Dc or ac welder

[dirt clod]

I can find some good deals on used "tombstone" welders. All the ones I find are ac only though.

What is the benfits of having a dc welder?
Would I give up much if I just bought a ac welder?

 

[gerard]

I can find some good deals on used "tombstone" welders. All the ones I find are ac only though.

What is the benfits of having a dc welder?
Would I give up much if I just bought a ac welder?

If memory serves DC is more versatile for some vertical welding and certain types of rods NEED DC. It also gives you a little nicer arc and hence a smoother bead.That said I have the lincoln tombstone AC225 and it does everything I need for mild steel. If you're looking to do "farm" welding you can get by just fine with an ac only. Not as easy as mig and won't work well on really thin stuff or sheet metal, but any kind of metal stock at least 1/16" think is weldable effectively with a stick. (Also can't beat the price - prbably looking under $300?)

 

[bota7800]

There was a lengthy thread on this very subject (although it got highjacked into a separate welding discussion. Good reading there. I have an AC machine but no experience with it yet. I have been using a nice DC machine at the local community college. There are less electrodes for use with AC but there are some and many people get by fine with it alone.

Oh, and unless you are looking new it should be well under $300- The going rate used seems to be less than $100 for most units. There is not much that can go wrong with them, I am told.

Here are a couple welding forums:

WeldingWeb - Professional Welding Forum - Powered by vBulletin

Weld Talk Message Boards - Powered by vBulletin

 

[dirt clod]

Thanks. The dc machine would be easier to give smooth welds?
I have a small 120v mig, for most things I would use it. Was thinking about stick welder for 1/4" and above. I've used a few mig machines, never used a stick machine though.

 

[California]

You can easily find 200 amp AC welders for under $100 on Craigslist etc that will make a solid weld on 1/4 inch and up.

I paid $50 for a 230 amp AC welder. It's maybe 40 years old. I took the cover off to clean out the cobwebs and there's nothing breakable in there, just a 100 lb transformer with massive windings. The fan is the only thing that could possibly wear out, and that would be a $10 repair. Maybe the case will rust someday - I can't imagine anything else breaking. 230 amps is still 230 amps after all those years. it's a simple brute-force tool like a hammer.

If you are willing to spend $400 and up then you might consider AC/DC. For me, I didn't see the need.

Sample weld photo.
http://www.tractorbynet.com/forums/...taking-welder-plunge-p1110932rweldgardoor.jpg
I posted this a while back. The hinge pivot pin on my garage door tore out of the main arm so I welded it back in.

That's the sort of utility welding I use this for.

 

[SpringHollow]

I have a used AC unit and recently bought another used AC/DC unit. I find the DC easier to weld with.

Ken

 

[Soundguy]

I agree with california.. I have a hobart stickmate 235xl.. it's just a big ole' ac stick welder.. busts thru rust and crud just fine with a 6011 rod.. have welded 1/2" and 3/4" material before... used it to weld the wing hinges back on my 15' batwing mower when they cracked and broke... never had a problem with them since. If I want a pretty weld and a strong weld.. I do the work with 6011, then grind it, then hit it with 6013... with a good hand you can get that row of dimes look almost like a mig...

I've used a 250a mig at work.. sure it is nice. but it cost 2200$ more than my 235a ac stick .. I'm not a welder.. I just glue a few things together on my farm..

soundguy

 

[wa9w00d]

Dirt,
Like others have said here, there is a lot of useful work to be done with an ac only machine. What would you give up? Overhead welding, but trust me you don't want to do that anyway. And vertical usually requires a "stop and go" technique. And for farm welding, you just can't beat the 6011 rod. Knock the bigger dirt clods off and weld. Everything else requires a pristine surface. The downside? 6011 slag is tougher than Chinese arithmetic. If you really want it off, get one of those needlegun attachments for an air hammer.
Later,
Wayne

 

[EastTexFrank]

Like you, I have a 120v mig that I use for most stuff and a Hobart AC stick for heavier stuff. The stick is for "farm welding" or superglueing things back together so it doesn't have to be too pretty which is just as well because my welding sucks. My welding buddies say the DC welding is easier and "cleaner" but for what I do with it, it probably doesn't make a whole lot of difference as I'm not too worried about the appearance, just the end result. It is nice not to have to spend a whole lot of time prepping the metal before running a bead as AC will burn through most rust and paint to give you a functional weld.

 

[Pennsylvania Weldor]

If you can afford it, go AC/DC. You won't be disappointed. As a former welding instructor, and recently retired from my welding/fabrication business, DC would be preferred over AC. AC machines are more reasonably priced, and for the occasional "stick it together" operation, just fine to deal with. DC machines are much more versatile. I have to disagree with one poster regarding MIG over Stick. When it comes to weld strength, I'll put my stick welding up against ANY Mig weld, ANY day. I have a couple of MIG machines, a Miller Spool gun for aluminum repairs, and a Digital Lincoln for steel MIG welding operations.

These are the electrodes I use the most. The Lincoln 5P+++++ (E6010), ESAB Atom Arc E7018, and the old "burn through anything E-6011. Of course I have many different electrodes, for different purposes. For extremely high strength welds I use the E11078.

A quick course in Electrode identification: The numbers imprinted on the rods identify them, i.e. E= Electrode; THE FIRST 2 or 3 DIGITS tell us the strength, thus the 60=60,000 PSI Tensile Strength.
THIRD or FOURTH DIGIT 1=Welding Postion, and in the case of 1 it's an ALL POSITION electrode, 2= FLAT AND HORIZONTAL ONLY, 3=FLAT ONLY.

The last digit tells us the Welding Polarity and Flux coating composition. You can check out and get all the specs from your local welding supplier, or, the AWS web site.

An E6010 rod is for DC Reverse Polarity only. Won't work worth crap on an AC machine. The E6011 will work on both the AC or DC machine. Much easier to use for the novice.

WELD PREPARATION can't be stressed enough. The cleaner your weld joint, the better the weld. Also, for cleaning slag, I use a 4 1/2" angle grinder with a wire wheel. Works great, saves time, makes the job look better.

If I can be of any help to anyone, please don't hesitate to ask. I'm a newbie to this forum, but not to the welding/maintenance world.