I am putting a SI/SO 18" Magnaflow on my 05 SCrew 4.6L and dumping it at the axle. My neighbor has a welder with spool gun and I was thinking of welding it all my self. All I would need is the muffler, 2.5" straight pipe and a 2.5" turn down tip. We are ok welders but havent done exhaust befor. I know I need to watch for exhaust leaks so I am not concerned how good it looks. I know I will have to probably get or reuse an exhaust hanger somehow... Any tips or pointers?

 

i have installed a few in the welding shop at my school. i did the same thing your about to do, dump it and use old hangers. i had never done exhaust before and thought i did a pretty decent job. exhaust pipe is very thin so dont crank the heat up to much or you'll start makin holes.

 

Im wondering how much of the old pipe will be straight enough to reach without a bend. If not enough I am gonna pick up a 2.5" fence post. It would be steal .065.... Should work

 

You're gonna want to be able to stand underneath to reach up around the top of the pipe, otherwise you'll get leaks. Its hard enough to reach up there on a lift, but laying on your back trying to do it, well, its a path to hot slag in your shirt

 

You know, I was wondering about that... I was gonna were heavy clothes for protection and all that kinda gear, but I was thinking with a spool gun it wouldnt be to hard to do it laying under the truck... hmm...

 

Get an extra 6 inches of the pipe you expect to use and cut it in half. Then cut it in half again then weld it back up. It is cheap practice and it will show you just how much heat to use to get the proper penetration. You can also examine the inside of the pipe. Now to lay under the truck will make it near impossible to properly weld the top of the pipe. But if that is all you have then you are stuck with it. I would recommend lining up the pipes an tacking them on 2 sides and removing them in sections to weld all around. This will insure proper welds all around the pipe. Just for a reference get under te truck now with your welder and have a first hand look at the limited space available. But welds are inherently weak. If you have a pipe expander then use it instead. The pipes will slide into each other and make a stronger joint. Weld the pipes at those joints and they should last the life of the pipes.

Regards

JMC

 

[QUOTE=JMC]Get an extra 6 inches of the pipe you expect to use and cut it in half. Then cut it in half again then weld it back up. It is cheap practice and it will show you just how much heat to use to get the proper penetration. You can also examine the inside of the pipe. Now to lay under the truck will make it near impossible to properly weld the top of the pipe. But if that is all you have then you are stuck with it. I would recommend lining up the pipes an tacking them on 2 sides and removing them in sections to weld all around. This will insure proper welds all around the pipe. Just for a reference get under te truck now with your welder and have a first hand look at the limited space available. But welds are inherently weak. If you have a pipe expander then use it instead. The pipes will slide into each other and make a stronger joint. Weld the pipes at those joints and they should last the life of the pipes.
[/QUOTE

i agree

 

The more and more replies I get, the more I rather an exhaust shop to it... Im looking at 80bux for the muffler and turn down tip, plus whatever pipe I need... Might as well spend 120 and have it done right... I will see how much I can pull off and do on the ground and bolt back on.. Maybe unbolt from cat back and make it all on the ground and then there would be no welding under the truck... Thanks again...