welding

[John V]

OB....I ain't complaining, thanks to this thread I now know a bit more about MiG welding than I did before.

 

Boathunter thanks for explaining......I had a massive amount of welding done on Sabina H. Most of it done by an excellent semi retired shipyard welder. He had more tickets for welding than I knew existed. It was nearly all done with a massive three phase twin operator "Oxford" that I bought from a shipyard closing down sale in Hull. It was so heavy that the trailer I used to transport it home developed a permanent kink. I learned a lot about welding from him but I never reached a standard where I was prepared to trust my own work below the waterline. I can stick things together that's about it!!! (and my verts were always 'orrid)

[bizzard]

OB....I ain't complaining, thanks to this thread I now know a bit more about MiG welding than I did before.

 

Boathunter thanks for explaining......I had a massive amount of welding done on Sabina H. Most of it done by an excellent semi retired shipyard welder. He had more tickets for welding than I knew existed. It was nearly all done with a massive three phase twin operator "Oxford" that I bought from a shipyard closing down sale in Hull. It was so heavy that the trailer I used to transport it home developed a permanent kink. I learned a lot about welding from him but I never reached a standard where I was prepared to trust my own work below the waterline. I can stick things together that's about it!!! (and my verts were always 'orrid)

Stick and mig welding need different techniques. A gentle sort of straight pushing motion for stick and a weaving motion for mig. That doing strings of overlapping tack welds with a mig welder is ridiculous and almost certainly means that the operator can't grasp the technique or has an unsteady shaky hand so rests the torches shroud up against the job for each buz on the trigger.

[mark99]

Critical or high end arc welding we use (not boats) is highly supervised/checked.

 

Most proper fabricators will know this but for the uninitiated, this is a brief summary in my game which contains lots of field full penetration arc welding (outdoor stick welding) of high grade steels up to 1" thick (although I've not been too involved in external high end fabbing recently).

 

1) The name of welder is checked against a central list of (welders) competency for the weld task in hand - if his list does not confirm his name, he is rejected.

 

2) The written proposed welding procedure is submitted for examination. This weld procedure details things like metal prep, angles, penetration bead, layers of weld, rods types, min weld temp, preheat required, equipment used and other kit etc. The (usually someone like Lloyds) weld inspector examines weld procedure and accepts/rejects the procedure subject to mechanical lab tests. If the theoretical procedure is accepted.........

 

3) A dummy or test weld/s is undertaken by the welder and the welded is observed examined at every stage by an accredited independent welding inspector who stands next to him like a shadow. He is also measuring temp of weld operation and if it falls too low, stops the welder who has to grab the preheat torch....... Inspector also ensures all slag and inclusions are ground out properly before next layer of metal laid down.

 

4) When welded , the weld will be crack tested with a suitable technique and certainly x - rayed in various positions when complete. The x ray can detect laminations, correct layering/metal deposition, bead continuity/adequacy and faults/inclusions. The weld inspector chooses the x -ray locations not the welder.

 

5) The dummy weld is then cut out and sent to an accredited materials performance laboratory that sections it, cleans it up does all sorts of lab tests (acid for cracks/inclusions, bead thickness, charpy notched tests for brittleness, tensile tests etc against the engineering and material standards for that type of weld/steel grade).

 

5) If the mechanical tests come back ok - that only validates the weld procedure not the welder. EG say the steel joint is lab tested and is too brittle, that does not mean the welder per say is substandard - he may merely have been following an incorrectly chosen weld procedure.

 

6) Each subsequent weld is then taken with the weld inspector standing over the welder (If he is not happy he may direct the welder to grind out or repair certain bits of the weld.) and every joint when completed is x-rayed on site by mobile radiographers/mobile darkroom. Each weld is sentenced by the weld inspector on site - again if he is not happy (x rays) either some of the weld is rejected and has to be reground out and repaired or completely cut out and started again. The weld inspector and the xrays validate the individual weld (and the welder as well as the weld inspectors assessment of the welders technique).

 

7) The weld inspector also passes the preparation of the butt joints (butt angles/bead gap) pre-heat before welding is allowed.

 

It sounds a bit formal and maybe it is initially but soon most welders and inspectors settle down and work well together once mutual understandings are gained.

 

 

The above is the true way of knowing what quality welding you are getting and whether the theoretical procedure and technique is fit for purpose.

