Chicago Electric Welder 90 Amp

[Scout3918]

I have a chance to do some trading for this welder. No Cash involved but about $70 worth of stuff laying around I don't use or have extra. The welder has not been used but bought new by a friend.

I have not welded in about 25 years and was just so so but did take a few classes at local college that came to my work place.

I wont be welding often but like to have it available if needed. I most likely wont be welding anything heavy think more repairs or at most fender on a small wagon or car hauler etc.

thoughts on this welder for home use?

thanks in advance

 

[sberry]

I spose if it is free then it may be of some value, some do manage to get them to work, lots of them used as dust collectors.

 

[Mitch78]

I'll be honest, I have the same welder and have yet to produce a quality weld with it. Someone mentioned to me that if you want this welder to work, it has to be plugged in close to the breaker and not on an extension cord. I haven't had a chance to test this theory out yet because I just finished my new shop and haven't pulled the welder out of storage so I can't say for sure if it will make a difference.

 

[gmwelder86]

I'm a union pipe welder by trade and have one for stuff around the house. It works ok at best. I've been looking to upgrade for a while.

 

[Corndoggeh]

I've done welding jobs for friends and a local business that needed carts to move freezers from event to event and have not had one weld break. No problems at all and I can make a decent weld using Lincoln electric mig wire and not the HF one that doesn't seem to penetrate as well.

The duty cycle is my only complaint at 20% but I can usually pair the off time with drilling or doing something else so I'm not too worried.

 

[erty67]

I had that welder and hated it. Traded it off for a old craftsman vise and bought a Lincoln welder cheap on Craigslist. Never looked back.

Sent from my SM-G930P using Tapatalk

 

[Codejack]

5 star review of the welder from Harbor Freight:

Good little A/C flux core welder.

I bought this little welding machine awhile back for $100. I needed to do exhaust repair and fence repair too. When i first got it i replaced the power cord with a 12ga and also replaced the ground clamp. I left the torch gun alone, this torch gun is a heavy duty model. After doing those upgrades and buying some 0.30 KT fluxcore wire. This machine lays down some nice weld beads. I have used it quite abit and let me tell you for beign A/C output its not bad. This weekend i am converting it to D/C output. I only wish Harbor Freight would make these D/C output from the factory. I wouldnt mind paying $200 for one. It would still be cheaper that the big dogs that own Mig/flux core game.

Here's a video about replacing (assuming it will tell you where they go...) the diodes for a bridge rectifier:

http://www.instructables.com/id/Mig-Welder-upgrade-diode-replacement-in-bridge-rec/

Edit: Here's a full video on converting that exact unit:

 

[Scout3918]

thanks for all the comments and replies.

 

[Scout3918]

I wondered about the ground clamp. I hadn't thought about the power cord.

I may trade for it only because I don't have a welder and more so, I don't use the extra trading material I trading so sorta like getting it free.

 

[cheechi]

I'm far from a pro welder. I have one, it collects dust most of the time but sometimes it gets used. When I need it, it works. I did buy the bigger HF ground clamp for it, but didn't change the power cord.

good welds are 90% prep work. Whether this or another unit, flux or other, gun or stick doesn't change that. This is the cheapest option and you get what you pay for, but in your case if you don't have welding gear, grinder, consumables, etc etc it may wind up costing more than the 'free' you are getting it.

 

[jessesandy]

I have the same 90A welder.
Converted it to DC output using alternator diodes from a couple old Dodge trucks at the junk yard. Also installed capacitors I had on hand. Can weld with very little spatter, now.

A question for the welders... the wire feed motor on this unit gets power from the secondary of the main transformer. As welding voltage drops, the wire feed slows down. Is this a feature (to try and self adjust wire feed) or a crappy design ??? Do name brand welders do this ?

I installed a separate transformer for steady power to the wire feed motor which seems to work better.

 

[Michael_in_DE]

I also have one. Mine also collects dust most of the time, but works well when I need it. I did follow the number 1 suggested change most have about this welder; get lincoln wire. Apparently the Harbor Freight wire is....less than the highest quality. i know, shocking. Lots of good reviews on this welder. I got mine for $80 on a black friday sale.

 

[Codejack]

So, from what I'm reading:

1. Change the ground clamp (will one off an old pair of jumper cables work?)

2. Convert to DC (alternator diodes or get a MDS-150A bridge rectifier)

3. (Maybe?) Change power cable to higher gauge (decent gauge extension cord is supposed to help, too).

4. Use Lincoln Electric wire.

----------------------------------------

That, or get a better unit from a pawn shop, in the first place

 

[Michael_in_DE]

Be advised, i believe you're only supposed to run this off a 20A outlet. And if are not running off a 20A outlet, your power cable swap is essential, and you'll need to use it in shorter bursts.

