Lap joint advice

[MM6CMC]

I'm doing a lap joint test piece tonight - 2 plates about 150x50x6 - had a few goes at it last week, but couldn't get a very good profile. The lecturer said to aim for just in front of the "step" - which I played about with, but still couldn't get it quite right.

Any advice?

 

[Marty2005]

The lap joint was the one I struggled with on my C&G Level 1 course. I couldn't get it to penetrate the bottom plate properly and the toe of the weld was 'undercut'. If I turned the power up then the edge of the top plate would burn away. As your lecturer says concetrate your weld on the bottom plate. In my case I was using 3mm and the line I would follow was about 2mm from the edge of the top plate. Don't worry, it'll come, I took more than 'a few attempts' to get it right.

 

[mikeb]

i stuggled with that one too, consuntrate your weld on the bottom plate and put a TINY bit of circler motion in, it'l give you a good profile if your settings are right, but dont show the lecturer because they dont like it. it'l work with all yor down hand fillet welds.

 

[runnach]

As others have stated, except, not too fast speed of travel, watch weld pool and build up, I normally watch top edge of 6mm plate, allow to slighty burn top edge away, use this burning back as your yard stick to achieve good consistant weld profile. Your course aint a tuesday night is it?

Cheers.

 

[MM6CMC]

Its a Thursday night - Kilmarnock College.

Did 2 hours of lap joints last night with varying success - I seem to be getting a wee "step" at the top of the weld which is really frustrating - is this "undercutting" ?

Runnach - watching the top corner burn away does help. Sussed that out last night!

Reducing the gas helped a fair bit, but there was still a wee line along the top of the weld that you could just feel and no more. Would that be OK or would it need sorting out?

How should I be aiming the gun at the joint?

 

[MM6CMC]

Top up!