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  1. #16
    Join Date
    Mar 2009
    Posts
    267
    Quote Originally Posted by MarkV View Post


    I rechecked my notes why I chose 7018 vs 7014 and found this:
    “7014 does not have a lot of penetration and should not be used for anything that is structurally critical or subject to lots bending and vibration.” If that is correct, 7014 would not be a good choice for things like tractor implements.
    I would guess the bending and vibration refers to bridges and other high-strength structures. If you are welding something that REQUIRES 7018, you'd better be a lot better than a self-taught welder who asks questions on a forum, not to mention the handling and storage requirements of 7018. Once you don't follow them, you might as well use 7014 anyway. Besides, most tractor implements are thin enough the penetration shouldn't be an issue. Now if you are repairing the arm on an excavator.......


    Another great option, although hard to find is Messer 80T AC+. 80,000 psi, easy to strike and good penetration.
    "never argue with an idiot; he'll bring you down to his level, and win by experience"

  2. #17
    Join Date
    Aug 2008
    Posts
    52
    Mark
    At the risk of confusing you even more- amps ARE amps. Think of amps as gallons per minute would be in a water delivery system- you have two things in a water supply that are of concern- gallons per minute and at what Pressure. In electricity we have the same thing, the volume is called current and measured in Amps and Pressure is called Volts.
    When you multiply voltage times amperage you get Volt Amps (VA) when those do 'work' it becomes Watts, thus VA and Watts are basically the same(trying to avoid the distinction physicists get concerned about).
    So you mentioned seeming a volt/amp curve- you can find the voltage on the curve for a given current (amps) and calculate the watts- and in this case the watts translate into Heat- lots of it so much that it can melt metal.

    Then when you get into AC vs DC voltage it gets a bit confusing. In a DC circuit-the voltage at any moment in time remains the same, it never changes. If you turn on the headlites on your car with the engine not running the lights stay at the same brightness (until the battery runs down). Not so on AC.

    If you were to hook up a light to a Slow turning Alternator - you would see the light get brighter and brighter until it reaches the maximum voltage it can produce- then start to get dimmer and there will a point where there is NO light and then it will start to get brighter again etc. If you look at the Sine wave of an AC voltage it goes up then down and then back up again. The voltage is constantly changing. People far smarter than I will ever be figured out how to calculate the 'average' voltage or RMS and this is what/why you see 120 volts or 240 volts on electrical devices. So the heat produced is going to be less because this AC voltage is not steady like it is on DC. In fact at one point on the sine wave it is literally Zero volts-but because this is occurring 60 times a second we can still use AC to weld but typically will have to 'add' more amps to produce the same intensity of heat that we could produce using DC at a lower voltage.

    Hopefully this hasn't confused you further. But if you take the time to get a basic understanding of how electricity works-especially volts and amps with respect to Watts (heat) in welding you become a better welder.
    Good chance you weren't taught about volts and amps because the instructor doesn't understand the physics behind welding himself.
    Last edited by 131RE; 10-24-2016 at 08:16 PM.

  3. #18
    Join Date
    Oct 2016
    Posts
    9
    Quote Originally Posted by mike landrich View Post
    I would guess the bending and vibration refers to bridges and other high-strength structures.
    Initially I looked at 7014 and 7018, chose 7018 for my needs, and did not pursue the specific characteristics of 7014. That is why I posted the issue of 7014 “bending and vibration” as a question, because information was contradictory.

    I did further research and the “bending and vibration” seems to refer to things subject to repeated hard impacts or high vibration, where the weld can fatigue. Things like the bucket and boom on an excavator, or suspension mount on a trailer towed on the highway.

    A plow pulled behind a tractor will not fail because of fatigue, therefore 7014 can be a good 'farmer rod.'


    This is one of instances where just a bit more information from those writing textbooks and electrode manuals would be helpful, to clarify what type of “bending and vibration” is a problem. This whole thread started because Miller did not specify in the manual whether they were talking about 7018 or 7018 AC.
    Last edited by MarkV; 10-25-2016 at 02:44 PM.

  4. #19
    Join Date
    Oct 2016
    Posts
    9
    Quote Originally Posted by mike landrich View Post
    If you are welding something that REQUIRES 7018,
    I was referring to welds that NEED 7018, not those that REQUIRE it.




    This thread may be read by new welders who have not been told the difference between NEED and REQUIRE, as used in the welding trade, so I will give a basic explanation.

    Just as SHOULD and SHALL have different legal meaning, so does NEED and REQUIRE, and every professional welder is required to know the difference.

    REQUIRE means the welder must follow a specific procedure, prescribed by an engineer, and must be certified to do that procedure. Such as high pressure pipe, structural steel on buildings & bridges, etc. It is a legal requirement, and has legal consequences if you ignore them.

    NEED means a “knowledgeable person,” such as the welder, has determined what is the best procedure for that weld. It does not require an engineer or certified welder. But it does require the welder to follow “best practices,” and there are legal consequences if they do not, and the weld fails. Using 7014 because it is easy, when the weld NEEDS the properties of 7018, means you did not follow best practices and are legally liable.

    Violating best practices because that is what the customer wanted, is not a legal defense. Neither is violating best practices because “the boss told you to.” The WELDER is deemed to be the “knowledgeable person,” not the boss, if the boss is not a welder himself. Yes the business owner or foreman may go down, but they could drag the welder down as well. Google “joint and several liability.” Basically even if the welder is only 1% responsible, he can be found liable for 100% of the damages.


