Silver soldering

[Dziadeczek]

Hi,

I need help with the silver soldering of small brass parts. I am trying to make brass reinforcing rings for the masts of my 74 gun ship model. I prepared (cut) thin strips from a brass sheet and soon after I solder both ends together to close a ring, frequently they spontaneously break apart. I need a stronger medium.

I tried to silver solder them, but every time I try to heat them, the flame from my torch immediately blows the tiny sliver of silver away from the place i put it, even before it gets melted.

How do I keep it there?

[Captain Slog]

I use 'easy' grade silver solder paste from a syringe but applied with a needle for tiny components and succesfully use it on 0.2mm brass wire.

The paste is sticky and once in place doesn't blow off with the torch.

Obtained from a jewellers supply shop.

 

Slog

[Barryc]

Hi sir,

 

I do a lot of soldering using Tix solder for strong joints that will not be under a lot of stress. It has a low melt point but is extremely strong.

https://www.micromark.com/Tix-Solder-Pkg-of-20-Three-Inch-Sticks

 

I use a silver based solder for joints that will be under potentially a lot of stress.

https://www.micromark.com/Stay-Brite-Silver-Solder

 

 

I have found that taking a small piece of apporiate (for need) and pound it flat. I then cut a piece to cover the expected solder

joint and place it between the properly cleaned sides to be solder. Clamp the solder between the ends and apply a small amount of flux and heat. Clamping can be tricky as you want to hold the pieces but not create a "heat sink" that will prevent proper heating. Usually not a problem when using a Torch.

 

 

I use a combination of Restrictive, Iron and Torch all for different approaches and techniques.

I hope you find this helpful.

 

Barry

[druxey]

The other possibility is to reduce the gas flow on the torch (if you can) so that the flame does not blow away the silver solder paillon.

[James H]

There's some stunning metalwork there 

[Mike from Aus]

So I suck at this also....but what I am learning is to make sure the surfaces are clean and slightly abraded then to use flux then small but blue flame.....it is beginning to work better for me......good luck...this is sometimes a frustrating hobby but also rewarding.........like coffee...sucks most of the time but when you get a good one it is great........not that I would know....I drink tea.....then beer...then a nice shiraz

[Patrick Matthews]

Barry- would love to see more of your M1 (?) !

[DelF]

19 hours ago, Captain Slog said:

I use 'easy' grade silver solder paste

As Slog says, silver solder paste is the way to go. I recently covered this in some detail in my Speedy log, here.

 

Derek

[druxey]

When starting out using silver solder, there will be more failures than successes. However, after a while, success will become routine stuff. Occasionally, though, there will be a day where nothing goes right. I  had one of those last week. Either the wind was in the wrong direction, the milk had gone sour or I'd stepped on the cat, but when one experiences failure after failure, walk away. The next day I nailed it first time. There's alchemy in there somewhere....

[Barryc]

15 hours ago, James H said:

There's some stunning metalwork there 

Thank you sir!

 

Barry

[Barryc]

6 hours ago, Patrick Matthews said:

Barry- would love to see more of your M1 (?) !

Yes, 1/16 RC M1A1 with the T.U.S.K I upgrades.

The complete build to date is found here. It's been going for 4 years and 10 months now., still a ways to go!

 

Barry

 

https://www.rctankwarfare.co.uk/forums/viewtopic.php?f=201&t=18880

 

 

[Patrick Matthews]

53 pages... sigh, just have to go through them!
The M1Ax was an obsession of mine for a while... had a lot of info, but I needed to crawl on one to get more. Had an appointment to do just that on the display unit parked in front of TACOM Sterling Heights (MI), behind their secure fence, just up the road from GDLS. The appointment was on 9/12/2001. Did not happen- there was much else on everyone's minds.

 

While I focus on boats today, I do have one HL 1:16 model in a box, and a 21st Century 1:9 corpse in a crate... someday...

[tlevine]

There is also a lot of misinformation about true silver soldering.  For example, the mating surfaces need to be clean but they do not need to sit in vinegar or pickle prior to soldering.  What they need is perfect contact.  Silver solder will not fill in a gap.  In a lot of situations, it is better to gradually heat the entire piece rather than concentrating on the solder site.  This will help prevent the solder chip from flying.  Try laying the silver chip under the piece instead of on top.

[Patrick Matthews]

?? I've filled ugly gaps and even created fillets with true silver solder. Biggest problem for me has been the amount of heat required for even "easy" grade silver solder- it totally anneals any brass I'm using. I do most all work now with Stay-Brite low content silver solder and flux.

[bartley]

1 hour ago, Patrick Matthews said:

?? I've filled ugly gaps and even created fillets with true silver solder. Biggest problem for me has been the amount of heat required for even "easy" grade silver solder- it totally anneals any brass I'm using. I do most all work now with Stay-Brite low content silver solder and flux.

 

I totally agree Patrick.  I solder most of my rings closed and when using true silver solder the annealing makes them so sloppy I may as well use a rubber band!  There is little force on these rings so Stay-Brite provides adequate strength.

