MIG welding question Options

[Brian_Boss]

I bought a MIG welder to do a job for the go kart business and I am hoping some people that do a lot of MIG can steepen my relearning curve. I am pretty good with oxy/acetylene and OK with TIG but have not touched a MIG in 10+ years. I am not prepping for a code test, just trying to be sure the parts I weld on the karts don't start falling off after delivery to the customer.

Question 1: Is it indicative of anything if I frequently end up with more wire sticking out after finishing a weld than the normal stickout used for welding? I have just been snipping it off before restarting.

Question 2: Is it indicative of anything if you have a glowing booger of weld at the end of the wire when you stop welding? I actually stopped this by fine tuning the settings but would like to know if it always indicates a particular problem.

Question 3: Should you be able to feel the gun pushing back from the work at all? I am talking about a very subtle amount, not wire forcing the gun back from the puddle?

Here is a picture of my first try at a 90 degree. Any comments? I am a little concerned about penetration. I put it in a vice and it took three or four whacks with a 24 oz hammer just to bend the joint a little.

Thanks for any input.

914 content: If I can get these karts finished before the customer sues me, I can use this machine to weld a new battery tray into my car to replace the plywood one I have now.

[JPB]

These issues you have mentioned don't seem to be much to worry about. Typically the wire dosen't stick at the end of the pass but might indicated your heat is to low for the size wire you are using. If you want good penatration, its always good to be welding a gap which would show a key hole during the welding process. Welding light gage stuff is tricky since it is easy to burn right through. I'd use .020 wire for this and a low heat setting. Flux core wire also penetrates deaper than solid wire and if used with gas, flux core gives a very smooth weld like E71T1. If you are welding carts, aren't they chromoly? (IMG:style_emoticons/default/beer.gif)

[IronHillRestorations]

PRACTICE! Try different wire speed and heat settings. Spend a couple hours practicing on the materials you'll be welding, and don't touch the paid project until your welds are correct. Some time on the front end getting things right will save going over bad welds.

The first and last part of the weld looks close, but it's hard to tell from a pic.

Q#1 No

Q#2 Make sure you've got the polarity correct. You may have the heat too low.

Q#3
If you feel the wire pushing the gun back, then the heat is probably too low.

The edges of the weld bead should be melted into the base metal. If the edges are sitting too proud above the base metal, or if it looks like you could get your fingernail under the edge of the bead, then you need more weld penetration.

You've got to practice until you get a nice even bead all the way along the weld bead, without fissures or inclusions.

This is a gas MIG right?