Help choosing a welder

[rebb]

Brian,

all i 'know' is what my welding instructor told me. he said he had been inside a big galvanized tank doing repair, and he woke up in the hospital. for me, i have always, therefore, seen to it i had the best ventilation i could get if i welded anything galvanized. you may be right; i don't know, and i'm NOT going to find out. someone has that signature line here that i think is great 'some learn by reading, some by observation, and some have to pee on the electric fence'...i have never been one to have to pee on the fence very often surely don't have to do it twice
rebb

 

[gemini5362]

Assuming that you're using the same electrode... no. Amps are amps, and 235 trumps 180, even though one is AC and the other is DC. If you're going to be welding the thick stuff and want to do it single pass, you'll have to switch the machine to AC to get the higher amps. The arc won't be as smooth, but it still works fine.

Since I only weld with a mig I wont be able to answer this from the perspective of what the different kind of rods will do like Pat g did. I will point out however that amps are not amps. DC amperage is exactly what the specs call for it to be. However AC amps are usally figured peak to peak since AC curent is in a sine wave then at any one instant of time the amperage will be less than 235 excpept during the peak of the sine wave it will be 235 amps (60 times a second) The average current in ac would be the RMS current which is found by taking the peak 235 amps and multiplying it by .707 which gives you 148.47 amps if that helps you with your question any.

 

[Soundguy]

Actually.. 'average' and 'RMS' are different calcs. Remember.. 240/120v are 'RMS' measurement already. To see the real votlage on your wall plug you need to get a peak reading volt meter.. or do the calc.. ( probably closer to 170 off hand.. )

soundguy

 

[patrick_g]

Thomas (Gemini) and Sound guy. Actually, the average voltage of a sine wave is ZERO although the average power is not since E squared over R is always positive in sign so the positive and negative alternations both produce positive power.)

I believe welder current specs are typically given in RMS (root mean square or DC equivalent) so there is no need to manipulate the ratings to adjust for waveform.

Thomas, what you said would be completely true if the welder specs were given in peak to peak but I don't believe that to be the case.

Even the MIG units typically have a means of changing between straight and reverse polarity (stinger has to be set to + or - depending on the wire in use. You need to swap polarity when you change to aluminum.

I hope the OP is not confused by out technical nitpicking.

Pat

 

[lovemytoys]

i just pick up a Miller Econotig still havent tried it out but soon

 

[xlr82v2]

Guys,

This technical nitpicking ONLY serves to confuse ANYBODY who is not familiar with the part of electricity that can't be observed without an oscilloscope. Myself included.

When I said "amps are amps", I did so from the perspective of the guy (or gal) holding the stinger running a bead joining 2 pieces of steel. I can assure you, that although the arc characteristics are a little different, overall performance and results with a buzzbox running a 1/8" 6013 electrode (for example) set at 130 amps DC are quite similar to those obtained with the box set at the same amperage level running AC current. Go fire up your buzzboxes and try it for yourself!! Tell me I'm wrong!! We're talking about making 2 pieces of steel into one here, with a good, sound weld. Not, "well, I've got steel part "A" here, which I intend to join to steel part "B". I've got my machine set on AC current, which, by it's nature, has a RMS of...." bullcrap. I guarantee that if you follow the advice offered by Gemini and weld at 140 amps DC, then set the machine to AC and set it to 235 amps because of what Gemini said, you'll be in for quite a suprise!!!

Introducing all of this hyper-technical babbling into the discussion started by the OP serves absolutely no purpose other than as an avenue for those engaging in it to attempt to do a little "techno-snobbery" and self-inflation against whoever. It truly serves no other purpose!!! If you can explain how it does positively contribute to the OP's concerns/questions, without confusing the overall topic of this thread or anybody reading it, really, I'm all ears.

So, in order to prevent this in the future, please keep your replies oriented from the perspective of the workshop, not from the laboratory. We're welding, guys, not building transmitters or whatnot... so please, let's keep it in that perspective.

 

[Soundguy]

Guys,

This technical nitpicking ONLY serves to confuse ANYBODY who is not familiar with the part of electricity that can't be observed without an oscilloscope. Myself included..

We aren't nitpicking.. we are asking questions. My question in particular was asking about penetration. I'm primarilly a AC welder.. i have access to an AC/DC machine.. but don't use it.. I have welded Mig.. which is DC.. but compairing mig to stick is not an apples to apples deal.. i was looking for a DC stick to AC stick comparison.. plus a little o fthe underlying principle in why/what where.

I've got my machine set on AC current, which, by it's nature, has a RMS of...." bullcrap. (..

It's not BC.. it's a technical discussion that falls within the topical nature of this thread.. it's completely germane to the topic being discussed. Just because you find it to be BC.. doesn't mean all the rest of the members of this board do.

