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Up Topic American Welding Society Services / Technical Standards & Publications / Backing Bar for Welder Qualification is essential or not?
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- - By bhichai.s (*) Date 09-23-2011 11:49
Dear Experts...

Normally, I have qualify welder by using 1" plate with CJP, welded form groove side, and then backgouged and welded from second side (with out backing bar).

Now, I have some comment form owner, He told, all welder qualified shall be away using backing bar by follow figure 4.21 or 4.22 of aws d1.1:2010.

But my understood, the backing bar is optional, It's right or wrong?

Thank you very much.

With Best Regards,
BST.
Parent - - By jwright650 (*****) Date 09-23-2011 13:15 Edited 09-23-2011 13:18
For D1.1, backing is an essential variable for welder qualification. They are either qualified "with backing or backgouging" or "without backing"...unless they took two seperate tests(one with backing and one open root).

See AWS D1.1:2010 Table 4.12(6)

EDIT:
I just re-read your post....I believe your guys are qualified "with backing or backgouging"...since they welded, then backgouged the root out and filled the second side. They however are not qualified for welding "open roots".
Parent - - By 803056 (*****) Date 09-23-2011 19:47
John, I need your help on this one. I cannot find a welder qualification test defined in AWS D1.1 that includes a back gouge operation. The figures provided in D1.1 are for the qualification tests "devised" to demonstrate the welder's abilty to deposit sound weld. All the figures, with the exception of the T, Y, and K and the fillet break test, include backing requirements. Where is the figure that permits the use of back gouging?

Best regards - Al
Parent - - By jwright650 (*****) Date 09-26-2011 11:54
Al,

How does using a backing bar vs the actual way that it WILL BE DONE in production, do anything BUT prove to the employer that the welder CAN successfully place a sound weld on the production parts?...can you provide clauses in D1.1 where it absolutely prohibits backgouging for qualification purposes? ie. actual proof of the welder's ability to use the backgouging equipment on production welds

I admit that here at work I use the Figs in Clause 4 vs backgouging but I fail to see the reasoning used in your post for not allowing backgouging, especially when the qualifying welder will be using that very process on production welds and not a backing bar.

I think that something needs to be addressed in the Qualification clauses of D1.1, if this is the only means to test a welder's ability(using a backing bar). Backgouging is routinely used here (seldom ever a backing bar), and should be a viable way to determine a welder's ability to use the process to deposit a sound weld.
Parent - By Lawrence (*****) Date 09-26-2011 13:38
Good thread.

Please gnaw on this one some more..

I'll just watch.
Parent - - By qcrobert (***) Date 09-24-2011 17:50
I believe backgouging is acceptable in lieu of a backing bar even when a backing bar was initially used in the performance test.

My justification rests on the definition of 5.10 Backing; Roots of groove or fillet welds may be backed by copper, flux, glass tape, ceramic, iron powder, or similar materials to prevent melting through.  The may also be sealed by means of root passes deposited with low-hydrogen electrodes if SMAW is used, or by other arc welding processes.  Steel backing shall conform to the following requirements:  Refer to Table 5.3 and 5.10.1 thru 5.10.5 for addtional requirements.

5.9 Backing, Backing Gas, or Inserts
Complete joint penetration groove welds may be made with or without the use of backing gas, backing or consumable inserts, or may have the root of the initial weld gouged, chipped or otherwise removed to sound metal before welding is started on the second side.

The sealing pass of deposited weld from first side becomes the backing for for the other side of weld joint.

Just my 2 pennys,
QCrobert
Parent - By 803056 (*****) Date 09-24-2011 23:07 Edited 09-24-2011 23:17
It is my contention that the welders in the original post were improperly qualified.

Let's not confuse production welding and qualification.

Just because something is permitted by a subordinate clause contained in Clause 5 doesn't mean it has anything to do with Clause 3 or 4. A case in point; since clause 5.10 is cited in a follow-up post regarding backing, I agree that the clause permits the use of copper, ceramic, flux, etc. However, only steel backing is prequalified. The contractor must qualify the WPS if anything other than steel backing is used for production welding.

Please read Clause 4.18 carefully. The opening sentence is, "The performance qualification tests required by this code are specifically devised tests to determine a welder's, welding operator, or tack welder's ability to produce sound welds. The qualification tests are not intended to be used as guides for welding or tack welding during actual construction."

