Tips for fillet welds? (1 Viewer)

[e9999]

OK, so you may already be painfully aware that I've taken up (slowly) welding.
Spent a few hours already practicing. Mostly with TIG. If I may say so myself, my practice "welds" on flat plates are starting to look pretty nice. The butt welds are pretty good too, but the concave fillet (90o) welds are terrible. Booger welds are nicer than those....

I think I'm battling a couple of issues. For one thing it seems like the gas is blowing too hard, sprays molten stuff around, and maybe even the arc a bit. Likely because of the funnel effect due to the geometry of the plates and how I hold the gun? The flowmeter is set to specs per manual (20 I forgot what units). I could try to lower that.

Also, it seems like the arc is often attracted more to one piece than the other. (Electrical contact issues, or heat sink effect if one plate is on the table?). Seems like the pool is skittish, goes from one side to the other and the added metal stays there as ugly blobs.

So, any suggestions specific to fillet welds?

 

[FRIZZLEFRY]

...Also, it seems like the arc is often attracted more to one piece than the other. (Electrical contact issues, or heat sink effect if one plate is on the table?). Seems like the pool is skittish, goes from one side to the other and the added metal stays there as ugly blobs...

I would say the angle of the torch and make sure your tungsten has a nice clean point on it (if your welding steel).Maybe a little more heat too.

Having a nice clean point makes for a more stable arc

 

[e9999]

I would say the angle of the torch and make sure your tungsten has a nice clean point on it (if your welding steel).Maybe a little more heat too.

Having a nice clean point makes for a more stable arc

Strangely enough, my tips -which always start pointy, I grind them regularly- usually end up being not so pointy after a while... But, it's getting better....

But what about the angle? I'm trying to bisect the metal corner, so close to 45 so to speak. What if one plate is thicker than the other?

 

[Wile E Coyote]

If the weld is in an inside corner, then by all means, reduce the gas flow. You are also describing what sounds like arc blow. Google 'arc blow' and see if the description fits. If it sounds like arc blow, then try extending the tung out of the cup a touch more to allow you to get a smaller arc gap. If you have a smaller cup, that too can allow you to get closer into an inside corner. Getting closer, along with slightly less amperage and resultant slower travel could help some with any arc blow.

Edit: "What if one plate is thicker than the other" Then apply more heat to the thicker side of the joint. Easiest way is to dally longer on that side when weaving or walking the cup, if that's your method. Also, angling the torch towards the thicker side helps, but with TIG, this is less helpful than the first method. Another advanced method is to use the foot pedal to vary amperage while weaving the joint.

 

[Pin_Head]

X2 on grinding. It sounds like you are either dipping your tip or contaminating it by losing shielding gas (bad torch angle?). You may also be running it too hot. About 200A max for 3/32.

I doubt it it is arc blow. If the arc takes a left turn off the tip, then maybe reposition your ground or leads.

Joint design gets increasingly important for thicker metal. Beveling and having a root gap can help to get full penetration to the root. Master flat welds and lap welds before biting off something harder to chew.

Get in a comfortable position with a rest for your forearm so you can have good hand control and don't drink that pot of coffee before welding.

 

[jasonmt]

Inside corners on a fillet weld I like to use a lens, turn down the flow to ~10cfh and a smaller/longer nozzle to allow better visuals in the inside corners.


Third torch to the right for an example:

 

[craptabulous]

put more heat into the top plate . manipulate the puddle up if you have to .

try moving your ground , i doubt thats your problem

turn the gas down to 15-10 , experiment . you don't always have to listen to the book .

keep it clean and keep your tip sharpened .

 

[e9999]

I think I may go back to flat welds for a bit. It's just that most of the stuff I envision doing would entail some sort of fillet weld... I may also look if they have some other caps.

How long can you run the typical tungsten electrode out of the cap / holder before it becomes problematic?

 

[jasonmt]

Generally the tungsten extension is anywhere from flush to a distance equal to the diameter of the gas cup/nozzle.

Gas cups/nozzles are sized in 1/16th of an inch so a #6 gas cup/nozzle would be 6/16" or 3/8" across so with a non gas lens setup you would not want your tungsten to stickout past the gas cup/nozzle more than 3/8".

A gas lense is a nice thing to use as it reduces shielding gas turbulence and provides a long, undisturbed laminar flow of the gas to the weld pool. Gas lenses also let you move the gas cup/nozzle farther away from the joint and extend the tungsten electrode past the nozzle by 1 inch or more.

 

[e9999]

oh, brother...

I tried out flux core to see how that would go, and sure enough, I got some very nice fillet welds (in most cases)...

bummer... I must really suck at TIG...

 

[denis]

So, any suggestions specific to fillet welds?

start with a bunch of amps and add some filler quickly. Once the joint has begun taking shape the heat will distribute more evenly on both parts and you can go straight ahead.

 

[e9999]

I can see that

One of the things I did with the FC is to spend more time on the thick plate side of the seam and then dash out briefly on the thin. Seemed to help.