Advise on Butt Welding Mild Steel

[Vai]

First of all, let me apologise for an amateur entering your forums, but I am in need of some expert advice.

I am in the process of fabricating a one off exhaust system, that was originally going to use Stainless Grade 304 1.5 inch OD, wall thickness 1.5 mm, but due to problems finding local Mandrel bending facilitys or a decent Tig welder to buttweld mandrel bends, I have decided to go down the route of using mild steel.

I have ltd experience of ARC welding ( car body repairs ect ), but I do own an ARC welder and have a plentiful free supply of Mild Steel pipes and Mandrel bends.

What wall thickness would you advise for the mild steel pipe ( once again 1.5 inch OD ) and what tips could you give me to enable a satisfactory buttweld. Also could I grind off the excess weld around the pipe or is it best left alone, the welds will be hidden.

The final job will be chrome plated.

Any advice would be very welcome to a very inexperienced welder.

 

[Gaz]

1-1.5mm wall pipe can be arc welded, use as small a rod as possible 1.6 - 2.5mm, and low amps. The secret is practice, practice, practice!!!. No don't grind off the excess weld as it will crack. You can neaten it up if required though. Good luck
Gary

 

[Vai]

I can go as low as 45 amps, but when getting the rods, I was told it would be a sod to do .....and that I should use a tig welder.

I keep getting these conflicting comments !!!

 

[Ron]

Vai,
TIG (Gas Tungsten Arc Welding-GTAW) would be easier to control burn-through on thin wall material; however, you can use SMAW (Shielded Metal Arc Welding) or GMAW (Gas Metal Arc Welding) as well. As Gaz indicated, you will need to use a small electrode (1/16" or 3/32&quot, and a low current to prevent burn-through. It will take to practice to start the arc with low current, but you can do it with a little patience.

Agree also with Gaz's comment...practice, practice, practice. This procedure requires a lot of finesse, not brute welding, but it can be done successfully!

Good luck.
Ron

 

[Vai]

I am going to give it a go with my basic Arc Welder and the rods that have been suggested, so 45 amps and loads of old material to practice on !

Thanks guys, will let you know if I manage it .