Welding questions

[trwebb26]

Well... I got a new lincoln 110V welder - a 140C. I also got a lease on a bottle of C25. It is filled with a spool of 0.030" lincoln wire (I forget the kind of wire right now). It was the kind of wire the welding shop reccomended for general use.

 

To learn how to use it - I took everyones advice and started in on a welding cart for it. I welded on it all day and I learned a LOT. But I have some quesitons:

 

1) My tacks are WEAK. They break loose all the time. This caused me to put in giant-sized tacks that were impossible to make look good when I went back for the finish welding. The metal was 100% clean. Do you vary the feed or voltage if you are tacking? I don't know what I'm doing wrong.

 

2) I got to be really good at bevel, butt, and rosette welds. They looked super clean with great penetration - but my fillets - oh boy... they looked TERRIBLE. I got really bad penetration, crappy looking welds, and overall a horrible experience welding fillets. I thought maybe I should be changing my stickout a little for these welds, but I'm really not sure what my problem is. Anything I should be looking out for?

 

3) I've read about making different shapes with your arc when you are putting down a pass - half moon, circles, back and forth, and just straight... What do you use - and do you change what you use for what kind of joint you are welding?

 

4) I never messed with the gas... I just left it at the reccomended setting (35 cfh i think?). When do you know to add or subract more gas?

 

I think that are my questions for now... Thanks for the help!

[JMortensen]

1. Sounds like you need to turn the juice up on the tack welds. Unless you're tacking sheet together you can actually turn it up pretty high, because you won't be there long enough to really burn through.

2. Not enough info for me to make any kind of assessment. One thing that helps me is to hold the gun with both hands like a pistol and then stick my left pinky out and touch the piece. This steadies my hand. Bad penetration = not enough power or you're moving too fast. I like to turn the wire speed down and move more slowly, but that puts more heat into the workpiece. For your cart that will be fine and will probably help a lot, can't do that with sheet metal though...

3. I make this sort of motion )))))))))))))))))))) with the gun and it works for me. Sometimes I'll vary based on the position I'm in, but I pretty much stick with that shape. Other people I know use other shapes, I think the shape you use is more about making it pretty.

4. When you run out of gas the first time you'll really find this out. When there is not enough gas the weld will suddenly sound "fuzzy" and when you look at it it will look all boogered up and very porous. I have my welder set to something like 25 and that works, but almost all my welds are done in the garage with the door closed. I've turned it up and tried to take the nozzle off the end of the gun but apparently couldn't get enough gas in there on one occasion, and I've turned it up when I had to weld outside on another. Generally I just leave it alone.

[Pop N Wood]

What Jon said. Sounds like you are not running hot enough. Play with turning the heat wayyy up and adjust the wire speed to match.

 

As for gas, my welder has a non-adjustable flow regulator. I would leave yours at the stock setting until you get much more experienced.

 

The weld definitely makes a different sound when the gas is off or runs out. I have read welding texts that recommend occasionally running a bead with the gas off just so you get use to reconginzing the sound of a weld with no gas. It is easy to forget to turn on the gas, and that makes for bad welds.

 

The other trick is to not move too slow. That can cause you to build the weld on top of the filler metal and not get penetration. Get some scrap metal, turn the heat up and practice some welds moving the bead quickly. If you are hot enough, especially with thick metal, then you don't need to work the puddle by moving the arc in circles. Just nice, fast, straight motion.

 

Also how do you know your getting great penetration? Have you cut welds in half to inspect them? Or are you getting some puddling on the back side of the metal?

[grumpyvette]

the guys above gave good info based on the limited info and no clear pictures, and are most likely correct. but one reason Ive found occasionally with the smaller amp rated welders is the machine just won,t put out the amperage necessary to get the needed heat, at the correct spot in the ideal time frame or the wire or rods your useing (mig/stick)are too small in dia. and thus melt too fast for the base metal to heat up and flow/mix with the filler rod or wire ,to get a good looking tack if the amps are ok but the main thing youll need is experiance and practice.

oxy-acetolene torches and TIG don,t tend to have this to the same extent because the heat and material feed are seperately controlled, thus you have potentially more areas of control

[lbhsbZ]

Check the door chart for recommended settings based on the material you are welding. This will get you in the ball park. The wire feed may need some adjustment though....The door settings will vary depending on your available power supply. When you are welding, pay attention to the wire...if the gun pushes back, like its feeding wire too fast...reduce the wire speed. If the wire is burning back towards the tip, and looks like a bunch of drops of molten metal landing on the workpiece, then increase the wire speed. Check out http://www.hobartwelders.com/mboard/

There is ton's of information there, read up and ask questions.

