Welding Tips and Tricks

i'm currently using a hobart 140 handler on 75/25 bottle.i'm looking to do patch panel repair and i'm concerned about the correct heat and speed settings for this.does anyone out there have any experience in this situation? also i'm using .024 wire. thanks for any help.

Leanjay8.

The welding guide chart on page two gives some recommended settings.
Check to see if the thickness of your panel is within the ranges of the welding parameters on the chart.

http://www.hobartwelders.com/pdf/spec_s ... er_140.pdf

Alexa

One trick with sheet metal (under 16 ga.) is to use a shielding gas with less CO2 and more argon.
somewhere around 90-10 to 94-6. It greatly decreases penetration and heat input which allows you
to actually run a bead instead of "blop and stop" as I like to call it. Remember, sheet metal only with
this type of gas. Not for structural welds.

rake-> are you sure about sheet metal only with this type of gas?

alannmoris wrote:rake-> are you sure about sheet metal only with this type of gas?

I should have clarified only for sheet metals in short arc mig.
90-10 is used a lot in spray transfer. Spray transfer is a different animal.
Usually .045 or 1/16th on heavy plate. (flat and horizontal only)

these are some great ideas from you fellows but my problem is more with performing the butt welds.either i burn thru the sheet metal patch or body panel or both. then i speed up the wire slightly and the wire sticks.heavier gauge metal is no problem,but sheet metal say .024 gauge is a pain in the a--.i've tried to weld off of the last spot weld but i still have no consistency.i've had the most success just shot gunning one weld on top of another,but this leads to a lot of grinding.it should'nt take three days to weld in a 4''x9'' patch panel. help!!

Leanjay8.

You may want to skip my comment, in that I do not have experience with thin walled sheet metal.

When you write 'patch', do you mean a lap joint (overlapping) or a butt joint (edge to edge)?

Were you able to tack weld the pieces without difficulty?
If you are able to tack weld without difficulty, then you may consider a series of tacks, considering the short lengths of weld needed.

The Hobart recommendations for running MIG, DCEP, ER70S-6, with 0.6 mm wire and 0.6 mm base metal, is a 1/30 (Volts/Feed) settings.

Alexa

"Shotgunning", as you call it, is the preferred method for body repair when you have butt joints.

BTW, 24 ga. and .024 are different thicknesses.

You can make your patch larger than it's "home", and use a specialty tool for the material thickness that mkes an offset edge, so your patch is welded as a lap-joint, but you still cannot run a continuous bead, or you will have excess shrinkage.

Your best bet is to do what you've been doing, spot-on-spot, moving around the panel each time, so you put very little heat in any one area at a time, and just accept the grinding as part of the job.

Steve S

thanks.thats pretty much what i've been doing.i was just hoping there was some other method that i was over looking.i have a lot to learn about patch panel installs. thanks to everyone for the suggestions.

This will be my first reply on the forum.

I've been doing bodywork for decades. So here are a few thoughts.

Use wire that is similar to the thickness of the material. On sheet metal, which is usually 19-20 gauge, I use .024 wire with CO2/Argon mix.

Take your time and fit the patch. Gaps are a problem. Too tight can be a problem.

Not sure who wrote about "decreased penetration" above, but . Like any weld, you need penetration otherwise when you dress the weld, you have no strength. Ideally I like 100% penetration and dress both sides of the joint. Then (and we are drifting away from welding and into metal shaping) I take a hammer and dolly to the weld and stretch it back out, straightening any shrinking that causes distortion.

In the restoration world the preferred way to join panels is TIG or O/A with no gap and no or very little filler. Fusion if you will. And, unlike MIG welds, those guys don't stop or skip around. They MOVE. The idea is to keep the HAZ as narrow and even as possible thus keeping the shrinking to a minimum and consistent.

Hope some of this helps you out. Practice, Practice, Practice. Cut up an old door or fender and Practice.