How To Weld Exhaust Pipe – Mig, Tig, Stick, and Flex Core

by Miles Bruner 0 Comments

Automotive welding is a major track for professional welders — including welding exhaust pipes, exhaust manifolds, mufflers, frames, etc. However, knowing how to weld exhaust pipe can also be helpful for the hobbyist welder or auto enthusiast in a pinch.

DIY muffler welding and exhaust pipe welding allows you to save money that you would spend at an auto repair shop, and increase your knowledge… win win if you ask us.

However, it’s important to note that using the proper technique is incredibly important so that you have a quality weld that will last.

Avoid welding when the exhaust pipe is attached to the vehicle – the sparks from welding can potentially lead to fires or explosions due to gasoline.

What tools do I need to weld an exhaust pipe?

In order to successfully weld your exhaust pipe — especially when conducting a repair, you’re going to need several common tools for working with metal. A welder, grinder, hacksaw, potentially a circular chain saw, and all your welding safety gear.


How To Mig Weld Exhaust Pipe

MIG welding is one of the more popular techniques (if not the most popular) for automotive work such as this. It produces minimal slag, which results in an aesthetic and strong weld (automotive enthusiasts are very particular about the aesthetics).

When using the MIG technique, make sure to spend quality effort on cleaning the metal. You may also find that doing some initial tack welds and transitioning to a bench works well (this is a common approach people who TIG weld exhaust pipes take). You’ll need to take care to not burn holes through the piping — so be aware of what your tubing measurements are and if it has rust (MIG may not be the best option if you’re working with rusted exhaust piping).

Using .023 wire is common.

The Process:

  1. Tack weld the pipe in place
  2. Remove from car and bring to welding table if possible
  3. Clean metal
  4. MIG weld slowly (perhaps using .023 wire)
  5. Once the weld has hardened, attach to car
Pros
  • Commonly used at autobody shops
  • Wire feed means no replacing rods
Cons
  • Risks burning holes through thin or rusted pipe

How To TIG Weld Exhaust Pipe

TIG welding is a popular choice for exhaust pipe, exhaust manifold, and header work — particularly with thin sheets of metal such as exhaust tubing where other techniques may burn holes.

TIG is well suited for sensitive metal alloys such as stainless steel. Like MIG welding, it’s important to make sure your metal is cleaned with no oils, rust, paint, or dirt present. Your standard TIG foot pedal will help with heat control, making this another good choice in many situations.

A popular choice is a 1/16 inch tungsten at roughly 60 degree position. Make sure you don’t do more blunt than a 45 degree angle to ensure you get a high quality weld, and remember TIG welding is perfected over time and repetitions.  Utilizing a pulsing technique can help reduce the HAZ.


How To Stick Weld Exhaust Pipe

Let’s just start by saying that stick welding is not the best choice for working with exhaust pipes in most cases. When you’re doing this type of welding, you’re generally working in tight spaces, and potentially at non-flat positions. Because stick welding produces a puddle, you’re going to need to watch it … and unless you have a special welding bench this might be difficult.

Now to mention, that stick welding generally requires two hands, which generally is not possible in tight spaces. Overall, consider stick welding as an option on a case by case basis which depends on the angles and positions as well as the metal you’ll be working with.

If you do decide to go the stick welding route know that the 6010, 6011, and/or 6013 are relatively popular rods if the shop you are working in has them.

 

Pros
  • Location and weather flexible, can be useful in pinch
Cons
  • Generally requires two hands, which can be difficult when working with exhaust manifolds and mufflers
  • Not ideal in tight spaces
  • Metal puddle you need to monitor
  • Slag is common

How To Flux Core Weld Exhaust Pipe

Similar to stick welding, flux core welding is another type that is not recommended for exhaust pipe related work. Flux core welding produces much hotter arcs due to the high amperage, and as a result can risk burning through the exhaust piping.

Pros
  • Wire is continuously fed, which may may for a quicker job since you don’t need to replace electrode rods
Cons
  • Can burn through thin metal such as exhaust piping
  • Spatter may produce an unaesthetic look

 

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