help with lap weld please :-)

[Oldbanger]

Hi guys I was hoping to get a bit of help with my lap welds.
Im using a clarke migpro 90en setup with 0.6 wire and a bottle of hobbyweld 5 set at 10lpm and the metal is 0.9mm thick
Initially I had the power turned right down (min1) - the welds seemed to sit very proud of the metal and had little penetration....

When I filled between the tacks I turned the power up to max1.... the welds seemed to be a lot flatter but I had a brown residue that looks like I was welding with no gas????

Flipped the metal over and did a constant tack-cool-tack-cool and I didnt get as much residue....

if anyone can shed any light on where Im going wrong it would be much appreciated - cheers

 

[Country Joe]

Hi there!
The gap looks quite big for such thin steel - but the main issue seems to be lack of gas coverage, as shown by the sooty deposits.
All the Best,
CJ

I see that you mentioned the flow rate being 10L/min - are you sure it's all getting through, doesn't look like it.

 

[FranV8]

Same thought from me. Any leaks in your set up? Shroud clogged up? Put us a photo of your torch up.

 

[carlos420uk]

I'm no expert by any means, but through my own learning curve I have found that this problem can be caused by stick out length being too long, and / or gun angle changes during welding.

When your starting out it's really easy to let the stick out drift during a run without noticing as your trying so hard to concentrate on the puddle.

 

[Oldbanger]

Thanks for the replies , need to check the shroud but after every use it gets a clean .. Ill post a pic - What sort of pressure should I be feeling at 10lpm??? Cheers guys.

 

[Oldbanger]

Ive had another play with my welder today and it seems like it may have been a combination of gas flow and torch angle - the flow was set at 10lpm but when I pull the trigger it dropped to 7/8lpm also tried to maintain a more perpendicular angle to the work peice.... I still have a little soot but Im welding outside with a very slight breeze.
My stickout was maybe 1-1.5cm I find that any more and it pops like hell , any less it starts to burn back to the tip??? Does this sound right???
I also had a general question about how best to tack a panel together???
is it best to work from one side to the other or start in the middle and work out the way switching sides in between tacks .

 

[octo0072000]

lpm

you want 10lpm when the trigger is pulled so remove wire feed pull trigger hold trigger on set lpm to 10lpm'release trigger lpm gauge may read higher12/15lpm as long as you get 10lpm when welding that's ok see how you go
if outside a windbreak works well couple of bits of plywood to shade against the wind

 

[jamster]

lap weld

Hi i am doing a MIG course at the moment and the residue you are seeing is glass. which is contained in the flux. i can't see your pic of your welds but i think you should have a gas flow rate at 10 li per minute and angle your gun
so that you are about centre of the joint and try a nice steady travel allowing the weld to build up to the edge at the top of the joint but not over
hope this helps

 

[BillJ]

There was no flux involved, as far as I can see. I understood the original poster was using fluxless wire with shielding gas. He is describing the brown, powdery residue that is usually a symptom of lack of gas coverage.

 

[BrokenBiker]

cant see the pics but the residue does sound like you don't have enough gas covering the weld area

 

[BillJ]

I suspect he's sorted it by now, Brokenbiker. It is almost a year and a half since he asked about it.