Powering welder through a dimmer

[carcentric]

I saw this on another board, ". . . welding VW sheetmetal is a royal pain in the ***. it is extremely thin for a car, so it burns through very easilly. . . . with the voltage AND the wire speed cranked ALL the way down to 1 it STILL burns through on ocasion... [another guy on this board] is using an in-line dimmer switch, between the wall outlet and the welder, to crank down the voltage being fed into the welder itself, thus reducing the output voltage at the tip of the welder...As soon as I can get some time to look it over, build one and test it, Ill post up some pictures and wiring instructions so you guys can build one yerself. seems safe enough (in theory) and I am pretty sure it will work ... mostly cuz [the other guy] has been using it on his build for months now with no problems . . . ."

What do you folks think about this way to "gear down" a MIG for ~24 gauge sheet metal?

Would the wire feed motor (or anything else inside the welder) be messed up?

And would a light bulb dimmer or a electric motor (e.g., fan) dimmer be best?

Thanks. BTW, I have a HH135 if it matters.

[MAC702]

So do you plan on also burning up the 120V fan on your unit? And underpowering the DC drive motor at the same time? What about the PC board that has a power supply that relies on the 120V input?

If it was that simple, there'd be a dimmer switch on the back of every unit sold.

[Brasco]

MAC702 is right on the money. Most of the 115 volt welders use the cooling fan coil as a transformer. The 24 VAC from the fan/transformer will be so low that smoking the board,drive motor ect. Take a look at the Hobart owners manuals link and look at the schematic for your welder. The Dimmer would go in series with the range switch and a seperate 24 VDC supply would be needed to power the wire feed motor.

[diesel]

Practice. VW sheetmetal is thin but not unreasonable. What wire are you using?
d.

[realitycheck]

Check out this thread right here, http://www.hobartwelders.com/mboard/...ht=handle+tada

[carcentric]

Practice. VW sheetmetal is thin but not unreasonable. What wire are you using?
d.

I'd be using .023" with the #1 setting on my HH135 (35-135 amp range).

The quote I started this thread with was from another person who I've learned is using a HF flux wire welder on Low of a Low-High setting choice (I don't know what wire size he's using). He's the one who's put the light bulb dimmer inline with the power cord, not me . . . .

When I tried to measure the thickness of the metal in my '74 SuperBeetle, it looked like about 24 gauge - does that sound right?

[realitycheck]

Not sure, check out that link that i posted though. MxTras built a beetle and he talks alot about it in that article. Me and him spent alot of time creating that thread, hehe. And him and alot of others give some very good advice in there.

[hankj]

I can't for the life of me picture what kind of "light bulb dimmer" would work in series with a welding power supply (even a HF one!) without burning up. I sure as **** wouldn't be trying it on anything I own!

The solution to the problem is NOT flux-core in the first place! That HH135 w/.023 and C-25 in careful hands will do the job fine.

Hank

[carcentric]

I can't for the life of me picture what kind of "light bulb dimmer" would work in series with a welding power supply (even a HF one!) without burning up. I sure as **** wouldn't be trying it on anything I own! . . .
Hank

See the picture in the 2nd post to this thread:
http://volksrods.com/forums/index.php?showtopic=14655

I've passed the general opinion of this (Hobart) forum on to the volksrods forum in the hope that no one gets hurt. I'm just the messenger here.

[hankj]

See the picture in the 2nd post to this thread:
http://volksrods.com/forums/index.php?showtopic=14655

I've passed the general opinion of this (Hobart) forum on to the volksrods forum in the hope that no one gets hurt. I'm just the messenger here.

Wow. I see it, but I don't believe it! What a rinky-dink setup! The "welder" can't be much more than a 60 amp thing. I've never seen that type incandescent dimmer rated for more than 1500 watts. That extension cord looks like 16 ga. to me!

Maybe us welding nuts are wound too tight on the electrics, but you won't see that Rube Goldberg in the Gadget Garage!

Still, whatever floats yer boat!

[halbritt]

I don't see any reason why it wouldn't work on a tapped welder. A lightswitch dimmer just chops up the AC sine wave which isn't going to provide any less peak-to-peak voltage but it will reduce the RMS voltage. I've never heard of any electronics being smoked from too little voltage, particularly passive ones. I've no idea how any active electronics would response. That'd entirely depend on the power supply. Assuming a bridge rectifier and a voltage regulator, I doubt that very little would happen. The downside is that I've seen very few dimmers that can handle more than 7 amps at 120VAC (~600W).

[Broccoli1]

here just use this one:
2500 Watt A.C. Molestat Dimmer



a bargain- Price: $1325.00


and it's lite weight @ 36lbs

[MAC702]

I don't see any reason why it wouldn't work on a tapped welder. A lightswitch dimmer just chops up the AC sine wave which isn't going to provide any less peak-to-peak voltage but it will reduce the RMS voltage. I've never heard of any electronics being smoked from too little voltage, particularly passive ones. I've no idea how any active electronics would response. That'd entirely depend on the power supply. Assuming a bridge rectifier and a voltage regulator, I doubt that very little would happen. The downside is that I've seen very few dimmers that can handle more than 7 amps at 120VAC (~600W).

Real electrical supply houses have several wattages of lighting dimmers for 120V incandescents; I've used the 600W (like you find at Home Desperate), 1500W, and 2000W varieties.

As mentioned, these machines are already rated for 24-ga. sheet metal with .023 solid wire and C-25 shielding gas. An expert can even go thinner.

The machine is designed (on SEVERAL different levels) to operate from 120V. Period.

[NOS]

Guys,,,,,,he's welding fenders on a Volks Wagon w/ a HF welder for cryin out loud! It works for him and he ain't set nothin on fire! If he's getting good results with this "rig" we oughta be callin him "McGuiver"! "Embarrassing" some guy thats doin the best he can with what he has ain't nice! Ya shoulda never done that link thing carcentric!
just remember this....ya did hurt him,,,, and pay-backs a *****! Post this on his tread. Tell him I admire him for makin it work!

[Mike W]

You can use a triac or scr's on the primary of a transformer, just keep full voltage to the fan, etc. That is what I did to my old arc welder. The anodized heat sink is for the scr's, not the greatest picture. I am going to use the same setup on the mig power supply I am working on.