for whatever reason, have decided to be inflexible in how they look at welding methods or differing points of view.
The one thing that I do know with regard to the welding trade as a whole is that as I learn a host of different things, both method and theory, there will always be something new to be learned, a host of old things to learn, and even a bunch of old things to be changed as a result of new learning. Regards, aevald

By Lawrence (*****)

Date 09-04-2007 07:42

I know we may be venturing a bit beyond the needs of the original poster........ And I'm about a day late jumping into this thread..

Al I'm going to disagree with your suggestion of the "lay wire" technique when it applies to aluminum alloys and AC current. (I don't think I've ever disagreed with you before :) )

Typically the lay wire technique is fine, it works fine with steels, nickel alloys and titanium unless a specific cosmetic number of ripples per inch are required.

With Aluminum alloys things change... The cathodic bombardment (cleaning action) that occurs on the DCEP side of the AC cycle will not etch and clean the back side of a filler wire laid in the path of the weld... For aluminum, the dip technique should be specifically used. If the lay wire technique is used for aluminum, lack of fusion at the root is a common RT indication due to the condition left at the unetched piece of filler... The oxide on an aluminum filler wire can be thought of almost like a sausage casing, the etching must blast off that casing for a good weld to consistantly occur. This cleaning action even on the back side of the wire can be observed while welding if you look for it as you go while using the dip technique.

Can it be done with lay wire?..... I suppose so, it's hard to argue with succsess.. Aluminum can also be welded with DCEN and helium, with no cleaning action at all....

I just wanted to put in a few words for what it think is a better technique when welding aluminum (and magnesium) alloys..... The Hobart institute also singles out aluminum alloys for the dip technique, warning that the lay wire is not a good choice with this particular alloy... They do however encourage welders to learn the lay wire with plain carbon and stainless steel plate and tube.

By 803056

Date 09-04-2007 21:06

Where did I say that I recommend the laywire technique for aluminum?

I said I like it and use it for nearly all GTAW.

I agree with what is being said about GTAW using AC on aluminum. I was trying to emphasize that the welder shouldn't pull the hot end completely out of the protective envelop of shielding gas. When working with new welders or when I'm trying to break a welder's "bad habit", I typically have the welder lay the wire on the work piece and feed it into the puddle as needed and as the torch advances rather than dipping it in an out like a "band leader".

Man is my back sore from the whipping I'm taking on this one. Owwwwwwwwwwwww!

Catch you later. I have an AWS E-board meeting to go to. I'll be BACK!!!!!

Best regards - Al

By Lawrence (*****)

Date 09-04-2007 21:42

Ok, Al; I see what you were saying.

Just wanted to be clear about technique limitations since the original post was directed to aluminum problems.

Diddn't mean to give you a whippin....

For everybody else:
I also forgot to mention that Plain Carbon and stainless lay wire welds can be done with a specific number of ripples per inch (for cosmetic purposes) if you use GTAW-P with a calculated and consistant travel speed and logical pulse rate.

By 803056

Date 09-05-2007 01:33

Did i say I didn't enjoy it?

Owwwwww - Al

By Tommyjoking (****)

Date 09-05-2007 05:43

When a good time turns around
You must whip it
You will never live it down
Unless you whip it
No one gets away
Until they whip it

I say whip it
Whip it good
I say whip it
Whip it good

da da da da da da da da da da da da da da

By ssbn727 (*****)

Date 09-05-2007 05:42

Hey Larry!
Not to disagree with your description, and analogy of why the "dabbing" technique of feeding the filler wire to the molten pool when welding Aluminum or magnesium & both of their respective alloys... Just to add on what you mentioned when you used the analogy of the filler wire having a "Sausage casing" of an Aluminum oxide layer that needs to be blasted off in order to to prevent LOF which is a common RT indication due to the condition left at the unetched piece of filler usually the backside of the filler wire furthest away from the arc plasma's cathodic inonic bombardment...

Another indication that can also be shown as an RT indication is porosity due to the Aluminum oxide containing "moisture" thus resulting in the moisture becoming trapped under the surface of the weld at or near the root of the weld along with LOF indications...:( That's why it's extremely important when welding aluminum using DCEN, that both the filler wire & base metal be cleaned properly, and slightly preheated prior to welding since there's no cathodic bombardment occuring when using only DC straight polarity!

