Mini brazing torch recommendation (not boaty)

[Skylark]

I have a couple of pin holes in a 60mm diameter, approx 2mm wall thickness, mild steel pipe. I’d like to braze a couple of similar thickness patches over the holes.

Does anyone have relevant experience of the mini brazing guns using map gas? Any specific model recommendations?

Many thanks.

 

[earlybird]

If by brazing you mean silver solder then that means a required temperature of around 600 deg. C. ie at least dull red. True brazing is even hotter. I have a map gas torch, I don't think it would cope with your requirement. A Sievert or Bullfinch torch with a nozzle ~30mm dia. or bigger, fed off a propane cylinder would be more appropriate I suggest. Surrounding the job with heat insulation would help a lot. Soft solder would be a lot easier, the map torch would cope.
If the pin-holes are due to corrosion, then that needs thorough cleaning.


.

 

[PCUK]

How about the low temp welding rods now on sale?

 

[Stemar]

Many years ago I had a small oxy-propane kit that I used to change the wing on my Dad's car when it got dinged. A bit later, I bought a nice looking Transit to turn into a camper. Unfortunately, it turned out to be mostly filler, but the gizmo helped me batch it up, brazing everything together.

Something like this

It was cheap and cheerful, but the gas wasn't cheap, and you didn't get a lot of it.

 

[greeny]

If you've got access to mains supply maybe think about arc welding set with the brazing attachment fitted with electrodes. I've brazed with one before but only on the bench. Not tried in situ on the boat. But maybe worth considering.

 

[Refueler]

If the pipe is not subjected to too much stress ... why not Plastic Steel ?? I have been amazed by some peoples use of it successfully ...

I even solved a problem of two blown engine plugs in my Perkins 4-107 .... the plugs had corroded and let go when we were going downriver ready to start 10 day Baltic cruise ... local car shops only had metric plugs ... so we bought two 'rolls' of epoxy based heat proof metal repair putty.

I have to say that I literally forgot about it after the cruise and it was nearly a year later I pulled the old plugs - STILL sealed nicely and replaced with new.

 

[Skylark]

Many thanks to you all, much appreciated.

The part in question is a car exhaust pipe (replacements NLA).

@earlybird yes I do mean brazing. I also fear that the map gas sets would not supply enough heat. It’s only a small job so doesn’t justify a large spend on kit. I’m familiar with the process but well out of date as my last experience was using oxyacetylene in the 1970s.

That would probably be suitable @Stemar but a quick Google search tells me that it’s no longer cheap and cheerful (for a small job)

I have an aversion to electric. I was only trained in conventional arc, MIG and TIG were pretty new in the early 70s. I fear blowing even bigger holes.

On another exhaust, I recently sealed a small hole using a 2-part putty and agree, @Refueler that it may be suitable. In this case I want to cover the hole (there’s 2) with a patch. Do you know if it works as the filling for a sandwich, if you know what I mean?

 

[Refueler]

On another exhaust, I recently sealed a small hole using a 2-part putty and agree, @Refueler that it may be suitable. In this case I want to cover the hole (there’s 2) with a patch. Do you know if it works as the filling for a sandwich, if you know what I mean?

Don't see why not .... smearing onto a curved pre-made plate and then fixing in place with clamps ...

But would that satisfy MOT ??

 

[rogerthebodger]

Like you I started like stick welding but have not gratitude to both MIG and TIG.

I would use MIG to tack weld a patch onto 2 mm MS keeping the heat down by joining tacks together until sealed.

 

[Skylark]

Like you I started like stick welding but have not gratitude to both MIG and TIG.

I would use MIG to tack weld a patch onto 2 mm MS keeping the heat down by joining tacks together until sealed.

Thanks, Roger, but I have absolutely no confidence in my ability to do that without watching the pipe disappear in front of my eyes, just as I strike an arc.

 

[Skylark]

Don't see why not .... smearing onto a curved pre-made plate and then fixing in place with clamps ...

But would that satisfy MOT ??

Thanks again.

I have a spare section of the pipe so can easily make a repair plate. The repair probably only needs to be 1/3rd of the circumference and about 20mm wide, so quite small. I don’t see why it should be an issue for MoT.

