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Lincoln Precision TIG 225

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Lincoln Precision TIG 225

Postby Wobulate » Sat Jan 29, 2011 10:22 pm

I would like to communicate with any welders that own a Lincoln Precision TIG 225.
My goal is to learn from others with more experience with this welder. I am in the process of experimenting with my new TIG welder and would appreciate any tips you could provide. :mrgreen:

UPDATE, SUN 30-JAN-2011
Today I spent 4 hours running beads on 0.090" 6061-T6. I had a number of tests to run and a plan to get-er-done. I used 3/32 Pure Tungsten and 1/16 4043 filler rod. I ran edge beads, stacked beads, gap filler beads and filler-less cleaning beads. And, once again, if I would just keep the tungsten out of the puddle and the filler rod off the tungsten life would be much better. I used Pulse/no Pulse/Balanced/Unbalanced/1 PPS/2PPS/20 PPS/and pulsed the foot control. I had a great time learning, and discovered that I had purchased the right machine for me.

One interesting adjustment I made to my position vs the weld bead direction. I first welded in the normal perpendicular to the travel direction of the weldment. Then I tried welding in parallel with the weldment, pulling the torch toward me and placing the filler rod near my left ear to align it with the puddle. This parallel method straightened up my bead profile and all I did was change my position relative to the weld.

Wob
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Re: Lincoln Precision TIG 225

Postby sschefer » Wed Feb 02, 2011 2:00 am

Hey Wob, you figured out that the studious posture of the video welders is not the only way to get er done.. I've been running a bunch of fillet welds on material that puts me over the center and nearly stretched out if I tried it by the book. I do just like you and line up inline with the joint and bring the torch towards me. For one, you can do away with walking the cup and freehand it all the way. My fillet welds look 100% better this way and I never loose sight of the arc. I run about 10" at a time and that's usually about as hot as I want to get 5052 or 6061 anyway.

I liked my 225 also, it was a great machine but now that I'm more familiar with my Inverter I like it better. I've been welding 1/4 and 3/16 stuff a lot lately and my machine stays on 225 amps with a 80/20 mix. I control the weld more with the foot pedal and filler rod than I do with the machine settings. Like you, I tried all the settings and twisted every knob. Now my favorite setting is either on or off. LOL.
Steve Schefer
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Everlast 250EX
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Current Project: 21' Glen-L Canyon Cruiser, Sled style Jet Boat.

Highly skilled at turning expensive pieces of metal into useless but recyclable crap..
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Re: Lincoln Precision TIG 225

Postby kermdawg » Wed Feb 02, 2011 11:27 pm

Might be interested to switch that pure tungsten out with some Lanthanated. Costs a bit more but welds alot better.
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Re: Lincoln Precision TIG 225

Postby sschefer » Thu Feb 03, 2011 1:44 am

Kerndawg, I found my 225 did best on the pure. The inverter does best on 1.5% lanth or 2% Thors.
Steve Schefer
Santa Rosa, Ca..
Miller 212/Spoolmate 3035 (HD)
Everlast 250EX
Everlast PowerPlasma 60
Current Project: 21' Glen-L Canyon Cruiser, Sled style Jet Boat.

Highly skilled at turning expensive pieces of metal into useless but recyclable crap..
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Re: Lincoln Precision TIG 225

Postby Wobulate » Sun Feb 06, 2011 5:48 am

Steve and Kermdawg,

I had written a long response to you both, but the Forum timed out and I lost all that I had written. :x
So, here is what I can remember.

I continued working with Pure Tungsten, but it has many of the bad properties that Jody informed us about (especially tungsten spitting). I did a small job for a friend (a HAM antenna bracket for a vehicle). The material was 2 x 4 x 1/8, rectangular mild steel tubing. For this job I used DCEN and 2% Ceriated, I was on the right track but I should have increased the size of the tungsten and the filler rod to 3/32". This mass of this bracket was considerable. Next time I will increase the consumables.

