Last joint to complete course!

[MM6CMC]

Hi all,

I've asked for some help with this before, but I'm really struggling to get a satisfactory lap joint in 6mm steel. I've had no problems with outside corners, t-fillet or butt joint, but I'm really struggling here. Your advice would be much appreciated.

What profile should the weld have?

How should I aim the torch?

Where should I be aiming?

 

[wannabewelder]

Hi MM6CMC
If it's any consolation I had exactly the same problem with MMA on my evening course - did all the other joints, the open corner was a bit tricky but after a bit of perseverance I managed it - but the lap was something else! My problem was consistency. I tried for weeks to get it right! Sometimes I got reasonable results and other times it was - well frankly, rubbish!
Keep at it. I got there in the end and I'm sure you will too and I'm sure there'll be some more positive tips than mine from the other guys on here.

Regards

Wannabe

 

[Marty2005]

Hi MM6CMC,

It'll come. I was on the same course as Wannabe and had exactly the same problem. I can remember I did two of the five test pieces on the same evening (T fillet and corner) and then had a go at the lap joint. I then spent a term and a half trying to get the damn thing right! So two test pieces in two hours and then one in about thirty hours?!?!

 

[runnach]

What profile should the weld have?

How should I aim the torch?

Where should I be aiming?

Did we not touch on this one before, apologies if we have?

1: No concavity, slight convexity, ideal profile build up to top edge of 6mm plate, approx 45 degree, with equal leg length.

2&3: Torch angle 45 degree on one plane, other plane approx 70 degree. Aim wire directly into centre of joint.

Watch out for you're speed of travel, same for arc length, I'm assuming plant is setup to give a good welding condition, just take your time, make sure you have good vision while depositing weld. You'll get there in the end, sometimes we can all have days when things don't go how we want them to!!

Cheers..........

 

[MM6CMC]

Aye, I did ask before, but I was getting right scunnered with it. Back for another go tonight - I was getting the odd good attempt last week, so we'll see if I can get more consistency tonight.

Thanks again for the tips....

 

[MM6CMC]

Right, I've cracked it! I had a go with the power up a fair bit from what I'd been using, and pulled a perfect clean weld first go! On 6mm plate, I was using a Lorch M2040 on 400v and full power.

What I found was that torch technique wasn't quite as critical as I'd thought, and that I now have the dexterity of a brain surgeon from practicing constantly for the past 4 weeks.

I guess jumping about from machine to machine over the past few weeks had knocked me a bit - the wee Fronius I'd been using hadn't the power of the Miller I started with, or the Lorch I used last night. Feeling pretty chuffed with myself now!