A careful reading of 4.20 is also in order. The required test types are listed by Clause 4.20. The specific joint details to be use for welder performance qualification are cited by the clause listed by Clause 4.20.

I've been doing this for a good number of years with many different editions of D1.1 and have yet to see a figure for a performance test that includes back gouging. In a similar vein, the reference says nothing about using any of the prequalified groove details depicted by Figure 3.4 for the purpose of welder performance qualification.

If my good friend Mr. Roberts is simply stating that backing or back gouging can be used in production welding provided the welder passed a grooved plate test with backing, I concur. However, I don't believe production welding is at issue. My concern is whether the welders are properly qualified in accordance with AWS D1.1. My position is, no they are not properly qualified.

Best regards – Al
Parent - - By jwright650 (*****) Date 09-26-2011 13:03
"I believe backgouging is acceptable in lieu of a backing bar even when a backing bar was initially used in the performance test."-Quote

Robert, "yes" if the welder qualifies with a backing bar, the welder is now qualified to backgouge. See 4.24

However, I've seen guys who could take a test with a backing bar all day long, but perform horribly when using the backgouger(speaking of air - carbon arc gouging) and make a mess out of the joint and even miss gouging the root altogther. This is why I think the D1.1 committe should re-evaluate this and allow backgouging during the welder qualification process. It only makes sense, if backgouging is to be used during production. I think anyone that can lay down a multi-pass fillet weld, can lay passes in a groove on a backing bar.
Parent - - By 803056 (*****) Date 09-26-2011 13:53
John;

It isn't that I disagree that it is useful to have the welder replicate production requirements as a preformance test, however, that isn't the position taken by the D1 committee. The act of back gouging the root isn't technically "welding" and in many cases is not performed by the same individual that welded the joint.

My understanding of the code is that you test the welder with a standard performance test, i.e., with backing, and then have the qualification supplimented with an additional test where they are required to back gouge the root side and back weld the test coupon. Then the welder has demonstrated the ability to use the CAC-A process if that is what you expect him to do in production. Not every fabricator perform BG with CAC-A, many grind the root side to sound metal. If that is the case, I assume the fabricator would once again replicate production requirements as a suppliment to the standard test required by D1.

Best regards - Al
Parent - - By jwright650 (*****) Date 09-26-2011 14:18
"I assume the fabricator would once again replicate production requirements as a suppliment to the standard test required by D1."-Quote

Isn't that exactly what the OP did when he had his welder weld out a test coupon, then backgouge it, and re-welded? He performed welding, cleaned the root back to sound material, re-welded the second side to prove that his welder could in fact produce a sound joint(provided it passed all of the bends, or RT required).

"The act of back gouging the root isn't technically "welding""-Quote
I agree, but the test isn't over quite yet when the backgouging is completed, you still need to re-weld the second side before the testing is complete.

I think the D1 folks should add this consideration somehow to the Qualifying clauses, is my point.
Parent - - By 803056 (*****) Date 09-27-2011 03:54
You have a point. Why not send a request to D1 for an interpretation?

I am only expressing my opinion on the subject. I could be wrong. It wouldn't be the first time.

Best regards - Al
Parent - - By jwright650 (*****) Date 09-27-2011 12:42
Al, I really appreciate your opinion, that is why I'm asking :wink:
I hope you are not taking any of this as me calling you out on the subject, I just want to make sure that I am not missing an important note somewhere. You, and many others here, have been at this alot longer than I have.
Parent - - By Lawrence (*****) Date 09-27-2011 13:26
Oh...

Now your calling him old!

Keep it up John,.
Parent - - By jwright650 (*****) Date 09-27-2011 13:36
He already knows that he's old, I just wanted to remind him because... well...he's old. :cool:
Parent - - By 803056 (*****) Date 09-28-2011 01:20 Edited 09-28-2011 01:23
Bite me. :smile:

I usually take the position that the code delineates the minimum requirements that must be met. The contractor can go the extra mile if he feels it is prudent to do so.

In this case I see little ambiguity regarding how welders are to be qualified when the appropriate clauses of D1.1 are used as the basis of making a determination of what has to be done. The groove details are provided for the grooved tests and the configuration of the T-joint is provided for the Fillet Break Test. I do not see any provisions, i.e., figures depicting a grooved joint where back gouging is involved. Nor do I read in any of the clauses where there are provisions for back gouging the grooved tests coupons in Clause 3 part C, Performance Qualification.

