Stick welding question

[dstig1]

The XMT304s are what we used in class and they were great. And that was all Stick. When I came upon a great deal on one, I pounced on it. I traded my way up to it also, which can be a great way of saving money.

I started with a tombstone AC/DC welder but was running into limits on the upper end on DC, and I wasn't a fan of the coarse steps of adjustment. I got a great deal on it, and I kept looking. A Thermal Arc inverter came up at a great deal (if it's not blue or red, it doesn't sell easy...) so I got that and then sold the Lincoln for 2x what I paid for it. I had troubles stick welding with it - arc starts were hard on all rod types, but it worked OK. Later on I came upon the XMT with a wire feeder at an auction and I basically stole it. Then I sold the TA for more than I paid for it. It took a while to sell it (couple months) which didn't surprise me (it's not blue or red...). So in the end I netted an XMT 304 with wire feed for probably 20 cents on the dollar, new.

Keep your eye out for good deals and be ready to pounce. Sometimes you can turn around and resell it almost immediately if you got a great deal, sometimes you might need to do some cleanup or whatnot, but that's about all I did. My 2 cents...

 

[rankrank1]

You really think so? I never thought of it that way.
Be interesting to see if that old girl still works! I wonder if those lead lugs will even unscrew from that machine? I know for a fact that machine has never been on AC so I don't know if it ever worked on AC. I bought that machine new, because I had to practice for an upcoming 6-G test. Last time I used it was to see if it would work on that generator, that must have been about 10 years ago.

Yes, I do think that Century buzzbox is a miniscule notch below say a Lincoln AC225/DC125 or an original generation Miller Thunderbolt AC225/DC150 top crank (I have no personal experience with the current generation of Miller Thunderbolts which are simply a blue painted Hobart Stickmates with front mounted adjuster cranks). For practical purposes they are all essientally the same class of machine and were only seperated by a few dollars in price when new and Century had not yet been bought out by Lincoln. (Really the primary differnce is OCV 72 volts compared to 79 or 80) which is not real significant. As a young teenager in the late 1980's I tried very hard to convince my dad to buy a cheap welder to help maintain his farm junk. We priced the Lincoln, Miller, and Century although I never did convince him to spend any money. IIRC it Seems like the Century AC/DC was like $219, the Lincoln AC/DC around $249, and the Miller AC/DC like $279. Again these were mid to late 1980's prices and I may not be remembering exactly but I do remember the Century was the cheapest of the three (and probably why my uncle that I mentioned earlier bought one).

If your machine worked on DC then it absolutely has to work on AC. In this class of machine the transformer converts to AC output first and foremost. From there the AC weld output is then rectified to obtain DC weld output if desired. There is almost always some amp loss in the conversion process from the AC to DC on this class of machine - which is why DC is less than AC output.

It is possible for an AC/DC welder like these to only work on AC if one of the four rectifier diodes blows within the DC rectifier bridge.

Symptons of a bad diode will be:
a) If lucky you can still use welder on AC only.
b) If it happens to trip breaker immediately. Then disconnect the leads to the DC bridge inside the welder. If it now works on AC without tripping breaker on AC, then troubleshooting and fixing the diode is the likely culprit if you desire to regain DC output (a cheap fix). If it still trips the breaker, then transformer is likely shorted internally and junk, but a bad tranformer almost never happens. (note: this is real quick and condensed troubleshoot guide that eliminates obvious flaws like bare wires and bad selector switches).

 

[Chilly807]

I've got one of the Sears branded Century AC/DC welders as well. I got it well used, and the price was right. Nice little machine for the money. About the only complaint I'd have about it is the adjuster. It's a nuisance.

Sean

 

[cowski]

i never used a century.but i have used both tombstone and thunderbolt.i would always choose a thunderbolt over the tombstone.i do not remember any arc difference ,that crank on the thunderbolt makes it better.they need a 50 amp breaker for full power.i have used a xmt 304 it works good it has digital display .i would not hesitate to recommend a acdc thunderbolt for a farm shop welder.you could add a 110 Lincoln wire welder for thin stuff.those 2 welders should cover most farm welding needs but no aluminum .

 

[rankrank1]

i never used a century.but i have used both tombstone and thunderbolt.i would always choose a thunderbolt over the tombstone.i do not remember any arc difference ,that crank on the thunderbolt makes it better.they need a 50 amp breaker for full power.i have used a xmt 304 it works good it has digital display .i would not hesitate to recommend a acdc thunderbolt for a farm shop welder.you could add a 110 Lincoln wire welder for thin stuff.those 2 welders should cover most farm welding needs but no aluminum .

With most of these little buzzbox machines you often do not even need a 50 amp breaker. Most of them specified a 50 amp fuse because a fuse did not have time delay capabilites like a breaker can have. Most of these will only pull 37-40 amps at WOT, but there will be very brief milli-second spikes at higher amps hence the bigger fuse recommendations.

Another nice thing is that any of these can be easily powered with 10 gauge wire at up to lengths of 95 feet from panel. (Heck Miller manuals permitted even 12 gauge wire on shorter runs but I would never go that small. First thing I did to both of my buzzboxes was remove the small 14 gauge 4' factory cords that came on them and replace with 10 gauge cords salvaged from used clothes dryers) While 10 gauge wire is only rated for 30 amps continuous load it is NEC code legal to oversize the breaker with 50 amp breaker for a welder like these due to these particular units low duty cycle. (That said, oversized breaker on undersized wire means that safety steps are also required to ensure that the circuit is used for the welders like these only - IT CAN NOT be used to power any other equipment or even other bigger welders that may have higher duty cycles).

With either a 115 mig or an AC/DC buzzboxes then some very crude welding of aluminum is possible. The mig requires a teflon liner be installed in the whip and keeping the whip as straight as possible to avoid wire bunching - do expect wire feed problems and lack of oomph though out of a 115 volts mig on aluminum. There are also aluminum rods for DC arc welder that can work decent too for some aluminum applications. Either will produce somewhat crude results but if we limit to farm shop applications then it can easily work in a pinch although neither would likely be acceptable to a true welding professional. That said, in a farm shop we are often dealing with repairs so the weld only has to be strong and sound - looking pretty is just a secondary bonus item.

 

[KYErik]

Yeah- I have my 225AC tombstone on a 30 amp breaker (it is in an outbuilding). I can weld at up to 115 amps just about continuously without a trip. I can do 140-150 amps in 15 second bursts without tripping it.

 

[cowski]

poor choice of words 'no aluminum ' should of said not the best for aluminum .i have not stick welded aluminum ,with a Lincoln wire welder to weld aluminum you need argon bottle,u rollers ,Teflon liner and a bigger tip. forgot to add a helper to hold the cable straight .really stressful way to weld ,but will work.i think i popped a 40 amp breaker with my thunderbolt.it was years ago.been on 50 amp ever since.hardly ever use it now ,can't part with it.

 

[deereman75]

Well I popped the breaker with my tombstone today. 30 amp breaker, welding at 130 amps. I had just been welding at 145 amps and it was fine. I think the issue was either a really bad ground, or I did the impossible and killed a lincoln tombstone.