Anyhow, back to my car. Well, almost. Unfortunately the daily driver (A 2006 Saab) is suffering from a very rattly exhaust, probably either the front cat or the flexi pipe. Both units together are several hundred pounds to replace, and potentially a full day in an average exhaust builders. But it did get me thinking, what if I could make my own?
First job, learn how to weld stainless steel. This was easy enough, got some stainless MIG wire, turned up the settings as the interweb said, and then proceeded to blow seven shades of stainless through the plate I was practising with! Turns out the settings don't have to be that far off normal steel welding, and soon enough I was getting a good strong weld between stainless plates. I then also welded stainless to mild, because it did occur to me that the existing exhaust may not be stainless all the way, and I only want to replace the parts I need.
Now that I'm happy with stainless welding, I've bookmarked a catalytic converter, a length of pipe and a flexi. Total price just over £100 (with the cat being most of that!).
Next stage, figure out how to do the bends. Now the top of the cat turns a sharp 90+ degrees into the turbo, and I'm not confident I could get a sharp enough bend without compromising the diameter (not what I need straight out of the turbo!). So I found a thing on the internet called 'lobster cutting'. Basically you chop a piece of pipe into segments, each with a certain angle on them. Then if you rotate every other segment 180 degrees, you end up with a bend!
Just for an experiment, here is my first attempt at a lobster cut bend with some spare tube I had;
As you can see, it's just taped together, but I think it's actually turned out really nice. And it'll be more than enough to get the curve off the turbo into the cat.
Next week, I might get chance to work on the car...
