One Welder to Rule Them All---HAPPY BLACK FRIDAY..

[marcusofcotton]

Poly Fiber Tube Seal is worth the small additional price. See:

http://www.supercub.org/forum/showthread.php?30393-Oil-the-inside-of-the-airframe

I very much respect Jerry's opinion.

http://www.aircraftspruce.com/catalog/cspages/tubeseal.php

[bergy]

I bought an Everlast TIG machine a couple of years ago (a model 250EX) because my OA skills had degraded excessively thru the years. My neighbor kid recommend Everlast. He has and Everlast and uses it for building motorcycles and stock-cars. So I then found out that my TIG skills suck too, especially when I know that a given weld will be responsible for keeping me alive. I have done my own fuselage tacking, some with OA and some with TIG.

So I made arrangements to get some help with my critical welding; I talked one of the welding instructors from the local technical college to stop in from time to time and finish up my welds. This welder happens to be an attractive young lady, about 37 years old. My wife usually feeds her well too (The way to a welder's heart is through their stomach). She has worked full-time in the aviation industry and (sad to say she is therefore quite busy) also welds and supervises the welding program at a local shipyard. And ... my professional welder also happens to own an Everlast TIG machine which she uses in her own home shop. For some unknown reason she says that she likes my machine better than her own... "It is smoother".

I bought a smaller gas-cooled torch for mine (which came with a bigger water-cool torch). The water-cooled one worked fine; I just connected it to a garden-hose which I ran on the lawn, but it was a bit bulky for getting into tight corners. The little gas-cooled unit has light/skinny hoses which makes it very user friendly. I also bought a bunch of cups/collets/lenses/etc off of eBay really cheap. I have less than $2K invested (inc the tank). When I bought mine I had been shopping around the country looking for the best deal. A sales-rep I was talking to was just too honest for his own good; he told me about a "special-deal" that the US distributor was offering via some obscure link on the Everlast web site, so I save a bundle there. I hope to get a sizable amount of that investment back in a few months by selling the machine when my Patrol is done.

[Bdflies]

A word of caution about using tap water for cooling TIG torches; the coolant flows through the hoses and the copper torch head. Minerals in tap water accumilate over time and become conductive. DC TIG will be least affected, except that you'll notice arc initiation will become more difficult, because the HF starting current will create a path to your faucet. AC TIG will become very unstable and depending on available ground paths, you'll notice much higher current demands, due to leakage to your plumbing. And then, forgetting to open the faucet usually ends up in a melted hose. Leaving the faucet on results in a big muddy puddle.
If you're in a warm climate, use distilled water in your cooler. If freezing is a possibility, use TIG coolant. It's got lubricant, in addition to the antifreeze propertiies. Actually, the purpose made coolant is always the best choice, in any climate.
When I did service work, I hated water cooled systems. Always a leak. Hoses were hard to change. Wrong coolant or tap water problems..etc..etc... But the weldors loved water cooled torches!

Bill

[bergy]

Interesting ... never thought of that. For what little I used/will-use tap water for my welding, it probably will not make a difference. Besides, I now have all plastic plumbing in my house. Pulled out all the copper a couple of years ago. We have our own well, and the water has only a touch of iron in it (no calcium and such so is quite soft). So the water eats up metal, first dissolves all the zinc out of copper leaving behind a crumbly copper sponge. Bathtub faucets last about 5 years. Water heaters last about 1 month beyond their guaranteed lifetime. So our whole-house copper piping was getting dissolved down to nothing, springing a new leak somewhere every couple of months. The good news is that the salvage value of the copper piping removed more than paid for the new Pex tubing I installed.

[fairchild]