I see no problem with a contractor that determines it is in their best interest to have the welder demonstrate the ability to use a carbon arc gouger to back gouge the root if that is how they are expected to do their production welds. However the test that includes back gouging supplements the testing mandated by the applicable welding standard. In this case at issue is what D1.1 requires. What is required by D1.1 is not the same as what is required by D1.2, D1.5, ASME Section IX, or any other code. What a different code requires is not relevant to D1.1. 

I remember taking a test with a contractor when I was still welding. The contractor had the welders weld the test plates in the 6G position and told us that the one position qualified us for all positions. I don't believe there are too many CWIs that would make that mistake in today's environment.

Let me play the devil’s advocate; can you cite the applicable clauses in Part C of Clause 4 that provides direction, i.e., a figure, or text that specifically allows the welder to back gouge the root of the test plate? To this point I haven't seen anyone present a case where they were able to cite a clause or figure allowing back gouging of the test plates.

Let’s not confuse what is permitted in production welding with what is required when qualifying the welder. To that point (paraphrased) I cite Clause 4.19 that states that the welder qualification tests should not be used as a guide for production welding. 

Make your case friends.

Best regards – Al
Parent - By jwright650 (*****) Date 09-28-2011 13:00
I think that we've talked on this forum(participants in general, no one specific) about when the code is silent on an issue that the code is actually saying that it isn't prohibited? I think this may be one of those cases where you can apply this thought process. I don't think that anyone can't say that you are going against the grain of the code by testing the welder to a real world welding senerio/situ to prove the welder's ability to produce a sound weld. You're giving him a test on the actual joint and conditions that he will see in production on a day to day basis and not a joint that he will mostlikey never see unless he's a welder for an erection crew. There are not many cases where our welders see a backing bar, exceptions would be a blind joint with no access to the second side, or maybe where a fillet weld has an excessive root opening.
Parent - - By jwright650 (*****) Date 09-28-2011 14:20
OK Al, I conceed. :cool:

I'm swayed to your side of the arguement, however....how would you go about adding the backgouging suppliments to the minimum requirements for welder quals in D1.1 using the appropriate Figs in Clause 4?

Have the welder weld it up with a backing bar, then backgouge the backing bar off and fill it up?

>"I do not see any provisions, i.e., figures depicting a grooved joint where back gouging is involved. Nor do I read in any of the clauses where there are provisions for back gouging the grooved tests coupons in Clause 3 part C, Performance Qualification."-quote


You lost me with the Clause 3 Part C.(maybe you meant to say Clause 4?)
If you use a prequalified WPS in Clause 3 like a B-U4b(not shown in Figs in Clause 4), that prequalified joint does require backgouging vs the B-U4a(shown in Fig 4.32).
Parent - By Lawrence (*****) Date 09-28-2011 19:43
Grooves qualify for fillets eh?  (for welder performance)

Grooves with backing qualify for grooves that require back gouge... (but not visa versa)  [again for welder performance]

Thats "welder performance qualification"  as deliniated by code.

Production qualifications in house?    You can add anything you want in "addition" to what the code requires.

Maybe it's just a case of two tests.. one for code compliance and something else for production.   I'm sure there are lots of producers who could devise a test that is closer to their production work.... For some reason the D1.1 committee has a short leash on testing, or at least it appears to be worded that way..

Heck, you could kill two birds with one stone by writing a WPS that requires the backing bar on the test coupon to be removed with CAAC, without ruining the coupon or reducing the thickness of base metal...  It's not identical to production gouging, but it takes a good touch and can be done without stepping on the toes of the scope of chapter 4.
Parent - By 803056 (*****) Date 09-30-2011 03:08
You are right, Clause 4 Part C is for performance qualification. A slip of the finger and everything goes to hell on a hand basket.

Al :lol:
Parent - By bhichai.s (*) Date 09-30-2011 17:11
Thank you very much for all answers and recommend....
- - By GusTX Date 09-27-2011 01:31 Edited 09-27-2011 03:18
Just my 2 bit's
We have been doing the same as the OP for years.
I would like to ref. D1.1 Interpretations  AWS Log: D1-85-031  Number (6).

