Look at getting a half decient pair of gloves too, it sucks when slag burns through a thin pair of gloves.

 

Everyone seems to have hit on the key concepts. Get yourself some scrap steel(old junk bedframes are a great practice tool with around the same thickness). PENETRATION- is the key. If it's too cold(not enough amps), it will look like it's putting down a bead but if not enough heat is getting the thicker of the two metals being welded, structural strength will not be there. Just practice and get all the paint off of the area to be welded b/c if the wire hits paints, it will quit arcing and you will stick the gun. Good luck, practice and prepwork and you're in there. I have done 4 classes at my community college and would highly suggest it and the "creative welding" usually brings in some hotties with welding talent. lol. I've mig welded floors in my bronco with a 110 miller cricket but it's hard as hell to make pretty welds with a small machine with no argon but they did their job at holding. I'll take a 220v machine any day for big jobs. And my favorite welding is oxy-accetylene, as it is so slow paced, it's kind of relaxing to me.

 

a way to tell if the bead is too cold, is it will be a skinny bead (not very wide) and it will be like a cylinder just sitting on metal (hard to explain). A good hot bead will be wide (but not too wide) and shapped like a half cylinder laying on metal. It may be hard to follow, but hopefully somebody knows what I am talking about and they can explain it better

 

I know what you are saying Patriot 95, it has to do with penetration. If the arc is too cold you are just laying metal on TOP of metal so it's shaped higher than if you have the mig penetrating and melting/welding the steel, then it is creating a "valley" which you are filling with the steel coming out of the mig(or rod in case of stick/tig). So, the weld is "blended" more into what you are welding. Is that what you are refering to Patriot?

 

exactly, thats a good way to explain it!

 

yes they need to look like fish scales. i usually do cirles as i move along with the weld. some people just go side to side, but you need to move from one peice of metal to the other to get the weld to penetrate both.

all it takes is pratice. the more you do the easier it will become. i have been doing it since i was 10 or 11. it really helps when your family has a huge welding and fab business

 

thanks everyone for all the great tips. I guess I'am going into the garage and welding every piece of scrape metal together I can find. Seriously thanks everybody.

 

Hey, I just had a question about tig welding. When is it better to use a tig welder or mig welder? thanks for the help guys.

 

TIG is the best welding, bar none. It takes much more skill than MIG, but it is stronger and looks better. TIGs are more expensive to buy, but well worth the money. I learned to TIG first, then I learned stick and oxy-fuel and MIG. I weld for our Formula SAE team at college, and TIG is the only method of welding we use, due to its strength. If you are just welding exhaust and SFCs and stuff like that, MIG is fine (and a lot easier to do when you're under a car), but TIG is just that much better. If you are welding aluminum, like motor plates and valve covers and fuel rails, etc you basically NEED to TIG it. HTH, just ask if you have any more specific questions.

 

So tig is definently better if you know how to do it right. correct? Is it true that tig welding produces less heat? Also, what type of major are you going for in college that allowed you to work with a team like that?Thanks for your help

 

Correct, there is definitly an overlap due to operator skill. In other words, MIG is superior in the hands of a skillfull operator than TIG in the hands of a novice. IMO the most common MIG error is when people weld with insufficient heat and end up just laying a nice looking bead on top of the base metal.

I wouldn't say less heat, the metal has the same melting temperature either way. It is a slower process and therefore has a built in warm up and cool down cycle. You can accomplish the same thing with a Mig by heating your base metal before and after the weld to accomplish a more uniform slow cooling.

I don't mean to step on Patriot's shoes, but i'll go out on a limb and say he's a Mechanical Engineer. I agree that in the hands of an experience welder TIG is ultimately the superior process. As PatriotTA said though, it's not like people need to go out and buy TIGs for welding mild steel SFCs. A MIG in the hands of a qualified welder will produce a weld stronger than the pieces to be joined.

-brent

 

thanks for the info

 

That's right, I'm a mechanical engineer. I'm going to Kettering University (formerly GMI) and we put a lot of time into our Formula SAE team. I didn't know how to weld before I went here, and since I've joined the team and took a few class, I'm learning a lot of fabrication and welding.

About the TIG producing less heat, it depends. You can set it so your work is DC positive (making the electrode negative) and that will allow the electrode to absorb more heat than your work. (In MIG, your work is negative so you have most of your heat in your work). Also, you can set your TIG for AC, which is really low heat, and your electrode absorbs a TON of heat (you need a really large diameter electrode or you'll melt it). AC is for aluminum. DC (-) is for most things, and that's how MIG is always set. DC (+) can be for really thin steel. HTH

 

Electrode negative will give you terrible penetration and is almost never used in anything, except really thin stuff like you said, or extremely dirty materials with strength not being critical.

The 3 main advantages of TIG welding are, ability to control filler metal, cleanliness, and ability to control the heat.

IMO, unless you are welding chromemoly, stainless, or aluminum on your car you are wasting your time using a TIG process.

 

Yeah, about the only thing we use electrode negative TIG for is welding our gas tank on the Formula car, which is very thin aluminum, like .035" or so. We don't even use filler rod, just push the bead along with the torch. Its lightweight and leak-free About TIG being a waste of time, I wouldn't go that far, but it is definitely overkill for most things. If you are an **** perfectionist, you can TIG everything, but like most people on here are saying, you can usually save yourself a few bucks (and a lot of time) using MIG. If you are using MIG, make sure you use gas, and not just a flux-cored wire.