Explain to me welding please.
 

Some one please explain to me welding. Why is one weld flat and smoothish and the other is bubbly? Which is correct and what am I looking for when I am welding?:confused: Thanks in advance.

http://forums.pelicanparts.com/uploa...1325305879.jpg

http://forums.pelicanparts.com/uploa...1325305984.jpg

Looks like one is TIG and mine is MIG. Plus one is a pro and I haven't welded in over 10 years. This was my first pass and with the lead in the seams, I had to build up a good base to grind off.

The second pass after I ground off this pass looked a lot cleaner. I don't think I too any pictures though.

Here is a picture of the 2nd pass before all the welds were ground off.
http://forums.pelicanparts.com/uploa...1324909661.jpg

Both welds are MIG. The second photo's welds aren't penetrating as deeply, I'd turn the amps up just a little more.

The weird thing with welding is that you can have the welder, feed, gas and metal all perfectly prepared and tuned in and getting awesome welds; repeat every setting the next day and you get crap welds.

So long as you're getting appropriate penetration, the difference between a good weld and a bad one is the time it takes to get a grinder to it ;)

+1 ^^

When welds "sit up" it means they are not penetrating, the metal is just building up on top of the work area. I've learned to turn up the heat, stitch the welds and use lots of compressed air to keep the area cool for the sheet metal on our cars. It's easy to get blow through so it's easy to fall into the trap of running low amps and lots of stick out.

take a look at this site:

Miller - MIG Welding Tips - Intro

Plenty of penetration, with the welds. It's pretty dirty at that area and if you burn through, you get a crap load of contamination, so for the first pass I did a small spot on both panels, then did a short stitch between both spots and gave it a little tap with hammer, then did a larger weld to tie it all together. The 2nd pass was much cleaner. My theory is turn up the power till you punch through, then back it off a hair. LOL

Wearing heavy gloves, it is possible to rest one hand on the work surface to steady the weld. Put the hand with the wig handle onto the work surface and orient the nozzle. When welding. Pause, then drag, Pause, then drag. You know when to drag by the glow around your weld. A lot of guys use their other hand to steady the tip itself.

I can't get a pretty weld without steadying the tip. Stop after half an inch or an inch. Go to the next section. When you go back, use the wire wheel to clean up the weld area again. If you get blow through, don't drag. Stop pulling the trigger and pause until the glow gets dull. Pull the trigger again and sweep the tip from side to side over the blowout, then release the trigger when you have partially filled the void. Let it get dull again, then repeat...

^^ Good point.

My father is a pro welder on offshore platforms, I get a lot of his hand-me-downs :) One of the best things I get from him are quality welding gauntlets. These allow me to work in full contact with the surface, I usually drop my left elbow onto the surface and use my left fingertips to control the gun's nozzle. Dad keeps telling me to rig up a foot-pedal operation so that both hands can be used to control the nozzle. One day :)

I was glad to read John's comments on getting different results from the same settings on different days. I thought it was just me and my inability to learn. I'm beginning to learn (at least I think I'm learning) that the condition of the metal and thickness in the adjoining area (read: be careful how you grind) is as important as the settings.
Tim
'69 911e

another thing to think about is sound. I also find that setup can change from day to day. The sound of the right setup is unmistakable though. after a while, you'll be able to know you've got it right from the sound. hard to explain but you'll know it when you hear it.

wew...this forum is good for my father coz his a welder...hehe

So true

I am still very new to welding and have had mixed results. Reading this post, it looks like I am in the same boat. Overall though, I subscribe fishcop said, the difference between a good weld and a bad weld is the amount of grinding afterward.

I have been starting to use this technique that has worked pretty well for me, still learning though. Basically, you are using making a series of cursive e's. I like it better than the pause and drag as I couldn't do that as consistently.

Mig Welding Technique Taught by Old Timer - YouTube

Just remember the "pause" can be quite important to keep heat down on the sheet metal. The big sheet metal welds I've done on my car took all day as I would do many small runs, moving around the car constantly to keep local heat out of the metal. I also used a wet beach towel as a heat sink.