newbie brazing questions

First off, I have zero experience brazing (or welding for that matter) anything.

I've got a motorcycle with a few significant holes in one of the mufflers. Given the advanced age of the cycle and the prohibitive $$ of a new muffler, I'd like to try my hand at brazing and cover the holes.

the muffler is thin (< 1/16") chromed metal. I've got a small dual-gas torch setup, and could use either propane or MAPP with oxygen for brazing. I'm looking for recommendations on:

  1. type of gas to use
  2. Type of brazing material. As I noted I have no experience brazing. I'm guessing there's probably different types of brazing filler for different applications, temperatures, etc.
  3. Type of flux. See #2, above.
  4. Tip size to use... I'm guessing the smaller the better given the thinness of metals I'll be working with.

I'm planning to use some scrap metal for my patches (have yet to search my basement for supplies) and I'm thinking something thin enough to bend by hand or with a mallet and wood form like a coffee can. Would this work?

Any tips on brazing, DO's and especially DON'T's greatly appreciated..

thx

Dave

Reply to
Dave
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Oh, boy are you signing up for a buncha misery. Oh well - you will learn. The very easiest way to solve your problem is to go find the money for a new muffler.

As soon as you heat the rust-holed muffler to hot enough to melt the brazing rod, it is going to start deforming is my guess. If you did manage to braze on some bits of steel, they will very very shortly rust through given the temperature of motorcycle exhaust systems. The old stuff was chrome-plated and it rusted through, how much quicker will non-chromed steel rust?

GWE

Reply to
Grant Erwin

Yeah. I kinda figured that. But, nothing ventured nothing gained.

Theoretically, at least what I've read, the idea behind brazing is that I don't have to heat up the metal to be joined hot enough to melt it. Just hot enough to melt the brazing rod which, again theorically, should melt significantly lower than chromed steel. No?

If you did manage to braze on

Hmm, I didn't think coffee cans rusted, at least not for awhile. I don't suppose it would do much for the cost-effectiveness of my project to buy some titanium or SS plate. How 'bout aluminum? Can it be brazed? I've got lots of aluminum cans. Hmmm, and they're pre-curved too...

Maybe I'll swing by the motorcycle junkyard first, just for fun to see what they've got for used mufflers.

Dave

Reply to
Dave

"Dave" wrote: (CLIP) How 'bout aluminum? Can it be brazed? I've got lots of aluminum cans. (CLIP) ^^^^^^^^^^^^^^^ If you can ask a question like that, I think you need to re-read what Grant wrote, and double it. First of all, aluminum cans are OUT OF THE QUESTION. Second, chrome is an obstacle--things don't stick to it very well. If you grind off the chrome on a muffler that's already rusted through, what will you have left? Some steel that's so feather edged that as soon as you start to heat it, it will start to sparkle and burn back, making the holes bigger. Coffee cans DO rust after the tin plating is gone, which it will be after it has been heated to brazing temperature.

If you are lucky enough to have a motorcycle wrecking yard in your area, that's your best bet. But if yours is an old bike, then the bikes like yours that happen to be in the wrecking yard are also going to be old. Chances of getting a good clean strong muffler seem slim.

If you were my neighbor, I could fix it by welding, but I wouldn't guarantee the looks. Where are you located?

Reply to
Leo Lichtman

If you can't find a good mufler at a junkyard, I would try an automotive parts place and see what they have for repairing car mufflers. I think they sell something like fiberglass tape with a thermosetting adhesive. If that fails think hose clamps and some high temp gasket material ( higher than silicon gasket stuff ) and some bent metal. One of the local hardware stores sells wood stove door gasket stuff.

Dan

Reply to
dcaster

They used to sell generic motorcycle mufflers, maybe one of those?

Reply to
Grant Erwin

I did a temp repair on a motorcycle one time by claming the patch in place with hose clamps. I ran it this way for about 6 months until I as able to fit a new muffler into the budget.

Jimmie

Reply to
Jimmie D

Okay, so it sounds like fixing a rusty muffler is a non-starter. Thanks for everybody's input.

Dave

Reply to
Dave

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