welding stainless steel exhaust pipe

[02GF74]

I plan to weld 50 mm OD stainless pipe but the pipe on the R1 can is 60 mm OD.

Is it ok to put the smaller pipe inside the can and then use strips of stainless bent into a circle to pad it out or am I better getting the 50 mm flared out so it is a tightish fit inside the other pipe and then weld that (no packing pieces)?

How did you do this if you had the same problem?

BTW I wouold be using MIG, with stainless wire.

[paul doran]

You would be better of buying a tapered fitting from a stainless steel supplier
otherwise it will look crap
use a light wire if posssible as the mig is not ideal for welding stainless

[Exhaust Craft]

If you want send me both bits and i will expand the 50mm tube so the 60mm tube will slide over it perfect,please do not mig it,it will turn out looking crap.
Dave wwwexhaustcraft.co.uk

[02GF74]

^^^ thanks for the offer, Most generous but I am not that fussed about looks - the carbon can has aluminium caps at each end that should hide the messy weld.

I haven't got the pipe I want to attrch to it yet ... and postage, to you and bakc would be more than I paid for the can (ebay) and probs may find someone local to me but I'd like to have a go myself.

[Exhaust Craft]

No problem,all the best with it.

[popsA1]

Are you any good at sheet metal development? You could try rolling a cone out of sheet.


Your flat blank will look like this


A rough way to calculate the rads and angle is to us the following – d1 and d2 are you finished diameters and L is the length of the cone. The inner radius that will form the small end of the cone is worked out as – the small dia multiplied by the length (d1 x L ) then divide that by the difference between the two diameters ( d2 – d1 )
The angle (angles are always difficult) is 180 times the small dia times the difference in diameters ( 180 x d1 x ( d2 – d1 ). Then divide that by the small dia times the length ( d1 x L ).

So for a cone of 50mm to 60mm by 30mm long your sums will be
Radius = 50 x 30 / 60 – 50 = 150
Angle = 180 x 50 x (60 – 50) / 50 x 30 = 60 degrees

This is only a rough guide as it doesn’t take account of material thickness or welding allowance but if you cut it out of a piece of paper first you will see if you’re on the right track.

All you need now are some bending rolls to go with your welder.