So, not only should the filler wire be clean and wire brushed with stainless steel wool in order to minimize or even eliminate the amount of aluminum oxide on the backside of the filler from being deposited into the weld, welding technique must be taken into consideration also...

Cleanliness should be the Mantra when preparing to weld aluminum!!! The base metal also must be cleaned as should the quality of the shielding gas be checked in order to ensure moisture content is'nt a potential porosity issue as would the possibility of a torch not in optimal working condition, especially a water cooled torch and the condition of the torch parts as well as the tungsten itself!!! Fixturing must also be taken into consideration in order to ensure cleanliness as should the cleanliness of the welding gloves also. :) :) :)

The "Dabber" technique or method is also used when rebuilding knife-edge seals for jet engines, rebuilding surfaces found to worn on steam turbines for power plants. in additon to being used to rebuildjet engine seals, it can be used to provide build-up on jet engine blades, saw blades, valve seats, milling cutters, drill bits, mower blades and other devices... However this method when used to rebuild the surfaces of these devices use an automated version of "dabbing" the wire into the molten weld pool and is a very precise, consistent method of depositing RT quality welds on these surfaces usually consisting of alloys such as titanium, high nickel alloys, and tool steels. CK worldwide also makes a semi-automated version of this equipment so that automated version of this technique can be deposited manually...

In other words, this variation uses a coordinated motion of the cold filler wire end, and the welding torch which varies the arc length... This motion duplicates the motions of a manual welder but is performed automatically... The cold filler wire is fed continuously however, it is fed inot and removed from, the arc by a dabbing or oscillating motion. At the same time, the arc is lengthened and shortened together with the feeding of the cold wire... The dabbing stroke length is sufficient to pull the end of the heated wire from which a droplet has just been detached... At the same time, the torch moves toward the puddle and the arc is shortened... (This part would have to be performed manually with the semi-automated version of this equipment) This simulates the tow handed action of a human welder... It was accomplished by moving the wire guide in and out and the torch up and down... The wire approaches the weld pool at a very shallow angle... This coordinated motion variation can also be used with pulsed current which is what I prefer (I personally used this equipment welding miles of Titanium alloys and of course, they also had trailing shields attached).

If one is GTA welding pipe, then the "dabbing" method or technique should be discouraged to use especially in open root deposits... If extra care is taken in preparation as mentioned above, and pulsed current is used then, one should be able to avoid any of the indications that may show using RT no matter what type of metal is being joined by using the continuous feed into the leading edge or the top of the leading edge of the puddle technique. Otherwise known as the "laywire" technique as Al coined it. :)
Now after the root has been deposited when welding on pipe, one can convert back to the "dabbing" technique if preferred and depending on the metal being welded, it's sometimes advantageous. ;)

So in summary, it comes down to the proper application of these techniques when necessary, the method of NDT required, and the skill level of the welder who should be able to recognize the advantages, and disadvantages of both techniques and how to properly apply then accordingly. :)

Respectfully,
Henry, but you can call me "Hank!" ;)

By DanS Date 09-24-2007 19:49

Okay, I am back. Been goofing off quite a bit and not practicing too much aluminum welding.
Thanks for all the suggestions.
My stepson showed me a cool way to tig weld carbon steel by just laying the rod into the root of a t joint and just moving the torch along . Very nice welds...won't work on aluminum though.
My main problem(back to Aluminum) now seems to be I either am running too hot or too cold. Cannot seem to get right in the middle.
I seem to have solved the torch angle problem and the melting of the aluminum rod. I seem to have a pretty good handle on making sure everything is nice and clean, cause I am not having any oxide problems.
Am using 100% argon, 3/32 inch zirconated tungsten,1/8 inch rod, amperage on welder from 150 down to 95 amps, using a one second pulse.
I can run a nice bead on the hot side but it is dull looking and looks like it has grains of sand in it. On the cooler side I don't think I am getting the penetration and I am getting too much wire in the weld.
I am using a one second pulse on the machine.
Any suggestions or just lots more practice?