If what Al is saying is right.  That would make about 6 of use wrong.

Please tell us what we are not reading or understanding.

Thanks to all

gus
Parent - - By ssbn727 (*****) Date 09-28-2011 02:06
He just did for crying out loud!!!:yell::yell::yell::twisted::twisted::twisted::eek::eek::eek::roll::roll::roll:

Both sides of the discussion bring out some valid points but in the final analysis, I believe Al is correct that there is a big difference between production, and qualification and Clause 4.19 makes it pretty clear... That is - unless of course, one cannot comprehend what clause 4.19 means or what it's referring to, or better yet...
Well, never mind:eek::roll::razz::wink::cool: I think it's best to leave it at that.:lol::wink::cool:

Respectfully,
Henry
Parent - - By GusTX Date 09-28-2011 02:45
Yes for crying out loud                we should read just a little bit more

4.20.1.1         In lieu of mechanical testing or RT of the qualification test assemblies, a welding operator may be qualified by RT of the initial 15 in [380 mm] of a production groove weld.
The material thickness range qualified shall be that shown in Table 4.11.

And yes I do respect your wisdom
What is not clear is your statement----That is - unless of course, one cannot comprehend what clause 4.19 means or what it's referring to

Thanks

Gus
Parent - - By Lawrence (*****) Date 09-28-2011 03:53
The plot thickens!
Parent - - By 803056 (*****) Date 09-28-2011 05:16 Edited 09-28-2011 05:19
What?

RT in place of bend tests? That clause applies to welding operators, not welders. D1.1 differentiates between welders and welding operators.

Al
Parent - By CLH1978 (**) Date 09-28-2011 13:48
????????????????????????????
Parent - - By GusTX Date 09-28-2011 15:33
Al

Yes that is correct we use this for our 3-oclock sub arc on tanks.

I would still like your opinion about D1.1 Interpretations  AWS Log: D1-85-031  Number (6).

Thanks

Gus
Parent - - By 803056 (*****) Date 09-30-2011 03:06
Can you send it to me?

Al
Parent - By jwright650 (*****) Date 09-30-2011 12:15
Can someone post a copy of that official interpretation?...I found where that question was asked, but not answered. In fact 5 of the 6 questions were answered...just not number 6.
Parent - - By GusTX Date 10-01-2011 02:14
Here is the AWS Log: D1-85-031.   This is Qualification requirements

Thanks  GusTX
Attachment: D1-85-031.pdf - D1-85-031 (366k)
Parent - By ssbn727 (*****) Date 10-01-2011 23:47 Edited 10-01-2011 23:49
Hi GusTX,

Could you please do me a favor???

Explain to me the relevance of this AWS Log: D1-85-031 with the Original poster's question??? There's also a discrepancy in which year of D1.1 you're referring to since AWS Log: D1-85-031 is referring to AWS D1.1 84 and the Original poster is referring to AWS D1.1 2010...:roll:

The point that I'm making here is that things might have changed in the current version of D1.1 since the date of the AWS Log you referred to and finally, what in the heck does this Log have to do with the Original poster's query???

I mean "what does this have to do with the price of tea in China???" Since there's no obvious relevance with the original query.:eek:

Respectfully,
Henry
Parent - - By 803056 (*****) Date 09-30-2011 03:09
But you are not welding the tank in accordance with D1.1 are you?

Al
Parent - - By Shane Feder (****) Date 10-03-2011 04:49 Edited 10-03-2011 04:52
Hi all - greetings from Thailand.
Sitting in an internet cafe on the Cambodian border so no access to AWS D1.1 but would like to throw a curve ball.
AWS D1.1 (to the best of my knowledge) states that a welder performing a PQR coupon is automatically qualified (if the coupon passes required tests).
So a backgouged PQR test plate therefore gives a welder automatic qualification for welding with backing.
What is to stop a company from then performing 10 qualification coupons with 10 different welders and calling them all PQR qualification coupons ?
I know it is a rather large bending of the rules but if it is acceptable for 1 welder, why not 10 ?

