silver brazing on outside of muffler?

[CamMann]

Just curious if it's a good option. Picked up a saw with broken baffle in the muffler. Not a common enough saw to easily find a replacement muffler & not a style of muffler than can be opened. I'll have to cut it open, make a new baffle, and close it up. Baffle material I'll use is thick enough to stick weld. Muffler material is way too thin to stick weld closed afterward. I have silver solder/brazing rods & propane torch, melting temp of brazing rods are somewhere around 1145 to 1650ºF (618 to 899ºC). Would that be a reasonable option to close the muffler back up? If not, maybe I should get a MAPP torch & brass rods instead?

 

[camel2019]

The muffler body will not be thick enough to stick weld the baffle too. Brazing will work if you know what you are doing but I’d use oxy/fuel(propane and map gas don’t work well for me) with bronze brazing rods(not brass. Brass is an alloy of copper and zinc bronze is an alloy of copper and tin) I actually just use romex copper house wire to braze.

 

[CamMann]

Your advice is much appreciated! I've had great results silver brazing with propane, I'll try my luck with Mapp & bronze. Oxy/acetylene or something like that would be great! Not aiming to buy $500+ of gear to fix a muffler though lol.

 

[camel2019]

Your advice is much appreciated! I've had great results silver brazing with propane, I'll try my luck with Mapp & bronze. Oxy/acetylene or something like that would be great! Not aiming to buy $500+ of gear to fix a muffler though lol.

I buy older used torches and gauges a lot of places want you to lease tanks now a days and your probably better off. I have a torch addiction that’s not as bad as my saw addiction but have 3 sets of old heavy duty purox torches common in my area to find at yard sales/barn sales and a 2 foot victor and a 3 foot Harris that were my grandpa’s and a copy of a smith little torch that I bought for sheet metal welding.

 

[Captain Bruce]

Just curious if it's a good option. Picked up a saw with broken baffle in the muffler. Not a common enough saw to easily find a replacement muffler & not a style of muffler than can be opened. I'll have to cut it open, make a new baffle, and close it up. Baffle material I'll use is thick enough to stick weld. Muffler material is way too thin to stick weld closed afterward. I have silver solder/brazing rods & propane torch, melting temp of brazing rods are somewhere around 1145 to 1650ºF (618 to 899ºC). Would that be a reasonable option to close the muffler back up? If not, maybe I should get a MAPP torch & brass rods instead?

Not a common enough saw to easily find a replacement muffler ? What can't be found?

 

[wise wood]

Not a common enough saw to easily find a replacement muffler ? What can't be found?

You will be fine with silver solder just clean the metal very well, apply flux, bring heat up slowly till flux melts, if
you heat to fast flux will boil and spatter, when flux melts you are about ready to apply solder. a little goes a long way
cause it will follow the flux s/solder is very strong if joints do not have large gaps
Wisewood

 

[pdqdl]

... I actually just use romex copper house wire to braze.

Really? How well does that stick to common steel? Flux options?
I'd think the copper melting point would be far too high for brazing.

Yes on silver soldering, although I've never done a muffler with it. That stuff is almost magic sometimes, but always works better if you get the higher percentage of silver. Short the silver, it doesn't work as well.

All the muffler welding I have done was MIG or acetylene with steel rod (usually coathangers) or brass. Brass works pretty well on rusting out gas tanks, but comes with the additional risk that you can never put any arc weld on it thereafter. You can, however, put lots of silver solder onto brazed repairs without disturbing the brass. If you are careful.

 

[wise wood]

you will be fine with s/solder keep joint tight ,and very clean also bring the heat up slowly so flux dries and then melts
it will spatter if heated to fast. when flux melts you are just about ready to apply s/solder it will follow the flux and a little goes a long way
wisewood

 

[Thommo]

I have used silver solder on mufflers without any problems.

 

[Mad Professor]

Brass/Bronze/Braze (name is often used interchangeably) is the cats azz! Done all sorts of things using oxy/act torches. Have not done silver rods.

Concerning getting torches. Near 40 years ago I got mine and was shocked at tank rental fees.

I bought my own small tanks, which are fine if you are not having to cut much, and recouped cost of buying tanks in a short time. I also like the the ability to be able to cut metal or put a lot of heat on things.

I've brazed whole quarter panels on cars but you have to be careful with heat or you can get warps. Same concern with small mufflers make sure you have right sized tips and proper flame.

 

[Dennisthemenace]

I have done plenty of brazing on mufflers, I clean up the area well, use low flame oxy /acet and 45%silver solder with plenty of flux. The rods with the flux on them are maybe the best. Got to be gentle with the flame,

 

[camel2019]

Really? How well does that stick to common steel? Flux options?
I'd think the copper melting point would be far too high for brazing.

Yes on silver soldering, although I've never done a muffler with it. That stuff is almost magic sometimes, but always works better if you get the higher percentage of silver. Short the silver, it doesn't work as well.

All the muffler welding I have done was MIG or acetylene with steel rod (usually coathangers) or brass. Brass works pretty well on rusting out gas tanks, but comes with the additional risk that you can never put any arc weld on it thereafter. You can, however, put lots of silver solder onto brazed repairs without disturbing the brass. If you are careful.

Flux all I ever used was borax made into a paste it works well enough for small repairs.

 

[link]

Brazing will work if you know what you are doing but I’d use oxy/fuel(propane and map gas don’t work well for me)

Propane is plenty for both silver and the much cheaper brass brazing if you have a proper torch.
This is a proper torch:


https://www.arboristsite.com/threads/my-038-foolium-adventure.340536/post-7211960

 

[link]

So, the silver solder should be above 50% silver, usually 56% silver. You can get silver solder in all variants all the way down to 2%. The 2% is really cheap and really difficult to use because it don't flow - it just stays in lumps. The 56% is really expensive but it flows really well at a low temp (650 C). You don't have 7 mufflers lined up to practice on so you need a perfect result at your first attempt - you get that with 56% silver.
Your silver solder bars should be coated with flux so you don't need to buy, use or have experience with powder flux.

 

[Squareground3691]

Harris Solder Kit 4531 & SSWF7 - Safety-Silv 45% 1/16 Solder 1 Ounce w/Flux https://a.co/d/cGZtjY8 This works pretty good .

 

[link]

This is how my silver bars coated with flux look like:

 

[HansFranz]

Propane is plenty for both silver and the much cheaper brass brazing if you have a proper torch.
This is a proper torch:
View attachment 999047 View attachment 999048

I'm surprised propane works for bronze brazing...are you using oxy-propane? I've tried brazing with silicon bronze with an air-acetylene torch and it was almost impossible. Oxy-acetylene, no problemo.

 

[huskihl]

I'm surprised propane works for bronze brazing...are you using oxy-propane? I've tried brazing with silicon bronze with an air-acetylene torch and it was almost impossible. Oxy-acetylene, no problemo.

It takes a hot torch and thin rods but it can be done. Oxy/ace is much faster though

 

[Paul Fithian]

I just did this on a G660 muffler, turned out great. The brazing material will flow and make a nice fillet where the parts join. I used an air/acetylene torch.

Cleanliness is your friend here. Remove all paint in the area to be brazed and degrease with acetone before applying flux. Oxidized contaminants on the metal will weaken the joint.