View Full Version : Spot welder review

10-23-2005, 12:58 AM
OK, it's a Harbor Freight spot welder (item 45690), Chicago Electric to be exact.

I saw it on a stroll through HF and she was on sale for $149.00 normally $219.00. Weird the online sale price is $179.99.

The first thing I had to do was lengthen the power cord and apply a plug. The original cord was only about three feet long. I made a 20ft cord using 12-3 (original was 14-3) and a large three prong 220v/50amp plug.

Next was the assembly of the tongs to the power unit. It is pretty straight forward. The positioning of the screws for the tong clamps make it a tight fit. I wanted to be sure to align the tips very accurately.

The next step is adjusting the spacing/pressure of the tips. At first the adjustment seemed awkward and difficult. After messing with the adjusting process for awhile it became easier. Basically you adjust the gap for the material you will be welding. I was gonna use 16gal mild steel so I made an estimate of what I though would be a good starting point then would adjust it after trying the welder.

Trying the welder, finally. I already had two trips to the hardware store, one extra due to my ignorance http://bbs.homeshopmachinist.net//smile.gif

After doing a cursory continuity check to make sure there wasn't a hot line to the body of the tool I plugged it into power. (Remember, I'm not an electrician so I gotta double/triple check all my wiring jobs). Cool, no noise, shocks or sparks.

I rough sheared some partly rusty 16ga. mild steel sheet metal with my shear (HF plate shear, plate? no way. sheet metal? easy).

I wanted to see if it would actually weld metal, I was sceptical.

So the first two strips were put between the tips and the tongs were adjusted to apply a slight pressure, just enough to hold the small strips. Then just slide the switch over (left or right, "omni-fingerable"). The area around the tip quickly became orange/red and glowing after about one second. I left the power on for another three seconds until the entire area around the tip was glowing (and a little smoke) then released the momentary power switch, stopping the weld.

My goal was to make a few welds and tear them apart to test for the best tip pressure and weld time.

If the tip pressure was too light a couple things would happen. If it was extremely light I would get multiple spots around the strips that would heat up (burned a finger tip while holding the strips, dummy) but no welding would take place. If the pressure was a little more but still too light I would get a weld but would also get some major flyin sparks after about three seconds.

I increased the tip pressure to where the sparks stopped and started testing the weld strength. I wasn't doing a precise test, just a seat of the pants observation.

On the strips I offset them to produce a large lap joint. Then I placed the welded strips into my large vise holding the edges, not the faces, and pressed the strips until the weld sheared apart. I only used one spot weld per strip, per test.

I continued welding and breaking until I found the right tip pressure and weld time. The pressure ended up being enough to hold the strips together quiet well but not too much so the weld pool would not get squeezed and distorted. If the pressure was too great the tips would sink into the strips too much as the metal melted. This caused the tips to distort slightly also. The time ended up being about a quick count to 4-1000, highly technical and very accurate http://bbs.homeshopmachinist.net//wink.gif

When the weld was a good one it took a considerable amount of force to shear it apart and ended with a pleasing "POW". Sometimes the weld would just slide apart without much drama.

I also tore one apart with a chisel, like I have done many times on cars. I used a good sized chisel along with a decent hammer and the weld still took several well placed wacks. Not as tenacious as some auto bodies I have separated but not too shabby.

Now, if I was gonna actually weld something worthwhile I would treat the job just like any other welding job. Proper prep! I would get the rust off or stabilized. The metal would be de-oiled, de-burred so the plates lay flat, clamped and so on...(this welder can clamp a certain amount but if the weight is heavy or the parts misaligned you should use welding clamps)

Overall the welder looks promising and wont get the "try and return" sequence I have used before. I wont hesitate buying something from HF, try it out, and immediately return it because it was a piece of junk.

OK, why a spot welder. I have MIG, TIG and Oxy/Act, I "needed" a resistance spot welder http://bbs.homeshopmachinist.net//biggrin.gif It may sit on a shelf getting dusty for awhile but if I do need it I'll be happy to have it.

By the way...This "appears" to be identical (in every way, including specs) to the Miller spot welder LMSW-52 which you can get everywhere from between $500.00 to $395.00.

Here are some links and photos.

Sorry for the long winded write, it was fun...JRouche




Four seconds, shear break


Four second, chisel break




[This message has been edited by JRouche (edited 10-23-2005).]

Forrest Addy
10-23-2005, 07:30 AM
Thanks Mr Rouch. Your experience almost exactly parallels mine except I did pay Miller a fortune 14 years ago for the 115 volt version.

It works but its stated capacity of 1/8 total thickness is all it will handle - two pieces of 16 ga. It will fuse the metal but without the strength of a spot weld as from a real spotwelder having 5 to 15 times the surge current and timed welding cycles.

10-23-2005, 09:38 AM
Thanks! I love tool reviews and appreciate you taking the time to put that together.

Every time I'm in HF I look at one...

Some day I'd like to have a stand mounted foot controlled spot welder and one of those would be just the ticket for it!

10-23-2005, 09:40 PM
I've got two of the HF 220v spot welders. One I use portable the other is on a stand. I like mine and they do a nice job. If you use them properly.

One thing for sure is you're holding the switch TOO LONG. You will burn your tips in no time, If you haven't already. It's evident by the large discoloration around your welds and the large pock marks. If you're holding the weld until the metal around it glows, that's way too long.

It's a resistance weld. The weld point is between the sheets at the tips--Not around the tips. I spot weld 18 and 20ga. a lot and the weld is no more than a "flick" of the switch--About .5 to .75 seconds. Your 16ga. should be welded to it's maximum strength in about 1.5 seconds at the most.

There should not be "glowing" at the weld tips and there should not be deep pock marks. Adjust your pressure and timing to get the best weld and save your tool.