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plunger
08-06-2011, 07:11 PM
I bought a cheap 200amp inverter welder. I was told they are fine for tig welding. I bought the regulator argon bottle and tig torch to go with it.
This is a scratch start. This is where my problems start. When I try to start it it sticks like crazy. It is driving me mad. It sticks so bad that I need to bolt the workpiece down because the part sticks to the gun and then when I try to get it loose the part starts getting real hot and invariably lands up flying across the workshop when i try to break it free.The only way I seem to get it to start is if i start an arc on a carbon brush.At least it helps me to get going. When I get it going on a flat piece of steel my weld is not to bad. I tried on a piece of stainless pipe 38mm in od and 1.5mm thick and it acts more like a plasma cutter even on low amps. What am I doing wrong
Will a automatic helmet make me a better welder because I am battling to try to start an arc and see what I am doing? Will a cheap one be bad for your eyes. Is there a big difference in the high frequency and scratch arc or is it just down to technique
I would hate to have bought all this to find out that there is a huge learning curve with tig.

Dr Stan
08-06-2011, 07:40 PM
All of my TIG experience is with square wave machines so I'm limited on the inverter versions regarding starting the arc. However one should be able to hold the torch more or less flat to the work then rotate the electrode in order to start the arc.

As to an auto helmet, get a good one. You have one set of eyes, so take care of them. I found a Speedglas on Craig's List for about 1/2 the new price, so look around.

As far as burning through, it simply sounds like you had the amps set too high. In addition I recommend becoming comfortable with simpler joints before jumping on pipe & tubing.

Start with just laying a bead (no filler) on a flat piece of mild steel. Once you have that down do it again with a filler. Next would be a butt joint followed by a lap joint and then a T joint.

If you know how to OA weld the learning curve should not be too steep. You may also want to look into some welding DVD's.

plunger
08-06-2011, 08:09 PM
I am also curious to know if One can get a lens made so you dont need to where glasses under your helmet. Also curious to know how to anchor pipes together so you can weld em straight. Also does any one have any photos of how a jig can be made to spin the pipe so that if I ever get good enough to weld i can spin the pipe while i weld. Although at this stage it doesnt feel like I will ever get there.

MichaelP
08-06-2011, 08:26 PM
I'd strongly suggest you to use a HF start machine to learn TIG. Its challenging enough with a dedicated TIG welder, so there is no reason to multiply your frustration with a castrated machine.

And I second Dr.Stan's suggestion to start with AO. It'd help immensely.

As for pipe welding, I'd go there only after you're comfortable with plate. It's not going to happen overnight (or over a few months, for that matter).

davidwdyer
08-06-2011, 08:29 PM
I think I have the same machine and have had the same results.

Am waiting anxiously for someone who finally figured out to use that little red piece of uh.... machinery.

Dr Stan
08-06-2011, 09:51 PM
I am also curious to know if One can get a lens made so you dont need to where glasses under your helmet.

One should ALWAYS were safety glasses under your helmet for as soon as you lift it your eyes are exposed to hazards from grinding, chipping, wire wheeling, etc.

As to a fixture, look into some magnets including adjustable ones. There are also welding turntables available although most welders fab their own. Some go as far as motorizing them with a variable speed drive.

Toolguy
08-06-2011, 10:05 PM
You need to be careful about using magnets for fixturing. The magnetic field can totally disrupt the welding arc, making it impossible to weld. This is variable, depending on the strength of the magnetic field and it's proximity to the arc.

Mike Nash
08-06-2011, 11:30 PM
I've spent several multiples of hours today perusing the following site:

http://www.weldingtipsandtricks.com/

He makes it look so easy. I also discovered today that the 3.5 minutes run, 6.5 minutes cool down for my Harbor Freight Tig welder is no problem as I get nowhere near 3.5 minutes before it's time for me to regrind my electrode yet again.

The good news is that I can actually see the puddle with the tig, unlike the mig. The bad news is that was about the only good news. There are way, way too many variables with this welding stuff, and you can't take any shortcuts with TIG.

Welding and women seem to have a lot in common.

P.S. I ordered a universal fit catalytic converter for my wife's van from Summit Racing yesterday about 4:20PM. FedEx delivered it before 3PM this afternoon. This was one time I would rather something was late as I am really not ready yet. That's why I was wanting to get this TIG thing figured out.

P.P.S. This really isn't a hijack. The link has lot's of TIG videos and tips.

JoeFin
08-06-2011, 11:47 PM
Cup size, tungsten size, CCs of gas, Gas diffuser it all makes a difference besides the type of machine your using.

rythmnbls
08-06-2011, 11:54 PM
Try this site. It has some good starter info.

http://www.mig-welding.co.uk/tig-tutorial.htm



Steve.

Dr Stan
08-07-2011, 12:27 AM
Welding and women seem to have a lot in common.


