120v Mig Welder Limitations

[jegg]

So....My wife bought me a little 120v Lincoln Weld Pak HD welder about 6 years ago for my birthday and I've just now started to set it up and start using it. I've bought the MIG conversion kit for it and hopefully I'll be able to pick up some gas this weekend.

I've read that 120s aren't ideal for structural type fab work and that I'll be limited to what I can weld. I've read that body work is good for these welders. Would fabbing up a weld table be ok with this machine? Will it be strong enough?

What about bicycle frames and repairing cracked ones with this machine? Will that be ok?

Forgive my ignorance.....I'm a straight up noob.

 

[e-tek]

As for bike repairs, most bike frames are chomoly, which doesn't weld easily with MIG (pre-heating required). A 120V MIG is good for sheet as you stated, up to 14G and even 12G. For structural steel, you can often do several passes (multi-pass) to add strength, but it may not be quite powerful enough power to puddle-in to the parent metal. 3/16" is about max for a 120V, which is actually fairly thick - you just may not be able to weld the top plate to the legs very well! The duty cycle is shorter on smaller welders to. If it's a 20% DC you 'supposedly' can weld 2 mins out of every 10 and not overheat it, but I find those to be VERY conservative ratings.

 

[GirlnAgarage]

Those small welders are typically rated for 1/8" max, and that's using fluxcore (which penetrates better than MIG). That said, I've used my little WeldPak on 3/16" & 1/4" with FC. These welds were NOT structural or critical. I say critical in describing critical to my life, not critical to the thing I was building (used for support pieces on my sheetmetal brake).

If you insist on using that 120, use FC, not gas, and bevel. Consider multiple passes and yes you must grind clean in between to get rid of any stubborn slag that won't scrape off. Also, watch your duty cycle. If you're welding a lot you will hit it. And welds get cold when the duty cycle starts reaching its limit. That will made for cold, inferior welds.

Anyway, you can build some things but you have to know the work arounds and especially the limits of the machine. Best case though, keep the small welder for thin projects and move to a more capable machine for larger projects. I know though that sometime you have to work with what you got. Just use your brain and stay safe.

 

[Outlawmws]

Agreed, bike frames would not be a good thing to be doing with a 120 wire welder.

As for heavier materials, if you preheat the materials (Torch, even a Bernz-O-matic in a pinch if not to heavy...) you can get much better penetration, and it actually welds "cleaner" (prettier) than cold welding.

Get some scrap and PRACTICE, and I'd urge you to take a night school class on welding in any case.

Another good thing to do in practicing is to weld two pieces together and do some 'destructive testing" -get a chunk of angle in a vise and weld a tab onto it then break it off.- keep doing that with different techniques, and passes, and different starting heat for the base materials. (One of the reasons multiple passes is so much better (assuming you don't let it cool off between passes), is the first weld heats it up and subsequent welds benefit from the "pre heat")

You can even rig a beam type torque wrench to get a better idea of how much force is needed to break the welded joint.

 

[willymakeit]

I have a 135 which is rated for 3/16. I dont weld over a 1/8 with it since penetraton seems suspect above that. Great for anything below that and on sheet metal I use a product called easy grind, which cleans up faster, seems alittle softer also.

 

[MoonRise]

RTFM.

In general, the little 120V wire-feed welders can usually go to ~16 gauge (about 1/16 inch thick) with GMAW and maybe up to ~14 gauge.

With FCAW, they can go a bit thicker usually (because FCAW wires burn 'hotter'). That usually gets you up to ~1/4 inch thick with some 0.035 FCAW wire like Lincoln NR-211-MP.

NOTE Lincoln's NR-211-MP wire has a MAX workpiece thickness rating of 5/16 inch for wire sizes of 0.045 and smaller No Matter What machine you are using. That is a thickness limit from the wire itself, not the machine or process or anything.

FCAW has spatter and slag to deal with, GMAW is a 'cleaner' process (when the correct parameters are being used by a competent operator). But for the same machine power-output limits, FCAW can usually let you work on slightly thicker workpieces than GMAW can.

Within their limits, the 120V wire-feed machines are fine. But those limits are a bit lower than even the next step up in power, the 240V input power 180-class machines.

For working on sheetmetal up to about 14-16 gauge (~1/16 inch thick or less), they have enough power to use GMAW (usually).

For working on 1/8 inch steel up to 1/4 inch steel or so, you pretty much have to use FCAW wire (and deal with the slag and spatter).

A cracked steel bicycle frame? A lot depends on the thickness of the steel, if the steel is plain low-carbon steel (can usually be welded without any issues, if the thickness of the steel is within the ouput power limits of whatever machine you are using and the operator is competent) or if the steel is an alloy-steel (can usually NOT be easily welded without various pre-heat, interpass, and post-heat limits, as well as possible alloy-matching between the parent material and the filler/electrode wire).

btw, Chro-Moly can be welded using plain mild steel electrodes. Sometimes. With the right parameters and dilution ratio and fillet size and ...

But something else to think of. If the OEM bike frame cracked, that means the design or material or workmanship of the OEM unit failed somewhere and thus the piece cracked.

Fixing a cracked or broken item properly depends on not only doing a good workmanship job, but also figuring out the 'why' of the failure so that your repair doesn't just fail in the same way.

Also, some steel bicycle frames are not welded, but are brazed (or lugged and brazed). No way can you just go and try to weld such an item back together if the previously brazed joint 'broke'.

And an aluminum bicycle frame? Forget about using a 120V wire-feed welder to do that. An aluminum bike frame is usually TIG welded (for the control that the TIG process enables).

