Joining stainless steel exhaust components

I am making a custom exhaust header for my Mig3 and 3W 55i using 25mm stainless components and flex header tube. What are the best materials and tools and techniques for soldering/brazing the parts and where is the best place to buy them from?

You can use standard softsolder if you use Phosphoric Acid as a flux.

It is also easier than copper/brass because of the lower heat conductivity of stainless steel.

ronp849 wrote: You can use standard softsolder if you use Phosphoric Acid as a flux.

Where would one get the acid from? I have needed to weld stainlessitems before and have had to take it a specialist welding shop

Ron wrote "You can use standard softsolder", I tried soft solder in a similar situation years ago, it lasted about 30 seconds until the heat of the exhaust turned it extra soft, even actual runny!

How about silver solder?

Now I have read the original post properly, I can see that soft solder would not be suitable!!!

It seems like Phosphoric acid can be used with silver solder as well but I have not personally tried it.

www.bssa.org.uk/topics.php?article=150

Ive dome a lot of SS exhaust work and always use this flux - it does what is says on the label



I recommend this company for your Silver Solder

www.cupalloys.co.uk/medium-temp-silver-solder/index.asp

I have an Oxy / Mapp gas facilities if you want me to solder it for you.

Thanks Kev, I may well take you up on that Kind offer. Hopefully learn from the master how to do it myself

kevinross wrote: Ive dome a lot of SS exhaust work and always use this flux - it does what is says on the label

I recommend this company for your Silver Solder

www.cupalloys.co.uk/medium-temp-silver-solder/index.asp

I have an Oxy / Mapp gas facilities if you want me to solder it for you.

Hi Kev, which of the silver solder diameter rods do you recommend?

Most solders will work but your choice is based on your heat source. My oxy-mapp torch has unlimited heat but if you use a std propane torch the lowest melting temp solders are preferred but that means higher si content and carries a higher price

The smaller 1mm 650deg can be "ringed" around the flange. then it will run and fillet the join very well with plain Mapp gas.

www.cupalloys.co.uk/medium-temp-silver-solder/index.asp

ps - there is a small brazing hearth in "Franks stuff" if you're interested.