In general women have better fine motor control than men. It really shows up in TIG welding.

justanengineer
08-07-2011, 01:07 AM
First off, there is no such thing as scratch starting a tig. Miller calls it a Lift-Arc start, because thats exactly what youre doing. Youre very momentarily/rapidly bringing the tungsten as close to the stock without actually touching it as possible. Then, youre lifting the torch (save calling it a "gun" for the poop gun migs that you shouldnt be using until long after youve mastered every single other process) slowly and only very slightly to get the specific arc length required. Its not a stick. At no time should your tungsten touch the stock, and if you need to resharpen the tungsten in under ten minutes of run time, youre probably doing something wrong. Also, you really should have a dedicated grinding wheel for sharpening tungstens. Using wheels that have been grinding on steel will embed the steel in your tungsten and make for a pretty lousy arc.

I would highly suggest taking a class at the local community college. Tig welding isnt the most difficult to learn (IMHO and those of many weldors, MIG is), but it will severely shorten the learning curve and allow you to learn things you likelly never would otherwise. That being said, pipe is usually the last thing you want to learn to weld on. With tig, usually you start by simply fusion (no filler) butt or lap welding two pieces of sheet metal together, progressively getting thinner on the stock to teach yourself to control the arc before adding any filler. Then you learn to add in as little filler as possible, and move into structural shapes involving out of position welding.

Many individuals think they know what a good weld looks like, and thereby can teach themselves. I would highly discourage it as much of the info you see on the net or read does not thoroughly explain concepts or show technique. Also, the appearance of a weld has very little to do with its strength, and learning to judge a weld is something that you really do need an experienced set of eyes to teach you.

alistair1537
08-07-2011, 02:41 AM
Hi Plunger

I was also a Durbs boy at one stage - I used a 140 amp inverter with tig setup for years before succumbing to a AC/DC "proper" tig welder. It is worth getting a hands free helmet - borrow a mate's to check for ease of use and quality - you don't need to spend too much - they should all conform to a standard, again, check with a welding mate - they'll likely steer you right. I used to know a guy by the name of Clive who was an Ace tig welder in Pinetown - just up the road from BP resins in Henwood road. Man, he could weld!!

Anyway - I wear strong reading glasses - 2.5 x for welding, normally, 1.5 x for reading - It helps see the puddle clearer, esp on A/C but that won't affect you on a D/C machine.

Get yourself a small piece of copper to scratch start on - I used a section of 15mm plumbing pipe that I'd flattened - and I placed that on the part in order to start smoothly - thinking about it now - it may be an idea to have a small magnet inside the pipe before you flatten it - that way you could stick it in any out-of-postion welding situations....

As far as pipe is concerned - use a section of Angle - perfect alignment unless the pipes are differing dia. - if you want to turn the pipe to tack evenly - weld a brace onto the angle and cut away the center portion to allow the bead to free to turn without fouling the "V".

I did a lot of work with my little tig setup - my mate Guy took it over from me when I left - he is still running it in Howick!!!

Good luck

boslab
08-07-2011, 03:16 AM
might sound obveous but you are using electrode Negative, what you describe sounds like electrode positive?
What electrode? white or green perhaps?
regards
mark

Tony
08-07-2011, 03:59 AM
sounds like amps are way too high. if the tungsten is sticking that bad, and
it's cutting like a torch -- make sure the current adjust knob hasn't spun on
its shaft.. keeping you from getting as low as you think you are.

scratch start should be very easy.. if you're learning, scratch start on the
surface itself .. copper etc is good idea but make it as easy on yourself as
possible at the get-go.

EVguru
08-07-2011, 04:52 AM
First off, there is no such thing as scratch starting a tig. Miller calls it a Lift-Arc start

Lift arc is an electronic system that allows arc starting without the use of HF where the environment makes that undesireable or imposible. A welding robot, or someone doing fabrication near live comuting equipment for example. Lift arc starts with the welding supply turned off. A pilot current is fed to the torch so that contact between the electrode and the base metal can be detected. The welding power supply is turned on as soon as contact with the base metal is broken, the arc being able to jump the tiny gap without any kind of HF assistance.

Essentially what the OP has bought is an a constant current welding power supply, which would be just great for stick welding. Most of these are advertised as being able to do TIG also as TIG requires a power supply with the same characteristics. The arc is inititiated by making contact with base metal, just like it would be with arc. I recall that the usual advice was to use a bit of copper along side the weld for arc starting.

914Wilhelm
08-07-2011, 05:23 AM
I started TIG with one of the $200.00 HF 140 amp DC scratch start jobs. The first week trying I just about went nuts and destroyed a lot of tungsten. I was convinced the unit was defective and would have taken it back except for the fact I live 60 miles from the store. Then it just suddenly fell into place and I was laying down bead like mad. My friend who was an experienced tig weldor on his Miller inverter never could make my scratch start work for him!

rollin45
08-07-2011, 10:53 AM
Scratch start is "scratch start", and there certainly is such a thing, did it for years and years.

