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Yeah another "Which Tig Machine" question...

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    OldSparks
    Senior Member

  • OldSparks
    replied
    O.K....so we agree that dhdh71 will be able to weld on his 1/4" attachments with one of the Maxstar/Dynasty 200 series. He's stressed a few times that he's not really interested in aluminum so it can be a dc machine. Maybe someone could write in on the value of the pulse arc for controlling distortion on the sheet metal. I imagine it's a must have for bodywork. In any case I think dhdh71 should go with one of the dc Maxstars or possibly the CST 250. He could spend the money he saved by sticking to dc on a set of anvils and his first tig/practice project could be building an english wheel.

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  • fun4now
    Senior Member

  • fun4now
    replied
    inverters

    it would seem that the inverters change the graph a bit as well, with a sharper arc controling the heat displacement you can get a bit more out of the same amp's . this has a lot to do with there advantage on aluminum. not discounting it's other advantages.

    also we must keep in mind that the .001 is just a good starting point not the law of metal god's. and wile welding co. want to impress you with great #'s they dont want to tell you you can weld 1" with 150amps then try to explain all the steps necicary to actualy make it work(i think someone already mentioned the disclaimer problem )

    long and short of it is the dynasty 200 will do 1/4" but if you intend to do 1/4" all day long 5 days a week to make a living you should look for a lil more omph. the 300DX would be great

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  • fun4now
    Senior Member

  • fun4now
    replied
    inverters

    it would seem that the inverters change the graph a bit as well, with a sharper arc controling the heat displacement you can get a bit more out of the same amp's . this has a lot to do with there advantage on aluminum. not discounting it's other advantages.

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  • burninbriar
    Senior Member

  • burninbriar
    replied
    Originally posted by OldSparks
    I've been following this thread because I thought 275-360 amps on 1/4" plate (Miller Tig Calculator) was meant as a production thing and not a necessity for a sound weld. I wanted to assure you that you could weld your 1/4" attachments at 150-170 amps and you could get away with the smaller machines you were looking at. I still think you can. But I've been wrong before and I won’t press the point. Seeing your vehicle is only as safe as its weakest link I guess you will have to get one of those big hunking machines.
    I found this other chart from 'Modern Welding' . Maybe you should get a second opinion.
    The 1 amp per .001 rule is a general guide line and works out to 250 amps on 1/4". The chart you posted shows 175-210 amps for 1/4".Pretty close concidering that the .001 rule is a general rule covering all applications.

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  • OldSparks
    Senior Member

  • OldSparks
    replied
    dhdh71

    I've been following this thread because I thought 275-360 amps on 1/4" plate (Miller Tig Calculator) was meant as a production thing and not a necessity for a sound weld. I wanted to assure you that you could weld your 1/4" attachments at 150-170 amps and you could get away with the smaller machines you were looking at. I still think you can. But I've been wrong before and I won’t press the point. Seeing your vehicle is only as safe as its weakest link I guess you will have to get one of those big hunking machines.
    I found this other chart from 'Modern Welding' . Maybe you should get a second opinion.
    Attached Files

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  • OldSparks
    Senior Member

  • OldSparks
    replied
    pjseaman

    Are you saying that there should be physical evidence of the fillet weld showing through on the bottom of the 1/4" plate?
    Attached Files

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  • burninbriar
    Senior Member

  • burninbriar
    replied
    Originally posted by fun4now
    as i understand it if you dont have the amp's you can play with the setup as in beveling and multy passing and preheating. but the miller calk is for single pass full penitration. so yes you can weld 1/4" with less than 250amps just gota use more time in prep amd procedure. time is $$$$ and it iss cheaper in the long run to spend the $$ to alow single pass than to pay someone to spend 2hr's preping for a 10min. weld

    that being said i have more time than $$$$ so it looks like ill be multy passing and preping
    Good to see youre enjoying you're retirement.
    HAVE FUN

    Leave a comment:

  • fun4now
    Senior Member

  • fun4now
    replied
    as i understand it if you dont have the amp's you can play with the setup as in beveling and multy passing and preheating. but the miller calk is for single pass full penitration. so yes you can weld 1/4" with less than 250amps just gota use more time in prep amd procedure. time is $$$$ and it iss cheaper in the long run to spend the $$ to alow single pass than to pay someone to spend 2hr's preping for a 10min. weld

    that being said i have more time than $$$$ so it looks like ill be multy passing and preping

    Leave a comment:

  • Paul Seaman
    Senior Member

  • Paul Seaman
    replied
    Old sparks the weld looks fine on the face but is there a nice weld crown on the root side, if not then you didn't get there!