 

[Scout3918]

I'm far from a pro welder. I have one, it collects dust most of the time but sometimes it gets used. When I need it, it works. I did buy the bigger HF ground clamp for it, but didn't change the power cord.

good welds are 90% prep work. Whether this or another unit, flux or other, gun or stick doesn't change that. This is the cheapest option and you get what you pay for, but in your case if you don't have welding gear, grinder, consumables, etc etc it may wind up costing more than the 'free' you are getting it.

I have everything but welding helmet and wire. somehow over time I gather few welding gear.

 

[Scout3918]

Be advised, i believe you're only supposed to run this off a 20A outlet. And if are not running off a 20A outlet, your power cable swap is essential, and you'll need to use it in shorter bursts.

the welder actually has that mentioned on the cord. when I had garage electric put in used only 20 amp outlets. done something right for once lol.

 

[kyles974]

Yes, plug it as close to power feed as possible.
And. Buy a HD ground clamp.
The best wife I've found for this unit is the green color pack off Amazon.

With those three things I produce decent looking welds.

The ground clamp and close to power source is a must!

Oh, i even added eclectical grease to the plugs. Makes a big difference in we'd.

Oh and make sure metal is clean and ground is close to where welding.
Good solid ground is everything!

 

[jessesandy]

About the ground...

HF used a fine strand, high current welding cable, so that's good

The clamp it comes with is "jumper cable" style with no big flat areas to make contact.
The end of the cable has an eyelet and one option is to bolt that to what you are working on.
When that won't work, I bolt a 1" tab of copper to the eyelet at the end of the cable and use visegrips to clamp to the work.

And, using the alternator diodes was only to save money (as they were free).
Took a lot of fabricating to make it work, and a tight fit.

 

[Codejack]

About the ground...

HF used a fine strand, high current welding cable, so that's good

The clamp it comes with is "jumper cable" style with no big flat areas to make contact.
The end of the cable has an eyelet and one option is to bolt that to what you are working on.
When that won't work, I bolt a 1" tab of copper to the eyelet at the end of the cable and use visegrips to clamp to the work.

Ah, so we don't want one off jumper cables, either; got it.

And, using the alternator diodes was only to save money (as they were free).
Took a lot of fabricating to make it work, and a tight fit.

Yea, easier to just buy the rectifier.

And I found one site that suggested adding a capacitor; what, exactly, does that do?

 

[Bretny]

90a is really not alot even for a 120v unit. And will weld fenders and a yard cart just fine but i wouldnt weld to much on the car hauler you speak of. I had a lincoln 135 120v and spent alot of time behind the gun. I upgraded to a 220v unit 12 years ago and am very happy with it.
But for occasional welding a 120v unit will work just fine as long as its not structural. The 120v units can be found quite cheap on craigslist.

 

[jessesandy]

Make sure to get a rectifier with a heat sink, or a separate heat sink to mount it to.

First of all, I'm no expert; but have researched this quite a bit.
Experts, please chime in

The capacitors will give you steady DC output in stead of an output switching from zero volts to max volts 120 times a second.

I've also found web sites that recommend an inductor (called a reactor in the welding world) in stead of capacitors.
Because, the fully charged caps discharge when the weld wire makes first contact and "blows up" the wire back to the tip.

I captured the weld voltage on a scope and found that it takes a little over a second to get a stable arc.

I don't have the experience with different machines to know if this is good or bad

 

[Codejack]

Make sure to get a rectifier with a heat sink, or a separate heat sink to mount it to.

Ah, I was assuming that everyone would bolt it to the big center sink...

First of all, I'm no expert; but have researched this quite a bit.
Experts, please chime in

OK, the cap + inductor gives you a classic rlc tuned circuit. If it's in series, then it's a harmonic oscillator that will flatten out the waveform; you'll never get full voltage, but you'll never get 0 volts, either.

You guys are REALLY tempting me to just hack one of these together out of pieces

 

[jessesandy]

90a is really not alot even for a 120v unit. And will weld fenders and a yard cart just fine but i wouldnt weld to much on the car hauler you speak of. I had a lincoln 135 120v and spent alot of time behind the gun. I upgraded to a 220v unit 12 years ago and am very happy with it.
But for occasional welding a 120v unit will work just fine as long as its not structural. The 120v units can be found quite cheap on craigslist.

Is there a way to calculate weld current from the voltage between the work and the tip while welding ?
This waveform shows 36Vdc before contact, then the wire blows back a couple times, then a steady arc of 14-ish Vdc without shorting or going open circuit.

 

[Codejack]

Is there a way to calculate weld current from the voltage between the work and the tip while welding ?
This waveform shows 36Vdc before contact, then the wire blows back a couple times, then a steady arc of 14-ish Vdc without shorting or going open circuit.

The current is probably (relatively) constant, I'd say it's the impedance that is changing as the weld starts.

 

[jessesandy]