Use a motion similar to striking a match but with less motion and less friction. You will get it with practice.

rollin'

Forestgnome
08-07-2011, 11:03 AM
Have you stick welded before? I was wondering because as a beginner you can run into the same problem using stick. You pretty much have to get a big plate and just practice starting the arc over and over. It's a fine technique.

bborr01
08-07-2011, 11:26 AM
Also curious to know how to anchor pipes together so you can weld em straight.

Plunger, see here.

http://bbs.homeshopmachinist.net/showthread.php?t=49254

Brian

mixdenny
08-07-2011, 11:50 AM
I am also curious to know if One can get a lens made so you dont need to where glasses under your helmet.

Yes. Rectangular lenses in the common reading glass strengths are readily available. They clip right into the welding helmet on the inside

http://cgi.ebay.com/MAG-LENS-CHEATER-LENS-2-X-4-25-1-75-MAG-9321451-75-/130480038932

Dennis

plunger
08-14-2011, 10:21 AM
An update on my tig experience. I bought a cheap auto helmet and it has helped me immensely. Also I am starting to get the hang of the scratch arc. One has to have their tungston real sharp and kept real clean. The copper trick has helped because you can get an arc close to the workpiece. Using the cup to rest has also helped me. I find if I can start on a edge it is also easier as it is easier to pull away from the work.
Wher I am now battling is doing plates at right angles.I am finding it hard to get the cup close enough to both plates. Would a smaller cup help.
Also I tried stick welding with this setup. Same story. The stick sticks like crazy and is hard to get started.I am using a 6013e rod. it amazes me how much spatter it creates. Does a stick have a shelf life It feels more like a sparkler than a welding rod. I dont understand how the splatter can stick to the metal in little balls that I cant even knock off with a welding hammer. How does it fuse. Surely it cant make the parent metal hot enough to bond. I

PTSideshow
08-14-2011, 11:00 AM
I am also curious to know if One can get a lens made so you dont need to where glasses under your helmet. Also curious to know how to anchor pipes together so you can weld em straight. Also does any one have any photos of how a jig can be made to spin the pipe so that if I ever get good enough to weld i can spin the pipe while i weld. Although at this stage it doesnt feel like I will ever get there.
Heres a thread on clamps for pipe and other ideas (http://bbs.homeshopmachinist.net/showthread.php?t=49254)

J Tiers
08-14-2011, 11:18 AM
Also I tried stick welding with this setup. Same story. The stick sticks like crazy and is hard to get started.I am using a 6013e rod. it amazes me how much spatter it creates. Does a stick have a shelf life It feels more like a sparkler than a welding rod.

try some 7018. In class we went through the 6011, 6013 etc, and most of that seemed to be just as you say. Stuff inside the helmet bouncing off the safety glasses :eek:

the 7018 is well-behaved by comparison. but you can still stick it. I found in class that if I didn't think about it, I scratch started perfectly, but if I thought about doing it right, I'd stick it 5 times in a row.

I kept a piece of scrap handy to 'pop" the rod on if the slag got over the rod end.

JoeFin
08-14-2011, 12:30 PM
Plunger - without sounding condescending - you just need to gather up a bunch of scrap and weld and weld and weld some more until you get the hang of it.

Pay particular attention to threads in the welding section of the forum where the guys are discussing welding preparation. Grinding off the scale, cleaning off the oils. See if you can find a thread discussing building a rod oven out of a 100 watt light bulb and an old metal bread box. Learn to use your hearing when you weld to judge the burning of flux on your stick welding. Learn the proper shaping of tungsten for the various types of TIG welding.

I know by experience it is instinctive to want to just grab a stick and watch it burn and hope for the best - but I'm sorry, it just doesn't work that way.

Even guys who weld 40hrs a week professionally often understate the necessity of proper preparation. But when you listen to them talk about how their day went, you'll always here them mentioning the preparation steps just as much as the actual welding.

JoeLee
08-14-2011, 12:56 PM
You never want to scratch start with tungsten. Once the electrode touches the work it's instantly contaminated and you will have an arc that wanders making it hard to control, especially for a beginner.
With HF your arc should jump with in 1/4" of your work depending on the current. Also proper pointing of the tungsten is very important to a stable arc. Don't point your tungsten on a wheel that you grind steel on as the steel deposits left in the wheel will transfer to the tungsten giving you hot spots and instability in the arc. Also the grain of your grind should not go around the dia of the electrode, it should go in line with it for better electron flow. The point of the electrode should have a slight flat spot, eg. 3/32" tungsten should have an .020 flat point. These are just some of the important things you should know.

JL.......................

TexasTurnado
08-14-2011, 01:08 PM
I will second the suggestion for attending a local junior college or such for formal schooling - you will be a better welder for it. If you think the cost is high, consider that you will probably use much more material for practice than the tuition!

I took this approach, and have never been sorry I took the time to do it right - best money and time I ever spent....:D

ak95xj
08-14-2011, 06:29 PM
Plates at right angles as in fillet welds, you can stick the tungsten out a little farther for them,get the tungsten as close as you can without touching, that is how you can get a nice tight bead..