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Thread: TIG Welding problems

  1. #21
    No Hope For Me Coils's Avatar
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    Retvet I didn't notice this before
    I'm going to call the argon supplier to ensure he didn't mix some CO2 in my tank, just to be sure. My tank is blue with a silver, yellow, then maroon band around the top.
    But isn't there a standard for tank colors and markings?
    I'm leasing a tank from AirGas (100% argon) and it's all brown with a gold cap, I doubt the cap color means anything but I would think the tank should?

  2. #22
    Gunco Rookie DrewBone's Avatar
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    Coils,

    Unfortunately, there is no standardized color code of welding tanks, and therefore gas identification should be made ONLY by the label appearing on it. The gas provider is responsible for affixing the correct label to the tank before you receive it so there is no possibilities of "mixup."

    But generally in these parts [East coast]...

    Black ~ Acetylene
    Green or Orange ~ Oxygen
    Brown ~ 100% Argon ~or~ 98/2 - 75/25 mixtures
    Dark Maroon ~ 75/25 mixture

    The military and certain scientific communities have their own marking systems for their typically used gases that are required to maintain specific quantities of this or that or specific levels of absolute purity for calibration purposes etc.

    Tanks that have different rings around them are generally specialty gases and as such don't apply to welding unless specifically required for an extremely critical automated welding process.

    =8^)-~

  3. #23
    U.N.C.L.E. Illya Kuryakin's Avatar
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    Quote Originally Posted by pirate56 View Post
    the guy I learned welding from said " welding is like sex, it is all about controlling your rod to get good penetration!"
    But what do ya do when the tip of your electrode gets corroded?


    Did I do that?

  4. #24
    Gunco Rookie DrewBone's Avatar
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    Default Hey RetVet...

    ...I meant to ask you this earlier...please describe the TIG rig you are running. When you say "HF" are you referring to "Harbor Freight?" Do you have to "strike" the electrode against the material to start an arc?

    If so I see they offer two machines...one for $269.99 and another for $1,349.99...neither of which seem to have "high frequency" start, and without this, learning to TIG will certainly be less gratifying and more frustrating, because if you don't strike the tungsten ever so lightly against the base material to start the arc it easily becomes contaminated. And once it's contaminated the arc becomes unstable, loses it's direction, causes undercutting and hence uncontrollability. An orangy/brown residue [and the smell of burning skin permiates from your fingers if not wearing gloves] that appears around the bead is clearly indicitive of a contaminated tungsten and the only thing to do at that point is stop, observe the extent of contamination [base/filler material attaches itself to the electrode and increases the diameter of it leaving you with blobs or a misshaped "point"] and resurface the tungsten, making sure to remove ALL foreign material. Sometimes it's just easier to break off the offending section and grind a new point.

    Back in '89 I worked a power plant job TIG welding chrome boiler tubes off a 6-pack DC welding machine, with "scratch start" TIG rigs. Some days I could weld for 6 hours straight with the same piece of tungsten and other days I used 10...luck of the draw I suppose, but either way, it certainly wasn't easy.

    Now, take a decent TIG machine with High Frequency Start, where there is no need for the tungsten to come in contact with the workpiece and you could end up welding for a long time without resurfacing a tungsten with less chances of contamination...but you would have to justify the expence of it, and they're not cheap. I'm looking into a portable diesel TIG rig and it should run me somewhere in the neighborhood of $6-7K, so I can make some extra coin on the side and for my own projects I'm working on outside of work.

    I've been asked millions of times by friends and aquaintances about different machines and my response is always the same; get the most you can afford. I tend to shy people away from the HF/Home Depot jobs because they will always be lacking in some respect, and as their welding skills become better and better they will be looking for more and more options that their machine lacks, and will eventually end up with the so-so machine gathering dust and spending 2-10 times the $$ they originally spent had they just spent the $$ in the first place for what they really "needed."