    Not to hijack the thread, but the purpose of these forums is to spread knowledge and help each other become better welders. That is how we learn.
    Last edited by MarkV; 10-25-2016 at 03:19 PM.

  5. #20
    Join Date
    Mar 2009
    Posts
    267
    Quote Originally Posted by MarkV View Post
    I was referring to welds that NEED 7018, not those that REQUIRE it.




    This thread may be read by new welders who have not been told the difference between NEED and REQUIRE, as used in the welding trade, so I will give a basic explanation.

    Just as SHOULD and SHALL have different legal meaning, so does NEED and REQUIRE, and every professional welder is required to know the difference.

    REQUIRE means the welder must follow a specific procedure, prescribed by an engineer, and must be certified to do that procedure. Such as high pressure pipe, structural steel on buildings & bridges, etc. It is a legal requirement, and has legal consequences if you ignore them.

    NEED means a “knowledgeable person,” such as the welder, has determined what is the best procedure for that weld. It does not require an engineer or certified welder. But it does require the welder to follow “best practices,” and there are legal consequences if they do not, and the weld fails. Using 7014 because it is easy, when the weld NEEDS the properties of 7018, means you did not follow best practices and are legally liable.

    Violating best practices because that is what the customer wanted, is not a legal defense. Neither is violating best practices because “the boss told you to.” The WELDER is deemed to be the “knowledgeable person,” not the boss, if the boss is not a welder himself. Yes the business owner or foreman may go down, but they could drag the welder down as well. Google “joint and several liability.” Basically even if the welder is only 1% responsible, he can be found liable for 100% of the damages.


    Not to hijack the thread, but the purpose of these forums is to spread knowledge and help each other become better welders. That is how we learn.
    And that is why no one wants to give specific advice. Assumed to be over-educated and under-trained.
    "never argue with an idiot; he'll bring you down to his level, and win by experience"

  6. #21
    Join Date
    Jun 2012
    Location
    Almost Paradise
    Posts
    439
    Quote Originally Posted by mike landrich View Post
    And that is why no one wants to give specific advice. Assumed to be over-educated and under-trained.
    I've learned through the years of website moderation this type of poster is best left to wither on the vine as they only join to stir the proverbial pot provoking responses to attack with "gibberish" having little to no merit.

    Expert without experience is how I see it. One doesn't learn this trade solely from any book as most WITH experience will attest. Alas, this poster knows it all right out of the gate without even knowing how to run a welding machine; correctly.

    I only wish I were that intelligent.
    Thanks for reading/listening.

    Antique Hobart Engine Drive Lover X5

  7. #22
    Join Date
    Mar 2003
    Location
    Brethren, Mi
    Posts
    11,582
    The trailer and the excavator may be different and the application may also in the sense that while the trailer may have stresses most of it should not depend on critical welding and approach the limits of it.

  8. #23
    Join Date
    Mar 2003
    Location
    Brethren, Mi
    Posts
    11,582
    I don't watch much video and have only seen the tips and tricks guy on a couple vids and I like him as he is noit pretentious and can really make a guy "feel" it. While I am a firm believer that a 200A mig is the right first machine for most hobby types I was a stick welder the first 15 years. I went all up and down the food chain and have made a living at some point with all those electrodes.
    I have used 13 and 14 when I had to and neither would be on my go to list if I have a choice. What I say applys to general work so keep that in mind. I like 3 things for this crowd and although I have used and tried others fall back to 1/8 in 6010/11, 3/32 in 7018 and 1/8 in 7018. While a Dial may technically be better than the AC/DC unit it doesn't matter and is mostly bigger.
    The 11 and the AC18 for AC machines for sure but the sizes apply. A 1/8 11 and a 3/32 13 run in the same current range along with the 3/32 18. I don't care for 13 and rather have the larger electrode with lower current for sheet. If its critical a guy can go to 3/32 there but the arc length is way too fussy and too small to bridge gaps. No point in running a mild pen rod if you got to run it at 120A and may as well run 7018 and often run it down on light sheet.
    You can run large electrode at hi current and bridge larger gaps, nice finish with low splatter.
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  9. #24
    Join Date
    Aug 2006
    Location
    Iowa
    Posts
    608
    My advice to the OP is keep an eye on Craigslist, especially this time of year after Christmas and going into the slow months. A lot of guys buy nice welding machines when the OT money is coming in but when work slows down they need the cash. You can't go wrong with either a Hobart or Miller AC-DC machine, look out for over priced junk however. If you do decide to purchase a AC machine there are usually so many used ones on the market, never pay top dollar for any of those, even if its Like New.

    I learned to weld on the farm with a POS Dayton AC welder. I was the only 12 year old kid repairing farm machines in a 3 mile area. I cleaned the metal and did a good job, not pretty but they held. The farmers decided to buy their own Lincoln tombstone and do their own welding. The problem is, they never cleaned off the paint, grease, oil or rust, and the term Farmer welds became true. By that time I was in the Air Force and did not really care.

    DC amps are more effective than AC, setting per setting. I used the Lincoln 7018 AC rod when I built my 3 point backhoe, 6011 root and 7018 cap. Never had any broken welds.
    Last edited by wmgeorge; 12-29-2016 at 05:46 PM.
    Retired...
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  10. #25
    Join Date
    Dec 2010
    Location
    S. E. Wisconsin
    Posts
    199

    Thumbs up Just catching up!

    The explanation of "Physics of AC/DC" was really good! Thought provoking to say the least!

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