Sheet Metal Welding and Fabrication - Tack Welding like a Laser
If you are into sheet metal welding and fabrication, pay close attention because this tip is a game changer.
But before you try it on the real part, get some scrap and set your machine right..we don’t want any surprises…
and by surprises, I mean holes because you will be using a lot more amperage than normal.
This tack welding trick reminds me of an Irish toast... that goes like this……
“May your soul already be in heaven an hour before the devil knows your dead."
because the metal gets tack welded before it even knows what happened.
What I mean by down and dirty laser is that by setting the tig welder at an amperage over twice what I would use to weld, I can use a micro burst of amperage from a tig torch that is so hot and so quick, the metal never knew what hit it.
I have written about this trick for sheet metal fabrication before and used videos of other welders doing it but I thought it was important enough to really break it down and show some up close and personal clips of how to tack weld using this method.And it makes a huge difference on stainless. It’s so fast, the back side of stainless does not have time to sugar. (if you do it right)
There are new tig inverters that have a micro burst feature and I have written about it in the past as a great way to tack weld stainless steel sheet metal joints.
This project is on hot rolled steel. All outside corner joints.I am tack welding together a small tool tote tray made from some left over pieces of 16 ga (.063”) hot rolled sheet.
After I tack weld it , I am planning on mig welding it using a Miller Passport mig inverter…but that is for another video and another web page.
Ok , lets talk about how to make it happen.
How do you set up your tig welding machine to make tacks like this?
So , if you want to try this technique, here is what you do…
* Get some scrap sheet metal that is the same thickness as what you will be welding.For transformer style tig welders, there are usually 2 switches for contactor, and amperage…usually there are both set to “remote” for using a remote foot pedal or torch amperage control…set the one that says amperage to panel.Set the main amperage to about twice what you need to weld.
* Practice tack welding using the video on this page as your guide.
* Keep adjusting the amperage until you can just quickly bump the pedal for a micro burst of an arc….(ever been driving down the freeway and some jerk just wont get off your butt…and you tap the brakes just to show some brake lights? That’s the way you tap the pedal)
Inverter tig welders require a little bit of savvy to set this up but if your tig inverter has a 2t setting, use it and set upslope and downslope to zero or turn them off.
Kemppi Welders makes a tig welding machine that has a built in feature to assist in sheet metal fabrication on their three-phase Mastertig MLS 3000 and 3003 AC/DC welding systems …its called the "Microtack" function.
Microtack welding uses a high current pulse for only few dozen milliseconds to create a low heat input to weld thin sheet materials and thin sheet to thicker sheet materials.
But if you don’t have a few thousand bucks to go out and buy a Kemppi tig welder with a microtack function built in, then why not try this down and dirty method for tack welding…But again be careful, and set the machine up using scrap metal.