Welding a steel hull

Discussion in 'Metal Boat Building' started by Wynand N, Jun 23, 2008.

  1. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    I tried to keep my nose out of this one and let the guys sort out their own grief with their welding beliefs. Then along came Brent Swain....

    Brent, you started with some views on welding which is within the spirit of this thread, then you were back at your old ramblings we had heard all before and I refer to the thread "Realistic Scantlings" http://boatdesign.net/forums/showthread.php?t=20941
    Do you not get tired with the same story told as we are tired hearing it:?: You know all our views on your claims and to refresh your memory, you can read it again at the above thread.
    As the starter of this tread to assist amateur and pro alike on different views and advise of welding steel boats, we like to keep it that way. If you can not stick to the issue at hand, please go troll somewhere else.:mad:

    Having said that and you claim to be a very logical man, and I apologize going a bit off topic here, lets get back to your fabled stability claim. Please send (post here) a cross section of your hull and deck at midships with the waterline drawn in and let us all do a stability check for you since it appear you do not know how. This is your chance to prove us all wrong and do not let us down. If your basic stability calcs are in question, surely everything else that goes with it on a hull design must also be in question.
    BTW, your logic on chainplates; no point in over designing them, the crux is in the way they are attach to a sound structure.
     
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  2. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    Will send the stability curves as soon as I get to a scanner. I'm out cruising for the summer, and don't have a scanner aboard.
    I was letting the issues ride until Mike resurrected them. I wont let any such lies go unchallenged. That would be grossly unfair to anyone who would believe his ********. So take your complaint to Mike.
    Brent
     
    Last edited: Aug 9, 2008
  3. tazmann
    Joined: Aug 2005
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    Location: California

    tazmann Senior Member

    Welder/Fitter
    Question On you choice of wire , I went to my supply outfit and they dont carry E70T-1 or the E70T-9. E71T-1 they do. I mentioned your statment about it being 5x the strength of stick and he laughed and said no way, its a little stronger but not by much. When I got back home I resurched it a bit between Lincoln and Esab Both with there testing data show its just a tad higher than 7018 . I was going to order a roll but come to find out E70T- is only for flat and horizontle. How would one build a boat like that? E71T-1 will do verticle up and overhead but the strength test are the same as E70T-1. I allso asked about welding out doors with it and was told it the same a regular mig if the wind blows the gas away you have same problem, is this true? and if so what is the benifit of using it over regular mig say 70S-6 wire? Like I said I have never used dual shield wire before.
    Tom
     
  4. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    welding

    I know a couple of people who welded with gas outside, but had to delay welding until absolutely flat calm conditions, which adds greatly to the building time. Building inside adds greatly to the cost of a building site and the total cost of the boat. If I were mass producing boats it would be co2, but for the backyard one off, stick welding with a buzzbox is all I've ever needed, and has huge advantages..The equipment for CO2 welding is also far more expensive, an expense that is totally unjustified for the one off. None of this high teck welding would work in the conditions shown in Alex's video.
    Brent
     
  5. tazmann
    Joined: Aug 2005
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    Location: California

    tazmann Senior Member

    Brent
    Yep I agree a buss box and stick welding is the cheapest and easyest to learn especialy for a one off built outdoors, I even recomend it for that but to some thats not good enough.
    Mig does have its advantages prettier welds less distortion and faster on long welds, does take a bit more to learn and the initial cost is higher. It can be used outdoors with wind breaks. To me it can be more of a pain at times but it can be done.
    I wouldnt say none of this high tech welding would work. I can hook up plasma cutter to the welder on the truck and have clean air for it from compressor, 3 different mig options that would reach most of the boat without moving truck spool gun with 25' lead, cobra push pull with 25' lead or wire feeder hooked to hoist. It is a royal pain setting it all up and looks rather messy with all the hoses cords and lines coming off the truck but it does work out in open field and I do do it on occation. Much easier to pull stinger and ground off and start stick welding but if the boss specifies I want this then no problem.
    Call me lazy I welded mine together with 6011 stick
    Some advocate I should have used 7018 because I am taking a chance of the 6011 welds cracking, heck why stop there 12018 would be even better!
    Tom
     
  6. TollyWally
    Joined: Mar 2005
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    Location: Fox Island

    TollyWally Senior Member

    As boats are all a compromise of sorts so are the standards of construction; ranging from best practice to good enough right now. We all make a personal choice where on the spectrum we choose to be. So long as you go in with your eyes open most choices have validity.