My understanding of the "mig on airframes" problem was not the particular welder or what plane--- but just how the Mig interacts thermally with the tubing. basicly
the same reason OA is considered the by some the best. High Carbon steels react to cooling by changing their grain structure to form a very hard steel. The more rapid
the cooling from a red heat- the harder the steel. Mig is a very rapid method to make a weld. Quick to start and quick to cool. OA heats slowly and cools slowly.
The heat effected zone is the transition zone between heated and non heated areas. the faster the heat/cool the narrower that zone. When it gets narrow with Mig----
that causes brittleness on the heat effected zone. When it gets hardened - that caused premature fatigue cracks to start there and the tubing can fail as the crack propagates
down the length of the heat effects zone. An OA anneal cycle can remove the problem by making the heat effected zone wider and softening the brittle zone. i think thats why
the whole-airframe anneal in a huge oven is done. Cant imagine how THAT sames time or money. ! I remember one of the rag+tube builders (i want to say maule-) used
Mig--- but them later they had recalls to repair cracking joints. Another problem with mig is that there is no way to "taper-off" at the end of the weld. You normally get a little
fat bulge at the end of the bead. That bump often has a pit or an "ugly place" there. That area can cause a crack too. Mis is best when welding low carbon sheet metal.
The OA guys like OA because it is slow on and slow off--- and usualy need no post weld anneal because of that. Tig is cleaner overall- but has a narrower
heat effected zone-- but its said for tubing less than .0125 wall--- it is not severe enough to call for a torch anneal. Thicker than 1/8 - post weld anneal
recommended.(after TIG)
Mig is best suited for low carbon sheet metal. ( IMHO) ----

So far between Tig, OA and stick---- can do anything I have needed to do--- never needed mig so far....
For high volume production on low carbon sheet steel--- MIG is the king.

Thats my brain dump on MIG ----
T

[Bdflies]

In the '70's, HSLA steels were becoming more common in more industries. At the same time, MIG welding was also becoming more commonplace in fab shops. The equipment was expensive and awkward, but the process was fast and less skill intensive than SMAW (stick welding) and Oxy-acetylene, which was becoming a rare artform - everywhere but the aviation industry. I've been in fab shops all over the country and several in UAE and I can confidently say that you'd be hard pressed to find many weldors versed in O/A welding today. SMAW still enjoys wide use, but not in production environments. MIG was taking over, painfully in some cases, but take over it did. Early on, only a few MIG wires were available. ER70S-2 was commonplace for high quality production piping and ER70S-3 was the less expensive choice, for mild steel weldments. Remember my statement about HSLA becoming more common? Well a new wire was introduced for welding the 4000 series steels. Initially, it was sold as ER70s-1B. This was sort of the infancy of MIG welding and the AWS hadn't adopted standards for HSLA wires. That wire came to be known and sold as ER80s-D2. It's a moderately deoxidized .5% Mo wire, that was developed specifically for welding 'hard to weld' HSLA steels. Today, there are lots of special chemistry mig wires available and even more flux cored and metal cored wires suited for any application you can imagine.
Whew! Can you believe I typed all that to lay groundwork to support the position that MIG is very well suited for welding HSLA steels, in addition to low carbon mild steels. One only has to look at the automotive industry to see lots of MIG welding HSLA weldments. Ever seen a 1000# roll of MIG wire? Yep, it's done. There are some programmable waveform MIG power sources that produce welds that would pass for TIG. Dan Denney (Kitfox founder) had a welding industry background. To my knowledge, every Kitfox out there was MIG welded, exclusively. Lots of planes have been MIG welded. While post-weld heat treatment is a method of stress relief, it's not the only method. I once had a conversation with a metallurgist, about TIG welding 4130 race car chasis and aircraft fuselages, without post-weld stress relief. He laughed and suggested that the vibration of the engine effectively stress relieves the structure more effectively than heat treatment would. I couldn't argue with that... Vibratory stress relief is not unheard of in industrial applications.
Now, I have to say that I would NEVER suggest that anyone MIG weld anything on an aircraft, unless you're a very accomplished and knowledgeable MIG weldor, with some well maintained quality equipment. While it's easy to weld a couple of pieces of angle iron, to make a flower stand, welding 1/2" x .035" tube clusters is a whole different animal! It takes a highly skilled weldor, using the right equipment and consummables. The process and procedures are tested, qualified and adhered to.
Now, to the original point of this thread: welders (the machines) are like a lot of things. Inexpensive ones don't perform as well as higher end ones. Machines that "do everything ", don't do anything particularly well. I know a lot of DC only TIG welders have been sold, but to my way of thinking a TIG welder should be capable of welding most any metal. Only AC/DC power supplies can do this in workshop environments. And yes, I'm aware that aluminum can be welded DCEN, but not without some very special procedures.
If you're wanting to be a weldor (person who welds) and make flower stands, a welder from a big-box store should work fine. If you're wanting to weld on any aircraft parts, I'd strongly suggest speaking with a knowledgeable welding distributor. Note that I said "knowledgeable". Just because the company has 1,000 locations, doesn't mean your store has a knowledgeable rep. Get a quality welder and ancillary equipment. Then practice, practice and practice some more!

