Stick to Tig conversion question

[FVRacer21]

For all the good welders out there.

I have a stick welder with a Tig conversion (with gas)

It is scratch start, which is not the problem, it is the finish that kills me.

I always get a mess no matter how I stop the bead.

Is there any technique I am missing, or would putting a foot switch to kill power help?

Thanks

ChrisZ

[cjsmith]

Can you be more specific regarding your issues. As in porosity or crater crack problems, under cut or tungsten contamination ?

[10rmotor]

I'm guessing that you have no gas postflow control, and that is causing contamination of the weld puddle and tungsten when the arc shuts off? What you may need is a torch with a manual gas valve control. If your welder has a gas solenoid it will somehow need to be bypassed so that your regulator is plumbed directly into the hose for the torch.

[Rick Silver]

Could be two things going on. First as said above, the gas on a TG welder runs for several seconds after the pedal goes to off. That gas needs to protect the weld as it cools. But also if it is stick on stick off, then as you pull the rod away you get a spread and dissipation of the arc. On my TIG, I slowly release the pedal for a smooth power down in the inert gas.

[FVRacer21]

Yes, the only way to break the arc is to pull up and away, where you lose the gas shield and usually end up with splatter or a crater.

if I could shut off the arc somehow and keep the gas on the weld, it might be good, or maybe run the arc onto a separate grounded metal.

it is a Forney DC stick welder with the tig adapter. It is a bit half-assed, but it is so much fun during the weld, you just have no real control over the arc when stopping.

I have a Lincoln MiG where I have been using flux wire. May hook up the gas to it and try regular wire.

the problem is I only weld every 3 or 4 months, so cannot justify nicer equipment…

ChrisZ

[10rmotor]

Not really familiar with that machine. The blue boxes I have in my shop would probably cause you some major drooling action! Keep your eyes on fb marketplace and you'll eventually find something you can justify. I found a low hours dynasty 350 for 3500! If you don't care about being able to weld aluminum (AC) a small maxstar 150 would fill the bill nicely.

[Steve Davis]

POSTFLOW GAS CONTROL. If you are using STICK electrodes, the only thing that protects the weld area is the FLUX that's on the sticks. You chip that off after you stop the weld. If you are trying to use bare rods of any sort, then you are going to HAVE to add some post flow gas control.. or alternately run CONSTANT gas to the weld area.. then cut off the welding arc (somehow) and let it cool before taking the (gas flowing) torch away from the welded area. You can empty an Argon tank pretty quickly (that Argon is getting pretty pricey too) that way.. but...

You can buy some really decent TIG welders from HF or other places for a bit over $200 that include the 'post flow' gas/arc switch and also include a gas pressure regulator. Really good ones can be had for well less than $1k. The amperage won't be high enough to weld 1/4+ plate, but it should be most of what you need for a race car. You really can't expect to have decent TIG welds without that capability.
Steve, FV80

[patman]

I don't think there is a solution to that problem. You may be able to rotate the torch or try different speeds of increasing arc length when you finish a weld. BUT I inspect welds by professional career welders and when they are using scratch start TIG there are always arc strikes.

Honestly, you can get a decent AC/DC inverter TIG from eastwood for less than $1k. You can get an everlast or yeswelder one even cheaper. Are they as good an investment as a name-brand unit? Probably not, but I have an eastwood MIG that I bought for my dad 15 years ago and it still welds fine. I have used a Yeswelder TIG at the track and it welded great. For the amount of money they cost now, I wouldn't waste another 5 minutes messing around with scratch-arc. You'll pay for it the first time you fix some broken aluminum or stainless gizmo.

[jrh3]

Can you be more specific regarding your issues. As in porosity or crater crack problems, under cut or tungsten contamination ?

A few pictures would be helpful