New to welding, looking for pointers

[DStanley1809]

Hi All,

Me and a buddy have decided to build a kit car and an important part of this project is learning how to weld!

We've started practising using 1mm sheet steel but haven't had a great deal of success there. Lots of sputtering, black residue and what looks like marbles on the surface. Somehow we managed to not blow through this steel at all.

At first we just tried running beads then tried welding to edges together, using settings from various different online "calculators":

From the ease with which we could separate the edges we know it was a bad weld, just sitting on the surface.

This was a a couple of weeks ago and we tried again today, using some angle steel and taking our own guesses at the settings. I think it went much better as we were getting a consistent crackling sound instead of popping and there is much less black residue. We seem to have had some success in attaching two edges together.

It's not pretty and looking underneath it doesn't seem to have penetrated all the way through but when you beat on it with a lump hammer the metal bends before the weld gives way. We couldn't get the weld to bend or crack at all.

After this we cut up some more angle and put it together to form box section and welded that up. Again, we were unable to break it and the metal walls started deforming before the weld did but inside the tube we couldn't see any penetration.

Is this a "good" weld or do we need more penetration?

 

[jimmyspeed]

You definitely did the right thing moving to thicker material its alot easier to get the basics. The top welds look like little or no shielding gas was used, check its coming out the nozzle there should be an audible tscchh when the triggers depressed - do not fire the wire into your face!

Online calculators are fine to get a basic setting but you will have to learn to fine tune the settings yourself, to cope with the materials temperature (as it warms up it will penetrate more). If its to cold it will sit proud like the third picture down, too hot and it will blow through or sag.

If you want to get better penetration on the thicker material you can Vee/chamfer the edges, also try moving the material apart by say half a mm this will allow the weld to go deeper.

From your lower pictures id say - slow down, you want a continuous bead of weld - crank up the volts - imagine your drawing a line with the torch travel across the metal, aim to keep the speed constant the height/angle constant and as straight as possible.

 

[norlander]

post details of your welder-ie make and model, what your gas set up is-ie disposable bottles and regulator or proper gauges and argon mix or pub gas etc.

 

[Kent]

I think you might be a bit nervous about cranking things up, its only scrap right? You can always turn things down to find the right level. Setting up to much wire and too much juice and work down can be easier than going up, work the wire down then the juice in stages till you find the sweet spot for the job. After a few goes at different stuff you will soon get the knack of were to start.
Never even seen an online calculator but I have the old lists and some seemed to be worked out from just one sweet setting and became steadily more unreliable the further you moved away from that point.
The point in this is its easier to spot too much than too little IMO. Get a plate and fill it with beads stack them up all over the plate

 

[DStanley1809]

Welder: Siegen S0816
Gas: Argon/CO2 5%
Bottle: 10L, 200BAR
Regulator: Has pressure and flow rate dials
Wire: 0.6mm

The better weld above that didn't break was done with a wire feed of 5 out of 10, power of 3 out of 4 and gas flow of 12 litres per minute.

The crappy black weld was done on wire feed of 3, power settings 1 and 2 and gas flow of about 10 litres per minute.

 

[norlander]

Welder: Siegen S0816
Gas: Argon/CO2 5%
Bottle: 10L, 200BAR
Regulator: Has pressure and flow rate dials
Wire: 0.6mm

The better weld above that didn't break was done with a wire feed of 5 out of 10, power of 3 out of 4 and gas flow of 12 litres per minute.

The crappy black weld was done on wire feed of 3, power settings 1 and 2 and gas flow of about 10 litres per minute.

OK looks a decent set up, first thing,
make sure you have a good earth.
back off gas flow to 5 LPM and try on that (you may be pushing too much gas in and pulling air in behind it)
try pushing torch along joint if not already doing so (supposed to give better gas coverage).

to do a gas check, lower the feed roller tension off (the thing with the screw down knob that site above the roller just before the wire goes into the liner) you should then be able to squeeze the trigger and hear gas come out and/or feel it on a wet finger without the wire feeding.

As the others have said, put some settings in and fire up on some scrap of the same material you are going to weld (thats quite normal practice for experienced welders-but the settings become intuitive after a while). I always go for plenty of juice and back off, I prefer to stay on the hot side of the settings and will "pulse" the trigger on thinner stuff to avoid blowing holes-sort of continous spot welds so to speak.
HTH.

 

[DStanley1809]

That's a large difference in LPM.

I guess too much gas would have a cooling effect and prevent proper penetration?

We have plenty of this angle going spare at the moment so we'll get back to practising on that at the weekend. Luckily, it's the same thickness as the box section we need to weld for the chassis so once we get it working properly on that we should be able to just leave the settings as they are.

 

[norlander]

I guess too much gas would have a cooling effect and prevent proper penetration? I'm not qualified to give an answer on that-but sometimes too much gas and angle of torch can pull in air and thus the gas shield is affected.
Experiment with how close you are getting the tip and shroud to the job-its quite common to have the tip too far out-usually to see better-lots of welders-me included-cut the shroud down.

 

[Richard.]

As Kent said crank it up to the high end of your machines capability and tune it down to suit. If your still not getting through V prep the joint. Once you have got your conditions sorted you can then start playing with different preps different size root gaps and root faces to get to know what works for your settings.