I am about to start fully welding my chassis, and have been spending some time reading several of the 'welding advice' threads. Great information, but I have one question that I haven't seen answered yet. So, here goes:

When two tubes meet at a T-junction, the sides resulting in 90 degree angles are obviously attached using a fillet weld that includes a side-to-side movement along with a push or pull motion (as appropriate).

My question involves the other two sides of the tube that meet flush to the other tube that they are being welded to. In this case, there is really just a straight line to weld, but I am wondering if a side-to-side motion is still used? I have seen what appear to be examples of both.

Thanks for any input.

Shaun

For those type of butt welds i turned my chassis over so i was welding down on to the joint and yes still use small zig zag technique to aide the weld pool

Not a great deal of experience but the important thing is to get both bits of the joint melting evenly....therefor it makes sense that you need to focus a bit more energy/time/zig or zag on the cornered side of the joint as the material is thickier here than on the bit that butts up to it. As long as your getting good penetration through this and even rates of meltingness it'll be strong....might not be pretty but thats what practice will do for you! Oli.

Are you using a MIG? I wouldnt be doing any weaving from side to side at all on steel of this gauge, if its all set up right you shoudnt need to. If it's TIG or gas then I've little knowledge of technique & if you're using stick then you're brave!

I've not found any need to weave/stitch the weld on thin stuff. If you get the settings right you can easily get full penetration (or more if you're too slow). I found it easier to turn the power up a bit and the wire feed down on the corner bits.

Sorry, yes, I am using MIG = Millermatic 175.

Thanks for the input so far!

Shaun

I always aim for a figure of 8 weave if possible, the tube that joins cannot disapate as much heat, as you are welding from a tube that extends both sides of the weld.

In welding the technique is to weld from thick to thin so you concentrate more heat on the solid tube and flow across to the thinner, cut end.

If you are butting up two tubes then weave across the join.

Regards Mark

Having some involvement in the welding trade I would have to agree with the no weave comments in this thread. Tube of this guage is difficult enough to weld with out ugly big welds with out weaving. You will also have a problem with undercut by weaving. Remember that if the tube is say 1.6mm thick then any weld thicker than this is waste and very unlikely to make the joint stronger. Most welds break alongside the weld and it would have to be a very poor weld to break in the weld.
Bruce

Don't build up welds on the side of the chassis as you only end up grinding them off to fit your panels. Use .8 wire and push the gun away from you and if your joins are reasonably accurate you will get both tubes at once without "weaving". You shouldn't need more than a slight side to side for any of your mig welds unless you are building something up. A 175amp Miller should murder the stuff you are welding even on a lowish setting so you should have no problem with penetration

yea, lots of talk of weaving on here, but don't worry about it.

As oliwb said, just make sure the heat is equal between both bits of steel, and move the torch to control this.

Again, thanks for all the input. I managed to get about half of the chassis welded on Sunday, and hope to do the rest this weekend. Then, on with the suspension!

Shaun