I have two of these cars, both in exceptional condition but their Achilles Heel is exhaust system. On the other car, a grey one, a few months ago I had the back box repaired by welding a huge patch in place. This was done by an MoT garage so I assume it satisfied their own requirements. The repair requirement on my black car is to the pipe so tiny in comparison to this:-

 

[thinwater]

Why not a similar part from a different car? If it has several pin holes, more are only months away.

 

[rogerthebodger]

Is there any custom exhaust manufacturer local to you.

I have a similar issue with my 1998 Nissan 200SX and I will go to a local custom exhaust to maybe get a stainless steel exhaust made

What car is it ?

 

[Skylark]

Is there any custom exhaust manufacturer local to you.

I have a similar issue with my 1998 Nissan 200SX and I will go to a local custom exhaust to maybe get a stainless steel exhaust made

What car is it ?

Big bore stainless steel exhausts are available but not my choice. I wish to maintain originality. I’ve tried a few custom exhaust manufacturers, all to no avail. I’ve recently found a new rear box made in Italy. One was available in Germany but the company refused to deal with me. Eventually, I found a UK company prepared to import one from Italy. It cost me more than twice the price of the one in Germany but hey, think of the benefits of you-know-what.

Car is Escort RS Turbo.

 

[Skylark]

These are the two holes in question:-

 

[KevinV]

These are the two holes in question:-
View attachment 157088

Well the traditional "fix" would be exhaust paste with a tin can wrapped around, held fast with some wire. Works a treat.
Exhaust paste with header tape around it might be prettier, or just bite the bullet and get a stainless one made up - it'll be cheaper in the long run.

 

[Blueboatman]

Many thanks to you all, much appreciated.

The part in question is a car exhaust pipe (replacements NLA).

@earlybird yes I do mean brazing. I also fear that the map gas sets would not supply enough heat. It’s only a small job so doesn’t justify a large spend on kit. I’m familiar with the process but well out of date as my last experience was using oxyacetylene in the 1970s.

That would probably be suitable @Stemar but a quick Google search tells me that it’s no longer cheap and cheerful (for a small job)

I have an aversion to electric. I was only trained in conventional arc, MIG and TIG were pretty new in the early 70s. I fear blowing even bigger holes.

On another exhaust, I recently sealed a small hole using a 2-part putty and agree, @Refueler that it may be suitable. In this case I want to cover the hole (there’s 2) with a patch. Do you know if it works as the filling for a sandwich, if you know what I mean?

Just mig weld it surely ?

 

[Skylark]

Well the traditional "fix" would be exhaust paste with a tin can wrapped around, held fast with some wire. Works a treat.
Exhaust paste with header tape around it might be prettier, or just bite the bullet and get a stainless one made up - it'll be cheaper in the long run.

When I bought back the car it had a SS exhaust fitted. The engineering was shockingly bad, albeit I sold it for £400. The pipe simply passed under the chassis and reduced ground clearance significantly. A real bodge to my eyes but a very common Aftermarket fitment. Fortunately, its original exhaust had been kept. I hope to make a robust and aesthetically pleasing repair.

I’ve only recently discovered that a replacement pipe is available. Only within mainland Europe so, just like the new back box, I’m trying to get one despite the individual trading difficulties.

 

[Skylark]

Just mig weld it surely ?

I’ve no experience of MIG. I respect the automotive mantra “don’t make it worse” and fear blowing even bigger holes each time an arc is struck. It’s an original mild steel exhaust, now approaching 35 years old.

 

[Daydream believer]

I have a MAP gas blow lamp with a single burner. This is OK for small items of silver soldering but useless for larger copper stuff where the heat is quickly disipated. I have since bought one of these

Twin Burner Turbo Swivel PRO MAPP Gas Or Propane Double Barrel Air-Fuel Torch Turbo Torch​

This is a different ball game & the heat given off is impressive. I have not used it in anger yet so I do not know how long the MAP gas bottles will last. But it is better than my gas torch attached to a propane bottle & that has about 5 different nozzles.