My Homemade TIG welder

[OrionBlade2003]

Originally Posted by brainstatic Not all NGK spark plugs intended for "street" autos are non-resistor type. My Jaguar V12 uses an NGK resistor plug. I would think best to contact NGK before purchasing. From their website: Technical Support hours: 8:30am - 5:00pm Monday-Friday EST tel: 1-877-473-6767 prompt #2 http://www.ngksparkplugs.com/About_nGK/contactus.asp

Dats wha we use dem dere race plugs. Makes dem 'lectrawns go faster.

[iEdd]

Anyone looking for the non-resistor type, get an NGK B7ES or B4ES (and many more), but they are the ones I remember are definitely not resistor type.

Just tested with a multimeter. The Champion Gold (resistor plug) have 94kΩ of resistance through the inner electrode. The NGK (non resistor) have about 5kΩ - I'm slightly surprised that this wasn't a lot closer to zero. I guess it is because the nickel-alloy electrode is not that great a conductor.

[integerspin]

I will have to move some stuff to get at the side of the tig to take a photo. The spark gap is a spark plug,as I said before, and L2 in the diagram looks like a car coil, L1 is an aircored inductor wound from thick section aluminium and will probably be visible in the photo. If I can get the top off the tig I will check the coil part number, it looks like a normal car coil and the capcitor values..

OK. Spark plug is a Bosch W8DC [M5 bmw?] picture[CLICK ME] picture is not brilliant but you can see how the electrode has been chopped off and the errosion of the electrode. It's been in use at least 20 years.

There is a picture of it place CLICK ME
Caps[C3] are 2 off 100uF 100V.

inductor 1 is HERE

coil isn't very exciting, it has HOGEFFECTSPOLE art 1120 12v written on it.

[OrionBlade2003]

er... integerspin...

Awesome. The electrode would have eroded away long ago had it not been ground off to begin with. I wonder if you cleaned the plug up, would it still work?! Looks like a nice sputtered coating of metal all around there, approximating an isopotential surface :-p

Anyhow, that helps a bunch. We used the plugs as-is, since our duty cycle was so low - a few dozen hertz at most, with nitrogen or argon flowing through the unit at elevated pressure, cooling it and altering the breakdown characteristics.

Anyhow, thanks again - very enlightening. I love old equipment - I've got a 1939 buick sitting in my garage that needed less work to get running and maintain than any other modern car I've had.

[iEdd]

js530, and anyone else that has made this:

How is your capacitor arrangement at arresting HV/HF and stopping it from killing the diodes? I got X2 mains suppression caps which are twice the microfarads of yours. Just want to know if there are any blown diodes or welder damage. Asking because other circuits I've seen have a 5k ohm resistor (10W or so) in parallel with the capacitor(s) which yours doesn't have and wondering if this affects it?

[slappynuts]

Originally Posted by diarmaid Wheres the thread on your DIY Plasma Cutter?

Exactly my thoughts.

You guys do realize that this could be done with junk from any junkyard and a few parts from the hardware store right? All these transformers and capacitors may have been the latest rage in the 40s when this circuit was designed but it is obsolete at this point in time.

Basically you can build your high frequency parts with a car coil and ignition module from the junkyard and a light dimmer sitch from the hardware store.

[slappynuts]

Here is the answer to all of your questions.

http://www.geocities.com/CapeCanaver.../simpleign.htm

[iEdd]

Originally Posted by slappynuts Basically you can build your high frequency parts with a car coil and ignition module from the junkyard and a light dimmer sitch from the hardware store.

Yep. (Warning: This one is for an AC Stick welder. For DC stick or TIG you will need the usual suppression circuitry across the -ve and +ve rails before the HF stuff.)

Too bad that gem of an article wasn't written until after I spent $120 on a Switchmode NST that doesn't work in this application.

[slappynuts]

Originally Posted by iEdd Yep. (Warning: This one is for an AC Stick welder. For DC stick or TIG you will need the usual suppression circuitry across the -ve and +ve rails before the HF stuff.) Too bad that gem of an article wasn't written until after I spent $120 on a Switchmode NST that doesn't work in this application.

Well isnt this part just a spark plug(gap) and wrap some wire from the spark plug ground around your tig torch lead? The one in the now missing DIY plasma cutter page used a GM coil and GM ignition module or something like that. Im looking for a better diagram ATM.

[slappynuts]

Ok I just tested this set up as working. This is as cheap and simple as it gets (and reliable).

http://i279.photobucket.com/albums/k..._Gill_Coil.jpg

I plan on using a spark plug for my spark gap (im thinking lawnmower plug and a solid core plug wire). To finish off the high frequency part i think a length of pallet banding thats anealed and wrapped in a loop with a few windings around each side.

I used a 4uf 660v oil filled cap I found at the local junk surplus store for $4 , chinese knockoff bosch coil from fleet farm for $11.79 and a cheapo dimmer switch from fleet farm as well $2.79 .

My next stop will be to harbor freight tool to get the cheapest stick welder they have and grab a tig torch from work and a regulator(more to come).

[scirturbo]

Punisher, any update of your project?

[punisher454]

Punisher, any update of your project?

Sorry, no progress yet, I have 2 projects in the works that have to take priority right now. A couple times a week I do look over at the arc welder, tig torch and box of electronic components sitting on top and wish I had time to put it together.
The thing I'm working on now should be finished by mid summer and then I'll be able to get on to the tig welder.

I am intrigued by the dimmer idea for the HF.