Thin sheet welding

[Craig-S]

Admittedly i should be doing more experimentation rather than just asking this. but is there a better tungsten angle for say 2.5mm sheet and under? I normally grind at 30 ish degrees, but i'm having trouble with laps on 2.5mm steel.

I have seen the tubers do laps on 3mm at 130 amps which to me and the tig amp chart screams noooo. but they seem to do well without melting the top edge. I struggle with 90 amps not melting the top off and i dont want to lower the amps to a point where i wait 5 minutes for a puddle. im using 2.4mm 2% thoriated and 1.6mm filler if that helps. maybe smaller tungsten?

Ill see if i can grab some pics later

 

[tigdlo]

Sounds like an arc positioning issue, with a lap joint you don't normally aim the arc so close to 45 degrees at the corner like a T joint but at the bottom plate aimed slightly towards the edge of the top plate, I find the thicker the material the more I aim at the top plate. Do you have a pedal? 130amps does sound the highest I would set the maximum on a pedal but maybe a bit lower, I would test as I weld infequently.

If you are looking for an excersise to learn then start with a vertical arc then angle a more to the edge of the top plate until you get a good weld at a reasonably travel speed and current setting, cut and etch or just cut and visually check the root to make sure. Depending on what you are welding you probably don't need to fully penetrate the bottom plate to get a good weld but you do need to get full fusion into the root and fully weld the edge of the top plate.

I don't think this is a tungsten issue, I assume you mean 30 degrees either side? 60 degree included angle? I would use a 2.4mm tungsten, about 60 degree included angle optically measured by squinting at it and 1.6mm filler for a 3mm lap joint.

 

[Craig-S]

It could be, but i find if i point more towards the bottom plate i get a bead that doesn't touch the joint. there are times it all works out but thats less common.

I do have a pedal but im fairly new with welding so i use it generally as a 2T switch. I assume the angle is 60 degree included, i just make it vagely pointy and use an angle measurer if it looks off. at least there shouldnt be an issue with filler/electrode, so just confirming the problem lays between the torch and the pedal.

This is just hobby stuff, i often break the joints to re-ruse and see how strong the welds are.

Ill grabs some photos in a couple of hours when i finish the day job

 

[tigdlo]

It could be, but i find if i point more towards the bottom plate i get a bead that doesn't touch the joint.

If it is an arc position issue you could try different angles at different distances from the joint, the more vertical you are the closer you should be able to get to the edge of the top plate without melting away the edge.

 

[Craig-S]

A cheeky quick practice. its that top edge. according to the tig amps sheet, a 2.5mm lap joint should be around 68 amps :/

 

[Misterg]

Are you left handed? (Which hand was holding the torch?)

 

[Craig-S]

Are you left handed? (Which hand was holding the torch?)

I am in left handed, or....special

 

[tigdlo]

Looks a little light on the filler, more filler will cool the weld and enlarge the fillet up to the top of the top plate without melting away the edge.

 

[Craig-S]

Looks a little light on the filler, more filler will cool the weld and enlarge the fillet up to the top of the top plate without melting away the edge.

I'll give that a try next

 

[Misterg]

I am in left handed

That's OK then.

Just checking you weren't trying to weld backwards.

 

[Craig-S]

At this point i feel im going backwards, blew through with the heat possibly going to othe other extreme with filler adding

 

[tigdlo]

I think you need to run some beads on flat plate to get up to speed, you are overheating your test pieces. You can switch between 2 or 3 plates to allow them to cool to get extra practice within the same timeframe or wait for 1 plate to cool a little between passes.

 

[Craig-S]

beads on plate are actually not bad, as are fillets, laps just seem to be the hardest for me to get on with...well under 4mm at least