Go to the Miller or Lincoln or ESAB websites and read up about welding.

http:/www.millerwelds.com

http://www.lincolnelectric.com

http://www.esabna.com

especially the info/education area

http://esabna.com/us/en/education/index.cfm

and

http://esabna.com/us/en/education/esab-university.cfm

 

[Capstone]

My MIG135 with FC did a great job with my Weld Table Build. It's 3' x 6' x 38" tall and all of the square tube I used is 14Guage in either 2x2 or 1x1. I've loaded it up with all the needed tools and a tool box. I estimate it to weigh around 800lbs rolling on 4-300lb rated tires and it rolls just fine. I'm going to do a complete write up soon, once I get all the photos hosted

 

[e-tek]

My MIG135 with FC did a great job with my Weld Table Build. It's 3' x 6' x 38" tall and all of the square tube I used is 14Guage in either 2x2 or 1x1. I've loaded it up with all the needed tools and a tool box. I estimate it to weigh around 800lbs rolling on 4-300lb rated tires and it rolls just fine. I'm going to do a complete write up soon, once I get all the photos hosted

Waiting to see this!

 

[sberry]

In all reality a good table design should put very little stress on the welding.

 

[crewchief888]

i run .035 flux core wire in my licoln 140 unless i'm doing a lot of sheetmetal.
then i'll switch over to .023 wire and mix gas.

i've built a lot of bumpers, mounts, rock sliders, cages, seat mounts, suspension mounts, and lincoln locked more than 1 axle with my "little" 140.
it's time consuming running multiple passes, and theres a little spatter to clean up

 

[Jeff Ivers]

I have owned a WeldPak 100 for about 15 years. I have made a ton of stuff, including a new tongue for a utility trailer that hauls up to 1000 pounds, a light pole for a restored gas station light, multiple tire racks... The welding experts and the company will all tell you about the limitations because of liability concerns and the fact they don't control the definition of "structural" in the minds of the user of these machines. Think about your design and what will happen if a weld fails - will the table top continue to set on top of the legs or will it drop to the floor because you tacked the legs to the side of the top? I would not attempt to fab a receiver hitch to tow a car trailer with one of these. I can't see any reason to not make a well-designed welding table.

 

[e-tek]

I have owned a WeldPak 100 I have made a ton of stuff, including a new tongue for a utility trailer that hauls up to 1000 pounds, ......... I would not attempt to fab a receiver hitch to tow a car trailer with one of these.

 

[theoldwizard1]

One thing about 120V welder that is also common with 120V air compressors is that they will both commonly trip a 15A breaker, especially in a detached garage, where the circuit from the house to the garage is wired with 14 gauge.

 

[2manytoyz]

I have the Lincoln WeldPak 100HD. I tried basic wire welding with it but didn't like the results. I later added the MIG kit, and really like it now.

It's rated up to 1/4" material, but I typically only weld 1/8" to 3/16". Does a fine job on those.

Here's a small hitch for my riding mower.

FWIW, I've never had it trip a 15A breaker, and recently ran it from my Yamaha EF2400iS generator.

If you're welding up big projects, get a big welder. For a homeowner like me, who occasionally needs to stick pieces of metal together, the 120V model works fine.

 

[Jagmandave]

I also have one of these little hobby welders and I've done some amazingly good stuff with it, just - as the others have said - be aware of it's limitations.

Here's a pic of something I was building, the material is about 3/16" thick or so, the only reason I stopped mid-weld is that my eyes aren't as good as they should be and I wanted to make sure I was where I wanted to be with my weld track.

This is an off brand (Clark) 120V welder that I've had for at least 20 years. My point here is only that you can lay down a nice bead and get good penetration with one of these - this was done with mig gas and .24 wire.

 

[GarageEnvy]

I have a little Hobart 135. It has tripped the breaker a couple of times. I frequently weld .120 wall tubing with it without problems. I wouldn't go much more than that though. I did the whole base of my welding table with it. However, when it came time to weld the 3/8" top on, I used a stick welder.

One other limitation that hasn't been mentioned yet is duty cycle. I made some ornamental iron gates with overlapping tubing. With lots of 1" welds so close together it was easy to exceed the duty cycle of the machine if I didn't slow down and wait a bit.

 

[GirlnAgarage]

One other limitation that hasn't been mentioned yet is duty cycle. .

You might have skipped these...

...The duty cycle is shorter on smaller welders to. If it's a 20% DC you 'supposedly' can weld 2 mins out of every 10 and not overheat it, but I find those to be VERY conservative ratings.

... Also, watch your duty cycle. If you're welding a lot you will hit it. And welds get cold when the duty cycle starts reaching its limit. That will made for cold, inferior welds.
....

 

[jegg]

I finally have time to reply back to this thread. Thanks for all the replies everyone. Looks like I just have to practice and find out what works if I were to weld thicker stuff.
Do any of you actually preheat your metal before you weld? If so, what do you all use?
I don't really want to buy a new oxy/acetyl torch setup for this. Are there other options? Can I just use a regular old hand propane torch?

 

[sberry]

Weld all the bikes you want with it.

 

[Outlawmws]

I finally have time to reply back to this thread. Thanks for all the replies everyone. Looks like I just have to practice and find out what works if I were to weld thicker stuff.
Do any of you actually preheat your metal before you weld? If so, what do you all use?
I don't really want to buy a new oxy/acetyl torch setup for this. Are there other options? Can I just use a regular old hand propane torch?

I often preheat, and always on heavy materials. small parts can be put in an oven, and a Bernz-O-Matic with a mapp gas cylinder can be used, but really heavy materials need a torch if they won't go into an oven...