SLS pipe leaking - repair options?

[JOEPRO]

I'd probably try Kunifer as well, but design pressure for even 1mm thickness 8mm steel pipe is 333bar-
View attachment 522372

The issue isn't likely to be static pressure, it'll be the shock pressures if you hit something hard.

I Believe the Kunifer will be just fine. If the kunifer bursts before the other 40 year old system components I will be very impressed.

Indeed, I will be re plumbing the whole car in Kunifer so watch this space for a SLS explosion. (I'll take new known Kunifer pipes any day over unknown rusty 40 year old steel pipes)

 

[dave h 2]

When you braze it make sure the brass really does flow in to the joint and not blob on the surface and don't leave the flux residue on the pipe.
You can use Rockwool or vermiculite bricks for insulation. Ceramic firebrick steals the heat and the flux can die before the work gets hot enough.

 

[reb78]

Just an ignorant question... I know you are talking about Kunifer, but i have dissolved copper washers to nothing trying to anneal them (badly before). Looking on google, copper and kunifer might have similar melting points. Will the Kunifer cope with the heat needed for brazing? Some of the descriptions above talk about red hot and holding it there etc. some of my old copper washers havent coped as well as i might have imagined they would with that level of heat. I am probably way off but kinda curious what the answer is.

 

[JOEPRO]

Just an ignorant question... I know you are talking about Kunifer, but i have dissolved copper washers to nothing trying to anneal them (badly before). Looking on google, copper and kunifer might have similar melting points. Will the Kunifer cope with the heat needed for brazing? Some of the descriptions above talk about red hot and holding it there etc. some of my old copper washers havent coped as well as i might have imagined they would with that level of heat. I am probably way off but kinda curious what the answer is.

I have not brazed anything before so I can speak freely on the subject

I would guess its a matter of directing the heat input. Ie heat the larger metal fitting up first and give the pipe just enough heat before dabbing the rod and remove heat before damage may occur.

Small copper pipes in AC systems etc are brazed all the time.

 

[iNf]

I have not brazed anything before so I can speak freely on the subject

I would guess its a matter of directing the heat input. Ie heat the larger metal fitting up first and give the pipe just enough heat before dabbing the rod and remove heat before damage may occur.

Small copper pipes in AC systems etc are brazed all the time.

I thought AC stuff was done with silver brazing(soldering) which melts at a lower temperature than the rods you have ordered. I also think the flux you ordered might not be suitable for brazing, it looks more like high temp/stainless silver solder flux. Your torch may struggle to get it up to temperature quickly enough before the flux is exhausted. Definitely have a practice 1st.

 

[JOEPRO]

I thought AC stuff was done with silver brazing(soldering) which melts at a lower temperature than the rods you have ordered. I also think the flux you ordered might not be suitable for brazing, it looks more like high temp/stainless silver solder flux. Your torch may struggle to get it up to temperature quickly enough before the flux is exhausted. Definitely have a practice 1st.

Thanks, what flux would you recommend for bronze brazing please and ill order some?

 

[iNf]

These guys are well respected https://cupalloys.co.uk/category/silver-solder-fluxes/
You may be able to get similar elsewhere but worth having a read of their website. If you've already got the other flux and can't return it, might be worth a practice with it. A bit like welding...proper prep and practice.

 

[indykid]

For your first foray, I'd be inclined to get yourself some fluxed silver solder rods. You know the flux is compatible with the alloy and its heat range then. Probably works out quite expensive in the long run, but for a small number of jobs, it takes the guess work out.

Just don't let them get damp if you order spares, or all the flux will fall off

 

[JOEPRO]

These guys are well respected https://cupalloys.co.uk/category/silver-solder-fluxes/
You may be able to get similar elsewhere but worth having a read of their website. If you've already got the other flux and can't return it, might be worth a practice with it. A bit like welding...proper prep and practice.

Thanks, I ordered 50g of their 600 brazing flux.

For your first foray, I'd be inclined to get yourself some fluxed silver solder rods. You know the flux is compatible with the alloy and its heat range then. Probably works out quite expensive in the long run, but for a small number of jobs, it takes the guess work out.

Just don't let them get damp if you order spares, or all the flux will fall off

Is silver solder as strong as bronze brazing? I dont mind buying some as I have all manner of projects it will get used for something.

 

[indykid]

Is silver solder as strong as bronze brazing? I dont mind buying some as I have all manner of projects it will get used for something.

The material isn't as strong, but if it allows you to make a better joint, the assembly ends up stronger. To finish first, first you have to finish and to make a joint strong, first you have to make the joint.

My calculations being a factor of 10 out didn't help, but you only need a ~1mm joint length to react the load with silver solder, so it doesn't need to be any stronger. If it was a fully steel joint, I'd say crack on with the bronze and see how you go, but I suspect you're going to end up melting the kunifer at temps to get bronze to flow.

 

[tom2207]

I would be using plated hydraulic pipe ,,,, if you are using kunifer it would be prudent to drop back to silver solder ,,,, hydraulic pipe will be a tad trickier to bend , but overall will be worth the effort I think ,,,

 

[mr haynes]

I know you will, but cut couple sacrificial pieces off your coil and try brazing together.
Getting the temp right for brazing to flow isn't as straightforward as soldering

 

[Morris]

I thought AC stuff was done with silver brazing(soldering) which melts at a lower temperature than the rods you have ordered. I also think the flux you ordered might not be suitable for brazing, it looks more like high temp/stainless silver solder flux. Your torch may struggle to get it up to temperature quickly enough before the flux is exhausted. Definitely have a practice 1st.

Copper to copper in refrigeration/ac etc is usually done with copper phosphorus rods.