    I understand that there aren't too many people tinkering with BIY projects that could justify spending $7K on a real TIG machine and are buying these inexpensive welding rigs on the advice of the manufacturers claims of "ease of welding," "no-gas required flux core" abilities, and "portability." Well, ease of welding is subjective due to operator skill, no-gas flux-core is a joke, and portability is a given considering their small 16"x14"x12" footprint. I liken this scheme to a paint manufacturer claiming their artist oil paints will turn you into a Leonardo da Vinci. It 'just don't happen that'a way!

    I may be overly critical and somewhat anal about welding but if I wasn't so damn fussy about it I wouldn't be where I'm at today...over the years I've had the pleasure of working on some really kewl stuff...I built the hullskins and transoms for the Isreali hydrofoil gunship, welded the cooling lines for the Grumman Space Antennae that was send aloft in the Space Shuttle, fabricated and welded two pedestals holding up aircraft aboard the USS Intrepid floating museum in NY Harbour, dozens of 50,000 gallon SS Chem-Mill chemical machining tanks and associated SS piping, 24" HP steam mains, 20 ton overhead bridgecranes spiders hangers and rails, resurfaced bronze bushings on 12" diameter hydraulic shafts, retubed dozens of diffusion pumps for 'Grumms electron beam welding machines and literally thousands of other weldments...and even though my appearance may be somewhat different [I wear a mohawk, some metal and ink - hahahaha], the suits at Grumman never cared as long as the work got done to their approval and the customers, who was primarily the US Navy.

    Now that I've used up some bandwidth here it's time to hit the rack, 'work tommorow, no, make that today! Happy trails and hope you've gotten your porosity problem solved.

    =8^)-~

  5. #25
    Angry White Man RetVet's Avatar
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    Thanks for the ton of info DrewBone! Clearly I have a lot to learn when it comes to TIG.

    Yep, a number of us here are using one of those cheap $199 Harbor Freight TIG units. For the few weld jobs I anticipate with my gun hobby, I can't really justify spending thousands on a proper unit. Just trying to squeak by you know, especially at this point where the building boom is dwindling and I already have more firearms built than any "normal" human could possibly want. (Fortunately most of us here are NOT "normal")

    The problems I'm seeing are as you identified and due to contamination. Looks like I've got some grinding and serious cleaning to do before pressing on further, not to mention getting my technique squared away.

    A couple days ago I pulled out some new stainless steel scraps I had and practiced on them. This was new virgin material and squeaky clean. Talk about the difference between night and day! Took my time and laid down a pair of the nicest beads yet (ie., high quality shit). Probably not on par with a pros job, but for me is was a definite high. The puddle formed with little effort, flowed smooth as melted butter, and it was really fun.

    With this HF unit I seem to have to tap the metal a time or two to get an arc started, so as you noted I'm introducing contamination more often than not.

    I've decided to set my MG42 build to the side for now until my welding gets better. I'm down to just two critical welds left (the two receiver halves and the muzzle piece) and I don't want to mess with them until I know I can do the job without mucking it up. As a fall back, there's a machine shop where I work with a guy who like you, has been doing TIG for many years. I can always get him to do it push comes to shove.

    Think I'll print a copy of this thread for my build book as well. Good info is worth reading again and again! I'll add it to my copies of Pirates and Pookies build notes.
    " The world is a very dangerous place, not because of those who do evil, but because of those who do nothing about them." - Albert Einstein, 1879-1955


  6. #26
    Gunco Rookie DrewBone's Avatar
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    RetVet,

    I just can't seem to shut the fook up about this shiza, heheh. Buy hey, don't blame me, you started it!

    Anyway, ahem, if you approach TIG with patience and a little understading of what's taking place before your eyes, before too long your skills will improve and you'll be more comfortable with it.

    Now, with your situation, a problem exists with the HF machines, in that you have no rheostat foot pedal amperage control, and this is extremely limiting and most certainly hinders your learning abilites from the start, as once you light off, you have but one heat to work with and no way to properly end your weld bead. TIG is ALL about control, which unfortunately is lacking with these low end machines.