 

A diluted down attachment to some of the principles above is used for less critical welds (use a coded competent welder, use an accepted detailed weld procedure and have an inspector drop in every now and again to check/xray a random weld).

Edited January 5, 2015 by mark99

[raymondh]

Some good video's on this site for the more DIY welders amongst us

 

http://www.kevincaron.com/videos/general-welding.php

 

Ray

[Mike Tee]

Folowing RLWP's comment about boatyard bashing, and in fairness to onionbargee, I struggled through the whole of the link made in post 11. Four pages of what could be Russian to me.

It may well be a criticism of a particular boatyard, but absolutely nowhere could I find any criticism or hint as to where this welding took place or who did it, not even which area of the country it was done. It just appears that onionbargee participates in a forum dedicated to welding.

It is, though, a good heads-up on the dangers of amateur substandard welding (actually, any welding, even the pro's mess up sometimes).

 

And boatyard bashing or not, I'd want to know that welding done to my boat was not done at this yard - although we still don't know which one it was, in the interests of harmony please don't identify it except by PM.

[alan_fincher]

I would be amazed if it were not the same boatyard as Onion Bargee has been openly critical of in previous threads.

 

Whilst it may not yet be named in this thread, it is very obvious which one he is talking about.

 

In cases like this, even if someone presents what looks like fairly damning material, we are still only hearing one side of the story. The operation involved may or may not know this is appearing on CWDF, but either way we are not hearing their version of events, are we?

[Groundhog]

I would be amazed if it were not the same boatyard as Onion Bargee has been openly critical of in previous threads.

 

Whilst it may not yet be named in this thread, it is very obvious which one he is talking about.

 

In cases like this, even if someone presents what looks like fairly damning material, we are still only hearing one side of the story. The operation involved may or may not know this is appearing on CWDF, but either way we are not hearing their version of events, are we?

 

I understand what you're saying and to an extent I agree but I can't help thinking based on the posts here from those in the know about welding that there is no other side to the story. The weld is unfit for purpose.

 

I don't think naming the yard or welder would be sensible from this site owners perspective but perhaps it would be good if with the the help of the resident experts here a thread existed with details of yards that were objectively good. Welded properly, decent service, reasonable prices for work carried out etc. Maybe the thread exists and I just didn't notice it.

[mark99]

Continuing.

 

We still do arc welded fabbing albeit in a welding shop (not external). We were probably welding every working day last year.

 

This is how I QA/oversee the work.

 

I have three basic levels. Lets calll them A, B, C.

 

A

 

1) Use a coded (listed, known competent, experienced) arc welder.

2) Weld to a known tested weld procedure with defined equipment, rods, materials/voltages steel preparation etc

3) Visual examination of final weld (we also do a pressure test - however that's testing the flange joints not the weld porososity so not relevant to boats).

 

 

B )

 

Same as A above but select 10% of welds to be radiographed

 

C)

 

Same as B but 100% radiography.

 

If new welder/change of procedure - will consider standing an independant welding inspector next to the new welder until he is proved.

 

All work done by Iso 9001 accredited contractor.

 

 

Level A as described, the (basic QA level) would give me a high level of confidence if a boatyard worked by it.

Edited January 5, 2015 by mark99

[alan_fincher]

 

I understand what you're saying and to an extent I agree but I can't help thinking based on the posts here from those in the know about welding that there is no other side to the story. The weld is unfit for purpose.

 

Yes, but we are effectively being asked to accept (I think) that this is the work of that yard's regular welder. (although I'm also sure I have seen it suggested elsewherethat that yard doesn't actually have it's "own" welder.).

 

Now whilst I have no particular reason to doubt that claim, can we be absolutely sure that we are looking at an example of work by someone who is their recommended or mandatory welder, and they are still happy with the work he produces. It is not impossible, is it, that this could be someone who has worked there, but they either don't endorse his work, or they would not use him now. Note, I'm not suggesting this is the case - I'm not involved, and have no idea if this is their primary welder, or not, or how much work this welder does at that yard.

 

What I am seeing are posts by someone who has clearly fallen out with that boatyard. These posts may be completely objective and fair - I'm not saying they are not.

 

However we are only hearing it from one side, aren't we?

[Groundhog]

 

Yes, but we are effectively being asked to accept (I think) that this is the work of that yard's regular welder. (although I'm also sure I have seen it suggested elsewherethat that yard doesn't actually have it's "own" welder.).

