need welding tips bad... real bad.

Just chopped the top to my 51 desoto. I'm running a 250 lincoln mig. Having trouble getting clean flat welds. Can anybody tell what the best wire and gas combo for welding sheet metal is?

 

Post up some pics of what you have done so far, maybe some suggestions based from there would be a good start to point you in the right direction....

 

.025-.030 wire, argon/co2 mix(75% and 25%) Flat welds? Gotta grind round to get flat.

 

Try turnings up your amprage, just don't burn through.

 

I'm d*&^ing off at work right now. I'm on my phone. When I get home to the computer I will post some pics

 

For low or unalloyed steel i run .030 wire and Argonmix 25 (75% Argon, 25% CO) and get clean welds. The best to do is to play around on scrap sheet metal with different amperes and wire-feeds until you get the perfect set up.

 

Thanx that's I will try that. Oh yeah. One more thing. When using gas . Flux core or solid wire?

 

Well, if it's "real bad" welding tips you seek, I'm your man. What exactly is it you want screwed up?

 

solid wire. and defiantly mess with the scrap, that'd help get your settings right. are you doing real small welds and letting them cool to keep warpage down?

 

Pardon my bluntness...... but flux core is only good for fixing wheelbarrows and things you really don't care about.


Oh, and flux core is what you use when you don't use gas. Solid has to have gas.

 

check into spool of EZ-GRIND wire has low alloy content making it softer and easier to work. less grinding =less heat=less warpage.

 

For those who want to make fun of flux core, you best do some research before opening your mouth...saying that it's only for wheelbarrows and things you don't care about is about as ignorant a statement about welding as you can get...and for your information, you can use flux core with gas, which is called Dual Shield, and it's a weapon of choice for many structural steel welders who need a STRONG penetrating weld on thick materials in one pass...for sheetmetal, solid wire is the way to go...

 

Not to imply anyting but I would think you should be a pretty competent welder before trying something like chopping a top. It's one of the main structural components of the car and I wouldn't want an amature welding on anything I would be riding in.
I know your rebutal is going to be "then I won't let you ride with me". Come on, lets get real do you want to subject ANYONE to that kind of possible failure?

Frank

 

X2.......also make sure the polarity is correct.

 

Exactly!!! We use dual-shield flux core at work for heavy plate all the time..

 

The thing that is really bad about his comment is , He's a METAL SHOP TEACHER !!!

I use flux core and works for me . I Just have more clean up ! Can't use bottle gas either when you are outside welding in the WIND either .
Just practice on some scrap pieces and take your time . Make sure you leave a gap between the two pieces to get a strong weld .
I also agree with "fab32" on the roof . You should have someone check to make sure it's safe or when you put too many people in the car and hit a bump , you might be closer to the ground than you want to as it folds up on you ! Just make sure ALL your welds are STRONG !

RetroJim

 

75/25 gas, solid wire..I use 030 wire. Each welder is a little different. I agree with
-practice on some sheet metal first until you find a good setting
-do a small weld over here, small weld over there, back over here, then over there until you have a nice weld all around, so it doesn't warp or get too hot on you. Sheetmetal isn't like 1/4, so relax and take your time. You are going to do some serious grinding if you are chopping a top. Don't keep the grinder in one place until it gets real hot too..same warping effect.
-to start try the next to lowest heat setting and a wire speed of around 4.....I have a similar welder.

 

one thing i have discovered is there are no good "how to weld" videos online, it is hard to get a video of the puddle moving along with a mig as the nozzle gets in the way, the other day someone posted a link to a welding video where the guy said he doesnt like to point in the direction of travel because he gets sparks on him, he had the gun layed over like 50 degrees off perpendicular, another video has a guy going on and on about safely then goes over and turns on the gas and theres a lense cover missing off one of the gauges, flux core is fine you just have to know how to weld to use it.

 

I found comments & pics in here quite useful.

http://www.mig-welding.co.uk/tutorial.htm

.