    All I can say is this...before welding on any critical part with your rig, do all your "homework [amperage setting trials]" prior on scrap material of the same thickness so if you do go too slow or go too high with the juice you won't blow a hole in your receiver or mess it up by overheating it or zonking the tungsten in the weld puddle...it's good practice to run beads on scrap material so when the time comes to hit it for real you will have a good idea of what you're looking at, what you need to see, and what you need to do. When you come to ending the bead, you can either just pull upwards quickly [by rolling the torch up with your fingers] or by speeding up and running the arc along the edge of the bead, until the arc is lifted from the material.

    I'm freakin' spoiled from having state of the art TIG machines at my fingertips for years...you have friends or co-workers in the field so ask them to let you run their TIG machine during lunchtime or after work to see how different and wonderful it is to have controllable amperage at your whim. I promise you, you will be absolutely amazed and might even soil yerself!

    Now, I've compiled another bandwidth stealing post for you should you find your eyeballs and fingers anxiously trembling in front of a real TIG machine, which incidentally contains info you can use with your machine in regards to what to look for, adding filler rod, etc...and here she be:

    ...strike an arc and continually increase your amperage, watching for the base material to "break down [this is when you see the base material become molten liquid, and the puddle sinks slightly]" until you see the puddle forming into the size bead [width] you wish to produce, then move ahead slightly, adding filler rod material in subsequent/equal amounts, and repeat the process. Sometimes it helps to count as you go...with a continuous and uninterupted forward movement of the torch, keep your travel speed steady and amperage consistant and count 1 [add-rod] 2 [add-rod] 3 [add-rod] and so forth. This method of filler rod application will give the bead that "row of dimes" look. By contrast a steady continous and uninterupted filler rod addition and travel -=speed will produce a smooth bead. Pick yer poison! If you happen upon uneven widths or depths to fill, simply slow down, go back and forth a bit to accomodate the wider width, or slow down a bit to add more filler rod material taking note to make the bead height the same as the rest of the bead. As you progress along you will notice that the workpiece is heating up from the welding...and as you approach the end of the weld bead or weldment, if your amperage remains as high as it was when you started, you will undoubtedly be running too hot, creating a wider than required bead with deeper penetration than desired. The way to avoid this is to take notice of this increased bead size and penetration on the fly, and reduce your amperage accordingly as you come to the end of the bead. The greatest thing about TIG is the operator ability to control the amperage via foot pedal rheostat...and when coming to the end of a weld bead you slowly decrease your amperage to avoid leaving a depression at it's end, then slack off even more on the heat until the base material becomes solid [the arc is still active], then bring the heat back up again and add what is known as a "button" of weld on the end, carefully filling what was once a depressed crater to match the size and height of the rest of the bead. Finally, you "fuzz out" the button you just added...this is when you slowly decrease the amperage until the button solidifies and you take your foot off the rheostat pedal, breaking the arc. You will notice that if you keep the tungsten centered on the button and fuzz out there will sometimes be a little raised tit of material in the middle of it, that later pops off all by itself and leaves a very small depression. This dark grey shiney material is oxides from the base material and/or filler rod that have tagged along with the weld bead...often times there's no avoiding this, but if you use a very quick small circlular motion with the torch as you are fuzzing out you can minimize it's affect on the finished weld bead and it ends up harmlessly on the side of the weld along the heat affected zone.

    Always use as a filler rod as close as possible to the base material for good metallurgy, and size [diameter] matters! I always go as small as possible and only increase diameter if I find myself using too much rod for the length of bead ran. The rule is similar to tungsten electrode diameter choice...fit it to the job. Who would use a 3/4" impact to tighten a 1/4-20 bolt or a 6" wide paintbrush to do trim work with? When I plan on running small beads on 1/16" or smaller material I use what I call "pussy hair wire." HA!! It's approx. .030" and works great...you need to see clearly what you're doing when encountering "small" work and bigger diameter filler rods just get in the way and add too much material at once making the weld much less "surgical." On the other side of the coin, if I needed to fill up a decent sized gap or chamfer, using the pussy hair wire ['still laughing here] would take too much time [less volume of filler material] plus I'd be having to go through wire after wire after wire...in this case a filler rod diameter of 1/16" or 3/32" would be more appropriate.