I changed the way that I prepare tungsten, lately I have been using my Belt Grinder with a Norton Zirconia belt. This method work, but I used one $9 belt in one 4 hour welding session. Tungsten is hard!!!!!! :o
I decided to grind with a hand held tungsten grinder. I purchased a Sharpie from Arc-Zone. (The Sharpie, HTP, and TechSouth are all the same, just a different label, in fact, TechSouth makes the grinding head on the grinder for all three sellers.) This was nearly the lowest cost grinder that Arc-Zone sells, so I thought the quality would go according to the price, but I was pleasantly surprised. The motor has three speeds (can't remember the exact speeds, but it is around 30,000/14,000/3,000) I used the lowest speed to keep the heat down. The motor housing is ergonomic with rubberized sections around the circumference of the motor housing. Switch has a protection lever that prevents the motor from being turned on while adjustments are being made. The design of the grinding head is very nice, just spending a few minutes with the unit and you will understand how to use it. The motor runs smooth and the feel of the bearings is tight.

Well, it is very late so I must sign-off
Wob
Last edited by Wobulate on Sat Mar 19, 2011 2:53 am, edited 1 time in total.
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Re: Lincoln Precision TIG 225

Postby Wobulate » Wed Mar 09, 2011 5:14 pm

To All Interested in a Lincoln Precision TIG 225 (or 275, or 375)

GTAW: Micro-Start Technology for TIG Welding

When it comes to welding processes, TIG is one of the most demanding. Creating a high-quality TIG weld requires good, consistent starting performance and arc stability even at low amperages. This can be challenging for even the most skilled welder, especially with a conventional TIG power source – But now with Lincoln Electric’s Micro-Start Technology™ there is nothing standing between the operator and a good weld.

The innovative Micro-Start TIG technology was developed with the user in mind. Numerous interviews were conducted with TIG operators – from those with an advanced skill level to the beginner. Lincoln asked these welding operators about their most common problems and set out to provide a technological advantage that would overcome those problems. What resulted was the Precision TIG™ with its Micro-Start TIG technology. This machine will help any TIG operator create their best possible weld – time and time again. Among SCR TIG machines, Micro-Start produces best-in-class DC welding.

Having a technology that addresses TIG welding problems is of critical importance today as more and more manufacturers are turning to new materials and exotic alloys that are thinner and in many cases, harder to weld. Any industry that welds thin materials, including aerospace and marine, can take advantage of Micro-Start TIG to provide precise control and top quality welds.

So what are these common problems that Lincoln’s Micro-Start TIG technology overcomes? Basically, they fall into four categories: 1) low-end performance; 2) low-end starting; 3) minimum starting amperages; and 4) crater fill.

Problem: Poor Low-End Performance
In many traditional, low amperage TIG applications operators have trouble maintaining a smooth, stable arc. When using a SCR (silicon controlled rectifier) machine to weld at low amperages, the SCR conductions in the machine are "phased back" to very short duration spikes of output. This results in a great deal of ripple in the output current as these minimal firings produce gaps between the spikes of current. Even with the normal output choke filtering, the choke cannot store enough energy between SCR firings to stabilize the arc. This ripple effect leads to arc instability and sporatic, high-frequency re-initiations, thus leading to inconsistency in the welds.

Trying to correct this problem, many operators traditionally purchased more expensive, conventional TIG machines. They believe these machines with larger chokes will better filter the arc current to produce more stability and better low end welding performance. But even the larger choke cannot adequately filter out the low current ripple.

The Micro-Start TIG Solution
Micro-Start TIG technology employs an independent power supply capable of welding without SCR assistance at low amperages – SCRs only fire to raise the current and supplement the 2 amp welding supply. This gives Micro-Start TIG very stable low current welding and provides it with the ability to eliminate erratic high frequency and weld thin materials in a consistent, high quality manner. Lincoln is the first manufacturer to offer a background circuit from which an operator can weld and smoothly transition to, or from, higher outputs.

Micro-Start TIG is capable of independently welding off of its electronic power supply when the amperage is down to the minimum rated 2 amps. As the operator depresses the foot Amptrol™ to increase the current, the main welding circuit (i.e. transformer and SCR bridge) turns on and provides amperage. The technology assists the transformer SCR choke circuit with its special electronic welding circuit instead of completely relying on chokes to smooth the arc as do conventional machines. The result is a very stable and smooth output at low amperage levels.

