Welding Tips and Tricks

Ok so I bought a new header pipe which includes flex pipe because I wanted to avoid having to weld a new flex pipe on the car with a tig after cutting the old one off.

I am having difficulty removing the bolts from the front header section of the flex pipe because they are rusted on. In my genius I thought I could make a plastic trough and fill it with Esprit to remove the rust over night. However the header is too thick for this to happen having tested it with a cut up container and some gorilla tape.

So then my second stroke of genius was to simply make the "container" out of gorilla tape to remove the rust. Wanting to test this first I used the new exhaust section to get an idea of the required shape. I then filled it with water and found a small leak where one of the mounting brackets meets the exhaust pipe.

The pipe is mig welded on the other side and I guess it wasn't perfect.

My question is with Stainless Steel can I roll the mounting bracket metal into the exhaust pipe without requiring filler material, like Jody did on his cart build http://youtu.be/jLSak7DUHOQ?t=5m30s for the hand bars, to seal this hole? Or will the hole even matter and not fail emissions testing?

I'm of the school of thought that all imperfections grow over time. Any discontinuity will trap carbon, attract moisture, allow NOX and other by-products to creep in...

Yes, you can easily close this without filler with your TIG torch, and it will take very little effort. Light up on the hole, and watch. The puddle will form, the hole will appear to open up a bit, then the puddle will fall into the opening.

If there are oils or other impurities in the hole, it may bubble up a bit... Let it cook on low heat 'til the boiling stops. Worst case, countersink the hole slightly with a small drill bit, then hit it again.

Steve S

Thanks for the advice. Now I just need to get some argon and practice.

Would also be nice to get the current exhaust off the car >_< Today I spent hours torching, lubing, hammering, anything I could to loosen the existing bolts. Looks like they will not be coming off. Thinking of paying someone to do it and bringing them the parts. But I want to make sure the new exhaust is good first ^_^

Just for future reference I assume it would also be possible to joints on a mig weld with a tig torch as well though I bet it is frowned upon.

I've used TIG quite often to fix an ugly mig weld. If the weld is adequate in strength, "as is", the TIG can pretty it up very nicely with out decreasing the quality.

You'd be surprised how often I've used TIG to polish someone's turd.

Steve S

Have you tried bees wax yet? If you buy "bees wax" (literal bee's wax) and rub it on the backside of the flange and wherever threads are it will wick down the threads using capillary attraction. When it solidifies after the metal cools you most likely will be able to break the nuts loose with relative ease.
In any case, a few dollars worth of bee's wax is way less than what I would charge to remove your rusty ass exhaust and install your new one for you, especially if I had to weld up pin holes where the bracket meets the exhaust pipe. Take it from somebody who lives in area where I'm pretty sure they just use the most caustic nasty shit they can to salt the roads with. As a mechanic, rust is your worst enemy. If I don't like the way that it looks I tack on a small upcharge or a slightly higher labor rate to account for the aggravation caused by it.

I will pick up some bees wax tomorrow if I can find it. I think our local farmers market might have some.

How hot do I need to get the bolt / flange before I apply the wax?

Don't melt it lol but get it hot. You don't have to get it cherry red but try and heat the flange and the stuff equally

--Sam