 

Make sure your welder wasn't set up for flux core and not gas...you have to change the polarity on the gun for the gas if it was set up to run flux from the factory.

You can weld metal with the gun polarity wrong, but you'll never get a good flat bead.

 

i had a look at this site, http://www.mig-welding.co.uk/tutorial.htm there have how to setup the feed roller tension wrong, one thing that is bound to happen is the wire will burn fast to the tip, it just happens from time to time, when it does the feed roller need to allow the wire to slip, if the roller is set to tight the wire all balls up around the rollers and can form whats called a "birds nest", so an easy to test this is to cut your wire off flush with the end of the tip, place the tip up against something that is NOT grounded, like a piece of wood, and pull the trigger, if the feed roller is set corectly the wire will slip, if it is to tight you get a birds nest, the roller still need to be tight enough to feed the wire under normal welding without slipping, now you can do the finger pinching the wire test, you should be able to go from lighty pinching the wire up to stopping the wire with your fingers, you want all the tension you can get without creating a birds nest.

i also forgot to add that the feed rollers are different for different sizes of wire, rollers that are ment to feed .035 flux core wire have a V that is to large to feed .023 solid wire properly, lots of mig welders have rollers with two sizes of V's so you can just flip them around to go from one size wire to another.

 

Agreed, you just saved me some typing my friend.

 

what a great link!

 

when you are done you'll know how....................

 

You do not want the feed roller to slip. You want the wire to feed consistently at all times, no slippage. If you have a bird's nest problem, you need to replace the liner, and or tip.

Inner shield, and dual shield are both inferior weld methods for sheet metal.

You can avoid all this by using a better weld method, either gas or tig. Both are superior to mig and require less grinding. You can do top-notch work with a mig as Randy Ferguson has proven, but it is slower, and creates more of a fire hazard.

Using either gas or tig, you can weld faster, and metal finish faster, with no grinding. It takes a bit more skill, which just requires practice.

John www.ghiaspecialties.com

 

haha... now THAT'S funny!

 

Tack and straighten/flatten. Start out with large areas in between tacks then keep going half the distance until they are close enough so you can finish welding. Patience and a dolly and hammer will be your friends.

 

i respect your work John but your off the mark about the feed rollers sliping, i can tell you have no background in production line mancfacturing where mig welders are used, for me this includes men and robots, picture this, the guy welding at the end of a welding line has his wire stick fast to the tip, now is the roller are set to tight he has a birds nest, what does this mean, now instead of just replacing the tip he has to call the line supervisor over and the supervisor had to go get a step ladder and spend 15 min cutting out a birds nest while the whole welding line say 20 guys stand around with there thumbs up there butts?, no the rollers have to slip when the wire sticks to the tip of the liner plugs up, now lets talk about a robot, robots dont notice if there is a problem, they just keep going like nothing is wrong, you end up with a ball of wire in a hurry, sometimes glowing red wire burning the hell out of everything, not good, now your $100,000 robot is shut down for how long, the rollers have to slip or you have the boss standing behind you reminding you that the last time the line went down it cost him $10,000 and hour.

 

Hi Budd,

Actually I do have experience with industrial welding using a mig. I used to weld King Crab pots 8 or 10 hours a day, and later on I ran dual shield in the shipyard for structural work, and I've spent a lot of time mig-welding on cars... before I got religion and went to gas-welding on all sheet metal : )

After reading what you wrote more carefully, I agree with you. However, I've never had a problem simply tightening the drive rolls down and welding, as long as the machine was otherwise set correctly.

John www.ghiaspecialties.com

 

If you are running arc supervision in your weld routine the robots do notice.When they burn back,They run an escape routine, you change the tip, hit OK on the teach pendant, go back to auto, the robot returns to the spot where it burned back, strikes an arc, finishes the weld, the line cycles.

Not that I have done this about a billion times or anything.