As for the price of tea in China Henry, off to China for my next project so will more likely be commenting on the price of beer. LOL !!
Regards,
Shane
Parent - By ssbn727 (*****) Date 10-03-2011 06:03 Edited 10-03-2011 06:06
The Thai beer is much better than that "Sino urine" Shane, so please be careful.:sad:
At least that's how it was the last time I drank, and that was over 21 years ago...
So things might have improved a bit since.:lol::wink::cool:

I do love most of their food even though most of what is offered here is not at all like what is available in the mainland...
That is, unless you know of a really authentic "hole in the wall' where the only folks in there are Chinese and you know what to order...

I grew up with a good friend named "Bill", and he turned me on to some really great Chinese restaurants down in Chinatown in the lower East side of New York City...

They were nothing more than rice houses or dumpling houses which were actually below street level where the only
customers there were Chinese...

So I learned from him and his girlfriend how to and what to order many moons ago...
Have fun in China Shane! But don't expect much of their beer especially since you already know what good beer is like coming from Oz.:lol::wink::cool:

Respectfully,
Henry
Parent - - By 803056 (*****) Date 10-03-2011 17:39
As is usually the case, you are correct Shane, at least on part of your response.

What would keep a contractor from having each of his welders weld a PQR? Cost is what comes to my mind. The expense of volumetric NDT, reduced section tensile tests, and four bends rather than two bends would be a major disincentive for most contractors.

As for the back gouging operation qualifying the welder for welds with backing, I would have to disagree on that point. The code states that a welder qualifying with backing is also qualified for back gouging, but there is no mention that the welder qualified with back gouging is qualified with backing.

Enjoy Thailand.

Best regards - Al
Parent - - By wall2112 (*) Date 10-03-2011 23:12
this has me confused. where dose it say you can backgouge a pqr test. i guess if the customer wanted it done that way. but looking at the visual acceptance i dont see it happening. the only test i can see is the square groove test that is back gouged. please explain. the shane guy has me confused.
Parent - - By Shane Feder (****) Date 10-04-2011 01:00
The Shane guy has a lot of people confused.
A PQR test coupon can be performed anyway you like - standing on your head if you like, however I can't remember the clause that allows that.

Al,
The point I was trying to make is the apparent anomoly in the code.
A welder must perform a test with backing bar to enable him to weld backgouged joints in production. However, a welder performing a backgouged PQR test coupon does not have to do this yet he obtains similar qualifications ?
I wrote a post on this subject a while back where backgouging was a critical part of the test (maybe Henry can hunt it down for me) and IMHO the test I required was much more stringent than the test required by AWS D1.1.
I now see that the tests I performed were not in accordance with AWS D1.1, regardless of stringency.

On an aside, my girls visited Thailand in the school holidays recently and the eldest had to do an assignment on conflicts between two neighbouring countries.
She chose Thailand and Cambodia as she thought I might be able to assist her.
My girlfriends grandfather was shot by Cambodian troops and her grandmother was kidnapped for 7 years - not a bad start to my daughters report.
Then about 4 months ago I sat drinking beer watching and listening to shells exploding overhead as both sides did a bit of "chest beating".
As we live close to the border we took her to the temple at the centre of the conflict.
Some good first hand information that should make her speech a bit more interesting.
All the best,
Shane
Parent - By 803056 (*****) Date 10-04-2011 02:12 Edited 10-04-2011 02:15
Hello Shane;

That's a report I would love to read!

How old is the young lady. The view point she expresses will be very surprising. She will see the issues through her eyes with the knowledge of how it has impacted her directly. She will be speaking in the first person rather than as someone who has no direct involvement in the conflict.

Don't misinterpret the opinions I have expressed. I have tightened up the requirements of typical welder performance tests I administer when it is my signature attesting to the fact that the welder has the ability to deposit a sound weld in accordance with AWS D1. For instance, I typically don't permit the use of power tools for interpass cleaning or to remove unacceptable weld metal before depositing additional weld. However, the configuration of the test plates in agreement with the details depicted by D1 (D1.1, D1.2, D1.5, etc.).

There are occasions when supplemental tests are required when it is mutually agreed to by the client and me. For instance, ASME allows the welder to weld a range of base metals provided the F number or process isn't affected. Example: if the welder qualifies on carbon steel (P1) using a F6 filler metal he is permitted to weld austenitic stainless stee (P8)l. Many welders will agree that CS and SS do not weld the same. Therefore, we feel it is prudent to require the welder to weld both CS and SS as separate qualification tests. We've done more than what the code requires, but never less than what the code requires.

