Thread: Tig welding stainless to mild steel

My opinion is that what ever you use they will be cracking at the interface of the two metals .

I take it is a diesel as most tractors are. The petrol engine cars have stainless sytems but diesel engine models do not has been my understanding.

Grahame

Some diesels do have stainless systems, i'd say though that most manifolds would be cast iron.

I stand corrected. my (wrong now) info was correct years ago as we tried that on a diesel car and had a crack fest..

I supppose technology has caught up to me again.Try 309 stainless and the same filler rod as it is a heat tolerant stainless.

Grahame

Arc welding stainless to mild steel box section 1.6 walls doesnt ever seem a problem with cheap mild steel 2.5 mill rods .Did some just the last few days as I got given a lot of 25x25 1.6 stainless shelve frames .Welds never seem to crack ,just rust a bit.You can get special [expensive] rods to braze stainless to mild with oxy.Give it a go with what you have its only a tractor -- not like loosing your exaust on the motorway at 110+ in a car .

I welded stainless steel exhaust pipe to mild steel flanges on the 4x4, with mild steel wire in the mig,and have not had a problem in 5 years. After weld and clean up, I painted it with pot belly black paint.
Dave

HI,
Thanks for the Replys. I will try the Local Boilermaker and see if He has some 309 Filler Rods. I have also been thinking of Making the Muffler in three pieces. The 1st Manifold to Silencer in Mild Steel, 2nd Silencer in Stainless Steel, 3rd Outlet in either Stainless or Mild Steel. I will let You know how I go. First of all I need to make a Circle Cutting Attatchment for My 40 Amp Plasma Cutter.
All The Best steran50 Stewart

Hi Stewart,
I got a link to this plasma circle cutter the other day while browsing, it might give you an idea or two.
Home-Made Circle-Jig for my Plasma Cutter - TractorByNet.com
Dave

You can get flexible S/S tube. All the trucks/ crane motors I've seen lately have this fitted , it seems you dont need to have the exaust rubber mounted if you use it close to the manifold. Tangent (no ass.) have circle cutters, I have one for oxy/ace and it works well. Ive used one for plasma with same results.
Cheers, Col.

HI,
Thanks Dave J - I had thought about a Magnet type, but will be Cutting Stainless as well. I however still might make a Magnetic attatchment as well for Mild Steel work. Especially when cutting vertically.
Thanks Col James, I know about the flexible S/S Pipe.As we fit it to the Air Compressors (Hookahs) Exhaust on the Abalone Boats where I work. The Deckhand puts the other end into the Water (Ocean) whilst the Hookah is running to help keep the noise down. The Flexible S/S is however not suitable for this Tractors Muffler. The Tractor is an 'Eastwind' with a Perkins Diesel Motor. The Exhaust Manifold is threaded with (from memory) 1 1/2" bsp straight. From their the Exhaust pipe goes straight up 1.5 to 2 feet to the Silencer. From the Silencer it goes up another 1.5 to 2 feet to its mounting point on the Tractors Fibreglass Roof ( a piece of rubber is used at this point to assist in anti vibration).
As for the 'Tangent' Circle Cutters, I think they are over priced. I for one am not going to spend what they want for one, for the amount of use it's going to get.
I think for now we are going to just Patch up the old Muffler till I can get a chance to make the new one.
All The Best steran50 Stewart

Something I have used to weld dissimilar metals with great results is silicon bronze brazing rods with either oxy or tig as the heat source. You can build up the fillet so that there is a large weld area, it is beautiful stuff to work with.
I believe it would be plenty strong enough for an exhaust system and probably cope with the vibration very well because you would avoid the HAZ on the stainless right near the weld if you tig it with filler rod.

Just a thought and good little "get out of gaol" trick for welding dissimilar metals.