 

Now whilst I have no particular reason to doubt that claim, can we be absolutely sure that we are looking at an example of work by someone who is their recommended or mandatory welder, and they are still happy with the work he produces. It is not impossible, is it, that this could be someone who has worked there, but they either don't endorse his work, or they would not use him now. Note, I'm not suggesting this is the case - I'm not involved, and have no idea if this is their primary welder, or not, or how much work this welder does at that yard.

 

What I am seeing are posts by someone who has clearly fallen out with that boatyard. These posts may be completely objective and fair - I'm not saying they are not.

 

However we are only hearing it from one side, aren't we?

 

Everything you say is right which is why naming the yard isn't a good plan, it could lead to a slanging match between supporters and detractors. Whatever the reason though, the "other side" of the story doesn't alter the fact of a weld being unfit for purpose.

 

It's why the second half of my post suggested the best approach to this is positive rather than negative.List yards that do consistently good work, only employ competent welders and used the right equipment. There must be plenty of people on here with truly great experiences of using yards. I don't need any welding but in the future I may well do. I would trust this forum as a whole to be able to make recommendations of places I could use. Far better and ultimately more useful than slating the bad ones.

[MtB]

I think the point is that from previous threads it seems the yard doesn't HAVE an 'in-house' welder, so this boater must have picked his own welder, or done the weld himself. Then later, the OP came along and took the photo.

 

It could be that any implied criticism of the boatyard is very misplaced.

 

MtB

[onionbargee]

The welder is reccomended by, but not employed directly by the boatyard in question.

[IanD]

If he's still recommended after this it doesn't say much for the boatyard...

[RLWP]

If he's still recommended after this it doesn't say much for the boatyard...

 

That is precisely what the OP wants you to think. I've seen a picture of some welding - that's all I know for sure

 

Richard

[Timleech]

 

That is precisely what the OP wants you to think. I've seen a picture of some welding - that's all I know for sure

 

Richard

 

A fairly fuzzy picture at that.

 

Tim

[IanD]

Regardless of what the OP wants me to think, the subsequent comments from posters with more experience of welding seem pretty conclusively damning. Usually if it's just a difference of opinion about the best way to do something (assuming there's more than one) you get both positive and negative comments, but nobody seems to have a word to say in the welder's defence here.

 

It would be better if we heard the other side of the story too, but I guess that's unlikely...

Edited January 7, 2015 by IanD

[RLWP]

And from what I remember, the comments are based on a fuzzy photo and a description from someone who didn't do the weld and isn't welcome in the yard - so where does the technical data come from?

 

Richard

[MtB]

 

That is precisely what the OP wants you to think. I've seen a picture of some welding - that's all I know for sure

 

Richard

 

Quite. Could be a sample of how not to do it, for a training school for example. Taken in the training school, not the boatyard.

 

If the OP wants to make accusations he should make them up front and stand by them, instead of all this childish whispering and innuendo.

 

 

MtB

[Alan Saunders]

Fascinating, having attempted some stick welding as an amateur, I then immediately aquired an angle grinder! I was amazed at the results produced by a professional. As a student I (~1965) I had a 3" diam. threaded boss welded to the bottom of a large oil tank. He nonchalantly knocked off the slag with a few light blows to reveal a beautiful, inclusion-free weld.

 

My, poor, understanding is that in thick materials it is essential to Vee the joint. With inadequate current, weld the bottom of the Vee, build weld either side, apply a central weld - repeat as necessary.

 

As an incompetant amateur I saw the photograph as 'poor' stick welding rather than MIG stitch welding. I would have ground it off to make it look good .

 

Alan

[onionbargee]

I have not mentioned who or where it was done.

[boathunter]

I have not mentioned who or where it was done.

Is it your boat?

[onionbargee]

Nope.

[boathunter]

Thanks.

[mark99]

 

 

My, poor, understanding is that in thick materials it is essential to Vee the joint.

Alan

 

 

Some example commercial weld prep angles/positions here about 1/2 way down.

 

http://www.irclass.org/section-6-welding

[DeanS]

If it's the uxter plate...isn't it true that it is not a part of the boat which needs to be water proof, as it's just something that's added onto the outside? In that case, lots of tacks would achieve the result. Just acting as devils advocate...and looking at the pic.