1.6mm can be stick welded if you are careful

ERW is the stuff to use rhs will usually be the black stuff and no good for a chassis as it isn't very square...

One major difference between RHS & ERW are the edge profiles.

RHS has a very pronounced rounded profile edge. Using this material will lead to a greater risk of welding distortion.

ERW is a precision electro welded sqare tube & has a very fine corner profile ;)

Yeah i've researching into welding 1.6mm, it would require buying some more rods and require a lot of practise as i dont want to end up blowing holes.

So does anyone know why ERW tube is used for chassis and the like? Whats so special about it? Does it add extra strength?

I have learned that ERW tube is made by taking a strip of metal and then folding or rolling it to the shape desired and then welding down the seam and cleaning off the outside weld.

ERW electric resistance welded, RHS really horrible stuff.:rolleyes:

With a bit of practice it's a breeze to stick weld 1.6mm.

ERW is electro resistant welded tube RHS is rolled hollow section....ERW is better quality where RHS is not so clever especially for a chassis.

Right looks like i might go down to my steel stockist and get some 1.6mm steel bar and have a practise. Someone on the mig welding forum has shown me a pic of where he's welded 1.6mm tube together using the 2.5mm rods im using so looks like i might just go down that route.

Im still curious as to why ERW is better though, what is it other than the corner profiles that makes it so much better.

RHS is black and full of crap where ERW bright and a better quality tube, there is a lot of iffy rhs out there and doesn't weld very well..

If your square tube is 1.6mm wall thickness it is almost certainly ERW ;)