    Stainless steel is a beeeeeeautiful and sexy material and I love working with it. But I tell you what...it's a bitch to weld out of position though, especially with stick, but that's fastly become an outdated welding process since the advent of MIG. But one thing is for certain...there is an element of skill that is still required for ALL of the different welding processes and materials that can be encountered; learning is the first hard step, but after that the fun starts when you become an artisan.

    I wish I had the coin to do a '42 build, but have managed instead to scrap up a bit for an MG47 project [if I ever get the parts from Robert/RTG or?], with some notable changes that I'm gonna' keep to myself for the time being ;o) I'll post some pics here as the build progresses, which will of course, involve "some" TIG welding so you guys here don't start thinkin' that 'ol DrewBone is talkin' out his patoot!

    See ya' around RV.

    =8^)-~

  7. #27
    Administrator pirate56's Avatar
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    Quote Originally Posted by Illya Kuryakin View Post
    But what do ya do when the tip of your electrode gets corroded?
    Seek immeidate professional help!!



    As far as a welder goes for a home hobbyest the HF machine is adequate. it doesn't have all the bells and whistles like hf or a foot control, but it will make structrually sound welds for your projects. the average guy is not going to be using it to build a rocket or reactor.

  8. #28
    Gunco Rookie DrewBone's Avatar
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    pirate56,

    "Adequate" surely is a subjective term both for welding machines AND welders...and "...structurally sound welds" are those that have been performed by qualified individuals to meet the required standards of strength in the workpiece/weldment, and this never happens by accident or luck. Unfortunately, a mere glance at a weld is not sufficient to judge both it's external and internal integrity, and I doubt that the "average guy" would know the difference.

    Case in point: I worked with a guy for years, a metallurgist, who's only job was the destructive and non destructive testing of materials, fasteners, and welds. Amongst his collection of failed weldments were some of the most beautiful beads I had ever seen...and dispite their good looks they failed. Some of the reasons were as follows: 'good penetration but improper fusion, 'right alloy but 'wrong filler material, 'should have post heated but didn't, 'too much heat ='s crystalization of the weld, 'wrong gas, undercut, concave, 'too cold...so you never know what lurks beneath the surface.

    My reasoning for posting here on this thread is not to blow wind up my own skirt but rather to help those who would like to learn a thing or two about the art of welding, and I love to share what I know. Surely, as you stated, noone here is planning on circumnavigating the globe in their own rocket or building a nuke reactor to power their neighborhood, but when I see pictures of ground down welds and hear stories of porosity I become nervous...not for me, but for those who may be taking a risk pulling the trigger for the first time, wondering if a bolt carrier is going to become an integral part of their face...and I'd hate to see that happen to anyone here or otherwise.

    I owe a debt of gratitude to those who took the time to help me along the way, and I am simply trying to return the favor here with my ramblings. I hope noone takes this as belittling, as that simply isn't the case I assure you. But I do have standards that I think everyone who strikes an arc should adhere to, for their own protection and for the furtherance of their skills.

    This is indeed a great site, and I have learned much from the short time that I've been visiting! Wheels are turning!! We can ALL learn something from each other here...and that's what's so great about the people who make up the gun community; the sharing of information, the creations of friendships, the generosity of it's members, and everyone's continued efforts to come up with kewl stuff! I love it.

    =8^)-~

  9. #29
    Gunco Member tanglewood16137's Avatar
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    Default tig welder

    Can you say ESAB 352 thats what i have foot control hw 18 torch and homemade water cooler pump system extra hi capacity 16 gallon and i have gotten it very hot via big tungsten and a simple turn of a screw in panel to jump it to near 500 amps but you need to let it cool longer between passes weld 2 mins cool 15 to be safe . you have those miller thrillers and stinkin lincoln's blow apart hobarts and then there is ESAB the rolls royce of the business.

  10. #30
    Administrator pirate56's Avatar
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    while I agree that flux welders and cheap migs in the hands of an inexperienced person who is just laying down a layer of slag and metal grapes on the surface of the metal is not welding, I don't agree that every weld made needs to be done with a 7k machine and x rayed and if it is not is is not a good weld. if that were tha case 90% of all the welding done by machine shops and fabricators would be faulty.

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