This is my 4th time practicing. It's 18 gauge sheet metal. Flux core .030 wire. How am I doing? Do I have enough penetration? All the videos I see have the welds looking the same on the back side I can't seem to get it like that. Is the white stuff on the back from the flux or the metal not being cleaned enough?

Not sure what you are going for there, but that looks more like a series of tack welds or even a TIG-like weld. If a continuous bead is what was attempted, that would be considered a very "ropey" weld. Some of this is caused by the nature of flux core welding. The flux is also leaving the white residue. If you can afford a small bottle of 90/10 and your welder supports it, you will get MUCH nicer looking and penetrating welds.

wireburn wrote:Not sure what you are going for there, but that looks more like a series of tack welds or even a TIG-like weld. If a continuous bead is what was attempted, that would be considered a very "ropey" weld. Some of this is caused by the nature of flux core welding. The flux is also leaving the white residue. If you can afford a small bottle of 90/10 and your welder supports it, you will get MUCH nicer looking and penetrating welds.

As I stated. I'm trying to how learn to weld. Which means I don't know how to. I want to repair the rust on my car so I'm practicing. On thin metal your supposed to use tacks to prevent the metal from warping. I'm practicing with flux so I don't waste money on gas. When I feel I'm ready I will move to gas. I don't know don't know how to be anymore direct with what im looking for.

let me re ask my questions.

How am I doing? Do I have enough penetration? All the videos I see have the welds looking the same on the back side I can't seem to get it like that.

So what type of welder are you using?

'68 Coronet R/T wrote:So what type of welder are you using?

Mig. An Eastwood mig 140

I am not a professional welder by any means but have learned through study and practice what seems to work for me.

I have a Gas MIG welder, however I did try the flux core wire and didn't like it.

I use .023 wire for thin automotive panels and the key is to get the heat setting for proper penetration and adjust the wire feed to fill the void. You will generally place the spot welds about 3" apart on the first go around to keep the panel from overheating and warp.

The second round will be spaced in the center of the 3" spaces and the third round centered again.


Now your spots are no more that 3/4" from each other. Generally I begin a continuous weld from one spot weld to the next in a single pass. Skipping every other one. Again, you need to make sure you don't overheat and warp the panel. It is at this stage that you should begin planishing the welds with a hammer and dolly if you have access to the back side.


One finished you should be able to grind the welds flat to the surface without any voids or low spot showing.

As a beginner to another,flat panels with no curved body lines close by will warp.No matter what.Blowing air spacing welds etc it will warp.
Tight fitting joints on the patch,weld around in a circle pattern.Meaning start at one side tack a few then look at the other side,it moved.So now you hammer dollie the welds to make it move back.
My mistakes were made by welding the four corners first locking it in.This warps the metal as the patch can't move.
Now if its a patch where theirs body lines etc the metal won't warp as easy but still proceed with caution.
Some will go as far as cutting out behind to gain access to hammer dolly,they say that's easier than dealing with warped steel.
Just a backyard hack but this is what Ive learned.

Oh and practice with gas,tight and I mean tight fitting joints this allows you to tack on a higher setting,I use C on a A,B,C,D. heat setting.110v wire welder.

Wolfy

Each welding Technique is very different. Stick welding, Oxy-Acetylene gas welding,Tig welding Mig welding with GAS and what your doing Mig welding with Flux.

Each requires its own technique so learning how to Mig weld with Flux wont be the same as with Gas. Yes it is very similar BUT the Bead will be different than with gas it will also require different heat and gas setting which will drive you nuts while trying to learn.

Your first pic
The Back side Yes that's full penetration, Not pretty but it is a what it is your learning a new skill.

Second Pic
Stacked Spot welds, They really don't look that bad a little proud but not bad at all, IF that's what your going after. I would try a little hotter and going faster.

That said Stacking spot welds is not the way too weld body panels YES a LOT of people do it! all in an effort to avoid warping. all the fairy tails about using spot welds or doing a spot weld and Blowing on it with compressed air on the bead too cool the bead its all dreams and fairy tails it doesn't work and makes a bad weld.

Real welding is continuous with Oxy-Acetylene welding OR Tig welding on thin sheet metal. Mig Flux or Gas has its place its just not on Thin auto body panels.

HEAT is not the Problem,
https://www.youtube.com/watch?v=Rv5bKXJ3kEM

Mig Flux for Beginner
https://www.youtube.com/watch?v=vVSBzRXWt10
Jody is one of the best