BTW, I spent 42 years in a family welding supply business. Attended every darned class possible, conducted by Airco Welding Products, Miller Electric and Lincoln Electric. I was the 'tech guy' who did the process and procedure recommendations and serviced the stuff we sold, for a long time. After the supply business, I did consulting for a few years. But, in all that time, in all those places, I NEVER, repeat NEVER! Never did I ever meet a 37 year old attractive young lady weldor!

Bill

[fairchild]

"37 year old attractive lady welder" ..................... Im waiting for pictures !
I KNOW there must be some out there ----- but never met one..... seen some on youtube. But they could be just stunt doubles ! :-)
Tim

[bergy]

Seeing is believing: https://images.search.yahoo.com/sear...g&action=click

[Bdflies]

Yep! Point made. I'm thinking that The Blonde wouldn't take too kindly to having her as my workshop helper...

Bill

[fairchild]

but seriously folks.......
If you THINK jyou want to buy a Tig machine.....
Find someone who has one that will let you try it for 10 or 15 minuites. You will know if you enjoy it or if you find it impossible. Only if you enjoy it buy a machine.
because it will take a lot of hours to get OK with it. If you enjoy it - those hours will go fast. If you hate it --- you will never have the patience to get good.
Seems like people either love it or hate it.
Tig can do anything mig can do--- and do it way better. just not as fat or as cheap.
People who have reported on the everlast units seem pretty happy with performance. The expected failure mode is if a circuit board blows--- can you get one.......
or do they suggest you throw away the whole machine......
Of coarse there ARE used miller inverters out there that are sitting unuse dbecaue they blew a board and no one want to buy a new board - maybe for fear
that if they replace the bad board they will find it was really multiple bad boards........ No perfect solutions I guess.
T

[Chris In Milwaukee]

Bill, Tim, thanks for the wealth of knowledge you share. Glad to know you’re around to lend your brain!

[Bdflies]

Thanks Chris. I've been 'away' from the welding industry for a lot of years now. Still get calls from old customers, who became friends. I light up like a light bulb, when aircraft come up! But I really light up when I hear talk of welding! I still can't walk past a weldment and not critique the process and procedure... Unfortunately, there's no medication to quell that. Something I've learned, however, is to avoid conversations about religion, politics and welding. Welding, I've found, can be more inflammatory than the other two. I know this and swear it's right. But I'll happily argue with a stop sign...😎

Bill

[Brad Ripp]

A buddy lent me a TIG machine last week. I'm hoping to get good enough to tac weld only for a pro to come behind me. Tabs and non structural stuff only. I'm an "o.k." stick/mig welder but so far I swear this TIG machine is broken! As mentioned by someone else, if you haven't tried it, I'd try it before buying a machine. I have a pro coming this week to hopefully show me how it's done. Maybe I shouldn't have started my first attempt on thin wall sheet metal. Somehow I'm hot enough to make a hole but not getting the filler rod to melt with it. Hopefully successful instruction later this week!

[marcusofcotton]

Some advocate MIG for tacking.

[Chris In Milwaukee]

Wyatt Swaim told us in class that a TIG won’t absorb a MIG tack. I don’t have any experience with that, though. Will O/A?

[S Lathrop]

Wyatt Swaim told us in class that a TIG won’t absorb a MIG tack. I don’t have any experience with that, though. Will O/A?

Your instructor was absolutely correct. MIG and TIG welds won't mix. That is my experience and not here say.

I have had luck using silicon/bronze TIG rod to work around a MIG weld. S/B is also good anytime I have a difficult or very thin piece to weld.

I changed from air cooled torch to a water cooled torch. I use a submersible pump in a tank for coolant. The pump was about $80 and the tank was a plastic storage container. I find that I get better welds with a water cooled torch and I don't need to wear a glove.

[Bdflies]

I've personally never had a problem TIG over MIG tacks. MIG wires with higher levels of deoxidizers will cause problems.
See Mr. TIG's tip: https://m.youtube.com/watch?v=5qvN6HGoAkQ

Bill

[Chris In Milwaukee]

Well that’s interesting. Right after he said not to do it.

[Bdflies]

Chris,

I'm telling you: Welding can stir up more controversey than politics! It's a real mixture of science, art and lots of Voodoo. Any of those 3 is wide open to interpretation and 'discussion'. Man, do I love a good 'discussion'!!!

Bill