With Micro-Start TIG, operators don’t have to buy more expensive machines to get low end welding capabilities – Micro-Start technology is able to provide inverter-like performance using a lower cost, conventional machine.

Problem: Low-End Starting
Today’s TIG machines establish an arc by using high frequency to ionize a path from the tungsten to the workpiece. Though high frequency is necessary to establish the arc, in most machines it remains on for a long duration and with a high intensity, thus creating “tracking” marks on the weld surface. For critical welding applications such as aerospace or nuclear qualified welds, these tracking marks can cause micro-cracking and lead to weld imperfections. Even in non-critical applications, high frequency can create starting with a great deal of objectionable arc wander.

Another problem with conventional machines is that they can’t start at very low current (typically below 5 amps). This is because at the minimal firing of the SCRs, the output choke cannot store enough energy to maintain the current at a welding voltage to initiate and sustain the arc without re-initiating high frequency.

To improve starting, many competitive TIG machines use a Hot Start feature. Hot Start utilizes SCR conduction spikes of high current at sufficient voltage and duration to heat the tungsten and establish an ion path quickly from the tungsten to the work piece in order to reduce duration of high frequency. For example, if the operator sets the machine for 5 amps, the machine may spike up over 100 amps for a significant period of time during starting. But this method is too problematic because on thin material, a Hot Start will erode the workpiece and burn away the base metal. Some operators have even resorted to starting on copper blocks or welding coupons before moving the arc onto the weldment to combat negative effects of high frequency and hot-starting. This method allows time for the arc to stabilize and prevents damaging the workpiece.

Operators may often manually “Hot Start” by pushing down the TIG machine’s foot pedal to a higher starting amperage. But with this approach, the machine never starts at a low enough amperage resulting in potential burn-through or erosion of the welded work piece. It also does not produce consistency since operators have to “guess” where to start.

The Micro-Start TIG Solution
With Micro-Start TIG technology, Lincoln Electric has devised a way to get the arc established quicker, smoother and with more stability using the electronic 2 amp welding power supply to supplement a SCR starting pulse height and duration appropriate for the welding level. An improved control circuit lets this new technology utilize a shorter, less intense pulse ignition to light the arc without “popping” or creating “burnthough”, thus allowing the high frequency to turn off virtually when the arc first strikes.

In fact, most users can’t even detect that the high frequency is on. This quick start is short and will not allow enough heat input to burn any material away. But the start offers enough energy to heat the tungsten and establish a plasma flow to the work piece. Micro-Start TIG also allows operators to adjust the minimum amperage of the machine. This allows the operator to adjust the low end of the machine to match the specific operating amperage range for the tungsten diameter being used, as well as his or her own low current skill level.

Problem: Minimum Starting Amperages
Most conventional machines allow operators to set only the maximum amperage, but will not allow for a minimum to be set. This means that if a tungsten and/or operator cannot start at the minimum output of the machine, than the foot pedal control must be “punched” to a higher level to achieve a start. This makes it difficult to achieve consistent starting, as well as repeatable crater filling.

Micro-Start TIG Solution
Lincoln offers the only machine with a minimum output control which lets the operator adjust the minimum amperage of the machine at minimum foot pedal depression to match the tungsten operating range or operator skill level. For example, if the operator is using a 3/32 diameter tungsten, its typical operating range is 10 to 150 amps. The operator can now set the minimum amperage of the machine not to go below 10 amps at foot pedal minimum to promote stability in welding and starting. Likewise for someone using a .020 or .040 tungsten – the minimum amperage can be turned down to 2 amps since this tungsten can run stable in this range. This minimum output control allows independent preset of minimum current level between 2 and 60 amps. This provides an optimum resolution range for remote control (foot pedal) between the minimum and maximum preset settings.

Problem: Crater Fill
One of the most frequent complaints conventional TIG operators voiced was the problem associated with lowering the current to fill a crater at the end of the weld. Traditional machines use a current sensing threshold approach, which means that when the operator ramps down and the arc becomes unstable, the machine detects the arc is in danger of extinguishing and initiates the high frequency again. With the current threshold method, the high frequency comes on at typically about 3 amps. The high frequency coming back on creates a wandering or “dancing” arc that leaves track marks on the weld allowing for contamination, microscopic cracking and surface imperfections.

