Spot welder for panel replacement

[flypaper]

personally,I wouldn't trust one of those garage units
too many unknown variables that you have to assume are correct
like what was just mentioned above.
real spot welders run off of high voltage and go for 15 to 25k
that is what they used to put the cars together.
there is a reason why the Car manufactures use them
to each his own

 

[71airgrabberRR]

You're absolutely correct about the factory using high voltage welders. Most are also 3 phase units so they have a more consistent output due to the "sign" of the wavelength dropping up and down between cycles.............. but that's another "Johnny Kilowatt" story. Your typical home is single phase.

I have been down this road............... I originally bought a cheap unit from Harbor Freight. I didn't use it for over a year and it sat brand new in the box.........

You see where this is going.

I finally used it to practice with and made a few spot welds using scrap sheet metal. It did "OK", then crapped out after about 20 welds were made. The switch failed. I took it back along with the box and receipt and explained to them about only using it for 20 or so welds. The tongs were still nice and shiny copper looking. The tips didn't even discolor too much from the heat that is generated during the welding............. I mean you could tell it was almost brand new.

They would NOT even consider offering a replacement unit. I didn't want a refund, just an exchange.

They told me that since I didn't purchase the "extended warranty" that I could pound sand you know where. This wouldn't have mattered anyhow since it was beyond a year.

So much for customer service.

I have not purchased anything from them since.............. not even a cheap bag of shop rags. They can kiss my @$$.

Next I went to the local Miller dealer and purchased this unit that has a timer to make sure the welds are consistent.

I had the cart, but by the time I purchased extra length tongs, and several bags of tips I had a little over $2K invested.

I have used it on several cars now and the welds look factory in appearance.

I did some practice welds first using scrap sheet metal of the same gauge thickness. Once I felt comfortable with it, and had the timer dialed in, I did some destructive testing, again on scrap sheet metal. I wanted to see how strong the welds were, and to make sure I had dialed in the correct time setting on the timer.

The metal tore around the weld............. the weld did not fail. This is the sign of a good spot weld.

As long as you have nice clean metal and no gaps, this will work great for a hobbyist. I will warn you that it gets very hot during use. You better use welding gloves !!!! I typically use mine for a while and let it cool off after a while. The unit is heavy, so you will want to take a break anyhow...... perfect time to let it cool off.

I would look for a similar "used" unit rather than waste your money at Harbor Freight.

This is a great home use welder. This one is a 220 Volt unit.

 

[MGKelly]

The Miller spot welders are discontinued, not sure why i think they were some of the better portable models. Tecna makes some nice stuff also but expensive.

 

[71airgrabberRR]

Wow this is too bad. I am very happy with mine. It seems like that happens to the good stuff. Discontinued. Bummer

 

[leakcheck]

You just drill a little and look, maybe even get the panel splitter in there and work it a little trying to separate the panels, then drill a little more when you find it isn’t enough, then check again with the panel splitter. Taking your time and splitting the panels without distorting the underlying panel is key. You can do this easily sometimes, other times not so easy and you have to hammer and dolly the underlying panel before you weld on your new one. That’s just part of the game, but if you take your time you can “unbolt” it just as you do your fenders up front. The more time you spend on splitting the panels the less time you will have to spend on cleaning up and straightening the metal. welder review

 

[pat1969charger]

You're absolutely correct about the factory using high voltage welders. Most are also 3 phase units so they have a more consistent output due to the "sign" of the wavelength dropping up and down between cycles.............. but that's another "Johnny Kilowatt" story. Your typical home is single phase.

I have been down this road............... I originally bought a cheap unit from Harbor Freight. I didn't use it for over a year and it sat brand new in the box.........

You see where this is going.

I finally used it to practice with and made a few spot welds using scrap sheet metal. It did "OK", then crapped out after about 20 welds were made. The switch failed. I took it back along with the box and receipt and explained to them about only using it for 20 or so welds. The tongs were still nice and shiny copper looking. The tips didn't even discolor too much from the heat that is generated during the welding............. I mean you could tell it was almost brand new.

They would NOT even consider offering a replacement unit. I didn't want a refund, just an exchange.