 

John

[kurtvd19]

Stay-Brite has plenty of strength to with sand any amount of tension that can be put on rigging a model ship.  I have used it with wire rigging on 1/12 scale models.  I would say that the yards or even the mast will break before a Stay-Brite joint.  Used to use silver solder all the time - started with radio control boats and needed it for certain joints - rudder, control arms, etc.  Tried Stay-Brite on those joints and tried to break them and gave up and it's very rare that I use silver solder today.

[No Idea]

I helped a friend who was struggling using silver solder. His problem turned out to be he was cleaning the joints using sand paper which was contaminating the joint. A quick swap to wire wool and the problem was solved. 

[Dziadeczek]

Thank you all for your input. After some thinking, I decided to go with a silver-enriched solder wire I obtained long time ago from Home Depot. I don't think it is called Stay Brite, but I forgot its exact name.

I remember that it can be applied either with a soldering gun or with a torch and it is significantly stronger than regular 50-50 or 60-40 wire. I have a tiny soldering pen that gives me a lot more control than a mini torch, so I've been able to resolder those broken joints with this wire and give it a bit thicker joint (previously I was filing off extra thickness of solder to make it as thin as the brass rings. That turned out to be too thin and week). 

The joints will be covered with a rubbing pounch anyway, so they will be invisible.

The solder joints don't get as black as the brass with Birchwood Casey, so I use just for these spots a different blackener - used for stained glass work, which seems to work there somewhat better.

Thanks again Everybody!!!    🙂

[kurtvd19]

Stay-Brite blackens very well.

 

[Roger Pellett]

The post about sanding is interesting.  This is a case where common sense doesn’t work.  One would assume that to get a really clean surface mechanically abrading with sandpaper would be the way to go.

 

60 or so years ago when welding was being developed to fabricate aluminum, a shipyard was having problems getting sound welds.  After trying everything they put two pieces of carefully aleaned aluminum in a clean room and told their best welder to weld them together while their welding engineer watched through a window.  

 

The welder flipped down his hood and then ran his gloved hand down the weld groove as was his habit to clean out any debris, contaminating the cleaned joint.

 

Roger

[hdrinker]

I’ve struggled and am still struggling with silver solder. Can’t seem to get even “easy” to melt with my mini butane torch. I thought using silver solder at different hardness’ would allow the successive joining of very small parts adjacent to one another without melting what I had previously soldered. But I’ve completely failed at this effort. Any suggestions?

Henry

[Roger Pellett]

I am presently building a model of a steel hulled ship that requires a great deal of soldered brass construction.  Although I am using some silver bearing lead free solder I see no need to use “real” silver solder.  But that doesn’t answer your question.

 

Is your solder not melting or not flowing? If you are willing to sacrifice a little of your solder, does it melt when you heat a piece on a non conducting surface?  If it does not, then your flame is not hot enough.  If it does, then your flame reaches the right temperature but the joint that you’re trying to solder is absorbing heat faster than your torch can supply it.  You need a higher capacity torch; one that supplies more BTU’s.

 

If your solder melts but doesn’t flow into the joint than the joint is dirty or your flux is not doing its job.  

 

IMHO, torch soldering is tricky.  Often, the flame contaminates the joint with oxidized residue before it gets hot enough to flow solder.  Masters of the process solder with a “reducing flame” to prevent this.

 

Roger

[Oldsalt1950]

Soldering is a skill that must be practiced in order to master. I prefer a soldering iron that I can adjust the temperature on for all my soldering, some like resistance soldering others use a torch still others a gun. For ship modeling and at the scales we work at, a fine tipped iron with adjustable heat is all you really need. Most common solder used in electronics is a lead/tin mixture which works fine for affixing components that are never subject to much stress from coming lose. For items under stress all we really need go to is silver bearing solder not true silver solder to hold the joint together. The parts to be joined should be clean of contaminants, this is best done by abrading with fine steel wool and acetone. When you solder, your finished joint should be bright silver with no pin holes or remnants of flux which usually shows itself as black spots in the solder. The finished joint should be cleaned after soldering again using acetone. Not enough heat will give you a cold solder joint which is usually a dull silver in color, to much heat will usually destroy or mis-shape the part or parts being joined. 

To stop heat from soldering from traveling to places that you don't want it use hemostats or similar devices as a heat sink to bleed off the heat. keep the tip of your soldering iron clean and well tinned. If you can no longer keep the tip clean or tinned replace it. Keep combustibles away from the soldering area.

Like everything else in model ship building, the skill must be learned and practiced in order to master, you also should not rush the job.

 

Jim

 

[Roger Pellett]

I have a 25w cordless soldering iron with two interchangeable tips; a conical and a chisel point.  It’s temperature of 950F is not adjustable.  It works for 90% of the work that I have been doing.  Photo below.  I prefer a “hot” iron.  A soldering iron’s job is to transfer heat to the joint being soldered. Capillary action then draws the melted solder into the joint.  The iron transfers this heat by conduction.  Conduction is time dependent.  The iron initially heats a small area.  If the iron is left on this area heat is transferred outward into surrounding metal.  The longer the iron takes to heat this area the more likely it is that this transferred heat will damage previously damaged work.  My little 25 watt is hot enough to quickly heat the joint without overheating other areas.