If the contractor believes it is prudent to have the welder demonstrate the proper way to back gouge, that is perfectly reasonable if it is a supplement (test) in addition to the code required performance tests. 

I'm not saying that my personal views are correct and everyone with a different opinion is wrong. It is just my personal understanding of what the codes say on a subject. Trust me, I've been wrong before and I'll be wrong again. My wife does a reasonably good job of letting me know when I screw up. I look at it the way my wife's uncle used to look at things. He used to say, "The only person that never lost a tool, broke a tool, or made a mistake is the person that never picked up a tool or made a decision." I can relate to those words of wisdom.

Best regards - Al
Parent - - By Joey (***) Date 10-04-2011 06:22 Edited 10-04-2011 06:25
Khun Bhichai - I believe you can opt for not putting the backing plate if your WPS indicates back gouging on other side before welding. You may explain to the owner that the welding personnel followed a WPS applicable to the qualification test required.

I think the only problem with the owner is if he/she don’t’ agree that double welded groove welds (back gouged) are considered welding with backing.

Sawadika Shane – I have this PULUTAN (finger foods) for our Singha beer session tonight.

~Joey~
Attachment: pulutan.pdf (135k)
Parent - By bhichai.s (*) Date 10-04-2011 17:48
Thank you very for all suggestion, this topic is very useful for everybody.

Hi Shane and Joey, Are you stay in THAILAND? when it right, I will pay Singha Beer for you...555++++

When are you ready, contact me by aws messages.

Thank you...
Parent - - By wall2112 (*) Date 10-18-2011 00:05
a backgouged pqr is not in conformance with d 1.1 , the reason the man taking the test is qaulified is because they took the  test with backing or 100% from one side no backgrinding. so depending on which way you welded pqr is the way your welder qualifies. with(backing) or without backing (welding from one side with melt thru). read visual acceptance for pqr and performance test they are the same. this is how i read it.
Parent - By Joey (***) Date 10-18-2011 09:55
:roll:
Parent - - By Lawrence (*****) Date 10-18-2011 11:18
Please explain double bevel PQR's ?
Parent - - By wall2112 (*) Date 10-18-2011 22:19 Edited 10-18-2011 22:52
please explain why a single vee with a backing bar pqr would not cover a double vee weld in production?
Parent - By 99205 (***) Date 10-18-2011 22:35
I see black clouds on the horizon.:eek:
Parent - - By wall2112 (*) Date 10-18-2011 23:01
how dose a double groove pqr qualify you to weld fillets?
Parent - By Joey (***) Date 10-19-2011 00:46
:cry:
Parent - - By bhichai.s (*) Date 10-19-2011 10:54
Since, our PQR's was done by back gouged. Welder test should be test by back gouging, that right or not?

However, I have one question in table 4.5 para. 31  of D1.1, when we done PQR's by some CJP groove weld, this PQR will qualified in any groove type of WPS e.g. single vee, single bevel, double vee, double bevel and fillet, That right or not?
Parent - - By welderbrent (*****) Date 10-19-2011 12:48
Something tells me there is more than just backgouging that made it necessary for you to do a PQR??  Then, the welder would have to test just as your WPS written up from your PQR states.  And if backgouging is included as the method to get CJP, then yes.  But he would also need to be tested to the standard conditions from Clause 4 in order to be qualified to all the Pre-Approved conditions of Clause 3.

Remember too, backgouging is not always done by air-arc.  It can be accomplished by grinding, chipping, machining, etc.  Any code stated method that prepares the surface for weld from the opposite side to the required specifications of the WPS. 

Have a Great Day,  Brent
Parent - - By eekpod (****) Date 10-19-2011 18:05
To get back to the original post,
I guess I understood it if a welder can test with a backing bar and pass (by putting in an acceptable filler material, especially the root) it is safe to conclude he could then install acceptable quality welds and backgouge them in production.

If he were to test with out a backing and by backgouging , then you would never know if he could put in an acceptable root to the backing in production (because during his test he would be backgouging the root out from the second side).

Especially in FCAW a welder could easily trap slag in the root and not fuse to the backing, but if he were allowed to backgouge during the test, he would fix that situation.  But in production if he had to weld a joint that didn't get backgouged and he were only used to always backgouging, that would be a potential failure.
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