[mikeatrpi]

Check your stickout. When I tack I keep it very short- 3/8" or less- for a little extra quick heat. I usually squeeze- count to 2- let go. For settings I use B 3.5 for 16 to 18 ga sheet metal on my Lincoln SP100T.

[A. G. Olphart]

With my 110 volt Miller Sidekick, I prefer .023 wire, thinking that if it takes a little less heat to melt a given length of wire, more heat goes into the base material for a given wire speed.

 

Then again, the heat is normally set fairly high, too.

 

Wire welders can be a lot of fun.

 

 

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[johnc]

Most people weld with too low a heat setting, fearing burn through. Turning up the heat will solve most of the problems you list above. Try going up one step from what's recommended in the manual that came with your welder, but be prepared to adjust the wire feed. Adjust your gas flow so that you're seeing 30 SCFH when welding.

[trwebb26]

Thanks for the advice everybody!

 

I got a chance to weld some more stuff this weekend. I had a few things to note from my experience:

1) Turning up the voltage made a big difference for the fillet welds. I was getting pretty ropey looking welds before - with the voltage turned up it helped a lot. I made a couple of passes that looked 1st class.

2) Position is EVERYTHING. Being able to see the puddle and control it without straining makes a BIG difference. I just don't have the skills for out-of-position welding, yet. Everything has to be flat with good access for me to get a nice looking weld.

3) Gun angle is key. I noticed that even 10 degrees in gun angle can make a world of difference in making sure your weld penetrates into both pieces of metal and that everything melts together.

4) Use a LOT of clamps and make sure things have cooled down before you let them go. I was amazed at how my welding cart shifted around with a little bit of heat.

 

 

Questions I have now:

1) If I'm running MIG (with C25 gas) - should I be pushing or pulling? I've heard different answers. Does it depend on the joint?

2) If you use smaller wire - is there less distortion? My inital reacting is to say no - because you should be getting the same amount of heat into the part... I just wanted to poll the "experts"

3) Is welding like riding a bike? I mean - do you retain your skills after a while - or do you need to keep welding to maintain your skills?

[Guest waiting_for_a_z]

Welding can be great fun, especially when you get to do it in comforatble positions. If you're feeling adventerous, try welding above you, or infront of you verticially and horizontally. Remember that as soon as you're welding on a car, the sheet metal isn't nicely laid flat infront of you.

 

If you do try over head, make forsure you're wearing the proper attire, such as welding gloves, face sheild, long sleaves, boots, etc. and if you smell buring clothes, make sure you're not on fire

 

In response to your questions, I have found that pushing a weld, regardeless of what kind of weld is a good idea. If you push a weld, you're adding heat into the area that is about to be welded, allowing for greater penetration. Also, when you pull weld, you increase your risk of distorting the sheet metal, by adding too much heat. Push welding allows the weld to cool much sooner than pull.

 

As for distortion cause by the gauge of wire, I've never heard of that. Metal distorts and warps because of too much heat, which causes "oil canning" or "tin canning". this of corse can be fixed, but a whole new set of skills and welders are needed to correct it.

 

I would compare welding more to something like painting. Yes, the skills you have will for the most part be retained, but like any other skill, it takes practice, and the occasional refresher to stay on your A-game.

[grumpyvette]

waiting_for_a_z

 

nailed the info fairly well,

 

just a suggestion keep a CO2 fire extinguisher somplace close and handy (EXAMPLE

by the shop / garage door )

while welding and always try to keep a water hose with a nozzle the can be nearly instantly turned off and on under pressure and near by, while you weld on cars , 99% of the time you won,t need them but if you do youll need them badly and won,t want to be looking for them or guessing as to thier location

[240zV8]

Pushing welds seems to produce better welds for me to. U can get a great weld either way, for me it's mainly preperation in getting the metal clean to get a good spatter free solid weld.

 

Before I got my welder, my neighbor welded a mechanical thumb for my excavator and when he was welding it onto the boom, a little fire started about 10 feet away from him welding, lol... And it didn't start for a couple minutes after he finished welding, so that means the ember was just burning for awhile, so its smart to keep a clean area to weld in.