Introducing all of this hyper-technical babbling into the discussion started by the OP serves absolutely no purpose other than as an avenue for those engaging in it to attempt to do a little "techno-snobbery" and self-inflation against whoever. It truly serves no other purpose!!! If you can explain how it does positively contribute to the OP's concerns/questions, without confusing the overall topic of this thread or anybody reading it, really, I'm all ears. .

This is by no means hyper-techno bable.. this is plain 1st year high school electronics 101.. E=IR type stuff...

If you don't understand it.. that's fine.. but please don't insult those of us that do. Frankly.. your 'snob' comment is rude. This is a technical discussion after all.. you don't supose some technical terms and concepts might actually come up do you?!?

It truly serves no other purpose!!! .

No purpose? perhaps none that you are aware of.. I'll agree to that.

So, in order to prevent this in the future, please keep your replies oriented from the perspective of the workshop, not from the laboratory. We're welding, guys, not building transmitters or whatnot... so please, let's keep it in that perspective.

If you don't like it here, why don't you go start your own board and set your own rules. Or.. do like everybody else does.. if you don't like or understand a thread.. just skip it and go to the next one. No one has forced you to reply to this thread... If a few electronic words make you uncomfortable.. just skip this thread... it's no biggie.. but please don't insult others.. or throw down your own rules on who can or can't reply to what thread.. or how the reply needs to be framed. that's for the mods and admins of the board.. not us.

soundguy

 

[flusher]

You might as well just get the AC/DC stick to be able to.

1. weld easier on DC
2. have more choices for whatever your welding.

My advice also. I have a Hobart Stickmate AC/DC welder that works great ($350 from Tractor Supply).

Welding isn't difficult. It just takes practice. My biggest challenge was holding the gap steady at 2-3mm. Mostly a matter of hand-eye coordination. After you burn 5-10 lb of 6011 rod, your muscle memory will start to take over and holding the gap and getting a decent bead will become easier.

Get yourself a good welder's jacket and gloves. I like to wear a hood (aka balaclava) rather than a cap to make sure I don't get spatter tossed into my ears or down my neck. I have a $50 autodarkening helmet from Harbor Freight that works fine.

 

[Soundguy]

Ditto on the jacket. I used to use an old denim jacket.. but finally upgraded to a nice flame retardent green material jacket with high collar, and leather sleaves.. that and some long cuff gloves and a good helmet and boots or shoe protectors and you are good to go.

soundguy

 

[patrick_g]

Sound Dude, Thank you so very much for your point by point comments and their obviating my need to make similar but less pleasant ones on that topic.

I good friend of mine, a professional welder, had a spark get in his helmet, past his skull cap with backwards bill, and into his outer ear where it burned a hole through his ear drum. He got it fixed but the whole experience was not good. This was wearing the standard approved safety gear. It is not a real likely event but it does happen. I think I want a Nomex balaclava.

When I really get into welding mode, especially using stick rather than MIG, I wear leathers that cover my shoulders, arms, and chest/lower neck. I discovered via an arc burn on my lower throat while wearing everything I thought was needed that the little leather flaps you can attach to the bottom of your helmet will protect your neck from arc burn.

I apologize to anyone who's day was ruined by any of my personal hyper-technobabel and also my condolences to anyone for whom anything more complicated than slip joint pliers is hyper technical and for them indistinguishable from magic.

The difference in welding with AC and DC is not such a fine distinction as to not be noticed by an observant person. The characteristics ARE NOT THE SAME.

Lets conduct a little poll and maybe learn something... Do we have any technically trained professional welders here? If not, do we have folks with access to same?

Given the availability of a welding machine that can provide either AC or DC, when and how often do they select AC over DC and why?

I personally have never seen a pro select AC over DC but maybe my observational experience is too limited or skewed. So lets get more data points.

Why grind on this issue? Someone asked for help/advice. If DC is as I suspect, better in most instances than AC, then good advice would be to go the extra expense and get a buzz box that also supplies DC. If in certain instances AC is to be preferred then the guy will be prepared as the welder will offer both AC and DC. This is not to say that AC doesn't weld OK but what if DC is better enough of the time to warrant the extra cost? Then it is better to advise the guy to go AC/DC.

Food for thought... If DC isn't needed or useful then why supply buzz boxes that are AC/DC? Why would folks pay more to get a feature that is inferior to the AC only machine which is cheaper? So is there a conspiracy among all the major manufacturers of buzz boxes to hoodwink the public into buying "bogus" extra cost features that perform worse than the cheap version? Probably not. Most likely DC offers utility worth the difference or the units wouldn't sell.

Pat