making a lap joint look good

[BrokenBiker]

as in the title...how? lol

i am usually welding 3mm onto 3mm mild steel, using lap joints. i start the arc where the metals meet, 4deg angle, treating it as a fillet pretty much, little bit of weave, and usuall speed of welding

power and wire settings are ok, they are what i use for butt and fillet welds using same metal, but when doing lap joints the weld seems to be drawn towards the bottom metal, as if th weld pool is falling away from the top peice

is my technique wrong, or is it the way ive placed the metals together. i usually have the top peice overlap the bottom by atleast 5mm

 

[cumbriasteve]

Without seeing the result. I think it is probably technique and the main culprit will be the torch angle and perhaps a touch of the power.

No idea if my method is the correct one but works for me, I tend to weld along the bottom plate 75% and the edge of the top plate 25% of the weld pool, if that makes sense.

 

[BrokenBiker]

cheers for that. unfortunately i have no pics, as its all work related stuff ive done up till now

i will be attempting a few tomorrow though so will photo the good and bad.

i understand your method, havent tried it though. i was thinking about trying to start the arc on the base material, then weave over to the top peice and back to the base for the entire run and see if that is any better.

will try your method aswell though as it never hurts to try

 

[chunkolini]

When you weave onto the top piece keep an eye out for the top edge of the top piece, with practice you can see when it it is just melting, it almost shines, hard to describe a pinpoint of light, not quite. I think this gives a fuly melted edge without any overlap or collapsing of the edge.

As said hard to describe. Most people I show this to on the job get the idea.
Hope that helps.

 

[BrokenBiker]

so weave until i see the top edge start to @soften up@ then weave down again? shall give it ago on my table

 

[chunkolini]

Something like that, as I said hard to describe, watch out for a shiny look along the edge.

 

[BrokenBiker]

well i gave it a go, one with weave as suggested by chunko, and one without weave with torch 45deg from bottom peice, and about 70deg in the direction of travel, and they both looked fairly decent, and are both strong, so it must just be arc welding i cant grasp them with, which doesnt matter too much as i dont really do them in work lol