Micro-Start TIG Solution
Lincoln’s Micro-Start TIG technology uses a voltage sensing method. This is a more “intelligent” sensing method that knows whether the operator is trying to maintain an arc. High frequency will only come back on if the sensed output voltage is greater than 35v (well above normal welding voltage). Therefore, the machine will provide a low current ramp down during cratering without unintended high frequency. In other words, during welding high frequency will not come back on again after the start of the sequence.

Traditionally, power sources are not sophisticated enough to sense whether or not an operator is actually welding – and when the operator wants to weld at low amperages. With Micro-Start TIG technology, once the high frequency initiates the DC arc, high frequency is no longer needed because of the low amperage stability of the background circuit.

Conclusion
With Lincoln’s Micro-Start TIG technology, an operator at virtually any TIG skill level will be able to make repeatable, high-quality starts, welds and finishes. This is because the new technology makes it easy to overcome the most common TIG welding issues with machines that overcome the most common performance limitations.

Wob :mrgreen:
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Re: Lincoln Precision TIG 225

Postby kermdawg » Wed Mar 09, 2011 10:32 pm

Not to get -too- off topic, but I know theres a couple pilots on here and I'm sure they would appreciate the metaphor-

I was reading a book earlier today waiting for the mail"person"(WTF?) to come. The book was an old book from the 80s, long story short It had a good section about the WW1 Biplanes, and how they developed into the 1920's and 1930's. The main part of the passage was they kept trying to do *everything* they could to get these biplanes to keep up with the monoplanes. EVERYTHING. Evenutally, well, how many biplanes do you see out there? Next to none.

Its the same thing with transformer-rectifiers vs. inverters. You can slap all the old technology you want on a transformer-rectifier, but it'll just barely keep up with the inverters, and eventually once the inverters have a few years to improve and upgrade, the transformer-rectifiers will probably go the way of the biplane. Theres nothing -wrong- with a transformer-rectifier, but an inverter does everything it does, just, most people would say, better. Im not putting down the transformer-rectifiers, they work fine. Its just techonology has evolved a bit and produced something, well, better.
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Re: Lincoln Precision TIG 225

Postby 98 SNAKE EATER » Mon Mar 14, 2011 9:59 pm

I'm a tig newb and just got a smokin deal on a PT225 + goodies last weekend, so I'll be watching this thread closely 8-)

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Here are some test beads the PO laid down....

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I have yet to match them or even come close (I made a real mess of the same piece), but I've only had about 20 minutes of tig time total, so I definitely have my work cut out for me :oops:
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Re: Lincoln Precision TIG 225

Postby kermdawg » Mon Mar 14, 2011 10:01 pm

Looks pretty damn good for 20 minutes tig time brotha!

Is that a -brand- new 225? Doesnt look like the 225 I learned on, then again that machine was probably 10 years old. Wonderin if they changed em.

How good was the deal? :)
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Re: Lincoln Precision TIG 225

Postby 98 SNAKE EATER » Mon Mar 14, 2011 11:00 pm

kermdawg wrote:Looks pretty damn good for 20 minutes tig time brotha!


Those are the seller's welds lol

Like I said, I have yet to match them or even come close :oops:

Is that a -brand- new 225? Doesnt look like the 225 I learned on, then again that machine was probably 10 years old. Wonderin if they changed em.


It's a little over a year old with minimal use (original receipt is from Oct/09)

How good was the deal? :)


$1000 bucks for everything 8-) (gotta love Craigslist)

List of goodies:

1 Foot Pedal
1 Full Bottle
2 Aircooled Torches (WP17's)
1 Watercooled Torch w/20ft lead and sleeve
1 CK Linear Hand Controller
1 Regulator Gauge
1 Flow Meter
Misc. Nozzles, Collets, Tungstens, etc.
Original receipt, warranty paperwork, etc.
Still under factory warranty.
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