    Peace,

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  • burninbriar
    Senior Member

  • burninbriar
    replied
    Not being a profetional welder myself,I'm just useing logic here.
    I have seen weld criteria that requires multiple pass welds so I dont think its a matter of sole strength but more a way to rate the machine.Obviously a single pass weld will be faster and more cost efective than multiple pass welds.

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  • OldSparks
    Senior Member

  • OldSparks
    replied
    I found some ¼” material and ran off a fillet at 200 amps. Not trying to maneuver around the corners made things easier and I found the 200 amp setting no problem. The Miller tig calculator calls for a minimum of 275 amps for this joint. Although I didn’t go that high I realize now it isn’t such an outragous number. A welder working in a nice comfortable position, straight line welding with large pieces to soak up the heat would be able to put in a beautiful weld. What I question is whether this heat is for maximum production and efficiency or if this number has to be taken as a minimum to produce a structurally sound weld? I think it would be pretty tough to handle 300 amps welding around small attachments while laying on your side on the floor. Isn’t it possible to get a sound fillet on ¼” at around 150 amps by going slower and/or multiple passes and/or beveling the material.
    As for my machine, I have an XMT 304 cc/cv. I got it a while back before the ac/dc inverters came out. I don’t really have any need for aluminum but it would be nice to play around with. Probably just as well I don’t have ac, I haven’t got dc figured out yet...
    Attached Files

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  • burninbriar
    Senior Member

  • burninbriar
    replied
    Originally posted by OldSparks
    I'll add a little confusion. I do a lot of steel tube butt joints and I can't even remember having to do a serious fillet. I was surprised to see the amperage you guys are talking about for 1/4" plate. I just went out and threw a few pieces together. The verticle pieces are 3/8" thick being welded to !/2" plate on the bottom. I ground a 1/8" chamfer on the 3/8" piece. The first picture shows the tack-up, the second is a three pass joint and the third is a single pass joint. All welds were at 170 amps. I really couldn't justify using any more heat and would feel more comfortable with less.. Do people really weld 1/4" steel at 250 amps?
    As for your machine selection, I recently spent some time on a 'CST 250' dc machine, valve on torch, no foot pedal. Bare bones but a real dandy stick/tig machine.
    It was me who originally mentioned the 250 amps.I was meerly quoteing the 1 amp per .001 metal thickness rule for single pass welds.I now the rule is very acurate for thin guage material witch is what I bought my tig welder for.I have not tested it on anything over 3/16".For heavy peices I will more than likely be stick welding but I beleive dhdh71 wants the tig weld for apearance.I dont know if this would be best acomplished wiyh single pass or not.
    Out of curiosity,what machine did you use to make youre welds.

    Harbor Freight is like politics,allways there for a good laugh.

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  • Paul Seaman
    Senior Member

  • Paul Seaman
    replied
    Oldsparks:
    In machine capacity nearly everyone will be referring to single pass capacity. Multi-pass is a possibility on many jobs but it isn't generally cost effective in a production tig shop. I know with Helium and multipass and preheat you can weld much thicker than the spec's refer to but these are extra steps. What kind of company would say that a low amp machine can weld 1/2" plate and then in the insurance disclaimer make a hundred prerequsites that have to be met to do it.

    I have welded much thicker with my machines that the spec's sheet list but these are known quantities and known process perameters.

    As for a 3/8" plate you referred to if someone is looking for a machine to weld a given thickness then I assume they want 100% penetration and the multi-pass may not {and probably wont} get them there, no disrespect intended you are right but not entirely.

    Thanks,

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  • OldSparks
    Senior Member

  • OldSparks
    replied
    fun4now

    I thought someone was talking 250 amps for 1/4" to 1/4" plate. I bevelled the bottom of the 3/8" plate to allow a larger bearing surface without needing the extra heat to penetrate to that depth. Doesn't that produce the same results?

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  • fun4now
    Senior Member

  • fun4now
    replied
    burninbriar

    i figured you were joking, i was just thinking if he got the dyn.200 and didnt like TIG he could just give it to me


    hummm i gess he could just keep the Harbor Freight speicial as a large papper wait.

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