View Full Version : Scratch Start TIG

04-21-2003, 01:59 PM
I see the term Scratch Start or Tap Start TIG on the internet, but can't find a lot of information on it. Is it possible to get a torch and regulators with a bottle of gas and add it to the DC side of a Miller Thunderbolt or an older Miller gas driven DC generator to do TIG welding on mild steel?

Most of the welding done in our shop is medium sized fabrication and repairs to the trucks and excavation equipment so the stick machines work well for that but I've been thinking that the mini-bike I've been building for my 6 year old son could look a lot tidier done with a TIG welder. My father-in-law got his journeyman welder ticket in the 50's and just won't bite on a MIG, but figures learning to TIG might be allright.

I'm just learning to weld and will buy a decent sized MIG machine one of these days but can't really justify having one now with all the stick machines sitting around to learn on.

Thanks for your thoughts on doing TIG welding on the cheap.


04-21-2003, 05:15 PM
I have often seen thunderbolts used for tig

04-21-2003, 06:14 PM
That's the impression that I have, that you can do it for welding mild steel on DC, but I can't find too much info on what it takes. Miller lists a High Frequency Conversion unit but I think you would be better off with an inverter machine for the price.

I should stop in at the Miller store but I don't ever seem to get to the city with enough time to fit it in and I would like to gather some knowledge from the folks on this board first. It's good to try and at least appear a bit bright when talking to salespeople :) . (I know that 'cause I am one!)

Thanks for the input - HB.

04-22-2003, 09:21 AM
Both TIG welders and Stick welders are Constant Current welderes so you can use your stick welder for TIG welding. Your stick welders probably don't have any fancy arc starting system but can use scratch start. Better to use stick welder with infinately vairable amp setting and not one with switched transformer tap amp settings. Best is having electrical remote amp setting or even one with fine amp adjustment with knob on welder that controls vairable resister that you can extend to foot or hand amp control. A stick welder does not have electric solenoid controlled shielding gas valve. That means you need TIG torch with gas valve and at least 10 ft elctrical/gas welding lead attached. Argon gas bottle, regulator with flow meter, LP hose and adapter to attach to end of gas hose part of welding lead.

The Thunderbolt welder will only make a fair TIG welder as you can't easly add remote amp control. It also has a fairly high minimum amp setting that will limit thinnest metal you can weld.

04-22-2003, 10:04 AM
As is normally the case with these kind of things, I can tell there is a reason true TIG welders were invented. I should know better after 20+ years of buying furniture making tools. Trying to patch together a cheap solution to a problem just creates more problems of it's own. After that many years spent convincing my wife that one more expensive woodworking tool is really the only solution, a little old welder for the shop shouldn't be too hard of sell :D .

G Austin
04-27-2003, 07:46 PM
The "Scratch Start" method is used in most manual welding applications in the field including boiler and pressure vessel repairs. CC stick machines are used.

I haven't used a thunderbolt for Tig but I have a 80 Amp thermal dynamics machine I made some Tig welds with that turned out OK.

You can see the welds by clicking the

"Pictures of some tig welds made with a $150.00 welding machine" on the following page

I bought a 40 cubic ft gas bottle for about $30.00 - $35.00 and had my tig rig I use for work.

Rocky D
04-28-2003, 12:20 AM
In the old days, making aircraft parts even X-ray quality welds with the old Hobart rotary generator welders left over from WWII, we had to scratch start all of our welds. For Xray we would light off on a piece of copper to start the arc. What a delight it was to see the Miller 300 Syncrowaves come in!:cool: :)

04-28-2003, 10:45 AM
Thanks guys. I'm not a real E-Bay power user, does anyone have any suggestions on what search words would work best to find a torch and regulators on E-Bay. It might be an interesting experiment to try TIG this way if a guy could get set up cheap.


G Austin
04-28-2003, 11:11 AM
Originally posted by Suburban_Guy
Thanks guys. I'm not a real E-Bay power user, does anyone have any suggestions on what search words would work best to find a torch and regulators on E-Bay. It might be an interesting experiment to try TIG this way if a guy could get set up cheap.


"Air cooled" Tig GTAW 90 Amp WP-9 Flowmeter heliarc are terms that could be used. Many variations of these will return various results.

Here is a torch athttp://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2524921010&category=11774 I found this by just using the term "Weldcraft" which is a major manufacturer of GTAW torches.

04-28-2003, 11:20 AM
Excellent, I'll put some of the terms on a watch and see what turns up.

Thanks - Harley