 

Some joint design is also necessary.  For example, a butt joint between two members seldom works.  A lapped joint almost always works.  Joints where laps fay tightly to each other are easily soldered.  Trying to bridge the gap between two poorly fitting joints is a waste of time.

 

Roger

Edited February 28, 2023 by Roger Pellett

[Toolmaker]

2 hours ago, Oldsalt1950 said:

Soldering is a skill that must be practiced in order to master. I prefer a soldering iron that I can adjust the temperature on for all my soldering, some like resistance soldering others use a torch still others a gun. For ship modeling and at the scales we work at, a fine tipped iron with adjustable heat is all you really need

My thoughts entirely. It takes some effort to become proficient but after that it seems so simple. I believe I could teach anyone to solder small brass parts within an hour. The quoted paragraph is what I do, using a gas soldering iron. I have never considered a flame since.

 

This component is 10 individual parts, I can’t imagine taking a flame anywhere near it, that would be a scatter gun approach.

How small can you go using this method? Less than 0.4mm 

 

Getting close to other parts requires serious heat sinks. In this case it’s just wet cotton wool.

 

The same method copes with bigger size parts equally well.

 

If it wasn’t for the thousands of miles between most of us, we could set up a little soldering workshop.

 

Thank you

 

Paul

[Dr PR]

I have been soldering things since I was a kid (more than 60 years) - mostly electronics. I remember my father using a 1" square cross section soldering "iron" that he heated on our kitchen gas stove to work on sheet metal.

 

I have used acid core solder, resin core and liquid flux. I prefer the liquid, especially the citric acid based flux. It smells like orange juice. You can even use lemon juice! What I like about the liquid flux is that it draws the solder into the joint as it evaporates. We have used it on extremely fine parts - 0.05 mm and smaller. And it cleans up with tap water.

 

I use a variable temperature soldering iron with a small point tip. I also have a soldering gun for soldering massive objects, and a resistance soldering unit. I am still learning to use the resistance unit. It has the advantage of not staining the metal surface with solder, and the heat is localized within the solder joint.

 

I use wet paper towels as heat sinks to prevent heat from a new solder joint from flowing to a previously soldered joint. Water absorbs a tremendous heat of vaporization (540 calories per gram - far more than most other substances) before it evaporates, so it makes possibly the best heat sink.

 

I have always ignored the "rule" that you should heat the metal and not the solder. If you put a dry soldering iron tip against a piece of metal the heat flows slowly from the iron to the metal, and can even cause oxidation at the heated point. This allows the heat to spread to more distant parts of the work (bad). I wet the tip of the iron with a drop of solder and apply it to the joint. Heat flows rapidly from the iron, through the solder, to the joint. I apply the solder to the joint at the iron tip and when the metal is hot enough the solder melts and flows into the joint. This is where the liquid flux really works well.

Edited February 28, 2023 by Dr PR

[allanyed]

Henry, as you are talking about silver soldering, you may be relegated to using a high temp flame.   I have used high temperature melt point silver solder pastes with different melt points for multipart assemblies and will continue to do so IF the parts are large enough not to melt in the process.   For small delicate parts I have gone to Solder-It a low temp silver solder paste and a soldering iron and delighted with the results and ease of use.

Allan.  

[Hsae]

5 hours ago, Toolmaker said:

My thoughts entirely. It takes some effort to become proficient but after that it seems so simple. I believe I could teach anyone to solder small brass parts within an hour. The quoted paragraph is what I do, using a gas soldering iron. I have never considered a flame since.

 

This component is 10 individual parts, I can’t imagine taking a flame anywhere near it, that would be a scatter gun approach.

How small can you go using this method? Less than 0.4mm 

 

Getting close to other parts requires serious heat sinks. In this case it’s just wet cotton wool.

 

The same method copes with bigger size parts equally well.

 

If it wasn’t for the thousands of miles between most of us, we could set up a little soldering workshop.

 

Thank you

 

Paul

Paul,

Nice work on the Corvette! Wish I could see your work. 
I am also sometimes struggling with soldering small parts. Would love to be in a soldering workshop!

 

Hermann

[druxey]

The best tip I ever got was from a jeweller. She showed me that one could solder successive joints that were close together without using a heat sink. Simply paint the joint to be protected with a slurry of yellow ochre powder in water. It prevents that joint from melting again.

[Toolmaker]

2 hours ago, Hsae said:

Paul,

Nice work on the Corvette!

Cheers, thanks.

That combination build really leaves you with no option but to solder. To try and ca the David Parkins sets just wouldn’t bode well.

 

The last paragraph that Dr PR (coincidently, my initials!) wrote sums up my method beautifully. It has to be said that almost all the soldering on that build is fairly thin photo etch but comparable to what many of us require in our modelling.

Its a different story when working with solid machined parts and silver solder.

 

Thanks

Paul