    A wise old bricklayer once told me that you couldn’t tell the difference between first rate brick work and shoddy work for 30 years. Pay your money and take your chances.
     
  7. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    I've never heard of 6011 cracking in small boats in the 40 years I've been messing around in offshore boats, so its like talking about how do to deal with a personal direct asteroid hit. With so many successful cruises done in wooden boats( dead vegitation) fastened with copper fastenings every 6 inches, small steel boats are so grossly overbuilt , that any discussions of welding rod choices is a purely acedemic debate, with nothing to do with the extremely remote liklihood of welds ever failing.
    Brent
    Yes , mig and other high tech methods work, but I'd hate to see any low income boatbuilder be suckered into beliveing that expensive options are the only option.
     
  8. welder/fitter
    Joined: Jun 2008
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    Location: Vancouver

    welder/fitter Senior Member

    Tom,

    From 2006 Lincoln consumables catalogue:

    Electrode Name: Outershield 70
    AWS classification: E70T-1, E70T-9
    Recm'd Shielding Gas: 100% CO2
    General Description: Optimum performance on dirty plate! Designed for superior performance on materials with high levels of rust, oil, or mill scale. Outershield 70 is excellent for flat and horizontal groove and fillet welds.

    There is, as well, Outershield 70-H, for Low hydrogen applications. E71T? Sure. All position. Then there are the lo-hi wires. Better out of position, not as good for rusty/oily/dirty/mill scale/etc., though. Used it on a job at the Grand Bahamas Shipyard. My partner ran 7 feet of swiss cheese. Had to remove root with a die-grinder & re-weld. Bit of a disappointment. E70T is, by definition, a flat/horizontal wire. O.k., maybe 5x strength is exaggerated, though that's the common comment. I still suggest trying it out & seeing the difference for yourself. I think you're simply looking to argue. So, what's new. I responded to Haidan, in a PM, for obvious reasons. Didn't hear back.

    From the solid wire builders, I'd be interested in knowing wire/shielding gas/cfh preferences. Despite the recommended 25-35 cfh for CO2, with FCAW, at the shipyards, we run at around 55cfh. Some suggest that you cannot use gas-shielded wire in the slightest breeze. If that were the case, ships would take many years to build, as most commercial ship construction/repair is done with FCAW, and there is a constant breeze at the yards I work at.
     
    Last edited: Aug 13, 2008
  9. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    How can a weld be 5 times as strong as the surrounding metal, and what's it worth?
    Brent
     
  10. lazeyjack

    lazeyjack Guest

    hi guys
    this is is the machine I am looking at, because the site I am renting will have no power to it
    I have a delta weld, already, it can lay in bulk on straight mig,
    this machine has a 64bh Deutz and a 60cumin air comp built in too, it is very expensive and I guess if I buy it,ll be coming home every night on the truck
    Anybody used an eng driven on mig?
    i can not get my head around inverter welders, I just dont trust fot the long haul, my old 450 hobart I had since 1984 and it has been dropped from a chain hoist and , goes forever, I love mig, tig, stick machines, ok the weld on mig is not as classy as on a late model inverter, but chucking in 2 spools wire a day, I just believe in the old stuff, someone can convince me otherwise that ok too:)) will use this on al al ,
    oh and brent, a weld cant be 5 times as strong, but once we used a 680 electrode, which I believe had a tensile of 140,000 or something like, so the metal was twice the tensile of mild steel

