Welding and Fabriction advice 101

[murray]

Originally Posted by murray

did you read his question he asked fo a cheap ten amp plug stick welder
so thats how i came to my answer.
grinding the earth plug down just causes probs with your house wiring
and yes i agree that duty cycle is everything
i use a 170 amp coz at around 110 amps it has a 80% duty cycle

the answer

[Auberon]

It's a term a few guys (weldors) use - there are many people out there who can strike and hold and arc for about an inch as they don't set up properly especially when they need to follow around a tightly radiused part like an axle.

It's like many blokes can't run a continuous root pass on TIG when the job requires it. They weld an inch at a time and then have to stop, reposition and start the arc again as they can't do a run right around the part. That is a technique thing.

However, when you can't feed the beast (the welder) with enough amps - well, you guys know what happens to the weld quality when wires get hot and can't carry as much current.

It goes beyond just wrecking insulation through overheating.

To start with household wirnig is only "supposed" to carry 10Amps for domestic use unless dedicated to 15 A.....add a quite few degrees so the wire when it carries too much current and current carrying capacity drops exponentially then a good welder can hold the arc but many people find they can't adapt as an experienced weldor would do.

Thus through poor conditions they are a 1" welder so it can happen though poor technique and asking too much of the supply available.

I hope that explains it.

[junglejuice]

So how does that go with a regulated inverter unit???

I will happily admit to not being the best welder around, am I better off doing the "inch" weld and then stagger it 120* around the tube and keep staggering it till it is fully welded?
Or am I better off using a big MIG to do the job as my MIG welding ability is better then my arc welding ability but I really need to learn I suppose....

[2JeepFamily]

Just to add a bit more, JJ most of your concentration should go to ensuring that you get it all lined up correctly or you end up throwing it away as it will drive like a pig (had plenty of mates with poor 9 inch conversions). Welding it in continous motion would be better as loss of heat on axle tubes is not what you want. They are heavy enough to handle it as long as it tacked in at least 5 or more places (evenly). A big mig is your best bet if you can get hold of it, it will be easier to get constant heat.

[junglejuice]

Originally Posted by 2JeepFamily

JJ most of your concentration should go to ensuring that you get it all lined up correctly

Ironically I actually want to mis-align it.....

As for the earth pin it is there in case there is a short to the chassis it can safely for a return path through the earth conductor and back to neutral via the M.E.N. connection instead of through you....

[2JeepFamily]

[quote=junglejuice;1322485]Ironically I actually want to mis-align it.....

No worries, just ensure your tacks are solid and weld in a continious motion
(well as far as you can) and don't back step, if you look at how it is welded now it should be continious.

[Auberon]

As current carrying capacity is directly proportionate to area...which is the default pathway in case of fault....what are the consequences of reducing its size and intrinsic ability to carry that extraneous current to earth and away from the user....along the pathway it is intended to travel to save your life.

Hence, by reducing its (current carrying capacity) size safety reduction is implied directly and reduced hugely.

Ever welded in a damp area? That is why no matter what style of welding m/c you use special precautions are needed.

It's your life or anyone you may care about who is at the end of the chain as the current will hit earth through them. Don't tell me that people weld alone at home I have seen and stopped too many examples that are dangerous.

Why argue about the safety? You chaps stated exactly why welders ARE earthed.