DIY brazing torch recommendations

[1969Mk3Spitfire]

There are a couple of pin holes in my exhaust pipe. I’d like to braze a patch over them.

Anyone successfully used one of the mini brazing sets / map gas? Any recommendations?

[Unkel Kunkel]

I use a Mapp  gas burner for various jobs, but mainly for soldering.

it gets certainly very hot and small items are braze-able, but I wonder if trying to patch an exhaust might have the problem of  the heat dissipating away quickly.

There  are also oxy -mapp sets ( Bernzomatic)/ Rothenberger like this:

I very occasionally use it  for brazing small items.

The O2  gets used up very quickly and It is expensive,( also Mapp gas isn’t cheap) and  the oxygen bottles don’t seem to be as readily available as they were.

I can’t recall the last time I brazed anything on a car, but this would probably work OK.

Almost  always I  turn to the MIG welder.

- Depending on the holes and how much good metal is there is,  mig can fill holes and patch really well and would be  faster and cheaper, so  for me that would be my first choice.

Edited May 25, 2023 by Unkel Kunkel

[1969Mk3Spitfire]

Many thanks, @Unkel Kunkel

This is the pipe and the two holes.

I’ve never used MIG and have visions of the pipe disappearing in front of my eyes as a struck an arc. Every time I see MIG on car restoration TV programs it looks to be a series of bird shit tacks.

I was taught oxyacetylene and conventional arc during my early 1970s apprenticeship, MIG and TIG were not available in the Training School.

I’m coming to the conclusion that I’m going to make a repair patch (I have spare 60mm dia pipe) and “glue” it on with a high temp repair putty.

[rlubikey]

Brazing sounds like the pukka way to fix these small holes. I use the quick and dirty method: silicone RTV sealant and, if it's bigger than a pin prick, a Jubilee clip or even a baked been can for larger holes. RTV silicone adhesive - AKA "bath sealant" - is good for surprisingly high temperatures, something like 200' to 400'C. Work it into the hole and, if it's larger, cover it with the clip (and can if necessary) which will take the back-pressure from the exhaust gas. I've been patching my modern's exhaust this way for years and MOTs are no problem.

Cheers, Richard

[Unkel Kunkel]

Since  you have a spare bit of pipe that widens your options.I would  consider cutting not just a patch but an entire broad band of old pipe , then cutting across it to open it up enough to place it in position by sliding  over hole in the the pipe.

Held in securely in place with wire until finished  you  then have a number of options - braze,  tack weld or use exhaust putty or  silicone and or big jubilee as Richard suggests.

 

[PeteH]

Old fashioned, but regular "repair" system = Two Worm drive clips wrap some steel sheet arount the Pipe with "Gun Gum" under it. clamp with the Clips. Been know to last the "life" of many an "old banger"👍

Pete

[ahebron]

Looking at the photo I would imagine that the inside of the pipe is very thin around the two holes.
A torch would make them one very big hole.
Chasing holes in tissue paper thin steel is not high on my list of fun things to do on a Triumph

[Colin Lindsay]

On 25/05/2023 at 18:26, PeteH said:

Old fashioned, but regular "repair" system = Two Worm drive clips wrap some steel sheet arount the Pipe with "Gun Gum" under it. clamp with the Clips. Been know to last the "life" of many an "old banger"👍

Pete

Sheet steel is for posh people. An old tin can works for us plebs.

[Peter Truman]

Short length of next size up pipe cut it longitudinally so you have two halves then Gun Gum sandwich them over damaged pipe compressing them on with either exhaust clamps or jubilee clips.

I successfully fixed a jags exhaust joint into a silencer using a stepped pipe joiner that way in the 80’s on both silencers and the bodge lasted around 5 years when the pipe joint in the silencer finally failed then SS throughout.