They told me that since I didn't purchase the "extended warranty" that I could pound sand you know where. This wouldn't have mattered anyhow since it was beyond a year.

So much for customer service.

I have not purchased anything from them since.............. not even a cheap bag of shop rags. They can kiss my @$$.

Next I went to the local Miller dealer and purchased this unit that has a timer to make sure the welds are consistent.
View attachment 807680
View attachment 807678
I had the cart, but by the time I purchased extra length tongs, and several bags of tips I had a little over $2K invested.
View attachment 807679

I have used it on several cars now and the welds look factory in appearance.

I did some practice welds first using scrap sheet metal of the same gauge thickness. Once I felt comfortable with it, and had the timer dialed in, I did some destructive testing, again on scrap sheet metal. I wanted to see how strong the welds were, and to make sure I had dialed in the correct time setting on the timer.

The metal tore around the weld............. the weld did not fail. This is the sign of a good spot weld.

As long as you have nice clean metal and no gaps, this will work great for a hobbyist. I will warn you that it gets very hot during use. You better use welding gloves !!!! I typically use mine for a while and let it cool off after a while. The unit is heavy, so you will want to take a break anyhow...... perfect time to let it cool off.

I would look for a similar "used" unit rather than waste your money at Harbor Freight.

This is a great home use welder. This one is a 220 Volt unit.

This is the exact one I used and bought, I like it although I’m having some trouble getting mine set up. It came with the large tongs like Shown in your picture on the cart. I put on the 6” and the tongs stick to the the steel when making a weld. Didn’t have this issue with the one I had borrowed.

 

[b-body-bob]

I got one of the 120v HF spot welders for Christmas. I have been messing with it some, and if you're lucky enough to get the thing dialed in I guess it works OK. In my experiments with same gauge steel, I've seen it blow out after 2 seconds, and also hold for 5 or more. I haven't figured out what I'm doing to cause that, but I suspect it's all in how tight you can clamp the tongs.

When I get it to glow for a second or two, the metal tears around the weld so it's penetrating fine, but again, inconsistency is the problem.

Worst case, I keep it around to make yard art. Best case, it's usable but I still end up having to plug/stitch weld in places (and to be sure). It's cheap fun so far though.

 

[b-body-bob]

Thanks
I will start looking. Is there any trick to aligning the electrodes to each other?
I would guess good clean metal and a good eye. How does it work with weld through primer?

I watched this video on setting it up

I just shot a couple of pieces of 18 gauge with NAPA weld-through, and it welded together fine after drying. I don't know if it matters but there was no paint on the tong side of the pieces, just between them.

I'll scout around in the scrap bucket for some ugly metal and try welding that together, to see how sensitive it is to less than perfect materials.

 

[pat1969charger]

I watched this video on setting it up

I just shot a couple of pieces of 18 gauge with NAPA weld-through, and it welded together fine after drying. I don't know if it matters but there was no paint on the tong side of the pieces, just between them.

I'll scout around in the scrap bucket for some ugly metal and try welding that together, to see how sensitive it is to less than perfect materials.

I had a 120v one when I was working on that dart last year but didn’t find it made welds I was confident in , at least not for structure on a unibody. That’s why I borrowed the 220v one. It did however make factory looking dimples after you ground the plug welds smooth.

 

[b-body-bob]

I had a 120v one when I was working on that dart last year but didn’t find it made welds I was confident in , at least not for structure on a unibody. That’s why I borrowed the 220v one. It did however make factory looking dimples after you ground the plug welds smooth.

Yeah after messing around with it pretty much all day yesterday that's basically my gut feeling on it too.

 

[70chall440]

I have a 220V HF unit and have used it for a variety of tasks to include inside wheel wells. It works ok so long as you have clean metal and good contact. I use my spot welder for making a lot of sheet metal things like shelves or perhaps an odd bracket, it certainly is not a stand alone tool, I rely on my MIG welders for probably 99% of panel replacement as I really don't car if it looks factory or not.

 

[barnfind]

Picked this up from an old body shop for a C note. Other welders are necessary, but this comes in handy.