Copper Exhaust???

[dracothered]

Ace Hardware and others sell pre-bent EMT. It comes in 90 and 45 degree short sections. Usually the bends are sharper than you can get using a conduit bender. Shop around, Home Depot, Tractor Supply or an electrical supply house should also carry it.

EMT welds nicely with TIG but it takes a little practice and skill due to its thin wall.
Some very nice exhaust systems have been made by members here using conduit and with a little work it can be polished to look like chrome or painted.

Tom

Ok, I will check some of the other places except for Home Depot because of their practices that I will not air here since this is about bikes and not my view points or beliefs. When I was at Lowe's the 90 degree I found there wasn't a small radius at all (maybe about 3"r).

 

[Mike B]

You can braze copper to steel with BernzOmatic copper phosphorus flux coated rod available at your local hardware store. Be careful, this rod melts just a little under copper melt temp.

 

[mew905]

Sweet advice, thank you, that sounds perfect. the copper piping I bought was 3/4", and it fits perfectly in the exhaust. I imagine that's OD? I also imagine electrical supply shops could probably bend the conduit there. I remember going to a shop looking for tubing for my intake and they mentioned using conduit.

 

[drewbob]

I have a Lincoln welder which is currently set up for flux core steel wire. I am brand new to welding, but decided to see if I could weld copper fittings to an expansion pipe I chopped up. It could be that I am horrible at welding pipe, but it wasn't easy putting down a good weld. The chrome plating on the chopped pipe was impossible to weld, but once I ground that off, I was able to get weld the copper and steel (only on the high setting of my 110V welder). Doesn't look pretty, but it might if you were good at it - I am not.

It is solid though...I messed up by welding the markings of the wrong side of the 45 union, and knew as soon as I'd done it that it was permanent. I added another elbow - 90 deg unfortunately, but waaaaay easier than trying to somehow remove the welded piece.

Be careful of welding EMT. Although I don't think it's necessarily galvanized, certain coatings cause poisonous gasses. Correct me if I'm wrong, please, but I think the zinc in galvanized steel is bad for you if you weld it.

 

[dracothered]

I have a Lincoln welder which is currently set up for flux core steel wire. I am brand new to welding, but decided to see if I could weld copper fittings to an expansion pipe I chopped up. It could be that I am horrible at welding pipe, but it wasn't easy putting down a good weld. The chrome plating on the chopped pipe was impossible to weld, but once I ground that off, I was able to get weld the copper and steel (only on the high setting of my 110V welder). Doesn't look pretty, but it might if you were good at it - I am not.

It is solid though...I messed up by welding the markings of the wrong side of the 45 union, and knew as soon as I'd done it that it was permanent. I added another elbow - 90 deg unfortunately, but waaaaay easier than trying to somehow remove the welded piece.

Be careful of welding EMT. Although I don't think it's necessarily galvanized, certain coatings cause poisonous gasses. Correct me if I'm wrong, please, but I think the zinc in galvanized steel is bad for you if you weld it.

How did you test the welds to see if they are indeed strong?

 

[drewbob]

in a bunch of places I could see that the copper had melted and mixed with the steel (not a common alloy, but sure looks the part). Everywhere else was a thick weld of steel covering the joint. I applied a good bit of torque to the pipe to see if I could break the weld. No chance. We'll see how it holds up to vibration, but I'd be very surprised if it doesn't hold. I'll post something if it falls apart anytime soon.

 

[abikerider]

The EMT sold by Home Depot and Lowes is galvanized. If you weld it be very careful. It will emit poisonous fumes that can make you sick. I would do it outdoors with lots of ventilation. A fan blowing fresh air on your face would be a good idea.

 

[MEASURE TWICE]

Super! I have a hobart auto arc 130 runs on 115v and have been only using it with AR 75 CO2 25 mix. I have some flux core that they gave a small roll with the welder and I will see if I can do like you did.

Other stuff I tried with the inert gas mix attached was always punching through stuff that was thin. I put the volts adjust all the way down and play with feed rate still no go. I will see if flux core means I can go thinner. They said you could weld thicker stuff with flux I read, but I got up to near a 1/4 inch and had just kept using the inert gas and it welded good.

My copper exhaust is done though and I used all adapters so no welding. I did have to abandon using the fiber high temp gasket material as it disintegrated. I made copper donuts very thin. I place 10 at each end of the place where the water pipe otherwise would have the rubber washer since rubber would melt and burn.

MT

PS
Oh also stainless steel has chromium in it and that is just as bad as zinc in the galvanized suff. I have a low profile gas mask for that purpose as it fits under the weld hood.

Forgot also that the galvanized coating also messes up the weld so grinding it off I do, but stainless there is nothing other than using mask and good ventilation as it is not a coating, just through an through metal. I have used sometimes a weak acid (ferric chloride) that I had left over from etching circuit boards to remove the zinc. It took a while and I used heavy rubber gloves and a gas mask. Neutralized the stuff when done with baking soda and rinsed a lot. Then sanded too.