Soldering/silver soldering Tri Clamps

[Roobrew]

Been having a 'mare trying to silver solder then solder tri clamps to 2 inch copper tubing, just could not get either to run. All was super clean, grease free and correct flux.
Only thing I can think of is the tube is 1 mm smaller in size than the clamp ferrule ...maybe no capillary action??

I am concerned because I have another 3 to join to copper, a stainless flange to join to the stainless vessel and a small brass flange to joint to the vessel to.

Any ideas or tips please?

Thanks

[rad14701]

Why the heck would you try soldering anything to a triclamp...??? Perhaps it's time to rethink what you're attempting to accomplish...

[Bushman]

+1, you must mean soldering the pipe to the ferrule?

[Black ghost]

I recently joined a 2" stainless pipe section to a 2" copper elbow and also need to connect 2" ferrules to copper pipe.
I found it much easier to silver solder the stainless pipe to the elbow because the pipe slid inside the elbow as opposed to being a butt join. So I will be using 2" copper joiners when I solder the ferrules to the other end.

I used silver solder 45% and the strongest acid flux they sold at BOC. After fluxing and fitting the joins I made a ring of solder around a smaller piece of pipe then stretched this over my join. I heated up the copper pipe then the stainless and as I did this the ring of solder started to soften and sit snug against the join. When I thought they were both hot enough I applied heat direct to the solder and it melted and fused into the join giving me a perfect fit.

[Black ghost]

And here is the end result.

[Roobrew]

+1, you must mean soldering the pipe to the ferrule?

Yes apologies ...the ferrule

[Roobrew]

And here is the end result.

pot still head.JPG

Nice work....

Looks like your have Acetylene there? Ive done joints in the past with the same but am using propane now which to me isn't as good due to the lower temperature / heat spread.
Easy when its copper to copper or copper to brass but stainless ...grrrr that's a bitch for sure.

[Halfbaked]

NICE!

[S-Cackalacky]

There are a few how-to's here on the forums for soldering copper to stainless or stainless to stainless. It's a bit different than doing copper to copper. It requires different solder, different flux, and a different technique. Do some research and you should be able to figure it out.

[Roobrew]

There are a few how-to's here on the forums for soldering copper to stainless or stainless to stainless. It's a bit different than doing copper to copper. It requires different solder, different flux, and a different technique. Do some research and you should be able to figure it out.

Done the above .....and used to braze years ago copper to copper, also did soft soldering , lead joint wiping , lead burning and oxy acet welding . But wow has this one got me scratching my head. Bought the more aggressive flux for stainless, silver solder and lead free soft solder....yet still cannot get them to low. I will have another go tomorrow as got fed up today.

Cheers

[S-Cackalacky]

Roobrew, another technique is to tin the two surfaces seperately and then join and heat them. This way you know that the surface is properly prepared, else the solder would simply run off. This should work for ss to copper, or ss to ss.

[skow69]

Been having a 'mare trying to silver solder then solder tri clamps to 2 inch copper tubing, just could not get either to run. All was super clean, grease free and correct flux.
Only thing I can think of is the tube is 1 mm smaller in size than the clamp ferrule ...maybe no capillary action??

No. even if it was rattly loose you could still join them where they touch. Are you turning the stainless black? If so back off and be patient. Heat away from the joint. It's impossible if you dont have enough heat.

+1 the tinning.

[googe]

I've always used plumbed soft solder and bakers fluid flux. fluid flux is heaps better than the paste. I've always heated the copper and let it slowly heat the stainless, takes a while.

[bellybuster]

When you say propane do you mean a pro style oxy/propane or a standard home style propane torch. The latter may be a bit shy in the heat department for 2" and your joint is cooling as fast as you are heating it.
Try making a shield of sorts to stop any breeze from cooling it

[frunobulax]

I've found it to be a PITA soldering them too. Seems the trick is keep it clean, fluxed and as mentioned heat-heat-heat.

[Roobrew]

When you say propane do you mean a pro style oxy/propane or a standard home style propane torch. The latter may be a bit shy in the heat department for 2" and your joint is cooling as fast as you are heating it.
Try making a shield of sorts to stop any breeze from cooling it

Thanks for the replies all.

Yes you are most likely correct and I am going to get a couple of fire bricks today. I am using just propane but the lamp I have should easily get to the correct temperature. Also I just spoke to the guy who I bought my solder etc off and apparently there was some confusion on my part with which flux to use with which filler rod...DOH.
Regarding tinning I used to do that as it is commonly done for brass fittings and lead piping. Also regarding the heating up slowly that is what I was doing but the guy who sold me the rods etc said to get as much heat into the joint as fast as possible when silver soldering as it is critical to get the temperature up so the rod will flow with ease. The flux he sold me is rated to well over 1000 deg c and so there will be no problem with oxidization of the flux and a dry joint. This of course is different than soft soldering where the opposite is better ie a slow heat in order the flux does not oxidize.

Cheers

Roo

[Roobrew]

Attempted the joint today, did as above and blasted it with heat till dull cherry red. Superb results , a lovely thin run of silver solder bonding both metals together, the metal would rip before the joint would if tested that's for sure. Another thing I learnt today and a good tip for anyone attempting the same is to get the flange square which I know some struggle with is to cut / file the end of the pipe totally square then stand the pipe so the ferrule is inside the pipe in the vertical position. That way it can be checked against a set square to see if it is plumb but more importantly the gap where the flange touches the pipe will be tiny...thus ensuring capillary action will occur.

[BigSwede]

Attempted the joint today, did as above and blasted it with heat till dull cherry red. Superb results , a lovely thin run of silver solder bonding both metals together, the metal would rip before the joint would if tested that's for sure. Another thing I learnt today and a good tip for anyone attempting the same is to get the flange square which I know some struggle with is to cut / file the end of the pipe totally square then stand the pipe so the ferrule is inside the pipe in the vertical position. That way it can be checked against a set square to see if it is plumb but more importantly the gap where the flange touches the pipe will be tiny...thus ensuring capillary action will occur.

Glad you had great results... If you hadn't, hopefully what I am going to throw out there might help someone.

There are two types of what we tend to call "silver solder". There is the far more common soft silver solder that we use to join copper copper, and it will also do a fine job with stainless WITH the proper flux. This solder is 6% silver and lower.

Then there is silver BRAZE which is 40% Ag on up. This requires dull red heat, LOTS of BTUs, and a totally different flux. Silver braze on large diameter copper is not trivial and is beyond most propane or MAPP torches, as the Cu wicks the heat away. Silver braze requires a tight fit, will not be happy with gaps at all.

So you have soft Ag solder like Stay Brite which is happy with plumbers flux for Cu, and preferably a fluoride-bearing water based flux for stainless, and silver braze which requires a different flux and a big torch (oxy acetylene helps) for large copper. Might get away with a MAPP gas torch for stainless joints, as stainless does not transfer heat from the joint well at all. This is what lets us get away with stainless fittings on a keg, which if made from Cu would steal the heat and make it impossible.

HTH someone, I am in a hotel and bored!