confused, what do i need?

[jon penryn]

Hello all... Ok so, for reasons of insanity i own a car that seems to fracture or otherwise hole its exhaust quite often and at £250 a throw its quite and expensive game, you can see whats coming ah.

It has occured to me that a way of fixing it would be a good thing. At first it seemed simple, MIG, cheap seems not to hard and sorted. They even have helmets you can see through nowdays! Then i got concerned about power settings and gas/no gas things....

Then i thought i might have to fill in pin holes etc so i went into the idea of brazing and the ability to join a motely collection of metals into something that will pass an MOT would be good. Then i got confused, i do use propane and do work with copper etc (not pipes usualy, but i do hard solder things) so many torches claim to be brazing torches but then forums say you need Oxy acet. I realy dont think my Lidl torch is up to it. A posh new torch would be very useful too. I even found a French thing that preheated a forced air stream and claims to be up to 2300 deg (onlygaz) That seems like it might work.

I am now compleatly confused. basicaly i want to join one inch dia mild steel pipe and patch it and bodge it together... whats my best way to go?

I have grinders, a huge bottle of propane, have used those hard solder sticks from B&Q and soft solder. Workshop has a 13amp plug....i am as ever pretty skint too, so cheaper the better.

any advice would be great.

 

[Bill Edwards]

I don't know anything about the torch with a preheated forced air stream, but I've certainly found that ordinary propane torches are useless for brazing. You can however braze with oxygen and propane.
Brazing does require parts to be properly cleaned, and for patching other parts of the car in the future as well as the exhaust I'd go with MIG, which is far more suitable.

I think you would be best with a MIG using gas (get a mixture of argon and CO2, plain CO2 isn't as easy to use on thin metal).

 

[brightspark]

your flogging a dead horse brazing old exhausts even with oxy acet. rust and soot must be removed and joining metals perfectly clean

 

[BrokenBiker]

Mig is the way forward on exhausts. Brazing isn't going to work unless you can get the exhaust spotless inside and out. Cheap mig, a bottle of gas and your sorted. You could even get away with gasless wire with some practice although it's no comparison to normal mig wore with gas

 

[addjunkie]

Firstly im in the mig camp too, in the old days many floor panels etc were brazed in, mot man dont like that now.

But do you plan to be inside workshop out of the wind to do the welding, this can make a difference to equipment selection.

No does it always go in the same place, is it a design fault. Could you put in a flexi section look on page xvi on this link and fix it properly. http://www.catalogue.bosal.com/pdf/prelim/pp_exh_bb_nfde.pdf

 

[jon penryn]

Ah so Mig.. and just to complicate things i learn one can MIG braze! sorry i realy do suffer from information overload. Yes i will be doing it inside a shed/workshop, and off the car. Fail mode is lumps of weld rusting off the join between the pipe and cigar type silancer and eventualy it falls off. And the rear has another box which is mounted on a rubber bobbin but the pipe flexes round the mount and snaps...It has a flexie pipe at the front which also snaps, (£50 a throw! ) i've solved that by getting some felxie pipe of ebay and cutting to size.

So many thanks for crytalising it, MIG it is, gas is best ...one thing, how would one tackle a pin hole? can one fill in pits? or do u have to patch it?

 

[addjunkie]

Yes you can, but when you get the mig have a play on thin metal, spot, wait spot wait, it will become obvious, think there is a tutorial on thin metal in the tutorial section.

 

[jon penryn]

I will, in fact i have various bits of old exhaust to play with ...

mant thanks to all who took the trouble to reply, much apreciated.

 

[Kent]

So your looking at buying kit and spending time on bodging up an old exhaust in its final days?
Fair enough it's it's a really dear part or difficult to obtain. Otherwise quite foolish
To my mind but perhaps it's me thats lost the plot

 

[jon penryn]

The part is £250, and a bit prone to snapping. not really from rotting, its just badly designed and new ones are just as bad. It seems a pitty to me to throw away a pipe thats fractured in one place when a weld would fix it.

again thanks for the info..

 

[BrokenBiker]

If it were n my car and I cared enough to to want to weld it I would be looking at altering the exhaust so as to remove the issue. Whether that be adding pipe, removing pipe or altering a bend I don't know as I haven't seen the car you will be welding but if it's a 250 quid exhaust then I assume it's either not a standard exhaust (so possibly a stainless flavour) or it's a fairly expensive car?

 

[jon penryn]

Well as i said in my first post "for reasons of insantity" Its not a perticularly posh car or a custom exhaust, its French, that could explain it. In fact the exhaust isnt realy the worst thing it does, exploding gear boxes and a drive system that wears out are another two of its endearing qualities. But its what i have and what with the mother in law etc etc...

Milk steel for some reason one inch diameter coated with the thinest paint you can imagine and rusty soon as it gets hot and oh so prone to snapping, that is my cars exhaust in a nutshell. Yes i might well try to improve it if i can weld....
Thanks again.

 

[BrokenBiker]

Renault?

 

[jon penryn]

nope not even that good!..... on the plus side i won't be tempted to attempt any bodywork welding, all i need to that is a soldering iron, its all plastic!

 

[Sparkey]

Did someone say French exhausts?????? I'm welding them these days for a living.....do you have any pics??

 

[Dee J]

Plastic bodied French car.... Citroën Mehari? So 2cv / Dyane based.....

 

[jon penryn]

Did someone say French exhausts?????? I'm welding them these days for a living.....do you have any pics??

Well im glad someone has done it too... I'm sure the French have many admirable qualities, but exhausts dont seem to be one of them. Nor glue (on a hot day all the interior trim drips of!) Nor chosing a gear box (though i will give then that is made in Italy) Nor chooseing brakes hubs (though again Italian, they spin their bearings and make it the devils own job to stick em) Nor putting in windscreens (the autoglass guy said its a good job you didnt have to stop fast it wasn't held in very well).. i could go on and on....and on..

 

[jon penryn]

Plastic bodied French car.... Citroën Mehari? So 2cv / Dyane based.....

Ok ok i will fess up..its an Aixam...... a french Microcar with a Kubota diesel engine and quite a few oddities, Italian gear box (reversing box) Italian running gear, French canadian belt drive system ( like an old daf) off a snowmobile i think....on the plus side no rust plastic body pannels and a full alloy rollover cage chasis, Bullet proof engine.. it is of course very slow too, but hell, so many cars tried to kill me all my biking days im OK with being a mobile chicane.

 

[Sparkey]

Ah yes, quite alot of those on the french roads here.....frigging dangerous too if you ask me, they have a normal license plate in france so you don't notice it untill you're almost parked on it....you're doing 90-100 km/h and you come up to a microcar that does 45-50 km/h......... Kubota, they have tractors too overhere! And i'm not sure if we also weld the exhausts for those microcars...we mostly do PSA, RSA,Nissan....

 

[mike os]

You can braze using oxy propane 9 or acetylene and flux... I used to do it annual for mot on several bikes.... It spits and is not really pleasant, but is doable with gas.. .. I found a quick clean where possible and then heating and add flux until the braze just starts to flow worked well

If you already have the equipment give it a go gas rods and flux are pretty cheap