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  11. tazmann
    Joined: Aug 2005
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    Location: California

    tazmann Senior Member

    Lazeyjack
    I use an SA 250 lincoln with the Deutz engine has cv tap and she runs mig great flux and solid. The only drawback I can think of is when I try to run .023" wire on light sheet metal, 16 gage is about the minumum I can go, amps dont go under 40.
    I bought mine about 10 years ago and I can say that deutz engine sure is nice very little maintinance, only probem I have had is the fuel return lines cracking after 5 years.
    Before I desided to get this one I was looking at the miller air packs but my welding supplier talked me out of it said they had some issues, never did say what the issues were but I had be dealing with this guy for years and he never steered me wrong.
    May I ask, what kind of welding are you doing to need that much amps?
    Tom
     
  12. lazeyjack

    lazeyjack Guest

    thanks for reply
    I run 230 amps on fillets all day on 8 and 10mm plate aluminium, so the hobarts ran 100% duty cycle 400 amps so there was lots of grunt, an anology would be a kenworth climbing a hill compared with an Isuzu truck
    The only reason i was looking at the air pac was, I use a weld chaser on an air grinder, so that appealed It may be that with the wire feeder and gun and remotes, that I can not run to this sort of money, they are 21000 USA for the machine alone
    but you are right, the machine would idle at that, I wll look further
    Sometimes on 1/8th plate when need to drop to say 14-16 volts then they are not so flash, yes my hobart had 50 amp min, but had arc force control which allowed welding of tig ss, the arc force is a wonderful tool esp on vert ups on smaw
    Monday I will try find something cheaper or second hand even
     
  13. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    Very serious welding machine Stuart:cool: However, for the last few years I had used a similar Lincoln machine in the mine shaft where I work with no ill effects.

    As for inverters, I believe in them - have 3 inverter DC Mig machines now, one Tig inverter and a few 200 Amp inverter arc welders. For whats its worth, we welded the Dix43 with a 200amp DC (220volt/25A supply) inverter Mig at an average 180 welding amps from dusk til dawn with no problem, overheating etc. And this is a baby, imagine the guts of the bigger ones....

    BTW, thanks for the drw.
     
  14. tazmann
    Joined: Aug 2005
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    Location: California

    tazmann Senior Member

    Lazeyjack
    Yep I under stand your anology, my lincoln is mounted on an Izuzu truck LOL I would emagine running that kind of amps you cant get by with air cooled guns eather.
    One other option if you cant find good used like you want, I have bought a couple on what they call a buisness lease, handy you dont have to come up with a big chunk of $. End of lease the equipment is yours, Bad thing you cant pay off early and you cant get out of it.
    I should mention one diferance I have noticed between engine driven and electric when it comes to mig. On mine and others I have used they do vary the voltage and amps on there own a bit. I can set the voltage dial on #4 and the amps in the middle range and I have pretty wide range on the wire speed. I like it that way for us ol time stick welders its a lot more forgiving.
    Tom
     

  15. lazeyjack

    lazeyjack Guest

    Thanks Tazz
    Well the hobart used to get hot (gun) but kept on running
    AS you know every stick and every wire has a max amperage, in 1.2 alloy wire its about 230 after that it vapourises!!, like you turn up a grunter on a 4mm stick will vapourise too
    i know nothing abt steel mig, in fact I have never used it, so i follow what some of you are writing learning, last steels i used only, SMAW .
    I often gaze at ships, those symetrical perfect seems on the topsides, how are they done, from both sides at once? in the flat position and then stood up as one giant plate?
    I have just been given 37k, plus gst here for that air pac!!marked up maybe 200% from import landed cost, greedy beyond belief, so I contacted an import agaent and tomorrow will callCanada, import the 300 version myself

    WELDFIT!! you made me larf, cut out 7 feet root
    , change to alloy my boy, weld from inside, come outside cut back with saw at 3 feet 30 seconds, lay in new weld at3 feet a minute:)) Welding steel, makes me tired just thinking about it all
    Tazz, those Cobras used to be very temperemental. down in NZ in the early 80,s they were 6k for the feeder and gun
    the Hobart Linear was the best of all, the wire ran trhough the centre of the motor, was picked up and spun out in a spiral, I had 5 of the suitcase linears, alas they stopped production, and now what to use? guns , assist type are so bulky compared to that Hobart pulling gun,
    this thread has some pros, it's nice to contribute
     
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